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GB/T 3906-2020 PDF in English


GB/T 3906-2020 (GB/T3906-2020, GBT 3906-2020, GBT3906-2020)
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GB/T 3906-2020English905 Add to Cart 0-9 seconds. Auto-delivery. Alternating-current metal-enclosed switchgear and controlgear for rated voltages above 3.6 kV and up to and including 40.5 kV Valid

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GB/T 3906-2020: PDF in English (GBT 3906-2020)

GB/T 3906-2020
GB
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 29.130.10
K 43
Replacing GB/T 3906-2006
Alternating-current metal-enclosed switchgear and
controlgear for rated voltages above 3.6 kV and up to and
including 40.5 kV
(IEC 62271-200:2011, High-voltage switchgear and controlgear - Part 200: AC metal-
enclosed switchgear and controlgear for rated voltages above 1 kV and up to and
including 52 kV, MOD)
ISSUED ON: MARCH 31, 2020
IMPLEMENTED ON: OCTOBER 01, 2020
Issued by: State Administration for Market Regulation;
Standardization Administration of PRC.
Table of Contents
Foreword ... 6
1 Scope ... 12
2 Normative references ... 13
3 Terms and definitions ... 14
4 Normal and special conditions of use ... 25
5 Ratings ... 25
5.1 Overview ... 25
5.2 Rated voltage (Ur) ... 26
5.3 Rated insulation level ... 26
5.4 Rated frequency (fr) ... 26
5.5 Rated current and temperature rise ... 26
5.6 Rated short-time withstand current ... 27
5.7 Rated peak withstand current ... 27
5.8 Rated short circuit duration ... 28
5.9 Rated power supply voltage of closing and opening devices and auxiliary and control
circuits (Ua) ... 28
5.10 Rated power frequency of closing and opening devices and auxiliary and control
circuits ... 28
5.11 Rated pressure of the compressed air source of the controllable pressure system ... 28
5.12 Rated charging levels for insulation and/or operation ... 28
5.101 Ratings of internal arc class (IAC) ... 29
5.102 Rated cable test voltage ... 30
6 Design and structure ... 31
6.1 Overview ... 31
6.2 Requirements for liquids in switchgear and controlgear ... 32
6.3 Requirements for gases in switchgear and controlgear ... 32
6.4 Requirements for the main circuits of switchgear and controlgear to use solid-
insulation embedded components ... 32
6.5 Earthing... 32
6.6 Auxiliary equipment and controlgear ... 34
6.7 Power operation ... 34
6.8 Energy storage operation ... 34
6.9 Operations that do not rely on human labor ... 34
6.10 Operation of trip unit ... 35
6.11 Low-pressure lockout, high-pressure lockout, monitoring devices ... 35
6.12 Nameplate... 35
6.13 Interlocking device ... 37
6.14 Position indication ... 38
6.15 Degree of protection of enclosure ... 38
6.16 Creepage distance of outdoor insulators ... 39
6.17 Gas and vacuum sealing ... 39
6.18 Liquid sealing ... 39
6.19 Fire (flammability) ... 39
6.20 Electromagnetic compatibility (EMC) ... 39
6.21 X-ray emission ... 39
6.22 Corrosion ... 39
6.101 Internal arc fault ... 39
6.102 Enclosure ... 40
6.103 High-pressure compartment ... 43
6.104 Removable components ... 47
6.105 Provisions for cable insulation testing ... 47
7 Type test ... 48
7.1 General... 48
7.2 Insulation test ... 50
7.3 Radio interference voltage (r.i.v.) test ... 56
7.4 Measurement of circuit resistance ... 56
7.5 Temperature rise test ... 56
7.6 Short-time withstand current and peak withstand current tests ... 57
7.7 Verification of degree of protection ... 60
7.8 Sealing test ... 60
7.9 Electromagnetic compatibility test (EMC) ... 60
7.10 Additional tests of auxiliary and control circuits ... 60
7.11 X-ray test procedures for vacuum arc extinguish chamber ... 61
7.101 Verification of making and breaking capabilities ... 61
7.102 Mechanical operation test ... 64
7.103 Pressure resistance test and gas state measurement of gas-filled compartments ... 66
7.104 Verification tests for personal protection against hazardous electrical effects ... 67
7.105 Weather protection test ... 68
7.106 Internal arc test ... 68
7.107 Performance verification test of metal-enclosed switchgear whose main components
in the main circuit adopt solid-insulation embedded components ... 73
8 Exit-factory test ... 75
8.1 Overview ... 75
8.2 Insulation test of main circuit ... 76
8.3 Testing of auxiliary and control circuits ... 76
8.4 Measurement of main circuit resistance ... 76
Alternating-current metal-enclosed switchgear and
controlgear for rated voltages above 3.6 kV and up to and
including 40.5 kV
1 Scope
This standard specifies the terms and definitions, usage conditions, ratings, design and
structure, type testing, exit-factory testing and other technical requirements for
alternating-current metal-enclosed switchgear and controlgear for rated voltages 3.6 kV
~ 40.5 kV.
