Iec 62505-1-2009.Pdf

IEC 62505 1 Edition 1 0 2009 03 INTERNATIONAL STANDARD NORME INTERNATIONALE Railway applications – Fixed installations – Particular requirements for a c switchgear – Part 1 Single phase circuit breake[.]

General

A circuit-breaker in correct condition of maintenance and adjustment shall be able to withstand all stresses that occur in service provided that these do not exceed its rated characteristics

The characteristics of a circuit-breaker, including its operating devices and auxiliary equipment, that shall be used to determine the rating are the following:

Circuit-breakers are characterized by several rated specifications, including rated voltage, rated insulation level, and rated frequency Additionally, they have a rated normal current, rated short-time withstand current, and rated peak withstand current For circuit-breakers without direct over-current release, the rated duration of short circuit is also specified Furthermore, the rated supply voltage and supply frequency for closing and opening devices, as well as auxiliary circuits, are essential characteristics to consider.

This document is licensed to MECON Limited for internal use in Ranchi and Bangalore, as supplied by the Book Supply Bureau It includes critical specifications such as the rated pressures for compressed gas supply during operation and interruptions, the rated gas pressure for sealed gas pressure devices, the rated short-circuit breaking current, the rated transient recovery voltage for terminal faults, the rated short-circuit making current, and the rated operating sequence.

Rated voltage (U Ne)

The rated voltage U Ne shall be chosen taking into consideration the maximum voltage level suitable to be permanently applied to the circuit-breaker (i.e highest permanent voltage

U max1 as defined in IEC 60850)

This standard references the values U max1 and U max2 from IEC 60850, which are used to define the expected values of U Ne, required to be equal to or greater than U max1 Additionally, the insulation characteristics must be adequate to accommodate the highest non-permanent voltage, U max2, as specified in Clause 5 and Clause 7.

Nominal voltage (U n)

The nominal voltage U n shall be one of the voltages listed in Table 1 of IEC 60850.

Rated insulation voltage (U Nm) [4.2]

The rated insulation voltage (\$U_{Nm}\$), rated impulse withstand voltage (\$U_{Ni}\$), and power-frequency withstand voltage (\$U_{a}\$) values are specified in Table 1, based on the standards outlined in IEC 62497-1.

LICENSED TO MECON Limited - RANCHI/BANGALORE FOR INTERNAL USE AT THIS LOCATION ONLY, SUPPLIED BY BOOK SUPPLY BUREAU.

Table 1 – Nominal voltages ( U n ), rated impulse voltages ( U Ni ) and short-duration power-frequency (AC) test levels U a for circuits connected to the contact line

U a kV kV kV kV kV

The selection of various values of U Ni for the same U n is determined by the maximum non-permanent voltages, such as U max2 as specified in IEC 60850, that are present in the system.

NOTE 2 OV3 and OV4 are overvoltage categories depending on the system configuration and degree of overvoltage control (inherent control or protective control) as given in IEC 62497-1

In situations where circuit conditions may lead to a higher voltage being applied to device terminals during transient states, it is essential to ensure that a higher rated insulation voltage between contacts is utilized.

The rated voltage U Nm is 52 kV for a nominal voltage U n of 25 kV, as specified in Table 1a of IEC 62271-1, which provides the nearest equivalence in test withstand voltages for single-phase voltages Additionally, these values can be selected by the purchaser or agreed upon It is important to note that these values are specifically used in railway applications and are not commonly utilized in broader industrial contexts.

Rated frequency [4.3]

Subclause 4.3 of IEC 62271-1 is applicable.

Rated normal current and temperature rise [4.4]

Subclauses 4.4.1 and 4.4.2 of IEC 62271-1 are applicable with the following additions:

The values of rated currents shall be selected from the following standard values:

NOTE The above values are selected from the R 10 series, and, if required, higher values than those shown should also be selected from this series

When a circuit-breaker is equipped with a series-connected accessory, like a direct over-current release, the rated normal current of the accessory is defined as the root mean square (r.m.s.) value of the current.

MECON Limited is licensed for internal use in Ranchi and Bangalore, with supplies provided by the Book Supply Bureau The accessory must maintain its performance at the rated frequency without deterioration, ensuring that the temperature rise does not exceed the limits outlined in Table 3 of IEC 62271-1.

Current transformers shall comply with IEC 60044-1.

Rated short-time withstand current [4.5]

Subclause 4.5 of IEC 62271-1 is applicable with the following addition:

The rated short-time withstand current is equal to the rated short-circuit breaking current

Rated peak withstand current [4.6]

The rated peak withstand current is equal to the rated short-circuit making current (see 5.16).

Rated duration of short-circuit [4.7]

A circuit-breaker equipped with a direct over-current release does not require a rated duration for short-circuit if it can handle the prospective breaking current equal to its rated short-circuit breaking current It must be capable of carrying the resulting current for the necessary break-time, with the over-current release set to its maximum setting and time delay, while operating according to its rated sequence.

Rated supply voltage of closing and opening devices and auxiliary circuit [4.8]

Rated supply frequency of closing and opening devices and auxiliary circuits [4.9]

Rated pressures of compressed gas supply for operation and for interruption [4.10]

The value of the pressures to which the circuit-breaker is filled

Subclause 4.10 of IEC 62271–1 is applicable to the pressure of the compressed gas supply for operation

No standard values are given for rated pressure of compressed gas supply for interruption

The rated pressures of compressed gas shall be given by the manufacturer of the circuit- breaker.

Rated short-circuit breaking current (I Nss ) [4.101]

General [4.101]

The rated short-circuit breaking current (I Nss) represents the maximum short-circuit current that a circuit-breaker must be able to interrupt, according to the specified conditions and behavior outlined in this standard, within a circuit that has a power-frequency recovery voltage.

This document is licensed to MECON Limited for internal use in Ranchi and Bangalore, as supplied by the Book Supply Bureau It pertains to the rated voltage of the circuit-breaker, which must have a transient recovery voltage that matches the rated value specified in section 5.14.1.

Short-line fault interruption is not a requirement for circuit-breakers to this standard Such a requirement shall be deemed to be special and subject to agreement between purchaser and supplier

The rated short-circuit breaking current is characterized by two values:

– the r.m.s value of its a.c component, termed "rated short-circuit current" for shortness, and

NOTE 1 If the d.c component does not exceed 20 %, the rated short-circuit breaking current is characterized only by the r.m.s value of its a.c component

For determination of the a.c and d.c components, see Figure 8 of IEC 62271-100

The circuit-breaker must effectively interrupt any short-circuit current, including its rated a.c component and a specified percentage of d.c component, under the outlined conditions.

The following applies to a standard circuit-breaker: a) At voltages below the rated voltage, it will be capable of breaking its rated short-circuit breaking current

NOTE 2 For circuit-breakers having proved rated short-circuit breaking currents I Nss at two different rated voltages U Ne , intermediate characteristics may be assigned from the straight line drawn between the two proved rating points on a plot of log U versus log I In case of doubt, tests should be carried out to check the validity of the interpolation b) At voltages above the rated voltage, no short-circuit breaking current is guaranteed except to the extent provided for in 5.18.

AC component of the rated short-circuit breaking current [4.101.1]

The r.m.s value of the a.c component of the rated short-circuit breaking current shall be selected from the values shown in Table 6

NOTE The values in Table 6 are selected from the R 10 series, and, if required, higher values than those shown should also be selected from this series.

DC component of the rated short-circuit breaking current [4.101.2]

The percentage d.c component value is determined based on the type of circuit-breaker For circuit-breakers that can trip due to short-circuit current without auxiliary power, the percentage d.c component corresponds to the minimum opening time of the circuit-breaker In contrast, for circuit-breakers that require auxiliary power to trip, the percentage d.c component is based on the minimum opening time plus one-half cycle of the rated frequency.

