标准编号:	GB/T 3906-2020
中文名称:	3.6 kV～40.5 kV交流金属封闭开关设备和控制设备
英文名称:	Alternating-current metal-enclosed switchgear and controlgear for rated voltages above 3.6 kV and up to and including 40.5 kV
中标分类:	K43    高压开关设备
行业分类:	GB    国家标准
发布机构:	国家市场监督管理总局 国家标准化管理委员会
发布日期:	2020-03-31
实施日期:	2020-10-1
标准状态:	现行
替代旧标准:	GB/T 3906-2006
翻译语言:	英文
文件格式:	PDF
中文字符数:	88000 字
翻译价格(元):	5400.00 元
交付时间:	付款后 1 个工作日

Codeofchina.com is in charge of this English translation. In case of any doubt about the English translation, the Chinese original shall be considered authoritative.



This standard is developed in accordance with the rules given in GB/T 1.1-2009.



This standard replaces GB/T 3906-2006 Alternating-current metal-enclosed switchgear and controlgear for rated voltages above 3.6kV and up to and including 40.5kV. The following main technical changes have been made with respect to GB/T 3906-2006:



——Terms such as solid-insulation embedded component are added (see Clause 3);



——Ratings of the internal arc classification (IAC) are added, and rated arc fault currents and rated arc fault duration are specified (see 5.101);



——Rated cable test voltages are added, and both a.c. and d.c. test voltages are specified (see 5.102);



——Requirements for use of solid-insulation embedded component in the main circuit of switchgear and controlgear are added (see 6.4);



——X-radiation emission test is added (see 6.21);



——The requirement that products under normal production shall be subjected to dielectric test once every 8 years is added (see 7.1);



——"For metal-enclosed switchgear and controlgear with compartments insulated by air and solid-insulation embedded component as main components of main circuit, if the conditions of use for condensation and pollution are stricter than the normal conditions of use specified in this standard, tests shall be conducted in accordance with Annex E. The tests for other types of metal-enclosed switchgear and controlgear may be determined by agreement between manufacturer and user" is added (see 7.2.9);



——Test requirements for use of solid-insulation embedded component in the fluid-filled and/or main circuit of switchgear and controlgear are added (see 7.2.10);



——The test voltage value and test duration of cable testing circuit are specified (see 7.2.101);



——Trial operation requirements for doors or covers, shutters, wrong directions, etc. are added; test requirements for manual operation handles are proposed; verification for integrity of sliders or other devices preventing access to the operation interface is required; additional test requirements for motor-driven interlock are proposed, and criteria are proposed for all of the above tests (see 7.102.2);



——The performance verification test for use of solid-insulation embedded component in the main circuit is added (see 7.107);



——The service continuity of equipment is reclassified into four categories of LSC1/2/2A/2B, with examples available (see 9.102.3);



——The content of 9.103 is adjusted, contents such as IAC classification are added, and Table 3 in GB/T 3906-2006 is adjusted to 9.104;



——Ratings of earthing circuit and cable test are added (see 9.105 and 9.106);



——Influence of the product on the environment is added (see Clause 13);



——“Comparison list of equivalent clause numbering of this standard with IEC 62271-200: 2011” is added (see Annex A);



——Degree of protection against electric shock of solid-insulation enclosed switchgear and controlgear is added (see Annex C);



——Annex E is re-modified according to IEC 62271-304;



——The maximum allowable partial discharge is adjusted; for metal-enclosed switchgear and controlgear filled with fluid and/or with solid-insulation embedded component in main circuit, the maximum allowable partial discharge under the test voltage is determined to be 20pC; for other types of metal-enclosed switchgear and controlgear, the partial discharge measurement test shall meet the requirements that the assembly shall not be greater than 100pC (see F.5).



This standard has been redrafted and modified in relation to IEC 62271-200: 2011 High-voltage switchgear and controlgear - Part 200: AC metal-enclosed switchgear and controlgear for rated voltages above 1kV and up to and including 52kV.



Many structural adjustments have been made with respect to IEC 62271-200: 2011, and comparison list of equivalent clause numbering of this standard with IEC 62271-200: 2011 is given in Annex A.



Technical deviations between this standard and IEC 62271-200: 2011 and their reasons are as follows:



——The adjustments of technical deviations are made for the normative references in this standard so as to adapt to the technical conditions of China. The adjustments are mainly reflected in Clause 2 "Normative references", with the specific adjustments as follows:



 IEC 62271-100 is replaced by GB/T 1984-2014 which is modified in relation to the international standard;



 IEC 62271-102 is replaced by GB/T 1985-2014 which is modified in relation to the international standard;



 IEC 60050-441: 1984 is replaced by GB/T 2900.20-2016 which is modified in relation to the international standard;



 IEC 62271-103 is replaced by GB/T 3804 which is modified in relation to the international standard;



 IEC 60529: 1989 is replaced by GB/T 4208-2017 which is identical to the international standard;



 IEC 60270 is replaced by GB/T 7354 which is identical to the international standard;



 IEC 62271-1: 2007 is replaced by GB/T 11022-2011 which is modified in relation to the international standard;



 IEC 62271-105 is replaced by GB/T 16926 which is modified in relation to the international standard;



 IEC 60060-1 is replaced by GB/T 16927.1-2011 which is modified in relation to the international standard;



 ISO/IEC Guide 51: 2014 is replaced by GB/T 20002.4-2015 which is modified in relation to the international standard;



 IEC 62262 is replaced by GB/T 20138 which is identical to the international standard;



 IEC 60050-151, IEC 60470: 1999, IEC 62271-201: 2006 and IEC/TS 62271-304 are deleted;



 GB/T 762, GB/T 1408.1-2016, GB/T 2423.1, GB/T 2423.2, GB/T 2423.22, GB/T 8905-2012 and GB/T 14808-2016 are added;



——"Scope” is modified: “above 1kV and up to and including 52kV” in 1.1 of IEC 62271-200: 2011 is changed to 3.6kV~40.5kV according to the actual power grid situation in China; “service frequencies up to and including 60Hz” in 1.1 of IEC 62271-200: 2011 is changed to “service frequencies up to and including 50Hz” in this standard (see Clause 1);



——Terms such as "solid-insulation embedded component" are added (see Clause 3);



——Requirements for use of solid-insulation embedded component in the main circuit of switchgear and controlgear are added (see 6.4);



