Iec 62271 200 pdf free download

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Rated voltage U r Subclauses 5. NOTE Components forming part of an assembly can have individual values of rated voltage in accordance with their relevant standards. This value may be lower than that of the main circuit. NOTE The short-circuit current ratings assigned to the earthing circuit define the possible earthing conditions of the system neutral of the network on which the assembly can be installed.

Refer to 9. The rated peak withstand current values I p assigned to the assembly are also applicable to the short-circuiting parts of the related earthing circuits, including earthing devices.

The rated short-time withstand current values t k assigned to the assembly are also applicable to the short-circuiting parts of the related earthing circuits, including earthing devices. Rated supply voltage of auxiliary and control circuits U a 5. The classification for the earthing function is not applicable when the earthing is performed by a circuit-breaker with the protection operative until the earthed situation is attained.

A rated DC cable test voltage is considered covering very low frequency testing e. If no rated duration t ct DC is specified, then by default this duration is 15 min. NOTE 2 IAC classification as defined in this document does not apply to opened compartments and to arc protection between compartments, except if opening is necessary to perform switching operations.

IEEE C The sides of the assembly which meet the criteria of the internal arc test are designated as F for front side; L for lateral side; R for rear side. The front side shall be clearly stated by the manufacturer. Two ratings of the arc fault currents are recognized: a three-phase arc fault current I A ; b single-phase-to-earth arc fault current I Ae , when applicable. The manufacturer shall specify the compartments to which the single-phase-to-earth arc fault current rating is applicable.

Such value may be assigned to an assembly where its construction will prevent the arc from becoming multiphase, as demonstrated during the internal arc test. In the case where all high-voltage compartments are only designed for single-phase-to-earth arc faults, instead of I A , the I Ae rating shall be assigned. NOTE Information about the relationship between the type of network neutral earthing and the single-phase-toearth arc fault current is provided in 9.

If applicable, the rated duration t Ae of the single-phase-to-earth arc fault shall be assigned by the manufacturer. This is not applicable to removable parts which become accessible after being separated from the assembly and to withdrawable parts in test position or in disconnected position refer to 6. Where earthing connections shall be able to carry the full three-phase short-circuit current as in the case of the short-circuiting connections used for earthing devices , these connections shall be dimensioned accordingly.

The connection from the short-circuiting point between phases to the earthing circuit may be dimensioned to the specifications of the earthing circuit. Small parts fixed to metal enclosure s , up to a maximum of 12,5 mm in diameter, for example screw heads, need not be electrically connected to the earthing point provided. All the metallic parts intended to be earthed and not belonging to a high-voltage or auxiliary circuit shall also be electrically connected to the earthing point provided.

The interconnections within each functional unit shall be made by adequate means e. Doors of the high-voltage compartments shall be electrically connected to the frame by adequate means. NOTE 1 Enclosure and doors are considered in 6. NOTE 2 EMC demands for the complete installation can require a special approach of the earthing circuit of the assembly.

Connections to earth in any position shall provide a current-carrying capability not less than that required for enclosures refer to 6. If the withdrawable or removable part includes any earthing device, intended to earth the main circuit, then the earthing connection in the service position shall be considered as part of the earthing circuit with associated rated values refer to 5. NOTE 1 unit. It is assumed that the short-circuiting point between phases of the earthing circuit is within each functional For transport units to be assembled during final installation, the resulting earthing circuit shall be capable of carrying its rated short-time and peak withstand currents and duration.

Parts of metal enclosures may form part of the earthing circuit. If a dedicated earthing conductor is applied as earthing circuit of the assembly, its cross-section shall be not less than 30 mm 2. The earthing circuit is normally designed to withstand one occurrence of a single short-circuit fault, and maintenance could be needed after such an event; refer also to 9. The information according to Table 1, of the complete assembly, shall be legible during normal service.

If applicable, one common nameplate for the complete assembly may apply with the general information, with a separate nameplate for each functional unit, containing the specific information. Detailed information of the fixed components applied need not be legible during normal service.

The removable parts, if any, shall have a separate nameplate which, if applicable, may contain data relating to the functional unit s they are designed for.

These nameplates need only be legible when the removable part is in the removed position. NOTE Fuses are removable devices that do not require such specific information because they respond to standardized dimensions. The following provisions are defined for switching devices of main and earthing circuits.

Conversely, it shall prevent the disconnection of the auxiliary circuits with the circuit-breaker closed in the service position. The operation of a disconnector shall be prevented unless the circuit is open. Regarding removable fuse-links, their withdrawal or engagement shall be prevented unless the fuse-base contacts are earthed or isolated from all sources of supply; see also 6.

The manufacturer shall give all necessary information on the character and function of interlocks. NOTE For interlocks with covers and doors, refer to 6. If electrical interlocks are provided, the design shall be such that no improper situations can occur in case of lack of auxiliary supply.

However, for emergency control, the manufacturer may provide additional means for manual operation without interlocking facilities. In such a case, the manufacturer shall clearly identify this facility and define the procedures for operation.

In addition, for all devices involved in disconnecting and earthing functions, 6. Additional requirements are specified in 6. In the case where a high-voltage compartment may be opened, i. Exempted from this requirement are: пїЅ high-voltage parts that are moved to the disconnected position with corresponding shutters closed; пїЅ high-voltage parts, if embedded by solid-insulation material and complying with at least protection category PA of IEC Disconnecting devices used for isolation shall be secured against re-connection.

If a withdrawable or removable part does not include an earthing device that is intended to earth the main circuit of that removable part before becoming accessible, it shall be possible, by manual earthing means, to safely discharge trapped charges from that removable part.

The manufacturer shall define the recommended procedure in the manufacturer's instructions reference. All removable parts and components of the same type, rating, and construction shall be mechanically and electrically interchangeable.

Removable parts and components of equal or greater current and insulation ratings may be installed in place of removable parts and components of equal or lesser current and insulation ratings where the design of these removable parts and components and compartment allows mechanical interchange ability.

This does not generally apply for current-limiting devices. NOTE Installing a removable part or component of a higher rating does not necessarily increase the capabilities of a functional unit or imply that the functional unit is capable of operation at the increased ratings of the removable part or component.

Components contained in an assembly shall be in accordance with their various relevant standards. This document supplements or even replaces the standards for the individual components regarding their installation in assemblies.

For main circuits with current-limiting fuses, the manufacturer of the assembly may assign the maximum peak and Joule integral of the let-through current of the fuses to the main circuit downstream of the fuse.

The floor surface below the installed assembly may be considered as part of the enclosure. The measures to be taken in order to obtain the degree of protection provided by floor surfaces shall be given in the installation manual. The enclosure shall be metal. The specified degree of protection shall be provided by the enclosure with all the doors and covers closed as under normal operating conditions, irrespective of how these doors and covers are held in position.

Enclosures shall also ensure protection in accordance with the following conditions: пїЅ Metal parts of the enclosures shall be designed to carry 30 A DC with a voltage drop of maximum 3 V to the earthing point provided. If the manufacturer states that it is necessary to stand or walk upon the assembly during operation or maintenance, the design shall be such that the relevant areas will support the weight of the operator. In such a case, the IP degree shall not be affected as well as no permanent deformation is allowed and the areas on the equipment where it is not safe to stand or walk, for example pressure relief flaps, shall be clearly identified.

However, covers and doors may be made of insulating material, provided that high-voltage parts are enclosed by metal partitions or shutters connected to the earthing point provided. When covers and doors that are part of the enclosure are closed, they shall provide the degree of protection specified for the enclosure.

Covers and doors shall not be made of woven wire mesh, expanded metal or similar. When ventilating openings, vent outlets or inspection windows are incorporated in the cover or door, reference is made to 6. Covers and doors that exclusively give access to compartments which are not high-voltage compartments e. Several categories of covers and doors are recognized with regard to the type of high-voltage accessible compartments they provide access to: a Covers and doors that give access to tool-based accessible compartments These covers and doors fixed covers need not be opened for normal use as stated by the manufacturer.

It shall not be possible for them to be opened, dismantled or removed without the use of tools. Special procedures are required to safeguard that opening can only be realized if precautions to ensure electrical safety have been taken.

Suitable procedures should be put in place by the user to ensure that a procedure-based accessible compartment is opened only when the high-voltage parts contained in the compartment being made accessible are isolated and earthed, or in the disconnected position with corresponding shutters closed.

Procedures may be dictated by legislation of the country of installation or by user safety documentation. If interlock-controlled or procedure-based accessible compartments have other covers that can be opened by tools, proper procedures or specific warning labels should be applied.

In this respect it should be noted that: пїЅ a partition or shutter becomes a part of the enclosure if it is accessible in any of the positions defined in 3. They shall be covered by a transparent sheet of mechanical strength comparable to that of the enclosure.

Precautions shall be taken to prevent the formation of dangerous electrostatic charges, either by clearance or by electrostatic shielding e. The insulation between high-voltage live parts and the accessible surface of the inspection windows shall comply with the rated insulation levels U d and U p according to 5.

Such openings may make use of wire mesh or the like provided that it is of suitable mechanical strength. High-voltage compartments should also be classified as accessible or non-accessible. Electrical connections between the main circuit of the assembly and the external conductors cables or bars to the electrical network or high-voltage apparatus of the installation shall be made within a high-voltage accessible compartment.

Where other main components e. The LSC category can only be assigned to functional units that include a connection compartment. This implies that a bus-sectionalizer or bus-coupler functional unit, for example, will have no LSC category, refer to Figure 9. Busbar compartments may extend through several functional units without the need for bushings or other equivalent means.

NOTE 2 The busbar system is not considered as a functional unit. Parts of the busbar at the end of the busbar system shall be considered as part of the adjacent compartment if their length out of the enclosure of the high-voltage compartment is less than 12,5 mm. If this criterion is not met, a separate compartment shall be defined for these busbar extension elements.

Gas-filled compartments, when permanently pressurized in service, are subjected to particular conditions of service which distinguish them from compressed air receivers and similar storage vessels. These conditions are such that gas-filled compartments are normally filled with a gas that is stable and non-corrosive in the conditions that prevail inside the compartment; since measures to maintain the gas in this condition with only small fluctuations in pressure are fundamental to the operation of the assembly and since the compartments will not be subjected to internal corrosion, there is no need to make allowances for these factors in determining the design of the compartments.

Gas-filled compartments with design pressures higher than kPa relative pressure shall be designed according to the pressure requirements of IEC For indoor installations, the design temperature of the fluid-filled compartment is generally the upper limit of ambient air temperature increased by the temperature rise of the fluid due to the flow of rated continuous current.

For outdoor installations, other possible influences, for example solar radiation, shall be taken into account. The design pressure of a compartment shall be at least equal to the maximum pressure difference between the fluid inside the compartment at design temperature that the fluid used for insulation can reach under specified maximum service conditions, and the surrounding media, like ambient air or insulation fluids in other compartments.

In addition to the design temperature, the design pressure calculation shall consider: a the full differential pressure possible across the compartment walls or partitions, including any evacuation process if used during filling or maintenance operations; b the resulting pressure in the event of an accidental leak between the compartments in the case of adjacent compartments having different service pressures.

If requested by the user, in order to permit entry to a fluid-filled compartment of closed or controlled pressure systems, the permissible leakage across partitions should also be stated by the manufacturer.

A partition, separating a compartment filled with insulating gas from a neighbouring compartment filled with liquid should not show any leakage affecting the dielectric properties of the two media. The pressure relief devices shall not operate below 1,3 times the design pressure. The pressure relief device may be a designed, deliberate weak area of the compartment or a dedicated device, for example a bursting disc. Conductors passing through partitions shall be provided with bushings or other equivalent means to provide the required IP level.

Openings in the enclosure of an assembly and in the partitions between compartments accessible during service, through which contacts of removable or withdrawable parts engage fixed contacts, shall be provided with automatic shutters to ensure the protection of persons in any of the positions defined in 3. Means shall be provided to ensure the reliable operation of the shutters, for example by a mechanical drive, where the movement of the shutters is positively driven by the movement of the removable or withdrawable part.

The status of shutters may not in all situations be readily confirmed from an open high-voltage compartment, e. In such situations, verification of the shutter status may require access to the second compartment or provision of an inspection window or reliable indicating device.

If one or more set s of fixed contacts can be made accessible through opened shutters e. If the automatic closing of shutters can be made inoperative in order to retain them in the open position e. This can be realized for example by preventing the switching device to return to its service position or by automatic restoration when returning the switching device to the service position.

It may be possible to use a temporary inserted partition to prevent the live set of fixed contacts being exposed refer to Insertion of such a temporary partition shall be possible before the compartment to be opened exposes the high-voltage parts that are intended to be kept energized.

For class PM, partitions and shutters between opened compartments and remaining high-voltage live parts of the assembly shall be metal; otherwise, the class is PI refer to 3. Discontinuity in the metal partitions and closed metal shutters which may become accessible shall be less than 12,5 mm. Removable parts for ensuring the isolating distance between the high-voltage conductors shall comply with IEC , except for mechanical operation tests refer to 7.