The minimum opening time mentioned above is the shortest opening time of the circuit- breaker obtainable under any service conditions whether in a breaking operation or a make- break operating cycle

The percentage value of the d.c component is dependent on the time interval τ Standard values and special case values are given in Figure 9 of IEC 62271-100

Rated transient recovery voltage for terminal faults [4.102]

General

The rated transient recovery voltage (TRV) for terminal faults, as defined in section 5.13.1, serves as the reference voltage that establishes the maximum prospective transient recovery voltage for circuits This voltage indicates the level that the circuit-breaker must be able to handle when interrupting a short-circuit occurring at its terminals.

Representation of transient recovery voltage waves [4.102.1]

The wave form of transient recovery voltages varies according to the arrangement of actual circuits

NOTE 1 The transient recovery voltage approximates to a damped single frequency oscillation This wave form is adequately represented by an envelope consisting of two line segments defined by means of two parameters

Methods of drawing TRV envelopes are given in IEC 62271-100, Annex F

The local capacitance on the source side of the circuit-breaker affects the voltage rise rate during the initial microseconds of the Transient Recovery Voltage (TRV), necessitating the introduction of a time delay.

The entire TRV wave can impact a circuit-breaker's interrupting capability, with the initial phase of the TRV being particularly significant for certain circuit-breaker types.

NOTE 2 This part of TRV, called initial TRV (ITRV), is caused by the initial oscillations of small amplitude due to reflections from the first major discontinuity along the busbar The ITRV is a physical phenomenon which is very similar to the short-line fault Compared with the short-line fault, the first voltage peak is rather low, but the time to the first peak is extremely short, that is within the first microseconds after current zero Therefore the thermal mode of interruption may be influenced

NOTE 3 Since the ITRV is proportional to the busbar surge impedance and to current, the ITRV requirement can be neglected for metal-enclosed switchgear and in most railway applications, because of the low surge impedance and for all switchgear with a rated short-circuit breaking current of less than 50 kA

NOTE 4 If the circuit-breaker has a short-line fault rating the ITRV requirements are considered to be covered if the short-line fault tests are carried out using a line without time delay (see 7.10.5.2).

Representation of rated TRV [4.102.2]

The rated Transient Recovery Voltage (TRV) is represented using specific parameters: a) the four-parameter reference line is not applicable; b) the two-parameter reference line, as illustrated in Figure 11 of IEC 62271-100, includes the reference voltage (\$u_c\$) measured in kV and the time (\$t_3\$) required to reach \$u_c\$ in milliseconds; c) the delay line of TRV, also shown in Figure 11 of IEC 62271-100, consists of the time delay (\$t_d\$) in milliseconds, the reference voltage (\$u'\$) in kV, and the time (\$t'\$) to reach \$u'\$ in milliseconds.

The delay line initiates at the specified time delay on the time axis, running parallel to the initial segment of the reference line for rated TRV, and concludes at the voltage u' at the time-coordinate t'.

Standard values of rated TRV [4.102.3]

Standard values of rated TRV for single-phase circuit-breakers are given in Table 2

Where the purchaser has requirements for higher severities of TRV than those in Table 2, these shall be identified in purchaser's specification

Table 2 – Standard values of rated transient recovery voltage –

Representation by two parameters – Single pole circuit-breaker

U n U max1 a U max2 a U c t 3 t d u ’ t ’ U c / t 3 kV kV kV kV μ s μ s kV μ s kV/ μ s

NOTE 1 The values in Table 2 are minimum values The values of Table 1 of IEC 62271-100 may be adopted with

NOTE 2 The TRV figures are for a single-pole circuit-breaker The equivalent three-phase circuit-breaker is tested with u c and U c /t 3 values equal to 1,5 times those shown in Table 2 Values for the time delay t d are to be in accordance with Table 1a of IEC 62271-100.

Standard values of initial transient recovery voltage [4.102.4]

Subclause 4.102.4 of IEC 62271-100 is not applicable to single-phase circuit-breakers for railway applications.

Rated short-circuit making current [4.103]

The rated short-circuit making current of a circuit-breaker, as specified in Figure 8 of IEC 62271-100, is defined at the rated voltage and is equal to 2.5 times the root mean square (r.m.s.) value of the alternating current (a.c.) component of its rated short-circuit breaking current.

Rated operating sequence [4.104]

There are two alternative rated operating sequences as follows:

Unless otherwise specified: t = 180 s for circuit-breakers not intended for rapid auto-reclosing;

NOTE 1 Instead of t ' = 180 s, t ' = 60 s is also used for circuit-breakers not intended for rapid auto-reclosing t = 0,3 s for circuit-breakers intended for rapid auto-reclosing (dead time); t' = 180 s

NOTE 2 Instead of t ' = 180 s, other values: t ' = 15 s (for rated voltages less than or equal to 52 kV) and t ' = 60 s are also used for circuit-breakers intended for rapid auto-reclosing

CO - t" - CO with: t" = 15 s, for circuit-breakers non intended for rapid auto-reclosing; where:

CO represents a closing operation followed immediately (that is, without any intentional time-delay) by an opening operation; t, t' and t" are time-intervals between successive operations

NOTE 3 t, t' and t" should always be expressed in s

If the dead time is adjustable, the limits of adjustment shall be specified.

Rated out-of-phase breaking current [4.106]

A single-pole circuit-breaker may be utilized in an open position with two different phases across its terminals if requested by the purchaser, particularly for providing an alternative feed during emergencies The test for this configuration will be conducted at a rating determined by the purchaser, based on the maximum fault current expected It is important to note that the out-of-phase breaking current must not exceed 50% of the rated short-circuit current, with phase displacements limited to a maximum of 120° or 180° The purchaser is responsible for specifying whether out-of-phase breaking current is applicable and under which conditions.

NOTE The 120° case occurs when voltage is derived from two different phases of a three-phase system The

180° case typically occurs when the neutral is the central point of a single-phase system (currently indicated as ±

The transient recovery voltage shall be as given in Tables 3 and 4

Table 3–Standard values of prospective transient recovery voltage for 120° out-of- phase breaking–Representation by two parameters – Single pole circuit-breaker

U n U max1 a U max2 a U c t 3 U c / t 3 kV kV kV kV μ s kV/μs

1,25 = corrected amplitude factor (see IEC 62271-100);

3 factor of maximum phase-displacement;

Table 4 – Standard values of prospective transient recovery voltage for 180° out-of- phase breaking – Representation by two parameters – Single pole circuit-breaker

TRV peak value Time Rate of rise

U n U max1 a U max2 U c t 3 U c / t 3 kV kV kV kV μ s kV/ μ s

1,25 = corrected amplitude factor (see IEC 62271-100);

Where the purchaser has requirements for higher severities of TRV than those given in

Tables 3 and 4, these shall be identified in the purchaser's specification.

Rated line-charging breaking current [4.107.1]

The circuit-breaker must be able to interrupt the capacitive current of the feeder cable or catenary, as specified by the purchaser, at a voltage of no less than U max1.

(see IEC 60850), and with a current not exceeding 10 A.

Rated cable-charging breaking current [4.107.2]

The rated cable-charging breaking current is the highest current that a circuit-breaker can interrupt at its rated voltage, adhering to the usage conditions outlined in this Standard It must also not surpass the maximum permissible switching overvoltages set by the manufacturer Recommended values can be found in Table 5.

The specification of rated cable-charging breaking current for circuit-breakers is optional and typically deemed unnecessary for those with rated voltages of 24 kV or lower However, if specified, it is advisable to set the rated cable-charging breaking current at 50 A for 15 kV systems and 80 A for 25 kV systems.

Rated single capacitor bank breaking current [4.107.3]

The rated breaking current of a single capacitor bank is the highest capacitor current that a circuit-breaker must be able to interrupt at its rated voltage, adhering to the specified conditions and behaviors outlined in this standard This must be achieved without surpassing the maximum allowable switching overvoltages set by the manufacturer Recommended values can be found in Table 5, column B.

NOTE 1 This breaking current refers to the switching of a shunt capacitor bank where no shunt capacitors are connected to the source side of the circuit-breaker

The specification of a rated single capacitor bank breaking current is not mandatory

NOTE 2 Values of rated single capacitor bank breaking current should be selected from the R 10 series and with a current not exceeding 200 A unless otherwise agreed between purchaser and supplier.