——The requirement that products under normal production shall be tested once every 8 years is added (see 7.1);



——"For metal-enclosed switchgear and controlgear with compartments insulated by air and solid-insulation embedded component as main components of main circuit, if the conditions of use for condensation and pollution are stricter than the normal conditions of use specified in this standard, tests shall be conducted in accordance with Annex E. The tests for other types of metal-enclosed switchgear and controlgear may be determined by agreement between manufacturer and user" is added (see 7.2.9);



——Test requirements for use of solid-insulation embedded component in the fluid-filled and/or main circuit of switchgear and controlgear are added (see 7.2.10);



——The performance verification test for use of solid-insulation embedded component in the main circuit is added (see 7.107);



——“Comparison list of equivalent clause numbering of this standard with IEC 62271-200:2011” is added (see Annex A);



——Degree of protection against electric shock of solid-insulation enclosed switchgear and controlgear is added (see Annex C);



——Method for calculating cross-sectional area of bare conductor according to thermal effect of short-term continuous current is added (see Annex D);



——Additional requirements for alternating-current metal-enclosed switchgear and controlgear for rated voltages above 3.6kV and up to and including 40.5kV for severe climatic conditions are added (see Annex E);



——For metal-enclosed switchgear and controlgear filled with fluid and/or with solid-insulation embedded component in main circuit, the maximum allowable partial discharge under the test voltage is determined to be 20pC; for other types of metal-enclosed switchgear and controlgear, the partial discharge measurement test shall meet the requirements that the assembly shall not be greater than 100pC (see F.5);



——“Regional differences” (Annex C) in former standard is deleted.



The following editorial changes have been made in this standard:



——In order to be consistent with China's technical standard system, the name of this standard is changed to Alternating-current metal-enclosed switchgear and controlgear for rated voltages above 3.6kV and up to and including 40.5kV;



——Explanatory notes are added (see Annex G).



This standard was proposed by China Electrical Equipment Industry Association.



This standard is under the jurisdiction of the National Technical Committee on High-voltage Switch Gear of Standardization Administration of China (SAC/TC 65).



The previous editions of this standard are as follows:



——GB 3906-1983, GB 3906-1991 and GB/T 3906-2006.







Alternating-current metal-enclosed switchgear and controlgear for rated voltages above 3.6kV and up to and including 40.5kV



1 Scope



This standard specifies the terms and definitions, service conditions, rating, design and structure, type test, ex-factory test and other technical requirements of 3.6kV~40.5kV AC metal-enclosed switchgear and controlgear.



This standard is applicable to prefabricated metal-enclosed switchgear and controlgear for alternating current of rated voltages 3.6kV~40.5kV for indoor and outdoor installation, and for service frequencies up to 50Hz or below. Enclosures may include fixed and removable components and may be filled with fluid (liquid or gas) to provide insulation or disconnection.



Note 1: Although primarily dedicated to three-phase systems, this standard may also be applied to single-phase or two-phase systems.



This standard defines several categories of metal-enclosed switchgear and controlgear which differ due to



——the consequences on network service continuity in case of maintenance on the switchgear and controlgear;



——the need and convenience of maintenance of the equipment.



Note 2: Safety of an installation results from the design, manufacture, use, adjustment, coordination, installations and operations of products.



For metal-enclosed switchgear and controlgear containing gas-filled compartments, this standard applies when the design pressure is limited to a maximum of 0.3MPa (relative pressure).



Note 3: Gas-filled compartments having a design pressure exceeding 0.3MPa (relative pressure) should be designed and tested in accordance with GB/T 7674.



Metal-enclosed switchgear and controlgear for special use, for example, in flammable atmospheres, in mines or on board ships, may be subject to additional requirements.



Components contained in metal-enclosed switchgear and controlgear are to be designed and tested in accordance with their various relevant standards. This standard supplements the standards for the individual components regarding their installation in switchgear and controlgear assemblies.



This standard does not preclude that other equipment may be included in the same enclosure. In such a case, any possible influence of that equipment on the switchgear and controlgear is to be taken into account.



Note 4: Switchgear and controlgear assemblies having an insulation enclosure are covered by IEC 62271-201: 2014.



This standard is also applicable to metal-enclosed switchgear and controlgear with rated voltage above 40.5kV, with air-insulation or inflatable compartments and with design pressure not exceeding 0.3MPa (relative pressure).



2 Normative references



The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.



GB 762 Standard current ratings (GB 762-2002, eqv IEC 60059:1999)

GB/T 1408.1-2016 Insulating materials - Test methods for electric strength - Part 1: Test at power frequencies (IEC 60243-1:2013, IDT)

GB/T 1984-2014 High-voltage alternating-current circuit-breakers (IEC 62271-100:2008, MOD)

GB/T 1985-2014 High-voltage alternating-current disconnectors and earthing switches (IEC 62271-102: 2001+A1: 2011, MOD)

GB/T 2423.1 Environmental testing - Part 2: Test methods - Tests A: Cold (GB/T 2423.1-2008，IEC 60068-2-1: 2007，IDT)

GB/T 2423.2-2008 Environmental testing - Part 2: Test methods - Tests B: Dry heat

GB/T 2423.22 Environmental testing - Part 2: Tests methods - Test N: Change of temperature (GB/T 2423.22-2012, IEC 60068-2-14: 2009, IDT)

GB/T 2900.20-2016 Electrotechnical terminology - High-voltage switchgear and controlgear (IEC 60050-441:1984, MOD)

GB/T 3804 High-voltage alternating current switches for rated voltage above 3.6 kV and less than 40.5 kV (GB/T 3804-2014, IEC 62271-103:2011, MOD)

GB/T 4208-2017 Degrees of protection provided by enclosure (IP code) (IEC 60529:2013, IDT)

GB/T 7354 Partial discharge measurement (GB/T 7354-2018, IEC 60270: 2000, MOD)

GB/T 8905-2012 The guide for management and measuring SF6 gas in electrical equipment (IEC 60480: 2004, MOD)

GB/T 11022-2011 Common specifications for high-voltage switchgear and controlgear standards (IEC 62271-1: 2007, MOD)

GB/T 14808-2016 High-voltage alternating current contactors, contactor-based controllers and motor starters (IEC 62271-106: 2011, MOD)

GB/T 16926 High-voltage alternating current switch-fuse combinations (GB/T 16926-2009, IEC 62271-105: 2002, MOD)

GB/T 16927.1-2011 High-voltage test techniques - Part 1:General definitions and test requirements (IEC 60060-1: 2010，MOD)

GB/T 20002.4-2015 Drafting for special aspects in standards - Part 4: Safety aspects for their inclusion in standards

GB/T 20138 Degrees of protection provided by enclosures for electrical equipment against external mechanical impacts (IK code) (GB/T 20138-2006, IEC 62262: 2002, IDT)



3 Terms and definitions



For the purposes of this document, the terms and definitions given in GB/T 2900.20-2016, GB/T 11022-2011 and the followings apply.