This disconnection facility is intended for maintenance purposes only. If removable parts are intended to be used as a disconnector or intended to be removed and replaced more often than only for maintenance purposes, then testing shall also include the mechanical operation tests according to IEC Any removable part shall be so attached to the fixed part that its contacts will not open inadvertently due to forces which may occur in service, in particular those due to a short-circuit.

In IAC classified assemblies, the transfer of withdrawable parts to or from service position shall not reduce the specified level of protection in the event of an internal arc. This is achieved, for example when the operation is only possible when doors and covers intended to ensure personnel protection are closed.

Other design measures providing equivalent level of protection are acceptable. This may be performed either from a dedicated test connection, or from the cable terminations. In both cases the assembly shall have rated cable test voltage s as specified in 5. However, where internal arc classification IAC is assigned, the assembly shall be designed to give a defined level of protection of persons in the event of an internal arc, when the assembly is in normal operating conditions.

Normal operating conditions imply that doors and covers are closed unless opening is necessary to perform switching operations. If IAC is assigned, then this designation shall be included in the nameplate refer to 6. Some examples for designations of the IAC classification are given in 9.

Because of the variety of types, ratings and possible combinations of components, it is not practicable to make type tests with all the arrangements of an assembly.

The validity of type tests performed on one test object with a defined set of ratings to other assemblies of the same family with a different set of ratings or different arrangements of components may be evaluated; in that case IEC TR [10] should be applied.

The type tests and verifications comprise: Mandatory type tests to verify the: a rated insulation level of the equipment see 7. Mandatory type tests, where applicable, to verify the: i auxiliary and control circuits see 7. Optional type tests subject to agreement between manufacturer and user : r tests to evaluate the insulation of the equipment by the measurement of partial discharges see 7.

Type tests may impair the suitability of the tested parts for subsequent use in service. Therefore, test objects used for type testing shall not be used in service without agreement between manufacturer and user. For the report regarding internal arc tests, refer to 7. For assemblies using fluid liquid or gas for insulation, dielectric tests shall be performed on the test objects filled with the insulating fluid specified by the manufacturer, to the minimum functional level also specified by the manufacturer.

All other conductors of the main circuit and the auxiliary circuits shall be connected to the earthing conductor or the frame and to the earth terminal of the test supply. If the phase conductors are segregated, only tests to earth shall apply. The dielectric tests shall be made with all switching devices closed and all removable parts in their service position.

Attention shall be given to the possibility that switching devices in their open position or removable parts in the disconnected, removed or test position may result in less favourable field conditions. Under such conditions the tests shall be repeated with such device s in those specific positions. However, switching devices do not need to be tested in open position when their component standard does not require to test them in this open position, and removable parts themselves shall not be subjected to these voltage tests whilst they are in the disconnected, test or removed position.

The earthing of removable parts in these positions during the tests shall be as in service. For impulse voltage tests, the arrangements according to 7. In case of doubt about the most unfavourable arrangement, tests shall be repeated with alternative configurations. In order to check compliance with the requirements of 6. In case of doubt about the most unfavourable situation, the tests shall be repeated with different situations.

For convenience of testing, subject to agreement between testing station and manufacturer, more than one metal foil may be applied simultaneously, or larger parts of the insulating material may be covered.

The isolating distance could be formed by: пїЅ a disconnector in the open position; пїЅ the distance between the two parts of the main circuit intended to be connected by a withdrawable or removable switching device; пїЅ the sum of the clearances between several open gaps in series. If, in the disconnected or test position, an earthed metal shutter is interposed between the disengaged contacts to ensure a segregation, the gap between the earthed metal shutter and the live parts shall withstand only the test voltages required to earth according to item a above.

The switching device of the withdrawable part shall be in the closed position. When it is not possible to have the switching device in the closed position e. The test voltage shall be raised for each test condition to the test value and maintained for 1 min.

The tests shall be performed in dry conditions. Instrument transformers, power transformers or fuses may be replaced by replicas reproducing the field configuration of the high-voltage connections.

A transformer, a coil, or a similar device normally connected between phases shall be disconnected from the pole stressed with test voltage. At common value power-frequency voltage tests, one terminal of the test transformer shall be connected to earth and to the enclosure of the assembly. For isolating distance power-frequency voltage tests, 7. For the special cases considered in 7.

Current transformers may have their primaries short-circuited too. For common value lightning impulse voltage tests, one terminal of the impulse generator shall be connected to earth and to the enclosure of the assembly.

For isolating distance lightning impulse voltage tests, 7. NOTE It is good engineering practice to carry out a partial discharge type test on a complete functional unit or assembly where possible. Voltage transformer secondary windings may be disconnected. Voltage-limiting devices in the auxiliary and control circuits, if any, shall be disconnected. Functions like voltage indication or voltage detection e.

For each rated cable test voltage value, the following test voltages shall be applied: a the rated voltage U r shall be applied as a single-phase voltage between all phase conductors on the busbar side connected together and earth; b the rated cable test voltage U ct AC or U ct DC shall be applied to each pole in turn of the cable test connection.

The other two cable test connections shall be connected to earth when energizing a pole. The test voltages defined under a and b shall be applied simultaneously. If, during this test, there is segregation between the cable test connections and the busbars, the test voltage on the busbar side may be omitted. The representative functional unit shall be mounted approximately as in normal service, including all normal enclosures, partitions, shutters, etc.

In case of functional unit s incorporating fuses, the test shall be performed with the fuse-links generating the highest power dissipation from the reference list provided by the assembly manufacturer. Alternatively, each functional unit may be individually tested for its rated continuous current with either heat insulation or heaters at the sides reproducing the same conditions as with the preceding testing procedure. When testing with the fuse-links generating the highest power dissipation, the continuous current indicated on the list of fuse-links provided by the assembly manufacturer shall be applied.

The temperature difference shall not exceed 5 K. However, in case this temperature difference exceeds 5 K, the test may be considered as valid if the above indicated point at 1 m from the assembly is the hottest and all criteria to pass the test defined in 7. This measured resistance shall be the reference for the routine test refer to 8. The maximum permissible temperatures and temperature rises to be taken into account for busbars are those specified for contacts, connections and metal parts in contact with insulation, as the case may be.

NOTE 1 The power dissipated by the fuse-link is defined by the product of the applied AC continuous test current RMS value and the measured steady voltage drop across the fuse-link.

NOTE 2 The voltage drop is measured on the fuse-link contacts as close as possible to the point of contact with the immediate mating contact piece. Parts of the main circuits which incorporate current-limiting fuses do not need to be tested if one of the conditions below is fulfilled: пїЅ the making and breaking tests of the switching function incorporating the fuses have been performed within the assembly; NOTE 1 An example of switching function incorporating current-limiting fuses is a switch-fuse combination.

Joule integral I 2 t are equal to or higher than, those which would be obtained with fuses at the rated voltage, has been performed within the assembly. In all cases, the performed tests shall at least cover the situations of maximum breaking current up to I k and I p of the branch of the assembly incorporating current-limiting fuses and of maximum let-through I 2 t for the fuses which can be used within the assembly according to the reference list provided by the manufacturer.

Connections to auxiliary devices such as voltage transformers, auxiliary transformers, surge arresters, surge capacitors, voltage detection devices, and similar items are not part of the main circuit refer to 3. They shall be tested as installed in the assembly with all associated components influencing the performance or modifying the short-circuit current.

The short-time withstand current and peak withstand current tests shall be carried out on the short-circuiting parts of each earthing circuit according to the number of phases of the corresponding earthing device I k , I p , t k. Additionally, single-phase tests shall be performed on all parts of the earthing circuit that are designed to provide the connection between the earthing device and the earthing point provided, at the rated short-time and peak withstand currents I ke , I pe , t ke.

When there are removable earthing devices, the earthing connection s between the fixed part of the assembly and the removable earthing device shall be tested at the rated shorttime and peak withstand currents I k , I p , t k and I ke , I pe , t ke пїЅ as applicable. Additionally, where the earthing device in the assembly can be operated in alternative positions to the service position, the test shall be repeated for all alternative positions. Each test shall be preceded by a no-load operation of the mechanical switching device s and by measurement of the resistance of the main circuit according to 7.

Earthing switches and earthing circuits are excluded from resistance measurement. The circuits of the test object shall be selected in such a way that the most onerous conditions are obtained concerning the maximum lengths of unsupported conductors, configuration of the conductors and connections within the equipment, and the assigned rated values.

In the case of assemblies incorporating the same switching device at several locations, it also shall be checked that the most onerous location of the switching device is tested. The test connections to the terminals of the assembly shall be arranged in such a way as to avoid unrealistic stressing of, or support to, the terminals.

The distance between the terminals and the nearest supports of the test conductors on both sides of the assembly shall be in accordance with the manufacturer's instructions reference. The short-time withstand current and peak withstand current tests shall be carried out according to the number of phases of the circuit under test.

However, each earthing circuit shall be tested with its number of phases at its I k , I p and t k , and tested single-phase at its I ke , I pe and t ke up to the earthing point provided on the test object. These tests may be performed on different test samples. Parts of the earthing circuit already satisfactorily tested may be replaced between tests on different earthing circuits.

Current transformers and tripping devices that may be present shall be installed as in normal service, but with the release made inoperative. Equipment which does not include any current-limiting device may be tested at any convenient voltage.

Equipment which incorporates a current-limiting device shall be tested at the rated voltage of the assembly, except if the test set-up at a lower voltage results in mechanical and thermal effects that are equal to, or higher than, those with the incorporated current-limiting device at rated voltage.

Refer to 7. Self-tripping circuit-breakers, if any, shall be set on their maximum tripping values. NOTE The definition of self-tripping circuit-breakers is provided in 3.

Current-limiting fuses, if any, shall be provided with fuse-links having the maximum rated current specified. The test arrangement shall be noted in the test report. The rated duration for these tests will be t k or t ke , whichever is applicable for the tested circuit. After the test on each earthing circuit, some deformation and degradation of the earthing devices, earthing conductors, earthing connections and other conductive parts forming part of the earthing circuit is permissible, but the continuity of the circuit shall be preserved.

Visual inspection should be sufficient to check that continuity of the circuit has been preserved. In case of doubt if certain earth connections are still adequate, the earthing shall be verified testing with 30 A DC to the earthing point provided. The voltage drop shall be lower than 3 V. Accessible partitions and shutters, as defined by the manufacturer, shall be verified on IP2X.

The leakage rate shall stay within the limits defined in Table 15 of IEC For a defined type of switchgear and controlgear, a tight compartment design is considered to be validated if all types of sealings for a specific design are tested at least once on representative compartments. These tests may be performed during other tests at temperature limits if any as specified in component standards. NOTE Functional tests on auxiliary and control circuits are performed as routine tests, refer to 8.

NOTE This test is applied to the vacuum interrupter, not to a functional unit. That is, they shall be tested as normally installed in the assembly with all associated components that may influence the performance, such as connections, supports, provisions for venting. These tests are not necessary if making and breaking tests have been performed on the switching devices installed in assemblies with identical or more onerous conditions. It is recognized that, in some cases, such influence can be quite negligible.

IEC TR lists the relevant design parameters that are considered to establish the same or less onerous conditions. As it is not possible to cover all possible configurations and designs of switching devices, the following procedures shall be followed: a if the appropriate making and breaking test series have been made with the switching device in a representative compartment, then the tests referred to above are also valid for compartments with similar or less onerous conditions; b if type tested switching devices, tested with or without an enclosure, are used and a is not applicable, the test duties set out in 7.

The tests shall be performed in accordance with the requirements for earthing switches of class E1 or class E2, as applicable.

If the class E1 or E2 earthing function is performed by the main switching device in combination with a class E0 earthing switch, then the test requirements shall be the same as for a combined function earthing switch as defined in 7. In this case the requirements of 7.

Test conditions and criteria to pass the test are identical to the ones defined on each corresponding switching device standard for mechanical tests. If a removable part is intended to be used as a disconnector, then the mechanical endurance shall be in accordance with IEC Otherwise, removable parts shall be inserted 25 times and removed 25 times to verify satisfactory operation of the equipment.

The reliable operation of shutters, for example by a mechanical drive, where the movement of the shutters is positively driven by the movement of the removable or withdrawable part, shall be checked. For functional units including several switching devices, the operations may be performed as part of a sequence of operations involving all these switching devices.

Any operations not included in this sequence should be separately tested. In the case of manually operated equipment, the normal manual operation handle shall be used to perform the tests.

The following tests shall be made in order to attempt to defeat the interlocks and locking devices: a 10 attempts to open any interlocked or locked door or cover; b 10 attempts to access or engage the operation interface, when access or engagement is prevented due to an interlocking or locking device shutter, selector lever, etc.

The normal manual operation handle if any shall be used to perform these tests. The force shall be applied halfway along the length of the gripping part of the handle or actuator. Where operating handles and actuators incorporate a feature which limits the transmitted force or torque, the maximum test force or torque shall be limited to that which can be applied by the handle or actuator, provided that the handle or actuator is not interchangeable with other handles or actuators.