Rated back-to-back capacitor bank breaking current [4.107.4]

The rated back-to-back capacitor bank breaking current represents the highest capacitor current that a circuit-breaker must be able to interrupt at its rated voltage, adhering to the specified usage conditions and behaviors outlined in this standard This must be achieved without surpassing the maximum allowable switching overvoltages set by the manufacturer Recommended values can be found in Table 5, column B.

The specification of a rated back-to-back capacitor bank breaking current is not mandatory

This breaking current pertains to the switching of a shunt capacitor bank, where one or more shunt capacitor banks are connected to the source side of the circuit-breaker, resulting in an inrush making current that matches the rated inrush making current of the capacitor bank.

NOTE 2 Values of rated back-to-back capacitor bank breaking currents should be selected from the R 10 series and with a current not exceeding 200 A unless otherwise agreed between purchaser and supplier

NOTE 3 Similar conditions could apply for the switching of cables

Rated capacitor bank inrush making current [4.107.5]

The inrush making current of a rated capacitor bank refers to the maximum current peak that a circuit-breaker must handle at its rated voltage, considering the frequency of the inrush current relevant to the specific service conditions.

The specification of a rated capacitor bank inrush making current is mandatory for circuit- breakers that have a rated back-to-back capacitor bank breaking current

Table 5 – Suggested values of maximum permissible switching overvoltage to earth

A B kV kV kV kV kV a p.u b kV a p.u b

NOTE 1 Values of rated capacitor bank inrush making currents should be selected from the R 10 series and with a rated current not exceeding 200 A unless otherwise agreed between purchaser and supplier

NOTE 2 In service, the frequency of the inrush current is normally in the range 2 kHz - 5 kHz

NOTE 3 The circuit-breaker is considered to be suitable for any frequency of the inrush current lower than that for which it has been tested

The values presented in Table 5 are specific to the test conditions of 7.15 and do not account for other overvoltages, such as those that occur when reclosing a line with trapped charges, breaking a small inductive current, or phase-to-phase overvoltages.

NOTE 5 The values shown in Table 5 cannot always guarantee that phase-to-phase flashovers will not occur

The values in column A of Table 5 pertain to circuit-breakers designed for general use, specifically for switching unloaded lines and cables commonly utilized in power systems.

The values in column B of Table 5 pertain to circuit-breakers designed for specific applications, particularly for switching capacitor banks or no-load lines and cables in supply systems These circuit-breakers address unique insulation coordination challenges, including the limitations on energy absorption by surge diverters and the spark-over of spark-gaps.

Rated time quantities [4.109]

General

Rated values may be assigned to the following time quantities:

Rated time quantities are based on:

– rated values for supply voltages of closing and opening devices and auxiliary circuits

– rated value for supply frequency of closing and opening devices and auxiliary circuits (see

– rated values for pressures of compressed gas supply for operation and for interruption

– rated value for pressure of hydraulic supply for operation;

– an ambient air temperature of 20 °C ± 5 °C If tests are carried out at other ambient temperatures, agreement between manufacturer and user may be necessary for the interpretation of the results

NOTE Usually it is not practical to assign a rated value of make time or of make-break time due to the variation of the pre-arcing time.

Rated break time [4.109.1]

The maximum break time during test duties T30, T60, and T100s, as specified in sections 7.12.2, 7.12.3, and 7.12.4, must not exceed the rated break time This testing is conducted with the circuit-breaker operating at the rated auxiliary supply voltage, frequency, and pneumatic or hydraulic supply pressures, all at an ambient air temperature of 20 °C ± 5 °C.

NOTE 1 According to 7.8.3 the basic short-circuit test-duties should be carried out at minimum voltage or pressure of the operating devices In order to verify the rated break time during these test-duties the recorded maximum break time should be amended to take account of the lower auxiliary supply voltage and pressure as follows:

The rated break time (\$t_b\$) must be greater than or equal to the maximum recorded break time (\$t_1\$) during test duties T30, T60, and T100s Additionally, \$t_2\$ represents the opening time recorded under no-load conditions with the auxiliary supply voltage and compressed gas supply pressures used in these test duties, while \$t_3\$ denotes the rated opening time.

If the calculated break time exceeds the specified rated break time, the test-duty with the longest break time may be repeated using the rated values for auxiliary supply voltage, frequency, and pneumatic or hydraulic pressure, as well as the rated pressure of the interrupting medium, if applicable.

NOTE 2 The break time during a make-break operation of test-duty T100s should not exceed the rated break time by more than 0,5 cycle.

Co-ordination of rated values

Co-ordinated values of rated voltages (5.2), short-circuit breaking currents (5.13) and rated normal currents (5.6) are given in Table 6, which is to be used as a guide for preferred values

Table 6 – Co-ordination table of rated values for circuit-breakers

Rated short circuit breaking current

The values in brackets represent the rated voltages as per Table 1a of IEC 62271-1, corresponding to the nearest test withstand voltages for single-phase equipment Additionally, these values are specifically utilized in railway applications and are not commonly used in broader industrial contexts.

Requirements for liquids in circuit-breakers [5.1]

Requirements for gases in circuit-breakers [5.2]

Earthing of circuit-breakers [5.3]

Subclause 5.3 of IEC 62271-1 is applicable

Auxiliary equipment [5.4]

Auxiliary equipment is used in the control and auxiliary circuits of circuits-breakers

Subclause 5.4 of IEC 62271-1 is applicable with the following additions:

– Connections shall withstand the stresses imposed by the circuit-breaker, especially those due to mechanical forces during operations

– In the case of outdoor circuit-breakers all auxiliary equipment including the wiring shall be adequately protected against dust, rain and humidity

– Where auxiliary switches are used as position indicators, they shall indicate the end position of the circuit-breaker at rest, open or closed

Special control equipment must function within the specified limits for supply voltages of auxiliary and control circuits, as well as quenching and operating media Additionally, it should be capable of switching the loads indicated by the circuit-breaker manufacturer.

Auxiliary equipment, including liquid indicators, pressure indicators, relief valves, and filling and draining equipment, must function within the specified voltage limits for auxiliary and control circuits, as well as within the acceptable parameters for quenching and operating media.

– The power consumption of heaters at rated voltage shall be within the tolerance of ± 10 % of the values stated by the manufacturer.

Dependent power closing [5.5]

A circuit-breaker arranged for dependent power closing with external energy supply shall also be capable of opening immediately following the closing operation with the rated short-circuit making current.

Stored energy closing [5.6]

Subclause 5.6 of IEC 62271-1 is applicable with the following addition to the first paragraph:

A circuit-breaker arranged for stored energy closing shall also be capable of opening immediately following the closing operation with the short-circuit making current.

Operation of releases [5.8]

General

Over-current release [5.8.101]

An over-current release shall be marked with its rated normal current and its current setting range

Within the current setting range, the over-current release shall always operate at currents of

110 % and above of the current setting, and shall never operate at currents of 90 % and below of this current setting

The operating time for an inverse time delay over-current release is measured from the moment the over-current occurs until the release triggers the circuit-breaker's tripping mechanism.

The manufacturer shall provide tables or curves, each with the applicable tolerances, showing the operating time as a function of current, between twice and six times the operating current

These tables or curves shall be provided for the extreme current settings together with the extreme settings of time delay

If the current in the main circuit drops below a specified threshold before the over-current release's time delay elapses, the release will not finalize its operation and will reset to its original position.

The relevant information shall be given by the manufacturer.

Multiple releases [5.8.102]

If a circuit-breaker is fitted with multiple releases for the same function, a defect in one release shall not disturb the function in the others.

Low and high pressure interlocking devices [5.9]

All circuit-breakers having an energy storage in gas receivers or hydraulic accumulators

According to section 5.6.1 of IEC 62271-1, all circuit-breakers, excluding sealed pressure devices that utilize compressed gas for interruption, must be equipped with a low pressure interlocking device Additionally, high pressure interlocking devices may also be installed, configured to function within the pressure limits specified by the manufacturer.