3.101

switchgear and controlgear

general term covering switching devices and their combination with associated control, measuring, protective and regulating equipment, also assemblies of such devices and equipment with associated interconnections, accessories, enclosures and supporting structures



[GB/T 2900.20-2016, Definition 3.1]



3.102

metal-enclosed switchgear and controlgear

switchgear and controlgear equipment completely enclosed by earthed metal, except for incoming and outgoing lines



[GB/T 2900.20-2016, Definition 4.4]



3.103

functional unit

part of metal-enclosed switchgear and controlgear comprising all the components of the main circuits and auxiliary circuits that contribute to the fulfillment of a single function



Note 1: Functional units may be distinguished according to the function for which they are intended, for example, incoming unit, outgoing unit, etc.



Note 2: GB/T 2900.20-2016 modified, Definition 5.5.



3.104

multi-tier design

design of metal-enclosed switchgear and controlgear in which the main switching devices of two or more functional units are arranged vertically (one above the other) within a common enclosure



3.105

transport unit

part of metal-enclosed switchgear and controlgear, suitable for shipment without being dismantled



3.106

enclosure

part of metal-enclosed switchgear and controlgear providing a specified degree of protection of equipment against external influences and a specified degree of protection against approach to or contact with live parts and against contact with moving parts



Note: GB/T 2900.20-2016 modified, Definition 5.1.



3.107

high-voltage compartment

compartment of metal-enclosed switchgear and controlgear containing high-voltage conducting parts, enclosed except for openings necessary for interconnection, control or ventilation



Note 1: Four types of high-voltage compartments are distinguished, three that can be opened, called accessible (see 3.107.1 to 3.107.3) and one that cannot be opened, called non-accessible (see 3.107.4)



Note 2: General definition of "compartment" is provided by 5.6 of GB/T 2900.20-2016, as "a part of an assembly enclosed except for openings necessary for interconnection, control or ventilation".



Note 3: A compartment may contain barriers, structures or components that are intended to provide various functions, such as mechanical or dielectrical, but not to function as a partition or enclosure.



Note 4: High-voltage compartments may be identified according to the main component(s) contained therein or to the main function provided.



3.107.1

interlock-controlled accessible compartment

high-voltage compartment, intended to be opened for normal operation and/or normal maintenance as stated by the manufacturer, in which access is controlled by integral design of the switchgear and controlgear



Note: Installation, extension, repair, etc. are not considered as normal maintenance.



3.107.2

procedure-based accessible compartment

high-voltage compartment, intended to be opened for normal operation and/or normal maintenance as stated by the manufacturer, in which access is controlled by a suitable procedure combined with locking



Note: Installation, extension, repair, etc. are not considered as normal maintenance.



3.107.3

tool-based accessible compartment

high-voltage compartment, that may be opened only through the use of tools, but not intended for opening during normal operation and maintenance



Note: Special procedures may be required.



3.107.4

non-accessible compartment

high-voltage compartment that cannot be opened



Note: Opening may destroy the integrity of the compartment.



3.107.5

connection compartment

high-voltage compartment in which electrical connections are made between the main circuit of the switchgear assembly and the external conductors (cables or bars) to the electrical network or high-voltage apparatus of the installation



Note: For example, cable connection compartment.



3.108

partition

part of metal-enclosed switchgear and controlgear separating one high-voltage compartment from other compartments and providing a specified degree of protection



Note 1: Movable shutters intended for shielding may become an integral part of the partition.



Note 2: Partitions may be fitted with parts that allow interconnection between compartments (e.g. bushings).



Note 3: It is revised from GB/T 2900.20-2016, Definition 5.7.



3.109

partition class

class defining whether metallic or non-metallic material is used for partitions



3.109.1

partition class PM

metal-enclosed switchgear and controlgear providing continuous metallic partitions and/or shutters (if applicable), intended to be earthed, between opened accessible compartments and high-voltage live parts



3.109.2

partition class PI

metal-enclosed switchgear and controlgear having one or more non-metallic partitions or shutters between opened accessible compartments and high-voltage live parts



3.110

shutter

part of metal-enclosed switchgear and controlgear that may be moved from a position where it permits contacts of a removable part, or moving contact of a disconnector, to engage fixed contacts, to a position where it becomes a part of the enclosure or partition shielding the fixed contacts



Note: It is revised from GB/T 2900.20-2016, Definition 5.8.



3.111

segregation (of conductors)

arrangement of conductors with earthed metal interposed between them in such a manner that disruptive discharges can only occur to earth



Note 1: A segregation may be established between the conductors as well as between the open contacts of a switching device.



Note 2: This definition does not specify any mechanical protection (IP and IK).



Note 3: It is revised from GB/T 2900.20-2016, Definition 3.11.



3.112

bushing

structure carrying one or more conductors through an enclosure or partition and insulating it there from, including the means of attachment



3.113

component

essential part of the main circuit or earthing circuits of metal-enclosed switchgear and controlgear which serves a specific function (for example, circuit-breaker, disconnector, earthing switch, load switch, fuse, instrument transformer, bushing, busbar, etc.)



3.114

solid-insulation embedded component

independent part of high-voltage conductive component encapsulated with solid insulating materials



3.115

main circuit

all the high-voltage conductive parts of metal-enclosed switchgear and controlgear included in a circuit which is intended to carry the rated normal current



Note: It is revised from GB/T 2900.20-2016, Definition 5.2.



3.116

earthing circuit

conductors, connections, and the conductive parts of earthing devices intended to connect the high-voltage conductive parts to the earthing system of the installation



Note: Parts of metallic enclosures connected to the earthing system may be considered as part of the earthing circuit, refer to 6.5.



3.117

auxiliary circuit

all the conductive parts of metal-enclosed switchgear and controlgear included in a circuit (other than the high-voltage parts) intended to control, measure, signal and regulate



Note: It is revised from GB/T 2900.20-2016, Definition 5.4.