This standard applies to factory-assembled AC metal-enclosed switchgear and
controlgear, which has a rated voltage of 3.6 kV ~ 40.5 kV, is installed indoor or outdoor,
has a frequency of 50 Hz and below. The enclosure may be equipped with fixed or
removable element AND may be filled with insulating and/or interrupting fluid (liquid
or gas).
Note 1: This standard is mainly for three-phase systems; however, it can also be used for single-
phase or two-phase systems.
This standard divides metal-enclosed switchgear and controlgear into several categories,
based on the following points:
- Continuity of grid operation when servicing switchgear and controlgear;
- The need and convenience of equipment maintenance.
Note 2: The safety of the equipment depends on the design, manufacture, use, adjustment,
coordination, installation, operation of the product.
For metal-enclosed switchgear and controlgear with gas-filled compartments, this
standard applies when the design pressure does not exceed 0.3 MPa (relative pressure).
Note 3: Gas-filled compartments with design pressures exceeding 0.3 MPa (relative pressure)
shall be designed and tested in accordance with GB/T 7674.
For metal-enclosed switchgear and controlgear for special purposes, such as in places
with flammable gases, in mines or on ships, it may need to add corresponding technical
requirements.
Each component installed in metal-enclosed switchgear and controlgear shall be
Follow the provisions of 4.5.2 in GB/T 11022-2011, with the following supplements:
The temperature rise of each component in metal-enclosed switchgear and controlgear
shall be in accordance with their respective technical specifications; their temperature
rise shall not exceed the limits specified in the relevant standards of these components.
When considering the maximum allowable temperature or temperature rise of the
busbar, it shall be determined according to the maximum allowable temperature or
temperature rise of the contacts, connections, metal parts in contact with the insulating
material, based on the working conditions.
The temperature rise of accessible enclosures and covers shall not exceed 30 K. For
enclosures and covers that are accessible but do not need to be touched during normal
operation, if they are not accessible to the public, the temperature rise limit may be
increased by 10 K.
5.6 Rated short-time withstand current
For the rated short-time withstand currents Ik and Ike, 4.6 of GB/T 11022-2011 applies
with the following supplements:
- Rated short-time withstand current Ik of the main circuit;
Note 1: In principle, the rated short-time withstand current of the main circuit cannot exceed
the corresponding rating of the weakest component among its series components. However,
for the high-voltage compartment or each circuit, devices that limit short-circuit current can
be used, such as current-limiting fuses, reactors, etc.
- Rated short-time withstand current Ike of the earthing circuit:
This value can be different from the value of the main circuit.
Note 2: The applicable short-circuit current rating for an earthing circuit depends on the
type of earthing used at the system neutral point. See 9.105.