Nameplates [5.10]

The nameplates of a circuit-breaker and its operating devices shall be marked in accordance with Table 10 of IEC 62271-100

Coils of operating devices shall have a reference mark permitting the complete data to be obtained from the manufacturer

Releases shall bear the appropriate data

In addition, it is desirable that the year of manufacture of the circuit-breaker is recognizable

The nameplate shall be visible in the position of normal service and installation.

Requirements for simultaneity of poles [5.101]

Subclause 5.101 of IEC 62271-100 is not applicable to single-phase circuit-breakers for railway applications.

General requirement for operation [5.102]

A circuit-breaker including its operating devices shall be capable of completing its rated operating sequence (5.17) in accordance with the relevant provisions of 6.5 to 6.8 and 6.12

This requirement is not applicable to auxiliary manual operating devices; where provided, these shall be used only for maintenance and for emergency operation on a dead circuit.

Pressure limits of compressed gas for interruption in gas blast circuit-

The manufacturer must specify the maximum and minimum pressures for compressed gas interruption that the circuit-breaker can handle according to its ratings, as well as the settings for the corresponding low and high-pressure interlocking devices.

Double-pressure gas-blast circuit-breakers have specified pressure limits for various performance capabilities These include: a) the ability to break their rated short-circuit breaking current during an "O" operation; b) the capacity to make their rated short-circuit making current followed by breaking their rated short-circuit breaking current in a "CO" operating cycle; and c) for circuit-breakers designed for rapid auto-reclosing, the ability to break their rated short-circuit breaking current, followed by a time interval $ t $ of the rated operating sequence, and then make their rated short-circuit making current, immediately followed by breaking their rated short-circuit breaking current in an "O - t - CO" operating sequence.

The circuit-breakers shall be provided with energy storage of sufficient capacity for satisfactory performance of the appropriate operations at the corresponding minimum pressures stated

For circuit-breakers equipped with individual pumps or compressors, it is essential that the output of these components, along with the capacity of the receivers, is adequate to support the rated operating sequence at all currents up to the circuit-breaker's rated short-circuit making and breaking currents The initial pressure at the start of the operating sequence must meet the minimum pressure specified by the manufacturer, ensuring the pump or compressor is functioning normally Additionally, manufacturers may define specific pressure limits for the operation of the pump or compressor as needed.

Vent outlet [5.104]

Circuit-breaker vent outlets must be positioned to prevent oil or gas discharges from causing electrical breakdowns and should direct any emissions away from areas where people may be present.

The construction must ensure that gas does not accumulate in areas where ignition could occur due to sparks generated during the normal operation of the circuit breaker or its auxiliary equipment.

Safety overpressure device

When specified by the purchaser, the circuit-breaker shall be equipped with a device allowing the release of accidental overpressures without breakages in the enclosure

General

Clause 6 of IEC 62271-1 is applicable with the following additions:

The type tests also include:

Mechanical and environmental tests are essential for ensuring reliable operation under various conditions These tests include evaluating mechanical performance at ambient air temperature, as well as conducting low and high temperature assessments Additionally, humidity tests are performed, along with tests to verify functionality in severe ice conditions and static terminal load tests.

– short-circuit making and breaking tests and out-of-phase tests, if applicable (see 7.8 to

– capacitive current switching tests, including line-charging, cable-charging, single capacitor bank and back-to-back capacitor bank tests (see 7.15);

– magnetizing and small inductive current switching tests (see 7.16)

This document addresses circuit-breakers with a maximum voltage of 72.5 kV, primarily focusing on single-pole circuit-breakers that operate at one phase voltage Some circuit-breakers may experience line voltage across their open terminals Two-pole circuit-breakers are typically used in series on a single-phase circuit or across phases that are 180° apart, as well as on different phases within a three-phase system However, in these configurations, the two poles rarely need to operate simultaneously when making or breaking the circuit.

Type tests for circuit-breakers should be conducted on units that are new and in pristine condition, with the possibility of performing different tests at various times and locations.

When conducting tests on a circuit-breaker with an accepted type test report, the manufacturer's responsibility is confined to the specified values rather than the outcomes of prior type tests.

Details relating to records and reports of type tests for making, breaking and short time current performance are given in Annex C of IEC 62271-100.

Dielectric tests [6.2]

Ambient air conditions during tests [6.2.1]

Subclause 6.2.1 of IEC 62271-1 is applicable.

Wet test procedure [6.2.2]

Subclause 6.2.2 of IEC 62271-1 is applicable with the following addition:

NOTE For dead tank circuit-breakers, see Note of 7.2.7.

Condition of circuit-breaker during dielectric tests [6.2.3]

Application of test voltage and test conditions [6.2.5]

Test voltages [6.2.6]

Lightning and switching impulse voltage tests [6.2.7.2, 6.2.7.3]

Subclauses 6.2.7.2 and 6.2.7.3 of IEC 62271-1 are applicable with the following addition

When the rated lightning impulse withstand voltages are chosen according to 5.4, a higher test voltage when testing the insulation across the open breaker may be required

– the test voltage shall be subject to agreement between manufacturer and user

Requirements of IEC 62497-1 in respect to isolating voltages shall be taken into consideration;

The initial test series involves applying 15 consecutive impulses at the specified peak voltage level to each terminal, with the opposite terminal grounded Any additional terminals, including the one receiving the voltage and the base, should be insulated to prevent disruptive discharges to the ground.

The second test series involves applying 15 consecutive impulses at the rated withstand voltage $ U_{Ni} $ to each terminal individually, while ensuring that the other terminals and the base are grounded.

Power-frequency voltage tests [6.2.7.1]

Subclause 6.2.7.1 of IEC 62271-1 is applicable with the following addition:

The test voltage values shall be in accordance with Table 1 and IEC 62497-1

In the event of a disruptive discharge on external self-restoring insulation during a wet test, the test must be repeated under the same conditions The circuit-breaker will be deemed to have passed the test successfully if no additional disruptive discharges occur.

For dead tank circuit-breakers, if the bushings have already been tested in accordance with the relevant EN/HD or IEC Standard, it is permissible to skip tests under wet conditions.

Artificial pollution tests [6.2.8]

NOTE 1 Appropriate tests for checking the open breaker insulation are under consideration

NOTE 2 To obviate the necessity of erecting large circuit-breakers for test purposes alone, in the case of circuit- breakers of modular construction one single module may be tested In this case, however, the test severity is different from that of the test of the complete pole.

Partial discharge tests [6.2.9]

No partial discharge tests are required to be performed on the complete circuit-breaker

However, in the case of circuit-breakers using components for which a relevant IEC or EN

Manufacturers must provide evidence that their components, such as bushings, have successfully passed partial discharge tests in accordance with the relevant EN or IEC standards, including IEC 60137.

Tests on auxiliary and control circuits [6.2.10]

Radio interference voltage (r.i.v.) tests [6.3]

Radio interference voltage tests shall be performed by agreement between manufacturer and purchaser

Tests shall be performed on one pole of the circuit-breaker in both closed and open position

Temperature-rise tests [6.5]

Conditions of the circuit-breaker to be tested [6.5.1]

Arrangement of the equipment [6.5.2]

Subclause 6.5.2 of IEC 62271-1 is applicable with the following additions:

For a circuit-breaker not fitted with series connected accessories, the test shall be made with the rated normal current of the circuit-breaker

For circuit-breakers equipped with series-connected accessories that have a specified range of rated normal currents, two key tests are required: first, a test of the circuit-breaker with an accessory that matches its rated normal current, conducted at the circuit-breaker's rated normal current; second, a series of tests involving the circuit-breaker and its intended accessories, performed with currents that correspond to the rated normal current of each accessory.

If the accessories of the circuit-breaker can be detached and it is clear that the temperature rise of both the circuit-breaker and the accessories do not significantly affect one another, then Test b) can be substituted with a series of tests conducted solely on the accessories.