3.118

pressure relief device

device intended to relieve over pressure from a compartment



3.119

fluid-filled compartment

high-voltage compartment of metal-enclosed switchgear and controlgear filled with a fluid, either gas, other than ambient air, or liquid, for insulation/disconnection purposes



3.119.1

gas-filled compartment

compartment of switchgear or controlgear, the gas pressure inside which is maintained by one of the following systems:

a) controlled pressure system;

b) closed pressure system;

c) sealed pressure system



Note: Several gas-filled compartments may be permanently connected into a common gas system (gas tightness assembly).



[GB/T 11022-2011, Definition 3.6.6.1]



3.119.2

liquid-filled compartment

compartment of metal-enclosed switchgear and controlgear in which the liquid is at atmospheric pressure, or under pressure that is maintained by one of the following systems:

a) controlled pressure system;

b) closed pressure system;

c) sealed pressure system



Note: For pressure systems, refer to subclause 3.6.5 of GB/T 11022-2011.



3.120

relative pressure

pressure, referred to the standard atmospheric pressure of 101.3kPa



3.121

minimum functional level (of fluid-filled compartments)

gas pressure (relative pressure) in Pa (or density) or liquid mass



Note: At and above this value the ratings of the metal-enclosed switchgear and controlgear are maintained.



3.122

design level (of fluid-filled compartments)

gas pressure (relative pressure) in Pa (or density) or liquid mass used to determine the design of a gas-filled compartment or mass for a liquid-filled compartment



3.123

design temperature (of fluid-filled compartments)

highest temperature which can be reached by the gas or liquid under service conditions



3.124

ambient air temperature (of metal-enclosed switchgear and controlgear)

temperature, determined under prescribed conditions, of the air surrounding the enclosure of metal-enclosed switchgear and controlgear



3.125

removable part

part of metal-enclosed switchgear and controlgear connected to the main circuit and that may be removed entirely from the metal-enclosed switchgear and controlgear and replaced, even though the main circuit of the functional unit is live



Note: It is revised from GB/T 2900.20-2016, Definition 5.9.



3.126

withdrawable part

removable part of metal-enclosed switchgear and controlgear that can be moved to positions in which an isolating distance or segregation between open contacts is established, while the part remains mechanically attached to the enclosure



Note: It is revised from GB/T 2900.20-2016, Definition 5.10.



3.127

service position (connected position)

position of a removable part in which it is fully connected for its intended function



Note: It is revised from GB/T 2900.20-2016, Definition 8.25.



3.128

earthing position

position of a removable part or state of a disconnector



Note 1: In this state, the closing of a mechanical switching device causes a main circuit to be short-circuited and earthed.



Note 2: It is revised from GB/T 2900.20-2016, Definition 8.26.



3.129

test position (of a withdrawable part)

position of a withdrawable part in which an isolating distance or segregation is established in the main circuit and in which the auxiliary circuits are connected



Note: It is revised from GB/T 2900.20-2016, Definition 8.27.



3.130

disconnected position (of a withdrawable part)

position of a withdrawable part in which an isolating distance or segregation is established in the circuits of the withdrawable part, that part remaining mechanically attached to the enclosure



Note 1: In high-voltage metal-enclosed switchgear and controlgear, the auxiliary circuits may not be disconnected.



Note 2: It is revised from GB/T 2900.20-2016, Definition 8.28.



3.131

removed position (of a removable part)

position of a removable part when it is outside and mechanically and electrically separated from the enclosure



Note: It is revised from GB/T 2900.20-2016, Definition 8.29.



3.132

loss of service continuity category; LSC

category defining the possibility to keep other compartments and/or functional units energized when opening an compartment of main circuit, as stated in definitions 3.107.1 to 3.107.3



Note 1: The LSC category describes the extent to which the switchgear and controlgear are intended to remain operational in case access to a high-voltage compartment is provided. The extent to which it is considered necessary to open high-voltage compartments with a live installation might be dependent on several aspects (refer to 9.102).



Note 2: The LSC category does not describe ranks of reliability of switchgear and controlgear (refer to 9.103).



Note 3: According to accessible compartments and service continuity, four categories are possible: LSC1, LSC2, LSC2A, LSC2B.



3.132.1

category LSC2 functional unit

functional unit with at least one accessible compartment for high-voltage connections (i.e. connection compartments, other than the busbar compartment of single-busbar switchgear)



Note 1: When such compartment is open, at least one busbar can remain energized and all other functional units can be operated normally.



Note 2: When LSC2 functional units have accessible compartments other than the connection compartment, further subdivisions into LSC2A and LSC2B are defined.



3.132.2

category LSC2A functional unit

functional unit of category LSC2 such that, when any accessible compartment (other than the busbar compartment of single-busbar switchgear and controlgear) is open, at least one busbar can remain energized and all other functional units can be operated normally



3.132.3

category LSC2B functional unit

functional unit of category LSC2A, where the high-voltage connections (e.g. cable connections) to the functional unit can remain energized when any other accessible high-voltage compartment of the corresponding functional unit is open



3.132.4

category LSC1 functional unit

functional unit having one or more high-voltage accessible compartments, such that, when any of these accessible high-voltage compartments is open, at least one other functional unit cannot remain energized



3.133

internal arc classified switchgear and controlgear; IAC

metal-enclosed switchgear and controlgear for which prescribed criteria, for protection of persons, are met in the event of internal arc as demonstrated by type tests



Note: The internal arc classification is described by the characteristics given from 3.133.1 to 3.133.4.



3.133.1

type of accessibility

characteristic related to the level of protection given to people accessing a defined area around the enclosure of switchgear and controlgear



3.133.2

classified sides

characteristic related to the accessible sides having a defined level of protection of persons given by the enclosure of the switchgear and controlgear in the event of internal arc



3.133.3

arc fault current

three-phase and, where applicable, the single phase-to-earth r.m.s. value of the internal arc fault current for which the switchgear and controlgear is designed to protect persons in the event of an internal arc



3.133.4

arc fault duration

duration of the internal arc fault current for which the switchgear and controlgear is designed to protect persons in the event of an internal arc



3.134

degree of protection

extent of protection provided by an enclosure, partition or shutter if applicable, against access to hazardous parts, against ingress of solid foreign objects and/or ingress of water and verified by standardized test methods



3.135

disruptive discharge

phenomena associated with the failure of insulation under electric stress, in which the discharge completely bridges the insulation under test, reducing the voltage between the electrodes to zero or nearly to zero



Note 1: The term applies to discharges in solid, liquid and gaseous dielectrics and to combinations of these.