5.7 Rated peak withstand current
Article 4.7 of GB/T 11022-2011 applies, with the following supplements:
- Rated peak withstand current of main circuit Ip;
Note: In principle, the rated peak withstand current of the main circuit cannot exceed the
corresponding rating of the weakest component among its series components. However, for
the high-voltage compartment or each circuit, devices that limit short-circuit current can be
used, such as current-limiting fuses, reactors, etc.
- Rated peak withstand current of the earthing circuit Ipe.
This value can be different from the value of the main circuit.
5.8 Rated short circuit duration
Article 4.8 of GB/T 11022-2011 applies, with the following supplements:
- Rated short-circuit duration of main circuit tk;
Note: In principle, the rated short-circuit duration of the main circuit cannot exceed the
corresponding rating of the weakest component among its series components. However, for
high-voltage compartments or for each circuit, devices that limit the duration of the short-
circuit current, such as current-limiting fuses, can be used.
- Rated short-circuit duration of earthing circuit tke:
This value can be different from the value of the main circuit.
5.9 Rated power supply voltage of closing and opening devices and
auxiliary and control circuits (Ua)
Follow the provisions of 4.9 in GB/T 11022-2011.
5.10 Rated power frequency of closing and opening devices and
auxiliary and control circuits
Follow the provisions of 4.10 in GB/T 11022-2011.
5.11 Rated pressure of the compressed air source of the controllable
pressure system
Follow the provisions of 4.11 in GB/T 11022-2011.
5.12 Rated charging levels for insulation and/or operation
Follow the provisions of 4.12 in GB/T 11022-2011.
system, which is specified in GB/T 762.
Arc fault current is divided into two ratings:
a) Three-phase arc fault current (IA);
b) When applicable, single-phase to earth arc fault current (IAe).
If only three-phase ratings are specified, the single-phase rating defaults to 87% of the
three-phase rating and does not need to be specified.
Note 1: The manufacturer's specifications apply to compartments with single-phase to earth arc
fault current ratings. Such values should be specified for switchgear and controlgear, which
have structures capable of preventing the development of arcs into multi-phase faults; they are
verified during internal arc fault tests.
Note 2: The 87% background is a two-phase ignition arc fault test. See B.5.2.
In the case where all high-voltage compartments are designed for single-phase-to-earth
arc faults only, the rating of IA need not be specified (see B.5.2).
Note 3: See 9.103.6 for information on the relationship between neutral earthing type and
single-phase-to-earth arc fault current.
5.101.5 Rated arc fault duration (tA, tAe)
The standard recommended values for three-phase arc fault duration (tA) are 0.1 s, 0.5
s, 1 s.
If applicable, the test duration (tAe) for single-phase to earth arc faults shall be specified
by the manufacturer.
Note: It is usually not possible to calculate the permissible arc duration for currents, which are
different from those used in the test.
5.102 Rated cable test voltage
5.102.1 Overview
If the design of the switchgear allows insulation testing of the cable, when the cable is
connected to the switchgear, the manufacturer shall specify one or more rated cable test
voltages.
5.102.2 Rated power frequency cable test voltage Uct (AC)
The rated power frequency cable test voltage is the maximum AC test voltage, that can
be applied to the cables, which are connected to the switchgear and controlgear (which
may be in operation).
5.102.3 Rated DC cable test voltage Uct (DC) (when applicable)
The rated DC cable test voltage is the maximum DC test voltage, that can be applied to
cables, which are connected to switchgear and controlgear (which may be in operation).
Note: For the rated DC cable test voltage, it can be considered that a very low frequency test
voltage (such as 0.1 Hz) is also applicable. Guidelines are given in IEEE 400.2.
6 Design and structure
6.1 Overview
Metal-enclosed switchgear and controlgear shall be designed, so that the following
operations can be carried out safely:
- Normal operation, inspection, maintenance;
- Determination of the live or uncharged status of the main circuit, including phase
sequence inspection;
- Earthing of connecting cables, positioning of cable faults, voltage testing of
connecting cables or other devices, elimination of dangerous electrostatic charges.
All removable components and components of the same type, rating, construction shall
be mechanically and electrically interchangeable.