Measurement of the temperature and the temperature rise [6.5.3]

Ambient air temperature [6.5.4]

Temperature-rise tests of the auxiliary equipment [6.5.5]

Interpretation of the temperature-rise tests [6.5.6]

Measurement of the resistance of the main circuit [6.4.1]

Short-time withstand current and peak withstand current tests [6.6]

Arrangement of the circuit-breaker and of the test circuit [6.6.1]

When testing a circuit-breaker equipped with direct over-current releases, ensure that the minimum operating current coil is set to activate at the maximum current and maximum time delay, with the coil connected to the source side of the test circuit Additionally, if the circuit-breaker can function without direct over-current releases, it should also be tested in that configuration.

Test current and duration [6.6.2]

Circuit-breakers equipped with direct over-current releases should only undergo the rated operating sequence for opening operations When conducting the test at the rated voltage, it is essential to utilize the prospective current value.

Behaviour of circuit-breaker during test [6.6.3]

Conditions of circuit-breaker after test [6.6.4]

The condition of circuit-breakers fitted with direct over-current releases shall comply with

Mechanical and environmental tests [6.101]

Miscellaneous provisions for mechanical and environmental tests [6.101.1]

When testing a complete circuit-breaker is not practicable, component tests may be accepted as type tests The manufacturer should determine the components which are suitable for testing

Components are separate functional sub-assemblies which can be operated independently of the complete circuit-breaker (e.g breaking unit, operating mechanism)

Manufacturers must demonstrate that the mechanical stress experienced by a component during testing is at least equal to the stress applied to the same component when the entire circuit-breaker undergoes testing.

Component testing must encompass all types of circuit-breaker components, ensuring that each test is relevant to the specific component The testing conditions should be based on the standard or unique service conditions and the rated characteristics of the circuit-breaker.

Auxiliary and control equipment components must be manufactured in accordance with relevant standards to ensure compliance It is essential to verify that these components function correctly in conjunction with other parts of the circuit-breaker.

7.7.1.2 Characteristics and settings of the circuit-breaker to be recorded before and after the tests [6.101.1.3]

Before and after testing, it is essential to document or assess the following operational characteristics: a) closing time, b) opening time, c) time spread between units of a single pole, d) recharging time of the operating device, and e) control circuit consumption.

The licensed content for internal use at MECON Limited in Ranchi and Bangalore includes critical specifications such as the consumption of the tripping device, the recording of release currents, and the duration of opening and closing command impulses Additionally, it addresses the importance of tightness, gas densities or pressures, resistance of the main circuit, and other essential characteristics or settings as outlined by the manufacturer.

And, if the design of the circuit-breaker permits, such measurements as: m) time-travel chart; n) closing speed; o) opening speed

The above operating characteristics shall be recorded at:

– rated supply voltage and rated operating pressure;

– maximum supply voltage and maximum operating pressure;

– minimum supply voltage and minimum operating pressure;

– minimum supply voltage and maximum operating pressure

7.7.1.3 Condition of the circuit-breaker during and after the tests [6.101.1.4]

The circuit-breaker must remain in a condition that allows it to operate normally during and after tests, capable of carrying its rated normal current, making and breaking its rated short-circuit current, and withstanding voltage values in accordance with its rated insulation level.

In general, these requirements are deemed to be fulfilled if:

– during the tests, the circuit-breaker operates on command and does not operate without command;

– during and after the tests, the characteristics measured according to 7.7.1.2 are within the tolerances given by the manufacturer;

– during and after the tests, all parts, including contacts, do not show undue wear;

After testing, if a layer of coating material remains on the contact area, the contacts are considered coated If no coating is present, the contacts are deemed bare, and the test requirements are met only if the temperature rise during the temperature-rise test (as per section 7.4) does not exceed the allowable limit for bare contacts.

During and after testing, any distortion of mechanical components should not negatively impact the circuit-breaker's functionality or hinder the proper installation of replacement parts.

After testing, the insulating properties of the circuit-breaker in the open position should remain essentially unchanged A visual inspection is typically adequate to verify these properties If there is any uncertainty, the condition checking test outlined in section 6.2.11 of IEC 62271-1 is considered sufficient to confirm the insulating properties For circuit-breakers equipped with sealed-for-life interrupters, conducting the condition check is mandatory.

7.7.1.4 Condition of auxiliary and control equipment during and after the tests

During and after the tests, the following conditions for the auxiliary and control equipment shall be fulfilled:

– during the tests, care should be taken to prevent undue heating;

– during the tests, a set of contacts (both make and break auxiliary contacts) shall be arranged to switch the current of the circuits to be controlled (see 6.4);

– during and after the tests, the auxiliary and control equipment shall fulfil its functions;

During and after testing, the functionality of the auxiliary circuits and control equipment must remain intact If there is any uncertainty, appropriate testing procedures should be followed to ensure reliability.

6.2.10 of IEC 62271-1 shall be performed;

During and after testing, the contact resistance of the auxiliary switches must remain unaffected Additionally, the temperature rise while carrying the rated current should not exceed the specified limits outlined in Table 3 of IEC 62271-1.

Mechanical operation test at ambient air temperature [6.101.2]

The mechanical operation test must be conducted at the ambient air temperature of the testing location, which should be documented in the test report Additionally, any auxiliary equipment that is part of the operating devices must be included in the assessment.

The mechanical operation test consists of 5 000 operating cycles

Except for circuit-breakers fitted with over-current releases, the test shall be made without voltage on or current in the main circuit

For circuit-breakers fitted with over-current releases, approximately 10 % of the operating cycles shall be performed with the opening device energized by the current in the main circuit

The minimum current required to activate the over-current release must be established For these tests, a suitable low-voltage source can provide the current needed for the over-current releases.

During the test, lubrication is allowed in accordance with the manufacturer's instructions, but no mechanical adjustment or other kind of maintenance is allowed

The tested circuit-breaker shall be considered successfully tested if it retains its electrical and mechanical characteristics after the test

7.7.2.2 Condition of the circuit-breaker before the test [6.101.2.2]

The circuit-breaker for the test must be installed on a dedicated support, and its operating mechanism should function as specified Testing will be conducted based on the circuit-breaker's type.

A two-pole circuit-breaker actuated by a single operating device and/or with all poles mounted on a common frame shall be tested as a complete unit

A two-pole circuit-breaker in which each pole is actuated by a separate operating device may be tested regarding each pole as a separate circuit-breaker in respect of:

– power and strength of closing and opening mechanism;

The circuit-breaker shall be tested in accordance with Table 7

Table 7 – Mechanical operation test at ambient temperature

Number of operating sequences for circuit-breakers Operating sequence Control voltage and operating pressure autoreclosing non-autoreclosing minimum 1 250 1 250 rated 1 250 1 250

A closing operation (CO) is immediately followed by an opening operation without intentional delay The time interval, denoted as \$t_a\$, between these operations is essential for restoring initial conditions and preventing overheating of circuit-breaker components This interval can vary based on the type of operation, with \$t = 0.3\text{ s}\$ specified for circuit-breakers designed for rapid auto-reclosing unless stated otherwise.

Low and high temperature tests [6.101.3]

Low and high temperature tests are conducted based on mutual agreement between the manufacturer and purchaser, and these tests do not need to be performed consecutively, allowing for flexibility in their order Notably, for class –5 °C indoor circuit-breakers, a low temperature test is not necessary.

For single-pole or two-pole circuit-breakers with independent poles, testing of one complete pole shall be made

Due to the constraints of testing facilities, multi-enclosure type circuit-breakers can be evaluated using alternatives such as reduced phase-to-earth insulation length, decreased pole spacing, or fewer modules, ensuring that the testing conditions do not favor mechanical operation beyond normal conditions.

If heat sources are required they shall be in operation

Liquid or gas supplies for circuit-breaker operation are to be at the test air temperature unless the circuit-breaker design requires a heat source for these supplies

No maintenance, replacement of parts, lubrication or readjustment of the circuit-breaker is permissible during the tests

NOTE In order to determine the material temperature characteristics, ageing, etc., tests of longer duration than those specified in the following clauses may be necessary

A manufacturer can demonstrate compliance with performance requirements for a specific circuit-breaker family by documenting successful field experience in at least one location where ambient air temperatures regularly meet or exceed the specified maximum limits.