Note 2: A disruptive discharge in a solid dielectric produces permanent loss of dielectric strength (nonself-restoring insulation); in a liquid or gaseous dielectric, the loss may be only temporary (self-restoring insulation).



Note 3: The term "sparkover" is used when a disruptive discharge occurs in a gaseous or liquid dielectric. The term "flashover" is used when a disruptive discharge occurs over the surface of a solid dielectric in gaseous or liquid medium. The term "puncture" is used when a disruptive discharge occurs through a solid dielectric.



4 Normal and special service conditions



Clause 2 of GB/T 11022-2011 is applicable with the following addition:



Unless otherwise specified in this standard, metal-enclosed switchgear and controlgear are designed for normal use.

Foreword i
1 Scope
2 Normative references
3 Terms and definitions
4 Normal and special service conditions
5 Ratings
5.1 General
5.2 Rated voltage (Ur)
5.3 Rated insulation level
5.4 Rated frequency (fr)
5.5 Rated normal current and temperature rise
5.6 Rated short-time withstand currents
5.7 Rated peak withstand current
5.8 Rated durations of short circuit
5.9 Rated supply voltage of closing and opening devices and of auxiliary and control circuits (Ua)
5.10 Rated supply frequency of closing and opening devices and of auxiliary and control circuits
5.11 Rated pressure of compressed gas supply for controlled pressure systems
5.12 Rated filling levels for insulation and/or operation
5.101 Ratings of the internal arc classification (IAC)
5.102 Rated cable test voltages
6 Design and construction
6.1 General
6.2 Requirements for liquids in switchgear and controlgear
6.3 Requirements for gases in switchgear and controlgear
6.4 Requirements for use of solid-insulation embedded component in the main circuit of switchgear and controlgear
6.5 Earthing
6.6 Auxiliary and control equipment
6.7 Power operation
6.8 Stored energy operation
6.9 Independent manual operation
6.10 Operation of releases
6.11 Low- and high-pressure interlocking and monitoring devices
6.12 Nameplates
6.13 Interlocking devices
6.14 Position indication
6.15 Degrees of protection provided by enclosures
6.16 Creepage distances for outdoor insulators
6.17 Gas and vacuum tightness
6.18 Liquid tightness
6.19 Fire hazard (flammability)
6.20 Electromagnetic compatibility (EMC)
6.21 X-radiation emission
6.22 Corrosion
6.101 Internal arc fault
6.102 Enclosure
6.103 High-voltage compartments
6.104 Removable parts
6.105 Provisions for dielectric tests on cables
7 Type tests
7.1 General provisions
7.2 Dielectric tests
7.3 Radio interference voltage (r.i.v.) test
7.4 Measurement of the resistance of circuits
7.5 Temperature-rise tests
7.6 Short-time withstand current and peak withstand current tests
7.7 Verification of the degree of protection
7.8 Tightness tests
7.9 Electromagnetic compatibility tests (EMC)
7.10 Additional tests on auxiliary and control circuits
7.11 X-radiation test procedures for vacuum interrupters
7.101 Verification of making and breaking capacities
7.102 Mechanical operation tests
7.103 Pressure withstand test for gas-filled compartments and gas state measurement
7.104 Tests to verify the protection of persons against dangerous electrical effects
7.105 Weatherproofing test
7.106 Internal arc test
7.107 Performance verification test of metal-enclosed switchgear with solid-insulation embedded components as main components in main circuit
8 Routine tests
8.1 General
8.2 Dielectric test on the main circuit
8.3 Tests on auxiliary and control circuits
8.4 Measurement of the resistance of the main circuit
8.5 Tightness test
8.6 Design and visual checks
8.101 Partial discharge measurement
8.102 Mechanical operation tests
8.103 Pressure tests of gas-filled compartments
8.104 Tests of auxiliary electrical, pneumatic and hydraulic devices
8.105 Tests after erection on site
8.106 Measurement of fluid condition after filling on site
9 Guide to the selection of metal-enclosed switchgear and controlgear
9.1 General
9.101 Selection of rated values
9.102 Selection of design and construction
9.103 Internal arc fault
9.104 Summary of technical requirements, ratings and optional tests
9.105 Ratings of earthing circuits
9.106 Ratings for cable testing
10 Information to be given with enquiries, tenders and orders
10.1 General
10.2 Information with enquiries and orders
10.3 Information with tenders
11 Transport, storage, installation, operation and maintenance
11.1 General
11.2 Conditions during transport, storage and installation
11.3 Installation
11.4 Operation
11.5 Maintenance
12 Safety
12.1 General
12.101 Procedures
12.102 Internal arc aspects
13 Influence of the product on the environment
Annex A (Informative) Comparison list of equivalent clause numbering of this standard with IEC 62271-200:
Annex B (Normative) Internal arc fault — Method to verify the internal arc classification (IAC)
Annex C (Informative) Electric shock protection grade of solid-insulation enclosed switchgear and controlgear
Annex D (Normative) Method for calculating cross-sectional area of bare conductor according to thermal effect of short-term continuous current
Annex E (Normative) Additional requirements for alternating-current metal-enclosed switchgear and controlgear for rated voltages above 3.6 kV and up to and including 40.5 kV for severe climatic conditions
Annex F (Normative) Partial discharge measurement
Annex G (Informative) Explanatory notes
Bibliography