When the design of these removable components and components and the
compartments allows for mechanical interchangeability, removable components and
components of the same or greater current rating and insulation level may be installed,
to replace the removable components and components of same or smaller current rating
and insulation level. This generally does not apply to current-limiting devices.
Note: Equipping higher-rated removable components or components does not necessarily
increase the capabilities of the functional unit, nor does it mean that the functional unit can
operate at the increased rating of the removable components or components.
Various components installed in the enclosure shall meet their respective technical
requirements.
When the main circuit has a current-limiting fuse, the switchgear and controlgear
manufacturer may specify the maximum peak value and Joule integral of the let-through
current of the fuse, for the main circuit downstream of the fuse.
advance. This does not include removable components, that become accessible after
being segregated from the switchgear and controlgear.
6.5.3 Enclosure earthing
The enclosure of each functional unit shall be connected to the earthing system. For
small components fixed to the enclosure, as long as the diameter does not exceed 12.5
mm, it does not need to be connected to the earthing system, such as nuts. All metal
parts to be earthed, except high-voltage circuits and auxiliary circuits, shall also be
connected to the earthing system.
The interconnection within the functional units is ensured by electrical continuity
between frames, covers, doors, partitions or other components (e.g., fixed by screws or
welding methods). Doors to high voltage compartments shall be connected to the frame
by suitable means.
During final installation, the transport units shall be connected to each other. This
connection between adjacent transport units shall be able to withstand the rated short-
time withstand current and peak withstand current of the earthing circuit.
Note 1: See 6.102 for enclosures and doors.
Note 2: When EMC is required for the complete facility, special methods may be required for
earthing circuits of switchgear and controlgear.
Note 3: See Appendix C for the degree of protection of electric shock protection from of solid-
insulation enclosed switchgear and controlgear.
6.5.4 Earthing of earthing devices
When the earthing connections are to withstand the full three-phase short-circuit current
value (for example, when the short-circuit connection is used in an earthing device),
these connections shall be dimensioned accordingly.
6.5.5 Earthing of withdrawable and removable components
The metal parts of withdrawable components, that shall be earthed, shall remain earthed
in the test and isolation positions and in all intermediate positions. At all locations, the
current-carrying capacity of the earthing connection shall not be less than that required
for the enclosure (see 6.102.1).
When inserted, the metal part of the removable component, that is normally earthed,
shall be earthed before the removable component of the main circuit comes into contact
with the fixed contacts.
If withdrawable components or removable components include other earthing devices
that earth the main circuit, the ground connection at the working location shall be
considered to be part of the earthing circuit and have relevant ratings (see 5.6, 5.7, 5.8).
6.5.6 Earthing circuit
The earthing return circuits of switchgear and controlgear shall be capable of carrying
the rated short-time and peak phase-to-earth withstand currents, from each functional
unit to the terminal connected to the earthing system of the facility.
Note 1: In general, if the earthing conductor extending to the entire length of the metal-enclosed
switchgear and controlgear has a sufficient cross-sectional area, it is considered that the above
requirements can be fully met. As a guide, if the earthing conductor is made of copper, then
under specified earthing fault conditions, when the rated short-circuit duration is 1 s, the current
density in it does not exceed 175 A/mm2; when the rated short-circuit duration is 2 s, the current
density in it does not exceed 125 A/mm2; when the rated short-circuit duration is 3 s, the current
density in it does not exceed 110 A/mm2; when the rated short-circuit duration is 4 s, the current
density in it does not exceed 95 A/mm2.
Note 2: See Appendix D for the calculation method of conductor cross-sectional area.
Earthing circuits are usually designed to withstand only a single rated short-time
withstand current; maintenance may be required after such an event. See 9.105.
If switchgear and controlgear use special earthing conductors as earthing circuits, their
cross-sectional area shall not be less than 30 mm2.
6.6 Auxiliary equipment and controlgear
Follow the provisions of 5.4 in GB/T 11022-2011.
6.7 Power operation
Follow the provisions of 5.5 in GB/T 11022-2011.