40 °C, and at least one location with satisfactory field experience in specified minimum ambient air temperature of –25 °C or –40 °C depending on the class of the circuit-breaker

7.7.3.2 Measurement of ambient air temperature [6.101.3.2]

The ambient air temperature of the test environment shall be measured at half the height of the circuit-breaker and at a distance of 1 m from the circuit-breaker

The maximum temperature deviation over the height of the circuit-breaker shall not exceed

The diagram of the test sequences and identification of the application points of the tests specified are given in Figure 17a of IEC 62271-100

After completing the high temperature test, the low temperature test can be conducted without performing items a) and b) Specifically, item a) involves adjusting the test circuit-breaker per the manufacturer's instructions, while item b) requires recording the characteristics and settings of the circuit-breaker.

7.7.1.2 and at an ambient air temperature of (20 ± 5) °C (T A ) The tightness test (if applicable) shall be performed according to 6.8 of IEC 62271-1 c) With the circuit-breaker in the closed position, the air temperature shall be decreased to the appropriate minimum ambient air temperature (T L ), according to the class of the circuit-breaker Values of T L may be –25 °C, or –40 °C, as appropriate The circuit- breaker shall be kept in the closed position for 24 h after the ambient air temperature stabilizes at T L d) During the 24 h period with the circuit-breaker in the closed position at temperature T L , a tightness test shall be performed (if applicable) An increased leakage rate is acceptable, provided that it returns to the original value when the circuit-breaker is restored to the ambient air temperature T A and is thermally stable The increased temporary leakage rate shall not exceed three times the specified permissible value F p (see 6.8 of IEC 62271-1) e) After 24 h at temperature T L , the circuit-breaker shall be opened and closed at rated values of supply voltage and operating pressure The opening time and closing time shall be recorded to establish low temperature operating characteristics Contact velocity should be recorded if feasible f) The low temperature behaviour of the circuit-breaker and its alarms and lock-out systems shall be verified by disconnecting the supply of heating devices for a duration t X During this interval, occurrence of the alarm is acceptable but lock-out is not At the end of the interval t X , an opening order, at rated values of supply voltage and operating pressure, shall be given The circuit-breaker shall then open The opening time shall be recorded

The manufacturer must specify the maximum time, denoted as $ t_X $, during which the circuit-breaker remains operable without auxiliary power for the heaters; if not stated, this time defaults to 2 hours Additionally, the circuit-breaker should remain in the open position for 24 hours During this period, a tightness test must be conducted at temperature $ T_L $, allowing for an increased leakage rate as long as it returns to the original value once the circuit-breaker is restored.

The circuit-breaker, licensed to MECON Limited for internal use, must maintain a thermally stable ambient air temperature (T A) and ensure that the increased temporary leakage rate does not exceed three times the permissible value (F P) as specified in IEC 62271-1 After 24 hours, 50 closing and 50 opening operations should be conducted at rated supply voltage and operating pressure, with a minimum 3-minute interval between each cycle The initial closing and opening operations must be recorded to establish low temperature operating characteristics, including contact velocity if possible Following these operations, three CO cycles should be performed without intentional delays, followed by sequences of C - t a - O - t a Once the 50 operations are completed, the ambient air temperature (T A) should be increased at a rate of approximately 10 K per hour, during which the circuit-breaker will undergo alternate operating sequences at rated values every 30 minutes After thermal stabilization at T A, a recheck of the circuit-breaker's settings, operating characteristics, and tightness is required for comparison with the initial characteristics.

During the complete low temperature test sequence, the total leakage from item b) to item k) must not cause the lock-out pressure to be reached without gas replacement, although reaching the alarm pressure is permissible.

The diagram of the test sequence and identification of the application points for the tests specified are given in Figure 17b of IEC 62271-100

If the high temperature test follows the low temperature test, it can commence after completing item k) of section 7.7.3.3, omitting items a) and b) Specifically, the circuit-breaker does not need adjustment per the manufacturer's instructions, nor is it necessary to record its characteristics and settings.

7.7.1.2 and at an ambient air temperature of (20 ± 5) °C (T A ) The tightness test (if applicable) shall be performed according to 6.8 of IEC 62271-1 c) With the circuit-breaker closed, the air temperature shall be increased to 40 °C, and the circuit-breaker kept in the closed position for 24 h after the ambient air temperature stabilizes at 40 °C

To accurately assess the impact of solar radiation, it is essential to replicate the natural conditions of radiation, including its intensity and direction, as outlined in IEC 60068-2-5 It is important to note that merely raising the ambient temperature of the test room does not effectively simulate the effects of solar radiation Additionally, the circuit-breaker should remain in the closed position for a continuous 24-hour period at the specified temperature.

At 40 °C, a tightness test should be conducted if applicable An increased leakage rate is permissible as long as it returns to the original value when the circuit-breaker is restored to the ambient air temperature $ T_A $ and is thermally stable However, the temporary leakage rate must not exceed three times the specified permissible value $ F_p $.

According to section 6.8 of IEC 62271-1, after being subjected to a temperature of 40 °C for 24 hours, the circuit-breaker must be opened and closed at its rated supply voltage and operating pressure It is essential to record the opening and closing times to determine the high-temperature operating characteristics, and if possible, the contact velocity should also be noted Additionally, the breaker should remain open for another 24 hours at the same temperature.

This document is licensed to MECON Limited for internal use at the Ranchi and Bangalore locations, as supplied by the Book Supply Bureau It is important to note that during the 24-hour period, the circuit-breaker must remain in the open position at the specified temperature.

At 40 °C, a tightness test should be conducted if applicable An increased leakage rate is permissible as long as it returns to the original value when the circuit-breaker is restored to the ambient air temperature $ T_A $ and is thermally stable However, the temporary leakage rate must not exceed three times the specified permissible value $ F_p $.

Humidity test [6.101.4]

The humidity test shall be performed by agreement between manufacturer and purchaser and is limited to circuit-breaker components which may be affected by humidity

The test procedure described in 7.7.4.2 is applicable to components with a thermal time constant of about 10 min

NOTE The test for components having higher thermal time constant is under consideration

The circuit-breaker components shall be arranged in a test chamber containing circulating air and in which the temperature and humidity conditions are as follows:

– the temperature of the room undergoes cyclic variations from (25 ± 3) °C to (40 ± 2) °C according to Figure 18 of IEC 62271-100;

– the relative humidity within the room is constantly above 95 % while the temperature is raised and during the period when the temperature is held at 40 °C

NOTE 1 In order to obtain these conditions, steam should be injected directly into the room or heated water should be atomized; the rise from 25 °C to 40 °C may be obtained with the provision of heat coming from the steam or atomized water or, if necessary, by additional heaters

No value of relative humidity is specified during the drop in temperature, however, the humidity shall be above 80 % during the period when the temperature is maintained at 25 °C

The air shall be circulated in order to obtain uniform distribution of the humidity in the room

The water used for humidity must have a resistivity of at least 100 Ωm and should be free from salt (NaCl) and corrosive elements.

NOTE 2 If the facilities of the test chamber permit, the times t 1 and t 3 may be reduced, but then the times t 2 and t 4 should be increased so that t 1 + t 2 + t 3 + t 4 remains constant

The number of cycles shall be 350

Post-test, the circuit-breaker components must maintain their operating characteristics The auxiliary and control circuits are required to endure a power frequency voltage of 1.5 kV for 60 seconds Any observed corrosion should be documented in the test report.

Test to prove the operation under severe ice conditions [6.101.5]

The severe ice conditions test is specifically designed for outdoor circuit-breakers with moving external components, applicable to those specified for ice thickness classes of 10 mm or 20 mm.

The test shall be performed under the conditions described in IEC 62271-102.

Guide for static terminal load test [6.101.6]

The static terminal load test is applicable only to outdoor circuit-breakers having rated voltages of 52 kV and above

For circuit-breakers rated below 52 kV, a static terminal load test may be conducted based on an agreement between the manufacturer and the purchaser This test is essential to verify that the circuit-breaker functions properly under the stresses caused by ice, wind, and connected conductors.