3.6kV～40.5kV交流金属封闭开关设备和控制设备
1 范围
本标准规定了3.6kV～40.5kV交流金属封闭开关设备和控制设备的术语和定义、使用条件、额定值、设计与结构、型式试验、出厂试验等各项技术要求。
本标准适用于工厂装配的、额定电压为3.6kV～40.5kV、户内或户外安装的、频率为50Hz及以下的交流金属封闭开关设备和控制设备，其外壳内可能装有固定式或可移开式的元件，并可能充有绝缘和/或开断用流体(液体或气体)。
注1：本标准主要是针对三相系统，但也可用于单相或两相系统。
根据以下几点，本标准将金属封闭开关设备和控制设备划分为若干类：
——维修开关设备和控制设备时，电网运行的连续性；
——设备维修的需要和方便性。
注2：设备的安全性取决于产品的设计、制造、使用、调整、配合、安装和运行。
对于具有充气隔室的金属封闭开关设备和控制设备，设计压力不超过0.3MPa(相对压力)时本标准适用。
注3：设计压力超过0.3MPa(相对压力)的充气隔室宜按GB/T 7674进行设计和试验。
特殊用途的金属封闭开关设备和控制设备，例如有易燃性气体的场所、矿井中或船舶上，可能需要增加相应的技术要求。
装于金属封闭开关设备和控制设备中的各元件按照各自标准的规定进行设计和试验。考虑到各个元件在成套开关设备和控制设备中的安装情况，本标准对单个元件的标准做了补充。
本标准不排除在同一外壳中使用其他设备，此时有必要考虑设备对成套开关设备和控制设备造成的影响。
注4：具有绝缘外壳的成套开关设备和控制设备，参照IEC 62271-201：2014的规定。
本标准也适用于额定电压40.5kV以上、采用空气绝缘或充气隔室、设计压力不超过0.3MPa(相对压力)的金属封闭开关设备和控制设备。
2 规范性引用文件
下列文件对于本文件的应用是必不可少的。凡是注日期的引用文件，仅注日期的版本适用于本文件。凡是不注日期的引用文件，其最新版本(包括所有的修改单)适用于本文件。
GB/T 762 标准电流等级(GB/T 762—2002，eqv IEC 60059：1999)
GB/T 1408.1—2016 绝缘材料电气强度试验方法 第1部分：工频下试验(IEC 60243-1：2013，IDT)
GB/T 1984—2014 高压交流断路器(IEC 62271-100：2008，MOD)
GB/T 1985—2014 高压交流隔离开关和接地开关(IEC 62271-102：2001＋A1：2011，MOD)
GB/T 2423.1 电工电子产品环境试验 第2部分：试验方法 试验A：低温(GB/T 2423.1—2008，IEC 60068-2-1：2007，IDT)
GB/T 2423.2 电工电子产品环境试验 第2部分：试验方法 试验B：高温(GB/T 2423.2—2008，IEC 60068-2-2：2007，IDT)
GB/T 2423.22 环境试验 第2部分：试验方法 试验N：温度变化(GB/T 2423.22—2012，IEC 60068-2-14：2009，IDT)
GB/T 2900.20—2016 电工术语 高压开关设备和控制设备(IEC 60050-441：1984，MOD)
GB/T 3804 3.6kV～40.5kV高压交流负荷开关(GB/T 3804—2017，IEC 62271-103：2011，MOD)
GB/T 4208—2017 外壳防护等级(IP代码)(IEC 60529：2013，IDT)
GB/T 7354 局部放电测量(GB/T 7354—2018，IEC 60270：2000，MOD)
GB/T 8905—2012 六氟化硫电气设备中气体管理和检验导则(IEC 60480：2004，MOD)
GB/T 11022—2011 高压开关设备和控制设备标准的共用技术要求(IEC 62271-1：2007，MOD)
GB/T 14808—2016 高压交流接触器、基于接触器的控制器及电动机起动器(IEC 62271-106：2011，MOD)
GB/T 16926 高压交流负荷开关 熔断器组合电器(GB/T 16926—2009，IEC 62271-105：2002，MOD)
GB/T 16927.1—2011 高电压试验技术 第1部分：一般定义及试验要求(IEC 60060-1：2010，MOD)
GB/T 20002.4—2015 标准中特定内容的起草 第4部分：标准中涉及安全的内容(ISO/IEC Guide 51：2014，MOD)
GB/T 20138 电器设备外壳对外界机械碰撞的防护等级(IK代码)(GB/T 20138—2006，IEG 62262：2002，IDT)
3 术语和定义
GB/T 2900.20—2016和GB/T 11022—2011界定的以及下列术语和定义适用于本文件。
3.101
开关设备和控制设备 switchgear and controlgear
开关装置及与其相关的控制、测量、保护和调节设备的组合，以及这些装置和设备同相关的电气连接、辅件、外壳和支撑件的总装的总称。
[GB/T 2900.20—2016，定义3.1]
3.102
金属封闭开关设备和控制设备 metal-enclosed switchgear and controlgear
除进出线外，其余完全被接地金属外壳封闭的开关设备和控制设备。
[GB/T 2900.20—2016，定义4.4]
3.103
功能单元 functional unit
金属封闭开关设备和控制设备的一部分，包括为满足单一功能的主回路和辅助回路的所有元件。
注1：功能单元可以根据预定的功能来区分，例如进线单元、出线单元等。
注2：改写GB/T 2900.20—2016，定义5.5。
3.104
多层设计 multi-tier design
两个或多个功能单元的主开关装置垂直布置(一个在另一个上面)在一个公共外壳内的金属封闭开关设备和控制设备的设计。
3.105
运输单元 transport unit
不需拆开便可以运输的金属封闭开关设备和控制设备的一部分。
3.106
外壳 enclosure
金属封闭开关设备和控制设备的一部分，它能够对外界影响提供规定的防护等级，对防止人员接近和触及带电部件以及触及运动部件提供规定的防护等级。
注：改写GB/T 2900.20—2016，定义5.1。
3.107
高压隔室 high-voltage compartment
金属封闭开关设备和控制设备的隔室，包含高压导电部件，除内部连接、控制或通风所必要的开孔外，其余均封闭。
注1：隔室分为四种类型，其中三种可以打开，称为可触及隔室(见3.107.1～3.107.3)，一种不能打开，称为不可触及隔室(见3.107.4)。
注2：GB/T 2900.20—2016的5.6给出了隔室的一般定义，即“总装的一部分，除内部连接、控制或通风所必要的开孔外，其余均封闭。”
注3：隔室可能包括挡板、结构件或元件，它们提供如机械或绝缘等多种功能，但不同于隔板或外壳的功能。
注4：高压隔室可以按内部安装的主要元件或提供的主要功能划分。
3.107.1