No adjustment shall be made to the switching devices, removable parts or interlocks during these tests. The integrity of sliders or other devices preventing access to the operation interface shall be verified in accordance with 7.

Where mechanical interlocks are designed to prevent the operation of motorized switching devices, the following additional tests shall be performed using the motor: пїЅ 20 attempts to operate the switching devices; пїЅ 10 attempts to operate the switching device in the wrong direction shall be carried out in addition to, but anywhere in, the above sequence of 20 attempts. In case of the test with N, damage is acceptable, provided that the interlock still prevents operation.

NOTE These tests can be performed as part of the mechanical operations test sequence. Alternatively, they may be evacuated, if allowed by the manufacturer; NOTE 1 The test is intended to demonstrate the over-pressure behaviour under service conditions; NOTE 2 The design pressure relative pressure already considers the situation of adjacent compartment evacuated, if allowed by the manufacturer.

The pressure relief device shall not operate; пїЅ then the relative pressure shall be increased up to a maximum value of three times the design pressure. It is acceptable that the pressure relief device may operate, as designed by the manufacturer, below this value. This opening pressure shall be recorded in the type test report.

After the test, the compartment may be distorted, but the compartment shall not rupture; пїЅ visual inspection of the orientation of the pressure relief device shall be made to assess the direction of escaping gases. Gas-filled compartments with design pressures higher than kPa relative pressure shall be in accordance with the testing requirements of IEC Alternatively, they may be evacuated, if allowed by the manufacturer; пїЅ The relative pressure shall be increased up to three times the design pressure of the compartment for 1 min.

After the test, the compartment may be distorted, but the compartment shall not rupture. Gas-filled compartments with design pressures higher than kPa relative pressure shall be in accordance with the testing requirements of 6. NOTE The test is intended to verify the safety margin for possible overpressures under service conditions. When these partitions contain bushings, tests shall be carried out under the appropriate conditions, i. Solid-insulation embedded high-voltage parts that are intended to remain live when accessing the high-voltage compartment shall be tested according to 6.

For the test set-up, refer to item a of 7. The appropriate test methods given in IEC [9] should be applied. For the test, the inner surface of the partition or shutter shall be earthed by applying a conductive layer of at least cm 2 , at the most onerous point. The test set-up shall be as specified in item a of 7.

The main circuit shall, at the discretion of the manufacturer, be connected either to a threephase supply of power-frequency voltage equal to the rated voltage of the assembly, with one phase connected to earth, or to a single-phase supply of a voltage equal to the rated voltage, the live parts of the main circuit being connected together.

For three-phase tests, three measurements shall be made with the different phases of the supply successively connected to earth. In the case of single-phase tests, only one measurement is necessary. A metal foil shall be placed in the most unfavourable situation for the test on the accessible surface of the insulation providing the protection against contact with live parts.

In case of doubt about the most unfavourable situation, the test shall be repeated with different situations. The metal foil shall be approximately circular or square, having an area as large as possible but not exceeding cm 2.

The enclosure and the frame of the assembly shall be earthed. The leakage current flowing through the metal foil to earth shall be measured with the insulation dry and clean.

The value of the leakage current measured shall not exceed 0,5 mA. If, as indicated in item d of 6. If these gaps are incorporated to avoid the passage of the leakage current from live parts to accessible parts of insulating partitions and shutters, the gaps shall withstand the test voltages specified in 7.

It is not necessary to measure leakage currents if earthed metal parts are arranged in an appropriate manner to ensure that leakage currents cannot reach the accessible parts of the insulating partitions and shutters. The internal arc test makes allowance for effects acting on all parts of the enclosure, such as internal overpressure, thermal effects of the arc or its roots, the effects of ejected hot gases and glowing particles.

All other equipment, for example measuring instruments and monitoring equipment shall be in the position as it is in normal service; пїЅ all covers and doors of the assembly shall be closed and correctly secured. Every high-voltage compartment of representative functional units of the assembly shall be tested. More than one test object may be necessary to perform all the internal arc tests.

The actual duration of the current flow will be controlled by the fuses. The tested compartment will be designated as 'fuse-protected'. The tests shall be performed at the rated voltage U r. Any device e. If compartments or functional units are equipped with devices intended to limit the duration of the arc itself by other means e.

However, if the manufacturer declares that these devices are an integral part of the design of the compartment or assembly which prevents to make them inoperative without modification of the construction of the compartment or the enclosure, the relevant compartment of the assembly may be tested with the device operative; but this compartment shall be qualified according to the actual duration of the arc.

The test current shall be maintained for the rated short-circuit duration of the main circuit. If, during the test, an arc ignites in other non-previously arc-tested compartment s of the same test object, the test shall be regarded as valid only for the compartment where the arc was initiated. The other affected compartment s shall be or have been tested for at least the number of phases involved in this take-over ignition. NOTE 2 Reason for not accepting the test result in case of transfer to a compartment that was already arc-tested, is that the test result can be influenced by the contamination in that compartment.

Mock-ups of internal components are permitted provided they have the same volume and external material as the original items and they do not affect the main and earthing circuits; пїЅ tests shall be performed on all types of functional units that may be combined into an assembly, as stated by the manufacturer regarding the different possible assembly lay-outs. NOTE 7. Test procedure The method to verify the internal arc classification is defined in Clause A.

Deformations are accepted, provided that no part comes as far as the position of the indicator mounting frames or the walls whichever is the closest on every side and no openings with dimensions larger than 50 mm occurred in the classified sides up to a height of 2 mm. The assembly does not need to comply with its IP code after the test. To extend the acceptance criterion to an installation mounted closer to the wall than tested, two additional conditions shall be met: пїЅ the permanent deformation is less than the intended distance to the wall; пїЅ exhausting gases are not directed to the wall.

Criterion No. NOTE 1 Holes in the enclosure which are created after the duration of the test by other effects than burning through, are disregarded. If indicators have been ignited after 1 s after the current duration and if proof is established of the fact that the ignition was caused by glowing particles rather than hot gases, the assessment criterion has also been met. Pictures taken by high-speed cameras, video or any other suitable means should be used by the test laboratory to establish evidence.

Indicators ignited as a result of paint or stickers burning are also excluded. Visual inspection is generally sufficient to assess compliance. In case of doubt, the continuity of the earthing connection shall be checked refer to 7. For this purpose, the manufacturer shall state the point of the assembly from which this distance is measured; NOTE Because the distance between the upper part of the assembly and the ceiling under internal arc test conditions can be different from the distance under installation conditions, the information in the test report is about the validity of the test results regarding the ceiling height for installation.

The test voltage specified in 7. The test voltage may be applied at higher than the rated frequency in order to avoid the disconnection of voltage transformers. Overvoltage protective devices shall be disconnected or removed during the test.

Functional tests as specified in the relevant IEC component standards shall be performed on auxiliary and control circuits of each component, subassembly or after mounted on the assembly. Additionally, all existing auxiliary and control circuits including electrical interlocks shall be verified on their proper operation in conjunction with the other parts of the assembly. The tests shall be performed with the upper and lower value limits of the supply voltage defined in 6.

If such a routine test is performed on the assembly, the procedure shall be in accordance with Annex B. NOTE The measurement of partial discharges, as a routine test, can be helpful to detect possible material and manufacturing defects especially for organic solid insulating components. The test can also serve as a quality manufacturing test of assembly. The tests shall be performed as specified in 7. Any divergence between any IEC Publication and the corresponding national or regional publication shall be clearly indicated in the latter.

Use of the referenced publications is indispensable for the correct application of this publication. IEC shall not be held responsible for identifying any or all such patent rights. International Standard IEC has been prepared by subcommittee 17C: High-voltage switchgear and controlgear assemblies, of IEC technical committee Switchgear and controlgear.

This first edition of IEC cancels and replaces the third edition of IEC , published in , and constitutes a technical revision. The main changes are: new definitions and classification of equipment, introduction of internal arc classes IAC and its testing. Clause numbering follows the clause numbering of that standard. Additional subclauses, as they relate to a particular clause or subclause from IEC , are numbered , , etc. The committee has decided that the contents of this publication will remain unchanged until IEC пїЅ High-voltage switchgear and controlgear is the publication number and main title element for the common publications.

The numbering of these publications will apply the following principle. The table below relates the new numbers to the old numbers. The parts numbered xxx will be given a final number pending the decision to publish the revised publication as standard or technical report. Enclosures may include fixed and removable components and may be filled with fluid liquid or gas to provide insulation.

NOTE 1 Although primarily dedicated to three-phase systems, this standard can also be applied to single-phase or two-phase systems. This standard defines several types of metal enclosed switchgear and controlgear which differ due to пїЅ the consequences on network service continuity in case of maintenance on the switchgear and controlgear; пїЅ the need and convenience of maintenance of the equipment. NOTE 2 Safety of an installation results from the design, implementation and coordination of products, installations and operations.

For metal-enclosed switchgear and controlgear containing gas-filled compartments, the design pressure is limited to a maximum of kPa relative pressure. NOTE 3 Gas-filled compartments having a design pressure exceeding kPa relative pressure should be designed and tested in accordance with IEC Metal-enclosed switchgear and controlgear for special use, for example, in flammable atmospheres, in mines or on board ships, may be subject to additional requirements.

Components contained in metal-enclosed switchgear and controlgear are to be designed and tested in accordance with their various relevant standards. This standard supplements the standards for the individual components regarding their installation in switchgear and controlgear assemblies. This standard does not preclude that other equipment may be included in the same enclosure.

In such a case, any possible influence of that equipment on the switchgear and controlgear is to be taken into account. NOTE 5 Metal-enclosed switchgear and controlgear for rated voltages above 52 kV insulated by ambient air may be covered by this standard taking into account the insulation levels of IEC For dated references, only the edition cited applies.

For undated references, the latest edition of the referenced document including any amendments applies.

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This can lead to a maximum of 25 voltage impulses. In addition. Increased demands on the circuitbreaker and earthing switch In contrast to the previous standard.

Above all. Tool-based Opening not for normal operation or maintenance. Procedure-based Opening for normal operation and maintenance. Access control via a suitable procedure work instruction of the operator combined with a locking device lock. Panel partition walls and isolating distance with compartmentalization to the busbar. LSC 2B пїЅ then the incoming cable. This applies generally to the gas-filled compartments of gas-insulated switchgear.

But also from an economic point of view. The busbar and the adjacent switchgear panels can remain in operation. Table 2 Type of accessibility to a compartment Access features Interlock-based Opening for normal operation and maintenance. Access is controlled by the construction of the switchgear. Access only with tool for opening.

As the switchgear is maintenance-free and climate-independent. Consequences for operators With the new IEC standard. A situation which has a number of advantages.

This means they are intended for use in rooms that are only accessible to authorized personnel closed electrical service locations. For example. Panel partition walls and isolating distance with compartmentalization to the busbar and to the cable.

Table 1 Loss of service continuity category When an accessible compartment of the switchgear is opened: пїЅ Constructional design LSC 1 пїЅ then the busbar and therefore the complete switchgear must be isolated. No partitions within the panel. A greater margin for your safety Not only that: the more stringent requirements of the dielectric type tests have been implemented without exception. As one of the first manufacturers. Siemens has already implemented the performance features requested by IEC at an early stage.

Without exception. This means for you as the operator: One hundred percent certainty that this combination of switchgear and switchgear panel functions reliably. All switching capacity tests for the various circuit-breakers and earthing switches were performed in installed condition. Overview of Siemens switchgear Distribution level PM The information in this document contains general descriptions of the technical features. An obligation to provide the respective performance feature shall exist only if expressly agreed in the terms of contract.

Report "IEC en". Please fill this form, we will try to respond as soon as possible. If earthing of a circuit is provided by the main switching device circuit-breaker, switch or contactor in series with an earthing switch, the earthing switch shall be interlocked with the main switching device. Provision shall be made for the main switching device to be secured against unintentional opening, for example, by disconnection of tripping circuits and blocking of the mechanical trip.

NOTE 2 Instead of an earthing switch, also a disconnector in the earthing position is possible. If non-mechanical interlocks are provided, the design shall be such that no improper situations can occur in case of lack of auxiliary supply. However, for emergency control, the manufacturer may provide additional means for manual operation without interlocking facilities. In such case, the manufacturer shall clearly identify this facility and define the procedures for operation.

The user shall make a proper selection, according to the characteristics of the network, operating procedures and service conditions refer to 8. If the switchgear and controlgear is installed, operated and maintained following the instructions of the manufacturer, there should be little probability that an internal arc occurs during its entire service life, but it cannot be completely disregarded. Failure within the enclosure of metal-enclosed switchgear and controlgear due either to a defect or an exceptional service condition or maloperation may initiate an internal arc, which constitutes a hazard, if persons are present.

Experience has shown that faults are more likely to occur in some locations inside an enclosure than in others. Table 2 in Clause 8 gives a list of such locations, causes of failure and possible measures to decrease the probability of internal faults. Other measures may be adopted to provide the highest possible level of protection to persons in case of an internal arc.