Ice coating and wind pressure on the circuit-breaker shall be in accordance with 2.1.2 of

Some examples of forces due to flexible and tubular connected conductors are given as guide in Table 14 of IEC 62271-100

The tensile force due to the connected conductors is assumed to act at the outermost end of the circuit-breaker terminal

For simultaneous action of ice, wind and connected conductors, the resultant terminal loads,

F shA , F shB and F sv respectively (see Figure 19 of IEC 62271-100) are defined as rated static terminal loads

If the manufacturer by calculation can prove that the circuit-breaker can withstand the stresses, tests need not be performed

The tests shall be made at the ambient air temperature of the test room

The tests shall be made on the complete pole of the circuit-breaker

Testing will be conducted in three phases: first, a horizontal force, \$F_{shA}\$, will be applied along the longitudinal axis of the terminal (direction A); second, a horizontal force, \$F_{shB}\$, will be applied in two successive directions at 90° to the longitudinal axis (directions B1 and B2); and third, a vertical force, \$F_{sv}\$, will be applied in two successive directions (directions C1 and C2) This approach eliminates the need for a special force to simulate wind pressure at the circuit-breaker's center of application.

The load may be applied at the terminal, as illustrated in Figure 19 of IEC 62271-100, and should be reduced in magnitude according to the longer lever arm, ensuring that the bending moment at the lowest part of the circuit-breaker remains consistent.

Two operating cycles shall be performed for each of the specified five load tests.

Miscellaneous provisions for making and breaking tests [6.102]

General [6.102.1]

A single-pole circuit-breaker shall make and break single-phase short-circuit currents, symmetrical and asymmetrical, between 10 % (or such lower currents as specified in 7.13.2 if

7.13.1 is applicable) and 100 % of the rated short-circuit breaking current at rated voltage (U Ne )

For a two-pole circuit-breaker, it is essential to demonstrate that all short-circuit making and breaking requirements are met with both poles functioning simultaneously, particularly when the poles are connected in series or are designated to operate together.

In laboratory tests, the applied voltage, current, transient, and power frequency recovery voltages should be derived from a single power source through direct testing In rare scenarios, particularly in traction circuit-breakers, these parameters may be sourced from multiple power sources, where the majority of the current comes from one source while the transient recovery voltage is partially or entirely obtained from separate sources, known as synthetic tests.

Single-pole testing is typically applicable for traction circuit-breakers, but in instances where a two-pole circuit-breaker is designed to operate simultaneously in a single-phase circuit, both poles are treated as separate units during testing For other applications, testing procedures should be established collaboratively between the purchaser and supplier to closely reflect actual operating conditions.

Particular requirements for single–pole circuit-breaker tests

This method involves testing a single-pole circuit-breaker in a single-phase setup by applying the same current and nearly identical power frequency voltage to the pole, simulating the conditions experienced during making and breaking operations.

Circuit-breakers designed for railway applications typically do not feature breaking units arranged in series and are tested as a complete pole However, if they are built with multiple units, unit testing is allowed and must comply with the relevant clauses of IEC 62271-100.

Arrangement of circuit-breaker for tests [6.102.3]

The circuit-breaker for testing must be mounted on its own support or an equivalent structure If supplied as part of an enclosed unit, it should be assembled within its own supporting structure and enclosure, including disconnecting features and vent outlets, along with main connections and busbars when feasible The operating devices must function as specified, particularly ensuring that electrically, pneumatically, or hydraulically operated devices commence at the minimum voltage or pressure outlined in the guidelines.

5.10, 5.12 and 6.7, unless otherwise specified in the relevant clauses

It shall be shown that the circuit-breaker will operate satisfactorily under the above conditions at no-load as specified in 7.8.6

Gas-blast circuit-breakers must undergo testing at minimum compressed gas pressures for interruption, in accordance with the series of operations outlined in section 6.11, unless otherwise stated in the applicable clauses.

NOTE Current chopping may be more pronounced at maximum operating pressure and/or maximum gas pressure/density

The two-pole circuit-breaker shall be tested as follows: a) Single-enclosure type

A two-pole circuit-breaker having all its arcing contacts supported within a common enclosure shall be tested as a complete two-pole circuit-breaker in single-phase circuits

– possibility of flash-over between poles or to earth due to the influence of exhaust gases;

– possible differences in the conditions of the extinguishing medium (pressures, temperatures, pollution levels, etc.);

– possible different stresses on the operating mechanism b) Multi-enclosure type

A two-pole circuit-breaker consisting of two independent single-pole switching devices can be tested single-phase according to 7.8.2.1

7.8.3.2 Circuit-breakers with over-current releases [6.102.3.4]

Circuit-breakers fitted with direct over-current releases shall, subject to the provisions of

7.9.4, be arranged for test-duties T10 to T100a (7.12) as specified below and the over-current release coils shall be connected to the live side of the test circuit:

The coil is configured to operate at the maximum rated current and maximum time-delay for test duties T10, T30, T60, and T100 seconds, while it operates at the minimum current and minimum time-delay for test duty T100a.

When the time-delay is excessively long for effective oscillographic recording, it is acceptable to use a shorter time-delay setting or to disable the time delay device specifically for test duties T10 and T30.

General considerations concerning test methods [6.102.4]

Subclause 6.102.4 of IEC 62271-100 applies except of 6.102.4.1.

Synthetic tests [6.102.5]

Synthetic tests are unlikely to be necessary for circuit-breakers in railway applications Should it occur reference shall be made to 6.102.5 of IEC 62271-100.

No-load operations before tests [6.102.6]

Before conducting making and breaking tests, it is essential to perform no-load operations and document the circuit-breaker's operating characteristics, including travel speed, closing time, and opening time.

For a circuit-breaker fitted with a making current release, it shall be shown that this does not operate on no-load

For electrically operated circuit-breakers, operations must be conducted with the closing solenoid energized at 105%, 100%, and 85% of the rated supply voltage Additionally, the shunt opening release should be energized at 110%, 100%, and 85% for alternating current (a.c.) applications.

110 %, 100 % and 70 % in the case of d.c of the rated supply voltage

For pneumatic or hydraulic operating devices, the operations shall be made under the following conditions with reference to the minimum, rated and maximum pressure specified in

6.5 and 6.6: a) minimum pressure with the shunt opening releases energized at 85 % in case of a.c.,

In the case of direct current (DC), the shunt releases are energized at 85% of the rated supply voltage, resulting in a 70% rated pressure When the shunt releases are energized at the rated supply voltage, the rated pressure is achieved For maximum pressure, the shunt releases must be energized at 110% of the rated supply voltage In alternating current (AC) scenarios, maximum pressure is attained when the shunt opening releases are energized at 85%.

70 % in case of d.c and with the shunt closing releases energized at 85 % of the rated supply voltage

Spring-operated circuit-breakers should be tested with shunt closing releases energized at 110%, 100%, and 85% of the rated supply voltage For shunt opening releases, the energization levels are the same for alternating current (a.c.) at 110%, 100%, and 85%, while for direct current (d.c.), the levels are 110%, 100%, and 70% of the rated supply voltage.

Alternative closing mechanisms [6.102.7]

When a circuit-breaker is intended for use with different closing mechanisms, it is essential to conduct a distinct series of short-circuit test duties for each mechanism This is necessary unless it can be demonstrated that changing the mechanism does not impact the performance of the common components, especially concerning the circuit-breaker's opening characteristics.

To demonstrate this satisfactorily, only one complete series of short-duty tests is necessary using an alternative mechanism However, any short-circuit test duty that involves operations (refer to section 7.12.5) must be repeated with all other alternative mechanisms.

Behaviour of circuit-breaker during tests [6.102.8]

During making and breaking tests, circuit-breakers must not exhibit excessive distress or pose a risk to the operator Oil circuit-breakers should not emit flames, and any gases produced, along with the oil, must be safely channeled away from live conductors and areas where people may be present.

For certain circuit-breakers, if there is significant emission of flames or metallic particles, it is necessary to conduct short-circuit tests using metallic screens positioned near the live components These screens must be separated from the live parts by a safety clearance distance specified by the manufacturer.