联锁控制的可触及隔室 interlock-controlled accessible compartment
按制造厂的规定，可以打开进行正常操作和/或正常维护，触及受开关设备和控制设备总体设计控制的高压隔室。
注：安装、扩展和修理等不是正常的维护。
3.107.2
基于程序的可触及隔室 procedure-based accessible compartment
按制造厂的规定，可以打开进行正常操作和/或正常维护，触及受适当的程序结合锁具控制的高压隔室。
注：安装、扩展和修理等不是正常的维护。
3.107.3
基于工具的可触及隔室 tool-based accessible compartment
可以打开，但不是为了进行正常操作和维护，仅能使用工具才能打开的高压隔室。
注：可能要求有专门的程序。
3.107.4
不可触及隔室 non-accessible compartment
不可以打开的高压隔室。
注：打开会破坏隔室的完整性。
3.107.5
连接隔室 connection compartment
将金属封闭开关设备和控制设备的主回路与电网或者其他高压电器的外部导体(电缆或母线)进行电气连接的高压隔室。
注：例如电缆连接隔室。
3.108
隔板 partition
金属封闭开关设备和控制设备的一个部件，它将一个高压隔室与另一个隔室隔开并提供规定的防护等级。
注1：用于屏蔽的可动活门可以成为隔板的组成部分。
注2：隔板可以装有允许隔室间相互连接的部件(例如套管)。
注3：改写GB/T 2900.20—2016，定义5.7。
3.109
隔板的等级 partition class
根据隔板所用的是金属还是非金属材料确定其分类。
3.109.1
PM级隔板 partition class PM
在打开的隔室和高压带电部件之间，金属封闭开关设备和控制设备具有的连续并接地的金属隔板和/或活门(如果适用)。
3.109.2
PI级隔板 partition class PI
在打开的隔室和高压带电部件之间，金属封闭开关设备和控制设备具有的一个或多个非金属隔板和/或活门。
3.110
活门 shutter
金属封闭开关设备和控制设备的一种部件，它具有两个可以转换的位置，一个位置是允许可移开部件的触头或隔离开关的动触头与固定触头接合，在另一个位置，它成为外壳或隔板的一部分，遮住固定触头。
注：改写GB/T 2900.20—2016，定义5.8。
3.111
(导体的)分隔 segregation (of conductors)
导体之间插有接地金属件，使破坏性放电只能发生在(导体)对地之间的一种导体布置方式。
注1：分隔可以建立在导体之间，也可以建立在开关装置打开的触头之间。
注2：本定义没有规定任何机械防护(IP和IK)。
注3：改写GB/T 2900.20—2016，定义3.11。
3.112
套管 bushing
能使一根或多根导体穿过外壳或膈板并使导体与外壳或隔板绝缘的一种构件，包括固定用的附件。
3.113
元件 component
金属封闭开关设备和控制设备主回路和接地回路中，具有特定功能的基本部件(例如断路器、隔离开关、接地开关、负荷开关、熔断器、互感器、套管、母线等)。
3.114
固体绝缘包覆元件 solid-insulation embedded component
将高压导电元件用固体绝缘材料封装组成的独立部件。
3.115
主回路 main circuit
金属封闭开关设备和控制设备中承载额定电流的回路中的所有高压导电部件。
注：改写GB/T 2900.20—2016，定义5.2。
3.116
接地回路 earthing circuit
用来将高压导电部件同设施的接地系统相连的导体、连接端子以及接地装置的导电部件。
注：可以认为与接地系统连接的金属外壳的部件是接地回路的一部分，见6.5。
3.117
辅助回路 auxiliary circuit
金属封闭开关设备和控制设备中用于控制、测量、信号和调节回路(非高压部件)的所有导电部件。
注：改写GB/T 2900.20—2016，定义5.4。
3.118
压力释放装置 pressure relief device
用于释放隔室过压力的装置。
3.119
充流体隔室 fluid-filled compartment
金属封闭开关设备和控制设备的高压隔室，其中充有绝缘和/或开断用流体，即气体(不是周围空气)或液体。
3.119.1
充气隔室 gas-filled compartment
开关设备和控制设备的隔室，隔室内部的气体压力由下列一种系统保持：
a)可控压力系统；
b)封闭压力系统；
c)密封压力系统。
注：几个充气隔室相互间可以永久联接成一公共的气体系统(气密性装配)。
[GB/T 11022—2011，定义3.6.6.1]
3.119.2
充液体隔室 liquid-filled compartment
金属封闭开关设备和控制设备的一种隔室，其中充有液体，内部的压力为大气压力，或其压力由下列系统之一保持：
——可控压力系统；
——封闭压力系统；
——密封压力系统。
注：压力系统参见GB/T 11022—2011的3.6.5。
3.120
相对压力 relative pressure
相对于标准大气压力101.3kPa的压力。
3.121
(充流体隔室的)最低功能水平 minimum functional level(of fluid-filled compartments)
气体压力值[相对压力，用Pa(或密度)表示]或液体的质量。
注：在此值及以上时，才能保证金属封闭开关设备和控制设备的额定值。
3.122
(充流体隔室的)设计水平 design level (of fluid-filled compartments)
用于确定充气隔室设计的气体压力值[相对压力，用Pa(或密度)表示]或充液隔室设计的液体质量。
3.123 (充流体隔室的)设计温度 design temperature (of fluid-filled compartments)
在运行条件下，充流体隔室的气体或液体所能达到的最高温度。
3.124 (金属封闭开关设备和控制设备的)周围空气温度 ambient air temperature (of metal-enclosed switchgear and controlgear)
在规定的条件下测得的金属封闭开关设备和控制设备外壳周围的空气温度。
3.125
可移开部件 removable part
金属封闭开关设备和控制设备中能够被完全移出并能被替换的连接到主回路中的部件(即使功能单元的主回路带电也不例外)。
注：改写GB/T 2900.20—2016，定义5.9。
3.126
可抽出部件 withdrawable part
金属封闭开关设备和控制设备的可移开部件，它可以移到使打开的触头之间形成一个隔离断口或分离(此时仍与外壳保持机械联系)。
注：改写GB/T 2900.20—2016，定义5.10。
3.127
工作位置(接通位置) service position (connected position)
为完成预定的功能，可移开部件处于完全接通的位置。
注：改写GB/T 2900.20—2016，定义8.25。