These measures are aimed to limit the external consequences of such an event. The following are some examples of these measures. The effectiveness of the design, at providing the prescribed level of protection of persons in case of an internal arc, can be verified by testing according to Annex A.

Designs which have been successfully tested qualify as IAC classified. Elle doit aussi assurer une protection conforme aux conditions suivantes. External parts of the switchgear and controlgear may be of insulating material, provided that HV parts are completely enclosed by metallic partitions or shutters intended to be earthed. Excepted are inspection windows complying with 5.

When the metal-enclosed switchgear and controlgear is installed, the enclosure shall provide at least the degree of protection IP 2X, according to IEC , Table 6. It shall also ensure protection in accordance with the following conditions. Metallic parts of the enclosures shall be designed to carry 30 A d. The floor surface, even if not metallic, may be considered as part of the enclosure.

The measures to be taken in order to obtain the degree of protection provided by floor surfaces shall be given in the installation manual. The walls of a room shall not be considered as parts of the enclosure. Parts of the enclosure bordering non-accessible compartments shall be provided with a clear indication not to be dismantled The horizontal surfaces of enclosures, for example, roof plates, are normally not designed to support personnel or additional equipment not supplied as part of the assembly.

If the manufacturer states that it is necessary to stand or walk upon the switchgear or controlgear during operation or maintenance, the design shall be such that the relevant areas will support the weight of the operator without undue distortion and the equipment will remain suitable for its purpose.

In such case, those areas on the equipment where it is not safe to stand or walk, for example, pressure relief flaps, shall be clearly identified. Excepted are covers and doors that may be of insulating material, provided that HV parts are enclosed by metallic partitions or shutters intended to be earthed. When covers and doors that are parts of the enclosure are closed, they shall provide the degree of protection specified for the enclosure.

Covers or doors shall not be made of woven wire mesh, expanded metal or similar. When ventilating openings, vent outlets or inspection windows are incorporated in the cover or door, reference is made to 5. Several categories of covers or doors are recognized with regard to the type of accessible compartments they provide access to. It shall not be possible for them to be opened, dismantled or removed without the use of tools; NOTE 1 They should be opened only when precautions to ensure electrical safety have been taken.

These compartments shall be provided with interlocking devices so that opening of the compartment shall only be possible when the part of the main circuit contained in the compartment being made accessible is dead and earthed, or in the disconnected position with corresponding shutters closed; пїЅ procedure-based accessible compartments.

These compartments shall be provided with provision for locking, for example, padlocking. NOTE 3 Suitable procedures should be put in place by the user to ensure that a procedure-based accessible compartment may be opened only when the part of the main circuit contained in the compartment being made accessible is dead and earthed, or in the disconnected position with corresponding shutters closed. Procedures may be dictated by legislation of the country of installation or by user safety documentation.

NOTE 1 A partition or shutter becomes a part of the enclosure if it is accessible in any of the positions defined in 3. NOTE 2 If a door is provided which can be closed in the positions defined in 3. They shall be covered by a transparent sheet of mechanical strength comparable to that of the enclosure.

Precautions shall be taken to prevent the formation of dangerous electrostatic charges, either by clearance or by electrostatic shielding for example, a suitable earthed wire-mesh on the inside of the window. The insulation between live parts of the main circuit and the accessible surface of the inspection windows shall withstand the test voltages specified in 4.

Such openings may make use of wire mesh or the like provided that it is of suitable mechanical strength. Ventilating openings and vent outlets shall be arranged in such a way that gas or vapour escaping under pressure does not endanger the operator.

Ces conditions sont les suivantes. Voir Article 2 de la CEI Compartments may be of various types, for example: пїЅ liquid-filled; пїЅ gas-filled; пїЅ solid-insulation.

Main components individually embedded in solid insulating material may be considered as compartments, provided that the conditions specified in IEC are met.

Openings necessary for interconnection between compartments shall be closed with bushings or other equivalent means. Busbar compartments may extend through several functional units without the need for bushings or other equivalent means.

However, in case of LSC2, separate compartments shall be provided for each set of busbars, for example, in double busbar systems and for sections of switchable or disconnectable busbars.

Gas-filled compartments, when permanently pressurized in service, are subjected to particular conditions of service which distinguish them from compressed air receivers and similar storage vessels. These conditions are as follows. For outdoor installations, the manufacturer shall take into account the influence of climatic conditions refer to Clause 2 of IEC The design temperature of the fluid-filled compartment is generally the upper limit of ambient air temperature increased by the temperature rise of the fluid due to the flow of rated normal current.

For outdoor installations, other possible influences, such as solar radiation, shall be taken into account. The design pressure of the enclosure shall not be less than the upper limit of the pressure reached within the enclosure at the design temperature.

If requested by the user, in order to permit entry to a fluid-filled compartment of closed or controlled pressure systems, the permissible leakage across partitions should also be stated by the manufacturer. A partition, separating a compartment filled with insulating gas from a neighbouring compartment filled with liquid, such as a cable box or a voltage transformer, shall not show any leakage affecting the dielectric properties of the two media.

The pressure relief devices shall not operate below 1,3 times the design pressure. The pressure relief device may be a designed, for example, weak area, of the compartment or a dedicated device, for example, bursting disk.

Partitions shall provide mechanical protection against the normal gas pressure still present in the adjacent compartment if applicable.

Conductors passing through partitions shall be provided with bushings or other equivalent means to provide the required IP level. Openings in the enclosure of metal-enclosed switchgear and controlgear and in the partitions of compartments through which contacts of removable or withdrawable parts engage fixed contacts shall be provided with automatic shutters operated in normal service operations to assure the protection of persons in any of the positions defined in 3.

Means shall be provided to ensure the reliable operation of the shutters, for example, by a mechanical drive, where the movement of the shutters is positively driven by the movement of the removable or withdrawable part. In such situations, verification of the shutter status may require access to the second compartment or provision of an inspection window or reliable indicating device. If, for maintenance or test purposes, there is a requirement that one or more sets of fixed contacts shall be accessible through opened shutters, the shutters shall be provided with means of locking each set independently in the closed position.

When, for maintenance or test purposes, the automatic closing of shutters is made inoperative in order to retain them in the open position, it shall not be possible to return the switching device to the service position until the automatic operation of the shutters is restored.

This restoration may be achieved by the action of returning the switching device to the service position. It may be possible to use a temporary inserted partition to prevent the live set of fixed contacts being exposed refer to For class PM, partitions and shutters between opened compartments and live parts of the main circuit, shall be metallic; otherwise, the class is PI refer to 3. Discontinuity in the metallic partitions and closed shutters shall not exceed 12,5 mm to be in line with degree of protection IP2X.

The appropriate test methods given in IEC should be applied. This disconnection facility is intended for maintenance purposes only.

If removable parts are intended to be used as a disconnector or intended to be removed and replaced more often than only for maintenance purposes, then testing shall also include the mechanical operation tests according to IEC NOTE 1 In some countries, regulations require that the isolating distance is visible.

Any removable part shall be so attached to the fixed part that its contacts will not open inadvertently due to forces which may occur in service, in particular those due to a short circuit. In switchgear and controlgear IAC classified, the transfer of withdrawable parts to or from service position shall be carried out without reduction of the specified level of protection in the event of an internal arc.

This is achieved, for example, when the operation is only possible when doors and covers intended to ensure personnel protection are closed.

Other design measures providing equivalent level of protection are acceptable. The effectiveness of the adopted design shall be verified by testing see Clause A. That is, when one side of the isolating gap is energized at normal system voltage to earth and tests are being carried out on the cable connected to the other side of the isolating gap. Refer to the dielectric test defined in 6. NOTE Attention is drawn to the fact that practically no safety margin is left in some cases between the rated power-frequency test voltage for the isolating distance and the resulting voltage stress across the isolating distance due to the application of the cable test voltage if the other side of the isolating distance of metal-enclosed switchgear and controlgear is still live.

The type tests shall be made on a representative functional unit. Because of the variety of types, ratings and possible combinations of components, it is not practicable to make type tests with all the arrangements of metal-enclosed switchgear and controlgear.

The performance of any particular arrangement may be substantiated by test data of comparable arrangements. NOTE A representative functional unit may take the form of one extensible unit. However, it may be necessary to bolt two or three of such units together. Mandatory type tests, where applicable: g Tests to verify the protection of persons against dangerous electrical effects see 6. Optional type tests subject to agreement between manufacturer and user : l Tests to verify the protection of the equipment against external effects due to weather see 6.

Type tests may impair the suitability of the tested parts for subsequent use in service. Therefore, specimens used for type test shall not be used in service without agreement between manufacturer and user. This is verified by at least five impulses without disruptive discharge following that impulse which caused the last disruptive discharge. If this impulse is one of the last five out of the series of 15 impulses, additional impulses shall be applied, provided that the total number of discharges does not exceed two in the complete series.

This can result in a maximum of 25 impulses per series. NOTE 1 For fluid-filled compartments tested with test bushings that are not part of the switchgear and controlgear, impulses resulting in flashover across the test bushings are not considered as part of the test series. Because of the great variety of designs, it is not feasible to give specific indications of the tests to be performed on the main circuit, but, in principle, they shall cover the following tests.

All other conductors of the main circuit and the auxiliary circuits shall be connected to the earthing conductor or the frame and to the earth terminal of the test supply. If the phase conductors are segregated, only tests to earth apply.

Attention shall be given to the possibility that switching devices in their open position or removable parts in the disconnected, removed, test or earthing position may result in less favourable field conditions. Under such conditions the tests shall be repeated.

However, the removable parts shall not be subjected to these voltage tests whilst they are in the disconnected, test or removed position. In case of doubt about the most unfavourable arrangement, tests shall be repeated with alternative configurations. In order to check compliance with the requirements of 5. In case of doubt about the most unfavourable situation, the tests shall be repeated with different situations.

For convenience of testing, subject to agreement between testing station and manufacturer, more than one metal foil may be applied simultaneously or larger parts of the insulating material may be covered. The isolating distance may be formed by пїЅ a disconnector in open position; пїЅ the distance between the two parts of the main circuit intended to be connected by a withdrawn or removed switching device.

If, in the disconnected position, an earthed metallic shutter is interposed between the disengaged contacts to assure a segregation, the gap between the earthed metallic shutter and the live parts shall withstand only the test voltages required to earth. If, in the disconnected position, there is no earthed metallic shutter or partition between the fixed part and the withdrawable part, the test voltages specified across the isolating distance shall be applied пїЅ between the fixed and moving contacts intended to engage, if conductive parts of the main circuit of the withdrawable part can inadvertently be touched; пїЅ between the fixed contacts on one side and the fixed contacts on the other side, with the switching device of the withdrawable part in the closed position if possible, if they cannot inadvertently be touched.

If it is not possible to have the switching device closed in the disconnected position, then this test shall be repeated in the test position with the switching device of the withdrawable part closed.

For test voltages to earth and between phases, columns 2 and 4 shall be used. For test voltages across isolating distances columns 3 and 5 shall be used. The test voltage shall be raised for each test condition to the test value and maintained for 1 min. The tests shall be performed in dry conditions. Instrument transformers, power transformers or fuses may be replaced by replicas reproducing the field configuration of the high-voltage connections.

Overvoltage protective devices may be disconnected or removed. During the power-frequency voltage tests, one terminal of the test transformer shall be connected to earth and to the enclosure of the metal-enclosed switchgear and controlgear, except that during the tests, in accordance with item b of 6.

If this is not practicable, one terminal of the test transformer may, with the agreement of the manufacturer, be connected to earth and the enclosure shall, if necessary, be insulated from earth. Fifteen consecutive lightning impulses at the rated withstand voltage shall be applied for each test condition and each polarity.

Overvoltage protective devices shall be disconnected or removed. Current transformer secondaries shall be short-circuited and earthed.

Current transformers with a low ratio may have their primaries short-circuited too. During the lightning impulse voltage tests, the earthed terminal of the impulse generator shall be connected to the enclosure of the metal-enclosed switchgear and controlgear, except that during the tests in accordance with item b of 6. If the test is made, it shall be carried out after the lightning impulse and power-frequency voltage tests.

NOTE 1 In the case of designs consisting of a combination of conventional components for instance, instrument transformers, bushings that can be tested separately in accordance with their relevant standards, the purpose of this partial discharge test is to check the arrangement of the components in the assembly.

NOTE 2 This test may be carried out on assemblies or subassemblies. Care should be taken that external partial discharges do not affect the measurement. Current transformer secondaries may be short-circuited and disconnected from earth. Voltage transformer secondaries may be disconnected.

Voltage-limiting devices, if any, shall be disconnected. The test values are subject to agreement between the user and manufacturer.

NOTE The test values agreed should be chosen to ensure a safety margin between the rated power-frequency test voltages for the isolating distance and the resulting voltage stress across the isolating distance due to the application of, for example, a d. This measured resistance shall be the reference for the routine test refer to 7. The representative functional unit shall be mounted approximately as in normal service, including all normal enclosures, partitions, shutters, etc.