The screens shall be insulated from earth but connected thereto by a suitable device to indicate any significant leakage current to earth

During testing, there should be no significant leakage currents detected in the circuit-breaker earthed structure or screens If there is uncertainty, earthed components should be connected to earth using a 0.1 mm diameter and 50 mm long copper fuse wire The absence of significant leakage is confirmed if the fuse wire remains intact after the test.

In specific situations, a permanent electrical connection between the circuit-breaker frame and the earth is essential It is acceptable to achieve this by earthing the frame through a suitable 1:1 ratio transformer, ensuring that a fuse is connected across the secondary winding and that the secondary terminals are safeguarded by a spark gap.

Overvoltages generated during line-charging, cable-charging, capacitor bank, and small inductive current breaking tests must remain within the maximum permissible limits set by the manufacturer Additionally, external flashover must be avoided.

Condition of circuit-breaker after tests [6.102.9]

After any test-duty, the circuit-breaker should be inspected to ensure its mechanical parts and insulators remain in nearly the same condition as prior to testing A visual inspection is typically adequate to verify insulating properties; however, if there is any uncertainty, the condition checking test outlined in IEC 62271-1, section 6.2.11, is sufficient to confirm these properties For circuit-breakers with sealed-for-life interrupters, where dismantling could impact inspection results—such as with certain GIS breakers—the condition checking test is mandatory.

7.8.9.2 Condition after a short-circuit test-duty [6.102.9.2]

Following each short-circuit test, the circuit-breaker must be able to make and break its rated normal current at the specified voltage, even if its performance for short-circuit operations is somewhat diminished.

The main contacts must be maintained in a condition that ensures they can carry the rated normal current of the circuit-breaker without exceeding a temperature rise of more than 10 K, as specified in Table 3 of IEC 62271-1 If there is any uncertainty, conducting an additional temperature rise test may be required.

Experience shows that an increase of the voltage drop across the circuit-breaker cannot alone be considered as reliable evidence of an increase in temperature rise

Contacts are classified as "silver-faced" if a layer of silver remains at the contact points following any short-circuit test duties; if not, they are deemed "not silver-faced" according to item 6 of section 4.4.3 of IEC 62271-1.

7.8.9.3 Condition after a short-circuit test series [6.102.9.3]

To verify the circuit-breaker's functionality post-testing, it is essential to perform no-load closing and opening operations after completing all short-circuit tests These operations must be compared with those conducted as per section 7.8.6, ensuring there are no significant discrepancies The circuit-breaker should successfully close and latch without issues.

Following the completion of short-circuit test duties, localized burning of the oil circuit-breaker enclosure lining may occur As long as this damage does not impair the lining's functionality, it is considered acceptable However, this allowance does not extend to linings, tubes, barriers, or other components that are integral to the main insulation of the circuit-breaker.

Minor distortions in non-metallic interphase barriers and tank linings of oil circuit-breakers are acceptable, as long as they do not hinder the circuit-breaker's normal operation during opening and closing.

If additional short-circuit test duties are required beyond the standard due to factors unrelated to the circuit-breaker's performance, and if the enclosure lining is significantly damaged, the manufacturer may opt to replace it before completing all tests In such cases, the test report must include a statement detailing the changes and necessary explanations.

Damage to the main insulation of a circuit-breaker, which is exposed to electrical stress during normal operation, disqualifies the device if the insulation is impaired However, damage to shields for bushing or arc control devices does not affect performance as long as the shields remain largely intact and functional Conversely, any damage to insulation surfaces that could lead to creepage under normal voltage conditions, whether to earth, between poles, or across the break, will invalidate the circuit-breaker's performance.

No criterion of oil deterioration can be given, as this will depend upon the particular circuit- breaker tested

7.8.9.4 Condition after a test series other than a short-circuit test series

The circuit-breaker shall, after performing the line-charging, cable-charging, capacitor bank and small inductive current breaking test series specified in 6.111.9.1 and 6.112 of

IEC 62271-100, before reconditioning, be capable of operating satisfactorily at any making and breaking current up to its rated short-circuit making and breaking current

In addition the circuit-breaker shall be capable of carrying its rated normal current with a temperature rise not in excess of the temperature rise permitted by Table 3 of IEC 62271-1

Internal punctures, flashover, or tracking of insulating materials must not be present, although moderate wear on arc control device components exposed to the arc is acceptable.

NOTE Verification of compliance with the above requirements is necessary only in case of doubt

7.8.9.5 Reconditioning after a short-circuit test-duty and other test series

After conducting a short-circuit test or similar evaluations, maintenance on the circuit-breaker may be required to restore it to the manufacturer's specified conditions This maintenance could involve repairing or replacing arcing contacts and other renewable components, renewing or filtering the oil or extinguishing medium, and adding the necessary amount to achieve the normal level or density Additionally, it may be necessary to remove deposits from the internal insulation caused by the decomposition of the extinguishing medium.

Circuit-breaker with short arcing times

When conducting breaking tests on circuit-breakers with short arcing times, significant variations in test severity can occur even with identical circuit settings, depending on the point in the current wave at which contact separation happens Therefore, the testing procedure for circuit-breakers with arcing times not exceeding one cycle, particularly those with switching resistors, is outlined in item b) below.

The tests outlined in item a), 2) involve three valid operations that are independent of the rated operating sequence Following the specified number of operations according to the rated operating sequence, the circuit-breaker can be reconditioned as per section 7.8.9.5.

NOTE 1 The same test procedure may be applied also for circuit-breakers having longer arcing times than one cycle a) Three-phase tests

Not applicable b) Single-phase tests

The initial valid breaking operation illustrates the earliest possible clearance following contact separation This occurs when a delay in the separation of the contacts relative to the current's zero crossing leads to the breaking happening at the subsequent zero crossing of the current.

NOTE 2 The resultant arcing time has been termed the minimum arcing time

In the second breaking operation, the control setting for the tripping impulse should be adjusted to approximately 60 electrical degrees earlier than the first valid breaking operation, ensuring that the resultant clearance coincides with the current zero of the initial valid breaking operation.

The tripping impulse for the third breaking operation must occur 90 electrical degrees earlier than that of the second breaking operation, with the condition that dt is less than a specified value.

The initial valid breaking operation illustrates the earliest possible clearance following contact separation This occurs when a delay in the separation of the contacts relative to the current's zero crossing leads to the breaking happening at the subsequent zero crossing of the current.

NOTE 3 The resultant arcing time has been termed the minimum arcing time

In the second breaking operation, the control setting for the tripping impulse must occur earlier than the first valid breaking operation by 180 electrical degrees minus a time differential (dt), where dt is less than 18 electrical degrees.

For the third breaking operation, the setting of the control of the tripping operation shall be

90 electrical degrees earlier than that of the first valid breaking operation

The sequence of performing the three valid operations is not specified

Both conditions 1) and 2) may be demonstrated by combining the above in one test series

The transient and the power frequency recovery voltages to be used shall be those applicable to the traction systems

To ensure effective arc extinction, the initial operation must be designed so that it occurs at the conclusion of the major loop, while contact separation should take place within or prior to the preceding minor loop.

It may be necessary to make more than one test to achieve this valid test

A second breaking operation will be performed after the moment of contact separation, with the control of the tripping impulse advanced by about 60 electrical degrees This operation is only applicable if arc extinction takes place after the minor loop; if arc extinction does not occur at this stage, the initial operation becomes invalid.

A third operation shall be made with the setting of the control of the tripping impulse retarded by approximately 60 electrical degrees with respect to the first valid operation

4) Out-of-phase test duties

Test circuit for short circuit making and breaking tests [6.103]

Short-circuit test quantities [6.104]

Short-circuit test procedure [6.105]

Basic short-circuit test-duties [6.106]

Critical current tests [6.107]

Capacitive current switching tests [6.111]

Tiêu đề	Particular requirements for a.c. switchgear
Chuyên ngành	Railway Applications
Thể loại	Standard
Năm xuất bản	2009

Định dạng
Số trang	126
Dung lượng	1,67 MB