6.8 Energy storage operation
Follow the provisions of 5.6 in GB/T 11022-2011.
6.9 Operations that do not rely on human labor
Follow the provisions of 5.7 in GB/T 11022-2011.
6.13 Interlocking device
Follow the provisions of 5.11 in GB/T 11022-2011, with the following supplements:
For protection and ease of operation, interlocks shall be installed between different
components of the equipment. When designing, mechanical interlocking shall be given
priority. Under the conditions specified in 7.102.2, incorrect test operation of any
relevant switchgear shall not damage the interlock. The following requirements are
mandatory for the main circuit:
a) Metal-enclosed switchgear and controlgear with removable components
A circuit breaker, load switch or contactor can only be withdrawn or inserted, when
it is in the open position.
The circuit breaker, load switch or contactor can only be operated, when it is in the
working position, isolation position, removed position, test position or earthing
position.
The circuit breaker, load switch or contactor can be closed in the working position,
only when the auxiliary circuits related to automatic opening are connected. On the
contrary, the auxiliary circuit cannot be disconnected, when the circuit breaker is in
the closed state in the working position.
b) Metal-enclosed switchgear and controlgear equipped with isolating switches
Interlocks shall be installed to prevent the isolating switch from being operated
outside specified conditions (see GB/T 1985-2014). The isolating switch can only
be operated, when the associated circuit breaker, load switch or contactor is in the
open position.
Note 1: In a double-busbar system, if the current is not interrupted when the busbar is
switched, the above requirements do not need to be considered.
A circuit breaker, load switch or contactor can only operate, when the associated
isolating switch is in the closed position, open position or earthed position (if any).
Additional or alternative interlocking provisions shall be based on the agreement
between the manufacturer and the user. The manufacturer shall provide all necessary
information, which is related to the characteristics and functions of the interlock.
The earthing switch shall be interlocked with the relevant isolating switch.
Locking devices (such as padlocks) shall be installed for those main circuit components,
that may cause damage, due to incorrect operation, OR components, that are used to
establish isolation breaks during maintenance.
If the circuit is earthed through a main switchgear (circuit breaker, load switch or
contactor), which is connected in series with the earthing switch, the earthing switch
shall be interlocked with the main switchgear; meanwhile it shall take measures to
prevent the main switchgear from accidentally opening, for example by disconnecting
the trip circuit or blocking the mechanical trip.
Note 2: In addition to the earthing switch, other devices may also be in the earthing position.
If there are non-mechanical interlocks, the design shall be such that no unsuitable
conditions will occur when auxiliary power is not available. However, for emergency
control, the manufacturer may provide other methods of manual operation without
interlocking facilities. In this case, the manufacturer shall clearly identify the facility
and specify operating procedures.
6.14 Position indication
Follow the provisions of 5.12 in GB/T 11022-2011. In addition, for all devices involved
in isolation and earthing, 5.104.3 of GB/T 1985-2014 applies.
6.15 Degree of protection of enclosure
6.15.1 Overview
Follow the provisions of 5.13 in GB/T 11022-2011, with the following supplements:
6.15.2 Protection against personnel access to hazardous parts and equipment and
protection against the entry of solid foreign objects (IP code)
Article 5.13.2 of GB/T 11022-2011 applies, with the following additions:
Specific requirements are specified in 6.102 and 6.103.
6.15.3 Protection against water intrusion (IP code)
Article 5.13.3 of GB/T 11022-2011 applies, with the following additions:
Equipment installed outdoors shall provide a minimum degree of protection of IPX3 or
IPXXW.
6.15.4 Protection of equipment against mechanical impact under normal operating
conditions (IK code)
Article 5.13.4 of GB/T 11022-2011 applies, with the following additions:
For indoor facilities, the lowest impact level is IK 07 (2 J) specified in GB/T 20138.
......
 
Source: Above contents are excerpted from the PDF -- translated/reviewed by: www.chinesestandard.net / Wayne Zheng et al.