The tests shall be made normally with the rated number of phases and the rated normal current flowing from one end of the length of busbars to the terminals provided for the connection of cables. When testing individual functional units, the neighbouring units should carry the currents which produce the power loss corresponding to the rated conditions. Where there are other main functional components installed within the enclosure, they shall carry the currents which produce the power loss corresponding to the rated conditions.

Equivalent procedures to generate the same power dissipation are acceptable. The temperature rises of the different components shall be referred to the ambient air temperature outside the enclosure and shall not exceed the values specified for them in the relevant standards.

For these tests, short connections to auxiliary devices such as voltage transformers, auxiliary transformers, surge arresters, surge capacitors, voltage detection devices, and similar items are not considered as parts of the main circuit. The short-circuit current tests shall be carried out according to the rated number of phases. Current transformers and tripping devices that may be present shall be installed as in normal service, but with the release made inoperative.

Equipment which does not include any current-limiting device may be tested at any convenient voltage. Equipment which incorporates a current-limiting device shall be tested at the rated voltage of the switchgear and controlgear.

Other test voltages can be used, if it can be demonstrated that both the applied peak current and resulting thermal effects are equal to, or higher than, those with rated voltage. For equipment including current-limiting devices the prospective current peak, r. Self-tripping circuit-breakers, if any, shall be set on their maximum tripping values. Current-limiting fuses, if any, shall be provided with fuse-links having the maximum rated current specified.

After the test, no deformation or damage to components or conductors within the enclosure, which may impair good operation of the main circuits, shall have been sustained. That is, they shall be tested as installed in the metal-enclosed switchgear and controlgear with all associated components influencing the performance or modifying the short-circuit current.

The short-circuit current tests with earthing devices shall be carried out according to the rated number of phases. Further single-phase tests may be necessary in order to verify the performance of all the circuits that are intended to provide the connection between the earthing device and earthing point provided. The earth-fault current shall flow between the earthing conductor of the fixed part and the earthing point of the removable part.

Where the earthing device in the switchgear or controlgear can be operated in alternative positions to the normal service position, for example, in double busbar switchgear and controlgear, a test shall be made in alternative positions. After the test some deformation and degradation of the earthing conductor, earthing connections or earthing devices is permissible, but the continuity of the circuit shall be preserved. Visual inspection should be sufficient to check that continuity of the circuit has been preserved.

In case of doubt if certain earth connections are still adequate, the earthing shall be verified testing with 30 A DC to the earthing point provided. The voltage drop shall be lower than 3 V. The test connections to the terminals of the switchgear and controlgear shall be arranged in such a way as to avoid unrealistic stressing of, or support to, the terminals.

The distance between the terminals and the nearest supports of the test conductors on both sides of the switchgear and controlgear shall be in accordance with the instructions of the manufacturer but taking into account the requirement above. The switching devices shall be in the closed position and fitted with clean contacts in a new condition.

Each test shall be preceded by a no-load operation of the mechanical switching device and, with the exception of earthing switches, by measurement of the resistance of the main circuit.

The test arrangement shall be noted in the test report. A higher degree of protection may be specified in accordance with IEC Generally no test is needed if adequate design is demonstrated. That is, they shall be tested as normally installed in the metal-enclosed switchgear and controlgear with all associated components, the arrangement of which may influence the performance, such as connections, supports, provisions for venting, etc.

These tests are not necessary if making and breaking tests have been performed on the switching devices installed in metal-enclosed switchgear and controlgear with more onerous conditions. NOTE In determining which associated components are likely to influence the performance, special attention should be given to mechanical forces due to the short circuit, the venting of arc products, the possibility of disruptive discharges, etc.

As it is not possible to cover all possible configurations and designs of switching devices, the following procedures shall be followed, the precise combination of tests being determined by the characteristics and location of the particular switching device being considered.

IEC short-circuit making operations according class E1 or E2, as applicable. Test duty 5 according to class E1, E2 or E3, as applicable, unless the switch does not have a rated short-circuit making capacity.

If a withdrawable or removable part is intended to be used as a disconnector, then testing shall be in accordance with IEC Fifty attempts shall be made to operate the switching devices and 25 attempts shall be made to insert and 25 attempts to withdraw the removable parts.

During these tests only normal operating forces shall be employed and no adjustment shall be made to the switching devices, removable parts or interlocks. In case of manually operated equipment, the normal manual operation handle shall be used to perform the tests.

The pressure relief device shall not operate. It is acceptable that the pressure relief device may operate, as designed by the manufacturer, below this value. This opening pressure shall be recorded in the type test report. After the test, the compartment may be distorted, but the compartment shall not rupture. NOTE The relative withstand pressure of 3 times the design pressure may not be tested for the compartment, because it is not always possible to test without the presence of the pressure-relief device or a dedicated relief area of the compartment wall.

When these partitions contain bushings, tests shall be carried out under the appropriate conditions, i. Non-metallic partitions and shutters, made or partly made, of insulating material shall be tested as follows. For the test set-up, refer to item a of 6.

For the test, the inner surface of the partition or shutter shall be earthed by applying a conductive layer of at least cm 2 , at the most onerous point. The test set-up shall be as specified in item a of 6. The main circuit shall, at the discretion of the manufacturer, be connected either to a three- phase supply of power-frequency voltage equal to the rated voltage of the metal-enclosed switchgear and controlgear, with one phase connected to earth, or to a single-phase supply of a voltage equal to the rated voltage, the live parts of the main circuit being connected together.

For three-phase tests, three measurements shall be made with the different phases of the supply successively connected to earth. In the case of single-phase tests, only one measurement is necessary. A metal foil shall be placed in the most unfavourable situation for the test on the accessible surface of the insulation providing the protection against contact with live parts. In case of doubt about the most unfavourable situation, the test shall be repeated with different situations.

The metal foil shall be approximately circular or square, having an area as large as possible but not exceeding cm 2. The enclosure and the frame of the metal-enclosed switchgear and controlgear shall be earthed. The leakage current flowing through the metal foil to earth shall be measured with the insulation dry and clean.

If the value of the leakage current measured is more than 0,5 mA, the insulating surface does not provide the protection required in this standard. If, as indicated in item d of 5. If these gaps are incorporated to avoid the passage of the leakage current from live parts to accessible parts of insulating partitions and shutters, the gaps shall withstand the test voltages specified in 4. It is not necessary to measure leakage currents, if earthed metal parts are arranged in an appropriate manner to ensure that leakage currents cannot reach the accessible parts of the insulating partitions and shutters.

The test shall be performed according to Annex A, in every compartment containing main circuit parts of representative functional units refer to Clause A. The actual duration of the current flow will be controlled by the fuses. The tests shall be performed at the rated maximum voltage of the equipment. NOTE Application of suitable current-limiting fuses in combination with switching devices can limit the short-circuit current and minimize the fault duration.

It is well documented that the arc energy transferred during such tests is not predictable by I 2 t. In the case of current-limiting fuses, the maximum arc energy may occur at current levels below the maximum interrupting rating. Further, the effects of using current-limiting devices that employ pyrotechnic means to commutate current to a current-limiting fuse must be considered when evaluating designs utilizing such devices.

Any device for example, protection relay that may automatically trip the circuit before the end of the prospective duration of the test shall be made inoperative during the test. If compartments or functional units are equipped with devices intended to limit the duration of the arc itself by other means for example, by transferring the current to a metallic short circuit , they shall be made inoperative during the test, unless they are intended to be tested.

In that case the compartment of the switchgear and controlgear may be tested with the device operative; but this compartment shall be qualified according to the actual duration of the arc. The test current shall be maintained for the rated short-circuit duration of the main circuit. This test covers the case of a fault resulting in an arc occurring in air, or in another insulating fluid liquid or gas within the enclosure or within components having housings which form part of the enclosure when the doors and covers are in the position required for normal operating conditions refer to Clause A.

The test procedure also covers the particular case of a fault occurring in solid insulation where this insulation is applied during assembly on site of metal-enclosed switchgear and controlgear and does not comprise prefabricated type-tested insulating parts refer to A.

The validity of the results of a test carried out in a functional unit of a particular metal-enclosed design of switchgear and controlgear can be extended to another one refer to 6. Refer to Clause 7 of IEC with the addition of the following routine tests: пїЅ mechanical operation tests The test voltage specified in Tables 1a and 1b, column 2, of IEC shall be applied connecting each phase conductor of the main circuit in turn to the high-voltage terminal of the test supply, with the other phase conductors connected to earth and the continuity of the main circuit assured for example, by closing the switching devices or otherwise.

For gas-filled compartments, the tests shall be performed at the rated filling pressure or density of the insulating gas refer to 4. This test is subject to agreement between manufacturer and user. The d. The measured value of the type test can be used to determine the limit of resistance value for the routine test.

The measurement of partial discharges may be appropriate as a routine test to detect possible material and manufacturing defects especially if organic insulating materials are used therein and is recommended for fluid-filled compartments. If such a test is agreed, the procedure shall be as described in Annex B. During these tests which are performed without voltage on or current in the main circuits, it shall be verified, in particular, that the switching devices open and close correctly within the specified limits of the supply voltage and pressure of their operating devices.

Each compartment shall be subjected to a test at 1,3 times the design pressure for 1 min. This does not apply for sealed compartments with a rated filling pressure of 50 kPa relative pressure and below. After this test the compartments shall show no signs of distress or any distortion likely to affect the operation of the switchgear and controlgear. During the test no adjustment shall be made.

The tests are considered to be satisfactory if the auxiliary devices have operated properly, if they are in good operating condition after the tests and if the effort to operate them is practically the same before and after the tests.

For parts which are assembled on site and for gas-filled compartments which are filled on site, it is recommended that the following tests be carried out. For the tests, one terminal of the test transformer shall be connected to earth and to the enclosure of metal-enclosed switchgear and controlgear.

If the voltage test after erection on site replaces the routine test at the manufacturer's premises, the full power-frequency test voltage shall be applied. NOTE Voltage transformers should be disconnected during dielectric site tests, unless the test frequency used for the site test is high enough to prevent core saturation.

The selection of metal- enclosed switchgear and controlgear essentially involves an identification of the functional requirements for the service installation and the form of internal partitioning that best meets these requirements. Explanation regarding the changes in classification, compared to the third edition of IEC and other current practice, is given in Annex C.

Such requirements should take account of applicable legislation and user safety rules. Table 2 provides a summary of the considerations for specifying switchgear and controlgear. The rated values of an assembly of switchgear and controlgear may differ from those of its component parts.

The rated values should be chosen in accordance with this standard having regard for the characteristics of the system as well as its anticipated future development. A list of ratings is given in Clause 4. Other parameters such as local atmospheric and climatic conditions and the use at altitudes exceeding 1 m should also be considered. The duty imposed by fault conditions should be determined by calculating the fault currents at the place where the metal-enclosed switchgear and controlgear is to be located in the system.

Reference is made to IEC in this regard. Development of switching devices with low maintenance requirement has reduced the need for frequent attention to some items subject to arc erosion. However, there remains a need for accessibility to expendable items, for example, fuses and for occasional inspection and testing of cables. Lubrication and adjustment of mechanical parts may also be required, for which reason some designs may make mechanical parts accessible outside the HV compartments.

If maintenance demands are infrequent, as is often preferred practice nowadays, then assemblies equipped with low- maintenance components, may provide a practical solution. Fixed pattern assemblies, particularly those employing low-maintenance components may provide a cost-effective through-life arrangement.

In the case where a main circuit compartment is opened, safe operation of switchgear and controlgear requires irrespective of whether of fixed or withdrawable pattern that the parts on which work is to be carried out should be isolated from all sources of supply and earthed. Furthermore, the disconnecting devices used to isolate should be secured against re- connection.

In this subclause, some guidance is given regarding the extent to which the different forms can provide maintainability. NOTE 1 Temporarily inserted partitions, if required to prevent incidental contact with live parts, while performing certain maintenance procedures, are addressed in There are four types of compartment, three being accessible to the user and one non- accessible.

Accessible compartments: Three methods of controlling the opening of an accessible compartment are defined. The first two types of accessible compartment are available to the user and are provided for normal operation and maintenance.

If a compartment requires tools for opening, then this is normally a clear indication that the user should take other measures to ensure safety, and possibly to ensure performances integrity, for example, insulating conditions, etc.

Le jeu de barres peut rester sous tension. A clear indication not to open is provided on, or by a feature of, the compartment, for example, a completely welded GIS tank. With appropriate sensing and auxiliary control devices, it is also possible to provide a level of protection against failure of insulation to earth ground.

Category LSC1: This form is not intended to provide service continuity during maintenance if needed and may require complete disconnection of the switchgear and controlgear from the system and making dead before accessing the interior of the enclosure. Category LSC2: This form is intended to allow maximum continuity of service of the network during access to the compartments inside the switchgear and controlgear. LSC2 has two recognized levels: LSC2A: When accessing components of one functional unit, the other functional units of the switchgear and controlgear may be kept in service.

Example LSC2A for withdrawable designs : In practical terms, this means that the incoming HV-cables of that functional unit shall be made dead and earthed and the circuit shall be disconnected and separated physically and electrically from the busbars.

Busbars may be kept live. The term separation is used here rather than segregation to avoid making a distinction at this stage between insulation and metallic partitions and shutters refer to 8. This means that there is another point of disconnection and separation, i.

Example LSC2B for withdrawable designs: If the main switching device of each functional unit of an LSC2B switchgear and controlgear is fitted in its own accessible compartment, maintenance may be performed on this main switching device without de-energizing the corresponding cable connection.

As a consequence, a minimum of 3 compartments for each functional unit is necessary in this example of LSC2B switchgear and controlgear: пїЅ for each main switching device; пїЅ for components connected to one side of a main switching device, for example, feeder circuit; пїЅ for components connected to the other side of the main switching device, for example, busbars. Where more than one set of busbars is provided, each set is in a separate compartment.

Voir 5. Selection of partition class does not necessarily ensure personnel protection in the case of an internal arc in an adjacent compartment, refer to Clause A. A shutter may or may not be in the opened compartment itself, provided that segregation definition 3.

Refer to 5. NOTE This class allows for opened compartments with no electrical field due to live parts and no possible influence on electrical field distribution around live parts, except for the effect of the shutter changing position. This protection is achieved by reducing the risk to a tolerable level. Therefore, the selection of adequate equipment, in relation to internal arcing, should be governed by a procedure to achieve a level of tolerable risk.

This procedure is based on the assumption that the user has a role to play in the risk reduction. For guidance, Table 2 gives a list of locations where experience shows that faults are most likely to occur.

It also gives causes of failure and possible measures to decrease the probability of internal faults. If necessary, the user should implement those applicable to the installation, commissioning, operation and maintenance.

Le paragraphe 5. Couple de serrage correct. Sectionneurs Fausse manoeuvre Verrouillages voir 5. Pouvoir de fermeture Interrupteurs de terre sur court-circuit pour les interrupteurs et interrupteurs de terre. Instructions au personnel. Enrobage personnel isolant des parties actives. Surtensions Protection contre la foudre. Coordination d'isolement convenable. Subclause 5. The change of state when moving from position defined in 3. Failures can occur during the racking-in or racking-out of withdrawable parts.

Such failures are not necessarily due to change of electrical field by the closing of the shutters, although this is one possibility. In defining classification IAC, the following points shall be considered: пїЅ not all switchgear and controlgear will be IAC classified; пїЅ not all switchgear and controlgear is of withdrawable design; пїЅ not all switchgear and controlgear is fitted with a door which can be closed in the positions defined in 3.

Table 2пїЅ Locations, causes and examples of measures to decrease the probability of internal faults Locations where internal Possible causes of internal faults are most likely to Examples of possible preventive measures faults occur 3 2 1 Cable compartments Inadequate design Selection of adequate dimensions Use of appropriate materials Faulty installation Avoidance of crossed cables connections.

Checking of workmanship on site. Delayed reopening. Independent manual operation. Making capacity for Switches switches and earthing switches. Use contacts of plating. Encapsulation, where possible Faulty assembly Checking of workmanship by suitable means. Correct torque. Adequate locking means Instrument transformers Ferro-resonance Avoidance of these electrical influences by suitable design of the circuit Short circuit on LV side for Avoid short circuit by proper means for example, VTs protection cover, LV fuses Circuit-breakers Insufficient maintenance Regular programmed maintenance Instructions to personnel All locations Error by personnel Limitation of access by compartmentation.

Insulation embedded live parts. Instructions to personnel Ageing under electric Partial discharge routine tests stresses Pollution, moisture ingress Measures to ensure that the specified service of dust, vermin, etc. Use of gas- filled compartments Overvoltages Surge protection. Adequate insulation co-ordination. In addition, the installation instructions of the manufacturer should be followed refer to Clause In particular, the location of personnel during an internal arc event is important.

The manufacturer should indicate which sides of the switchgear and controlgear are accessible, according to the testing arrangement and the user should follow the instruction carefully. Allowing personnel to enter an area not designated as accessible may lead to personnel injury.

Classification IAC gives a tested level of protection of persons under normal operating conditions as defined in Clause A. It is concerned with personnel protection under these conditions; it is not concerned with personnel protection under maintenance conditions nor with service continuity. Technical requirements, ratings and optional tests for metal enclosed switchgear are summarized in Table 3. Beyond these items the enquirer should indicate every condition which might influence the tender or the order, as, for example, special mounting or erection conditions, the location of the external high-voltage connections or the rules for pressure vessels, requirements for cable testing.

Information should be supplied if special type tests are required.

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Download facebook app for me	The functional unit is tested for a fault current of 20 kA for 1s except the voltage transformers compartment which is tested with the dummy fuse type that causes the highest cut-off current refer to 7. NOTE The definition of self-tripping circuit-breakers is provided in 3. Cancel Send. If a removable part is intended to be used as a disconnector, then the mechanical endurance shall be in accordance with IEC If the phase conductors are segregated, only tests to earth shall apply. For dated references, only the doanload cited applies. The tests shall rfee performed in accordance with the requirements for earthing switches of class E1 or class E2, here applicable.
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Iec 62271 200 pdf free download	In such a case, the IP degree shall not be affected as well as no permanent deformation is allowed and the areas on the equipment where it is not safe to stand or walk, for example pressure relief flaps, shall be clearly identified. In this case the requirements of 7. The learn more here tests shall be made in order to attempt to defeat the interlocks and locking devices: a 10 attempts to open any interlocked or locked door or cover; b 10 attempts to access or engage the operation interface, when access or engagement is prevented due to an interlocking or locking device shutter, selector lever, etc. All removable parts and components of the same type, rating, and construction shall be mechanically and electrically interchangeable. Moreover, the materials involved may produce hot decomposition products, iec 62271 200 pdf free download gaseous or vaporous, which may be discharged to the outside of the iec 62271 200 pdf free download. Gas-filled compartments with design pressures higher than kPa relative pressure shall be designed according to the pressure requirements of IEC If the applied voltage is equal to the rated voltage, the peak value of the prospective current shall be set to 2,5 times for frequencies just click for source to 50 Hz or 2,6 times for both 50 Hz and 60 Hz the RMS value of the AC component defined in A.

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This standard is also applicable to the operating devices of circuit-breakers and to their auxiliary equipment. However, a circuit-breaker with a closing mechanism for dependent manual operation is not covered by this standard as a rated short circuit making- current ot be specified, and such dependent manual operation may be objectionable because of safety considerations.

Related Information Download. IEC Low-voltage switchgear and controlgear Part 5. AS IEC pdf download. Methods of measurement of touch current and protective conductor current. For maximum safety, a test transformer for isolation T2 in For convenience of testing, subject to agreement between testing station and manufacturer, more than one metal foil may be applied simultaneously or larger parts of the insulating material may be covered. The isolating distance may be formed by пїЅ a disconnector in open position; пїЅ the distance between the two parts of the main circuit intended to be connected by a withdrawn or removed switching device.

If, in the disconnected position, an earthed metallic shutter is interposed between the disengaged contacts to assure a segregation, the gap between the earthed metallic shutter and the live parts shall withstand only the test voltages required to earth. If, in the disconnected position, there is no earthed metallic shutter or partition between the fixed part and the withdrawable part, the test voltages specified across the isolating distance shall be applied пїЅ between the fixed and moving contacts intended to engage, if conductive parts of the main circuit of the withdrawable part can inadvertently be touched; пїЅ between the fixed contacts on one side and the fixed contacts on the other side, with the switching device of the withdrawable part in the closed position if possible, if they cannot inadvertently be touched.

If it is not possible to have the switching device closed in the disconnected position, then this test shall be repeated in the test position with the switching device of the withdrawable part closed. For test voltages to earth and between phases, columns 2 and 4 shall be used. For test voltages across isolating distances columns 3 and 5 shall be used.

The test voltage shall be raised for each test condition to the test value and maintained for 1 min. The tests shall be performed in dry conditions.

Instrument transformers, power transformers or fuses may be replaced by replicas reproducing the field configuration of the high-voltage connections.

Overvoltage protective devices may be disconnected or removed. During the power-frequency voltage tests, one terminal of the test transformer shall be connected to earth and to the enclosure of the metal-enclosed switchgear and controlgear, except that during the tests, in accordance with item b of 6. If this is not practicable, one terminal of the test transformer may, with the agreement of the manufacturer, be connected to earth and the enclosure shall, if necessary, be insulated from earth.

Fifteen consecutive lightning impulses at the rated withstand voltage shall be applied for each test condition and each polarity. Overvoltage protective devices shall be disconnected or removed. Current transformer secondaries shall be short-circuited and earthed. Current transformers with a low ratio may have their primaries short-circuited too. During the lightning impulse voltage tests, the earthed terminal of the impulse generator shall be connected to the enclosure of the metal-enclosed switchgear and controlgear, except that during the tests in accordance with item b of 6.

If the test is made, it shall be carried out after the lightning impulse and power-frequency voltage tests. NOTE 1 In the case of designs consisting of a combination of conventional components for instance, instrument transformers, bushings that can be tested separately in accordance with their relevant standards, the purpose of this partial discharge test is to check the arrangement of the components in the assembly.

NOTE 2 This test may be carried out on assemblies or subassemblies. Care should be taken that external partial discharges do not affect the measurement. Current transformer secondaries may be short-circuited and disconnected from earth. Voltage transformer secondaries may be disconnected. Voltage-limiting devices, if any, shall be disconnected.

The test values are subject to agreement between the user and manufacturer. NOTE The test values agreed should be chosen to ensure a safety margin between the rated power-frequency test voltages for the isolating distance and the resulting voltage stress across the isolating distance due to the application of, for example, a d. This measured resistance shall be the reference for the routine test refer to 7. The representative functional unit shall be mounted approximately as in normal service, including all normal enclosures, partitions, shutters, etc.

The tests shall be made normally with the rated number of phases and the rated normal current flowing from one end of the length of busbars to the terminals provided for the connection of cables. When testing individual functional units, the neighbouring units should carry the currents which produce the power loss corresponding to the rated conditions. Where there are other main functional components installed within the enclosure, they shall carry the currents which produce the power loss corresponding to the rated conditions.

Equivalent procedures to generate the same power dissipation are acceptable. The temperature rises of the different components shall be referred to the ambient air temperature outside the enclosure and shall not exceed the values specified for them in the relevant standards.

For these tests, short connections to auxiliary devices such as voltage transformers, auxiliary transformers, surge arresters, surge capacitors, voltage detection devices, and similar items are not considered as parts of the main circuit. The short-circuit current tests shall be carried out according to the rated number of phases.

Current transformers and tripping devices that may be present shall be installed as in normal service, but with the release made inoperative. Equipment which does not include any current-limiting device may be tested at any convenient voltage.

Equipment which incorporates a current-limiting device shall be tested at the rated voltage of the switchgear and controlgear. Other test voltages can be used, if it can be demonstrated that both the applied peak current and resulting thermal effects are equal to, or higher than, those with rated voltage. For equipment including current-limiting devices the prospective current peak, r. Self-tripping circuit-breakers, if any, shall be set on their maximum tripping values.

Current-limiting fuses, if any, shall be provided with fuse-links having the maximum rated current specified. After the test, no deformation or damage to components or conductors within the enclosure, which may impair good operation of the main circuits, shall have been sustained. That is, they shall be tested as installed in the metal-enclosed switchgear and controlgear with all associated components influencing the performance or modifying the short-circuit current.

The short-circuit current tests with earthing devices shall be carried out according to the rated number of phases. Further single-phase tests may be necessary in order to verify the performance of all the circuits that are intended to provide the connection between the earthing device and earthing point provided.

The earth-fault current shall flow between the earthing conductor of the fixed part and the earthing point of the removable part. Where the earthing device in the switchgear or controlgear can be operated in alternative positions to the normal service position, for example, in double busbar switchgear and controlgear, a test shall be made in alternative positions.

After the test some deformation and degradation of the earthing conductor, earthing connections or earthing devices is permissible, but the continuity of the circuit shall be preserved. Visual inspection should be sufficient to check that continuity of the circuit has been preserved.

In case of doubt if certain earth connections are still adequate, the earthing shall be verified testing with 30 A DC to the earthing point provided. The voltage drop shall be lower than 3 V. The test connections to the terminals of the switchgear and controlgear shall be arranged in such a way as to avoid unrealistic stressing of, or support to, the terminals. The distance between the terminals and the nearest supports of the test conductors on both sides of the switchgear and controlgear shall be in accordance with the instructions of the manufacturer but taking into account the requirement above.

The switching devices shall be in the closed position and fitted with clean contacts in a new condition. Each test shall be preceded by a no-load operation of the mechanical switching device and, with the exception of earthing switches, by measurement of the resistance of the main circuit. The test arrangement shall be noted in the test report. A higher degree of protection may be specified in accordance with IEC Generally no test is needed if adequate design is demonstrated.

That is, they shall be tested as normally installed in the metal-enclosed switchgear and controlgear with all associated components, the arrangement of which may influence the performance, such as connections, supports, provisions for venting, etc.

These tests are not necessary if making and breaking tests have been performed on the switching devices installed in metal-enclosed switchgear and controlgear with more onerous conditions. NOTE In determining which associated components are likely to influence the performance, special attention should be given to mechanical forces due to the short circuit, the venting of arc products, the possibility of disruptive discharges, etc. As it is not possible to cover all possible configurations and designs of switching devices, the following procedures shall be followed, the precise combination of tests being determined by the characteristics and location of the particular switching device being considered.

IEC short-circuit making operations according class E1 or E2, as applicable. Test duty 5 according to class E1, E2 or E3, as applicable, unless the switch does not have a rated short-circuit making capacity. If a withdrawable or removable part is intended to be used as a disconnector, then testing shall be in accordance with IEC Fifty attempts shall be made to operate the switching devices and 25 attempts shall be made to insert and 25 attempts to withdraw the removable parts.

During these tests only normal operating forces shall be employed and no adjustment shall be made to the switching devices, removable parts or interlocks.

In case of manually operated equipment, the normal manual operation handle shall be used to perform the tests. The pressure relief device shall not operate. It is acceptable that the pressure relief device may operate, as designed by the manufacturer, below this value. This opening pressure shall be recorded in the type test report.

After the test, the compartment may be distorted, but the compartment shall not rupture. NOTE The relative withstand pressure of 3 times the design pressure may not be tested for the compartment, because it is not always possible to test without the presence of the pressure-relief device or a dedicated relief area of the compartment wall.

When these partitions contain bushings, tests shall be carried out under the appropriate conditions, i. Non-metallic partitions and shutters, made or partly made, of insulating material shall be tested as follows. For the test set-up, refer to item a of 6. For the test, the inner surface of the partition or shutter shall be earthed by applying a conductive layer of at least cm 2 , at the most onerous point. The test set-up shall be as specified in item a of 6.

The main circuit shall, at the discretion of the manufacturer, be connected either to a three- phase supply of power-frequency voltage equal to the rated voltage of the metal-enclosed switchgear and controlgear, with one phase connected to earth, or to a single-phase supply of a voltage equal to the rated voltage, the live parts of the main circuit being connected together.

For three-phase tests, three measurements shall be made with the different phases of the supply successively connected to earth. In the case of single-phase tests, only one measurement is necessary. A metal foil shall be placed in the most unfavourable situation for the test on the accessible surface of the insulation providing the protection against contact with live parts. In case of doubt about the most unfavourable situation, the test shall be repeated with different situations.

The metal foil shall be approximately circular or square, having an area as large as possible but not exceeding cm 2. The enclosure and the frame of the metal-enclosed switchgear and controlgear shall be earthed. The leakage current flowing through the metal foil to earth shall be measured with the insulation dry and clean.

If the value of the leakage current measured is more than 0,5 mA, the insulating surface does not provide the protection required in this standard. If, as indicated in item d of 5. If these gaps are incorporated to avoid the passage of the leakage current from live parts to accessible parts of insulating partitions and shutters, the gaps shall withstand the test voltages specified in 4.

It is not necessary to measure leakage currents, if earthed metal parts are arranged in an appropriate manner to ensure that leakage currents cannot reach the accessible parts of the insulating partitions and shutters.

The test shall be performed according to Annex A, in every compartment containing main circuit parts of representative functional units refer to Clause A. The actual duration of the current flow will be controlled by the fuses. The tests shall be performed at the rated maximum voltage of the equipment.

NOTE Application of suitable current-limiting fuses in combination with switching devices can limit the short-circuit current and minimize the fault duration. It is well documented that the arc energy transferred during such tests is not predictable by I 2 t.

In the case of current-limiting fuses, the maximum arc energy may occur at current levels below the maximum interrupting rating. Further, the effects of using current-limiting devices that employ pyrotechnic means to commutate current to a current-limiting fuse must be considered when evaluating designs utilizing such devices.

Any device for example, protection relay that may automatically trip the circuit before the end of the prospective duration of the test shall be made inoperative during the test. If compartments or functional units are equipped with devices intended to limit the duration of the arc itself by other means for example, by transferring the current to a metallic short circuit , they shall be made inoperative during the test, unless they are intended to be tested.

In that case the compartment of the switchgear and controlgear may be tested with the device operative; but this compartment shall be qualified according to the actual duration of the arc. The test current shall be maintained for the rated short-circuit duration of the main circuit. This test covers the case of a fault resulting in an arc occurring in air, or in another insulating fluid liquid or gas within the enclosure or within components having housings which form part of the enclosure when the doors and covers are in the position required for normal operating conditions refer to Clause A.

The test procedure also covers the particular case of a fault occurring in solid insulation where this insulation is applied during assembly on site of metal-enclosed switchgear and controlgear and does not comprise prefabricated type-tested insulating parts refer to A.

The validity of the results of a test carried out in a functional unit of a particular metal-enclosed design of switchgear and controlgear can be extended to another one refer to 6. Refer to Clause 7 of IEC with the addition of the following routine tests: пїЅ mechanical operation tests The test voltage specified in Tables 1a and 1b, column 2, of IEC shall be applied connecting each phase conductor of the main circuit in turn to the high-voltage terminal of the test supply, with the other phase conductors connected to earth and the continuity of the main circuit assured for example, by closing the switching devices or otherwise.

For gas-filled compartments, the tests shall be performed at the rated filling pressure or density of the insulating gas refer to 4. This test is subject to agreement between manufacturer and user. The d. The measured value of the type test can be used to determine the limit of resistance value for the routine test.

The measurement of partial discharges may be appropriate as a routine test to detect possible material and manufacturing defects especially if organic insulating materials are used therein and is recommended for fluid-filled compartments.

If such a test is agreed, the procedure shall be as described in Annex B. During these tests which are performed without voltage on or current in the main circuits, it shall be verified, in particular, that the switching devices open and close correctly within the specified limits of the supply voltage and pressure of their operating devices. Each compartment shall be subjected to a test at 1,3 times the design pressure for 1 min.

This does not apply for sealed compartments with a rated filling pressure of 50 kPa relative pressure and below. After this test the compartments shall show no signs of distress or any distortion likely to affect the operation of the switchgear and controlgear. During the test no adjustment shall be made. The tests are considered to be satisfactory if the auxiliary devices have operated properly, if they are in good operating condition after the tests and if the effort to operate them is practically the same before and after the tests.

For parts which are assembled on site and for gas-filled compartments which are filled on site, it is recommended that the following tests be carried out.

For the tests, one terminal of the test transformer shall be connected to earth and to the enclosure of metal-enclosed switchgear and controlgear.

If the voltage test after erection on site replaces the routine test at the manufacturer's premises, the full power-frequency test voltage shall be applied. NOTE Voltage transformers should be disconnected during dielectric site tests, unless the test frequency used for the site test is high enough to prevent core saturation.

The selection of metal- enclosed switchgear and controlgear essentially involves an identification of the functional requirements for the service installation and the form of internal partitioning that best meets these requirements. Explanation regarding the changes in classification, compared to the third edition of IEC and other current practice, is given in Annex C. Such requirements should take account of applicable legislation and user safety rules.

Table 2 provides a summary of the considerations for specifying switchgear and controlgear. The rated values of an assembly of switchgear and controlgear may differ from those of its component parts. The rated values should be chosen in accordance with this standard having regard for the characteristics of the system as well as its anticipated future development. A list of ratings is given in Clause 4.

Other parameters such as local atmospheric and climatic conditions and the use at altitudes exceeding 1 m should also be considered. The duty imposed by fault conditions should be determined by calculating the fault currents at the place where the metal-enclosed switchgear and controlgear is to be located in the system.

Reference is made to IEC in this regard. Development of switching devices with low maintenance requirement has reduced the need for frequent attention to some items subject to arc erosion. However, there remains a need for accessibility to expendable items, for example, fuses and for occasional inspection and testing of cables.

Lubrication and adjustment of mechanical parts may also be required, for which reason some designs may make mechanical parts accessible outside the HV compartments. If maintenance demands are infrequent, as is often preferred practice nowadays, then assemblies equipped with low- maintenance components, may provide a practical solution.

Fixed pattern assemblies, particularly those employing low-maintenance components may provide a cost-effective through-life arrangement. In the case where a main circuit compartment is opened, safe operation of switchgear and controlgear requires irrespective of whether of fixed or withdrawable pattern that the parts on which work is to be carried out should be isolated from all sources of supply and earthed.

Furthermore, the disconnecting devices used to isolate should be secured against re- connection. In this subclause, some guidance is given regarding the extent to which the different forms can provide maintainability. NOTE 1 Temporarily inserted partitions, if required to prevent incidental contact with live parts, while performing certain maintenance procedures, are addressed in There are four types of compartment, three being accessible to the user and one non- accessible.

Accessible compartments: Three methods of controlling the opening of an accessible compartment are defined. The first two types of accessible compartment are available to the user and are provided for normal operation and maintenance.

If a compartment requires tools for opening, then this is normally a clear indication that the user should take other measures to ensure safety, and possibly to ensure performances integrity, for example, insulating conditions, etc. Le jeu de barres peut rester sous tension. A clear indication not to open is provided on, or by a feature of, the compartment, for example, a completely welded GIS tank. With appropriate sensing and auxiliary control devices, it is also possible to provide a level of protection against failure of insulation to earth ground.

Category LSC1: This form is not intended to provide service continuity during maintenance if needed and may require complete disconnection of the switchgear and controlgear from the system and making dead before accessing the interior of the enclosure. Category LSC2: This form is intended to allow maximum continuity of service of the network during access to the compartments inside the switchgear and controlgear. LSC2 has two recognized levels: LSC2A: When accessing components of one functional unit, the other functional units of the switchgear and controlgear may be kept in service.

Example LSC2A for withdrawable designs : In practical terms, this means that the incoming HV-cables of that functional unit shall be made dead and earthed and the circuit shall be disconnected and separated physically and electrically from the busbars. Busbars may be kept live. The term separation is used here rather than segregation to avoid making a distinction at this stage between insulation and metallic partitions and shutters refer to 8. This means that there is another point of disconnection and separation, i.

Example LSC2B for withdrawable designs: If the main switching device of each functional unit of an LSC2B switchgear and controlgear is fitted in its own accessible compartment, maintenance may be performed on this main switching device without de-energizing the corresponding cable connection. As a consequence, a minimum of 3 compartments for each functional unit is necessary in this example of LSC2B switchgear and controlgear: пїЅ for each main switching device; пїЅ for components connected to one side of a main switching device, for example, feeder circuit; пїЅ for components connected to the other side of the main switching device, for example, busbars.

Where more than one set of busbars is provided, each set is in a separate compartment. Voir 5. Selection of partition class does not necessarily ensure personnel protection in the case of an internal arc in an adjacent compartment, refer to Clause A. A shutter may or may not be in the opened compartment itself, provided that segregation definition 3.

Refer to 5. NOTE This class allows for opened compartments with no electrical field due to live parts and no possible influence on electrical field distribution around live parts, except for the effect of the shutter changing position. This protection is achieved by reducing the risk to a tolerable level. Therefore, the selection of adequate equipment, in relation to internal arcing, should be governed by a procedure to achieve a level of tolerable risk.

This procedure is based on the assumption that the user has a role to play in the risk reduction. For guidance, Table 2 gives a list of locations where experience shows that faults are most likely to occur. It also gives causes of failure and possible measures to decrease the probability of internal faults. If necessary, the user should implement those applicable to the installation, commissioning, operation and maintenance. Le paragraphe 5. Couple de serrage correct.

Sectionneurs Fausse manoeuvre Verrouillages voir 5. Pouvoir de fermeture Interrupteurs de terre sur court-circuit pour les interrupteurs et interrupteurs de terre.

Instructions au personnel. Enrobage personnel isolant des parties actives. Surtensions Protection contre la foudre. Coordination d'isolement convenable. Subclause 5. The change of state when moving from position defined in 3. Failures can occur during the racking-in or racking-out of withdrawable parts. Such failures are not necessarily due to change of electrical field by the closing of the shutters, although this is one possibility.

In defining classification IAC, the following points shall be considered: пїЅ not all switchgear and controlgear will be IAC classified; пїЅ not all switchgear and controlgear is of withdrawable design; пїЅ not all switchgear and controlgear is fitted with a door which can be closed in the positions defined in 3.

Table 2пїЅ Locations, causes and examples of measures to decrease the probability of internal faults Locations where internal Possible causes of internal faults are most likely to Examples of possible preventive measures faults occur 3 2 1 Cable compartments Inadequate design Selection of adequate dimensions Use of appropriate materials Faulty installation Avoidance of crossed cables connections.

Checking of workmanship on site. Delayed reopening. Independent manual operation. Making capacity for Switches switches and earthing switches.

Use contacts of plating. Encapsulation, where possible Faulty assembly Checking of workmanship by suitable means. Correct torque. Adequate locking means Instrument transformers Ferro-resonance Avoidance of these electrical influences by suitable design of the circuit Short circuit on LV side for Avoid short circuit by proper means for example, VTs protection cover, LV fuses Circuit-breakers Insufficient maintenance Regular programmed maintenance Instructions to personnel All locations Error by personnel Limitation of access by compartmentation.

Insulation embedded live parts. Instructions to personnel Ageing under electric Partial discharge routine tests stresses Pollution, moisture ingress Measures to ensure that the specified service of dust, vermin, etc.

Use of gas- filled compartments Overvoltages Surge protection. Adequate insulation co-ordination. In addition, the installation instructions of the manufacturer should be followed refer to Clause In particular, the location of personnel during an internal arc event is important.

The manufacturer should indicate which sides of the switchgear and controlgear are accessible, according to the testing arrangement and the user should follow the instruction carefully. Allowing personnel to enter an area not designated as accessible may lead to personnel injury. Classification IAC gives a tested level of protection of persons under normal operating conditions as defined in Clause A. It is concerned with personnel protection under these conditions; it is not concerned with personnel protection under maintenance conditions nor with service continuity.

Technical requirements, ratings and optional tests for metal enclosed switchgear are summarized in Table 3. Beyond these items the enquirer should indicate every condition which might influence the tender or the order, as, for example, special mounting or erection conditions, the location of the external high-voltage connections or the rules for pressure vessels, requirements for cable testing.

Information should be supplied if special type tests are required. In the case of classification IAC switchgear and controlgear, guidance on safe installation conditions for the case of an internal arc shall be provided as well. The hazards of the actual installation condition shall be assessed with respect to installation conditions of the test specimen during the internal arcing test refer to Clause A. These conditions are considered as minimum permissible conditions.

However, if the purchaser user considers that the risk is not relevant, the switchgear and controlgear can be installed without the restrictions indicated by the manufacturer. NOTE Partitions and supports provided for mechanical protection only are not subject to this standard. After a short-circuit event in service, the earthing circuit should be examined for potential damages and replaced in whole or in part if needed. For indoor installations, arcing due to an internal fault in the metal-enclosed switchgear and controlgear may cause overpressure within the switchgear room.

This effect is not within the scope of this standard but it should be taken into consideration when designing the installation. This classification is intended to offer a tested level of protection to persons in the vicinity of the equipment in normal operating conditions and with the switchgear and controlgear in normal service position, in the event of internal arc.

For the purpose of this annex, normal operating conditions means the conditions of metal- enclosed switchgear and controlgear required to carry out operations such as opening or closing HV switching devices, connecting and disconnecting withdrawable parts, reading of measuring instruments and monitoring equipment, etc. Removing or replacing active components for example, HV fuses or any other removable component are not considered to be normal operations, neither those required to carry out maintenance works.

Internal faults inside metal-enclosed switchgear and controlgear can occur in a number of locations and can cause various physical phenomena. For example, the arc energy resulting from an arc developed in any insulating fluid within the enclosure will cause an internal overpressure and local overheating which will result in mechanical and thermal stressing of the equipment.

Moreover, the materials involved may produce hot decomposition products, either gaseous or vaporous, which may be discharged to the outside of the enclosure. The Internal Arc Classification IAC makes allowance for internal overpressure acting on covers, doors, inspection windows, ventilation openings, etc.

It also takes into consideration the thermal effects of the arc or its roots on the enclosure and of ejected hot gases and glowing particles, but not damage to internal partition and shutters not being accessible in normal operating conditions. NOTE Influences of internal arc between compartments are not yet covered by this standard.

The internal arc test described below is intended to verify the effectiveness of the design in protecting persons in case of an internal arc.

It does not cover all the effects which may constitute a hazard, such as the presence of gases with potential toxic characteristics that can be present after the fault. From this point of view, immediate evacuation and further ventilation of the switchgear room, before re-entering the site, is required. The hazard of fire propagation after an internal arc to combustible materials or equipment placed in the proximity of the metal-enclosed switchgear and controlgear is not covered by this test.

Accessibility Type B: unrestricted accessibility, including that of the general public. Corresponding to these two types of accessibility, two different test conditions are described in Clause A.

The metal-enclosed switchgear and controlgear may have different types of accessibility on the various sides of its enclosure. For identification purposes of the different sides of the enclosure refer to Clauses A.

Mock-ups of internal components are permitted provided they have the same volume and external material as the original items and they do not affect the main and earthing circuits. In case of switchgear and controlgear consisting of extensible modular stand- alone units, the test specimen shall consist of two units connected together as in service.

Testing shall be made at least in all compartments of the end of the switchgear and controlgear adjacent to the indicators. However, if there is a substantial difference to be declared by the manufacturer in strength between the joining sides of adjacent units and the side forming the end of a switchgear and controlgear, three units shall be used and the test of the different compartments repeated in the central unit.

NOTE A stand-alone unit is an assembly that may contain within a single common enclosure one or more functional units in horizontal or vertical arrangement tier.

However, the ceiling shall be located at a distance of 2 m from the floor, as a minimum. This provision is applicable when testing specimens of less than 1,5 m high.

The manufacturer may carry out an additional test with lower clearances to the ceiling, in order to assess criteria for installation conditions. A lower clearance can be chosen provided that it can be demonstrated that any permanent deformation of the lateral side of the test specimen is not interfered with or limited by the wall. The manufacturer may carry out an additional test with higher clearances to the lateral wall, in order to assess criteria for installation conditions.

A lower clearance can be chosen provided that it can be demonstrated that any permanent deformation of the rear side of the test specimen is not interfered with or limited by the wall.

This test arrangement is deemed valid for an installation mounted closer to the wall than the test arrangement, provided that two additional conditions are met refer to Clause A. If these conditions cannot be demonstrated, or the manufacturer requires direct qualification of a wall-mounted design, a specific test without clearance to the rear wall shall be carried out.

However, the validity of such a test shall not be extended to any other installation condition. When the test is carried out at any larger clearance to the rear wall, as stated by the manufacturer, this clearance shall be declared as a minimum admissible for the installation instructions. The instructions shall also include guidance on the obligation to adopt measures preventing persons to enter that area.

An additional test may be performed with lower clearances, to prove the capability of the switchgear and controlgear to operate correctly when reduced room is available for example, to justify the installation close to a wall, in a no rear-accessibility arrangement. The test shall be carried out with simulation of such exhausting ducts. The output end of the exhausting ducts shall be at least 2 m away from the switchgear and controlgear tested.

NOTE The possible effects of hot gases outside of the room containing the switchgear and controlgear are not covered by this standard.

Simulation of cable access ways shall be constructed, if necessary, as indicated above. From the point of view of internal arc, a metal-enclosed switchgear and controlgear passing the test for indoor application is considered to be valid for outdoor application with the same accessibility requirements. In cases where switchgear and controlgear for outdoor application are intended to be placed under a shelter for example, for protection against rain which is less than 1,5 m above the switchgear and controlgear, a corresponding ceiling should be considered.

Care shall be taken to see that the vertical indicators can not ignite each other. With the horizontal indicators, care shall be taken that glowing particles do not accumulate. This is achieved if the indicators are mounted without frame refer to Figure A. This means that the mounting frame on each side пїЅ if applicable пїЅ shall be mm longer than the unit under test in case of accessibility type B, or mm in case of accessibility type A, provided that the position of the wall in the arrangement of the room simulation does not limit this extension.

NOTE In all cases the distance from the indicators fitted vertically to the switchgear and controlgear is measured from the surface of the enclosure, disregarding protruding elements for example, handles, frame of apparatus and so on. If the surface of the switchgear and controlgear is not regular, the indicators should be placed to simulate as realistically as possible the position that a person usually may adopt in front of the equipment, at above indicated distance, according to type of accessibility.

Indicators shall also be arranged horizontally at a height of 2 m above the floor as described in Figures A. When the ceiling is placed at a height of 2 m above the floor refer to indent a of A. Indicators shall be fitted vertically at all accessible sides for the metal enclosed switchgear and controlgear up to 2 m above the floor. If the actual height of the specimen is lower than 1,9 m, vertical indicators shall be fitted up to a height mm higher than the test specimen.

Indicators shall also be arranged horizontally at a height above the floor, as described in Figure A. Where normal operation requires persons to stand or walk upon the equipment, horizontal indicators shall be placed above upper accessible surface, as described in Figure A.

NOTE Un niveau de courant plus faible peut influencer le comportement des dispositifs limiteurs de pression et la performance de perforation. Le courant doit rester en principe constant.

The short-circuit current applied during the test corresponds to the rated short-time withstand current. It may be lower, if specified by the manufacturer. A test performed at a given voltage, current and duration is generally valid for all lower values of current, voltage and duration. NOTE Lower current level may influence the behaviour of the pressure relief devices and the burn through performance.

For short-circuit current levels lower than tested, care should be taken in the interpretation of the results. If the capability of the test plant does not permit this, a lower voltage may be chosen provided the following conditions are met for the duration of the test: a the true r. If the applied voltage is equal to the 0 rated voltage, this tolerance applies to the prospective current. The current should remain constant. If the capability of the test plant does not permit this, the test shall be extended until the integral of the a.

NOTE For other, higher, d. Standard recommended values are 1 s, 0,5 s and 0,1 s. NOTE It is in general not possible to calculate the permissible arc duration for a current which differs from that used in the test. The maximum pressure during the test will generally not decrease with a shorter arcing time and there is no universal rule according to which the permissible arc duration may be increased with a lower test current.

The neutral point of the supply circuit may be either isolated or earthed through an impedance, in such a way that the maximum earth current is less than A. In this situation, the arrangement covers all situations of neutral treatment. NOTE 1 Internal arc faults with a directly grounded neutral are less severe. When the test is made on part of the switchgear and controlgear where phases are segregated, the supply circuit shall be single-phase, one of the terminals earthed.

The test current shall be equal to the three-phase value stated in A. Care shall be taken in order that the connections do not alter the test conditions. Feeding direction shall be as follows: пїЅ for a cable compartment: supply from the busbar, through the main switching device; пїЅ for a busbar compartment: the supply connections shall not introduce any opening in the compartment under test.

Supply shall be made through one barrier, if barriers are fitted to create separated busbar compartments between functional units, or through the main switching device located at one end of the switchgear and controlgear, if the busbar compartment is common for the whole switchgear and controlgear; NOTE 2 In case of non-symmetrical designs of busbar compartment, the most onerous internal arc initiation should be considered, with respect to arc energy and burn through.

The point of initiation shall be located at the furthest accessible point from the supply, within the compartment under test. Except for case b , solid insulation shall not be perforated. The supply circuit shall be three- phase to allow the fault to become three-phase if applicable. The third phase shall be provided with a plug-in connector as can be used in service, able to be energized. NOTE Experience shows that the fault generally does not evolve towards a three-phase fault; therefore, the choice of the fitting for the third phase is not critical.

In all these cases of phase-to-phase fault, the test current shall be the phase-to-phase fault current of the three-phase supply circuit defined according to A. In solidly earthed networks non-floating neutral , or in networks with earth-fault protection, the single phase-to-earth short-circuit current, which is generally lower than the possible two-phase fault current, will be switched off rapidly.

For switchgear and controlgear, only intended for this restricted use, it is acceptable to test accordingly, instead of the two-phase test described above. The arc will then be ignited as single-phase to ground, provided that the other phases are energized to allow the arc to become three-phase. As the specified internal arc withstand current, the tested single-phase value applies.

Criterion No. Deformations are accepted, provided that no part comes as far as the position of the indicators or the walls whichever is the closest in every side.

The switchgear and controlgear do not need to comply with its IP code after the test. Should they start to burn during the test, the assessment criterion may be regarded as having been met, if proof is established of the fact that the ignition was caused by glowing particles rather than hot gases.

Pictures taken by high-speed cameras, video or any other suitable means can be used by the test laboratory to establish evidence. Indicators ignited as a result of paint or stickers burning are also excluded. Visual inspection is generally sufficient to assess compliance. In case of doubt, the continuity of the earthing connection shall be checked refer to 6.

For pole-mounted metal-enclosed switchgear and controlgear, the pole characteristics with the method of fixing to the pole shall be given. This designation shall be included in the nameplate refer to 5. Experience shows that partial discharges may, in particular arrangements, lead to a progressive degradation in the dielectric strength of the insulation, especially of solid insulation, and fluid-filled compartments.

On the other hand, it is not yet possible to establish a reliable relationship between the results of partial discharge measurements and the life expectancy of the equipment owing to the complexity of the insulation systems used in metal-enclosed switchgear and controlgear.

Because of the design variations, a general specification for the test object cannot be given. In general, the test object should consist of assemblies or subassemblies with dielectric stresses which are identical to those which would occur in the complete assembly of the equipment.