3.128
接地位置 earthing position
可移开部件的位置或隔离开关的状态。
注1：在此状态下，机械开关装置的合闸操作使主回路短路并接地。
注2：改写GB/T 2900.20—2016，定义8.26。
3.129
(可抽出部件的)试验位置 test position (of a withdrawable part)
可抽出部件的位置，在此位置，主回路形成一个隔离断口或分隔，辅助回路是接通的。
注：改写GB/T 2900.20—2016，定义8.27。
3.130
(可抽出部件的)隔离位置 disconnected position (of a withdrawable part)
可抽出部件的位置，在此位置，可抽出部件回路中形成一个隔离断口或分隔，但可抽出部件仍与外壳保持机械联系。
注1：在高压金属封闭开关设备和控制设备中，辅助回路可以不断开。
注2：改写GB/T 2900.20—2016，定义8.28。
3.131
(可移开部件的)移开位置 removed position (of a removable part)
可移开部件的位置，可移开部件在外壳外面，且与外壳脱离了机械和电气联系。
注：改写GB/T 2900.20—2016，定义8.29。
3.132
丧失运行连续性类别 loss of service continuity category；LSC
根据主回路隔室打开时其他隔室和/或功能单元是否可继续带电划分的设备类别，可触及隔室如3.107.1～3.107.3的规定。
注1：LSC类别描述了当需要触及髙压隔室时开关设备和控制设备可以保持运行的程度。认为有必要打开装有带电设备的高压隔室的程度取决于多种因素(见9.102)。
注2：LSC类别不规定开关设备和控制设备的可靠性类别(见9.103)。
注3：根据可触及隔室和运行连续性，可能有四种类别：LSC1、LSC2、LSC2A、LSC2B。
3.132.1
LSC2类功能单元 category LSC2 functional unit
至少具有一个用于高压连接的可触及隔室(即连接隔室，且单母线开关设备的母线连接隔室除外)的功能单元。
注1：该隔室打开时，至少一条母线能保持带电且所有其他功能单元可以正常运行。
注2：如果LSC2类功能单元除连接隔室外还有其他可触及隔室，可以进一步细分为LSC2A和LSC2B。
3.132.2
LSC2A类功能单元 category LSC2A functional unit
如果任何一个可触及隔室(不同于单母线开关设备和控制设备的母线隔室)打开时，至少一条母线能保持带电且所有其他功能单元能够正常运行的LSC2类功能单元。
3.132.3
LSC2B类功能单元 category LSC2B functional unit
如果功能单元的任何其他可触及高压隔室打开时，功能单元的高压连接(例如电缆连接)能保持带电的LSC2A类功能单元。
3.132.4
LSC1类功能单元 category LSC1 functional unit
具有一个或多个高压可触及隔室的功能单元，当其中任意一个高压可触及隔室打开时，至少一个其他功能单元不能保持带电。
3.133
内部电弧级开关设备和控制设备 internal arc classified switchgear and controlgear；IAC
经型式试验验证、在内部电弧情况下，为人员提供规定的保护要求的金属封闭开关设备和控制设备。
注：内部电弧类别通过3.133.1～3.133.4给出的特征来描述。
3.133.1
可触及性的型式 type of accessibility
人员接触幵关设备和控制设备外壳周围限定区域时，其所能提供的、与保护水平相关的特征。
3.133.2
面板的类别 classified sides
在内部电弧情况下，开关设备和控制设备外壳的可触及面板对人员提供的、与防护水平相关的特征。
3.133.3
电弧故障电流 arc fault current
在内部电弧情况下开关设备和控制设备设计的、与人员保护相关的三相以及单相对地(适用时的)内部电弧故障电流的有效值。
3.133.4
电弧故障持续时间 arc fault duration
在内部电弧情况下开关设备和控制设备设计的、与人员保护相关的内部电弧故障电流的持续时间。
3.134
防护等级 degree of protection
外壳以及隔板或活门(适用时)提供的、防止接近危险部件、防止固体外物进入和/或防止水的浸入以及外壳防止机械撞击，并由标准试验方法验证过的保护程度。
3.135
破坏性放电 disruptive discharge
在电场作用下伴随绝缘破坏而产生的一种现象，此时放电完全跨接了被试绝缘，使电极之间的电压降到零或接近于零。
注1：该术语适用于在固体、液体和气体介质以及其组合中的放电。
注2：固体介质中的破坏性放电，会导致永久地丧失绝缘强度(非自恢复绝缘)；而在液体和气体介质中可能仅是暂时丧失绝缘强度(自恢复绝缘)。
注3：破坏性放电发生在气体或液体介质中时，叫做“火花放电”；破坏性放电发生在气体或液体介质中的固体介质表面时，叫做“闪络“；破坏性放电贯穿于固体介质时，叫做“击穿”。
4 正常和特殊使用条件
按GB/T 11022—2011中第2章的规定，并做如下补充：
除本标准中另有规定外，金属封闭开关设备和控制设备是按正常使用条件设计的。
5 额定值
5.1 概述
金属封闭开关设备和控制设备的额定值如下：
a)额定电压(Ur)和相数；
b)额定绝缘水平；
c)额定频率(fr)；
d)额定电流(Ir)(主回路的)；
e)额定短时耐受电流(Ik，Ike)(主回路的和接地回路的)；
f)额定峰值耐受电流(Ip，Ipe)(主回路的和接地回路的)；
g)额定短路持续时间(tk，tke)(主回路的和接地回路的)；
h)金属封闭开关设备和控制设备中各元件(包括它们的操动装置和辅助设备)的额定值；
i)额定充入水平(充流体隔室的)；
j)内部电弧级别(IAC)的额定值(如果制造厂有规定)。
5.2 额定电压(Ur)
按GB/T 11022—2011中4.2的规定。
注：对于金属封闭开关设备和控制设备的各组成元件，可按其有关标准具有各自的额定电压值。
5.3 额定绝缘水平
按GB/T 11022—2011中4.3的规定。
5.4 额定频率(fr)
按GB/T 11022—2011中4.4的规定，并做如下补充：
金属封闭开关设备和控制设备的标准值为50Hz。
5.5 额定电流和温升
5.5.1 额定电流
按GB/T 11022—2011中4.5.1的规定，并做如下补充：
金属封闭开关设备和控制设备的某些主回路(如母线、馈电线路等)可以有不同的额定电流值。
5.5.2 温升
按GB/T 11022—2011中4.5.2的规定，并做如下补充：
金属封闭开关设备和控制设备中各元件的温升应按照它们各自技术规范，其温升不得超过这些元件的相关标准中规定的限值。
当考虑母线的最高允许温度或温升时，应根据工作情况，按触头、连接及与绝缘材料接触的金属部件的最高允许温度或温升确定。
可触及的外壳和盖板的温升不应超过30K。对可触及而在正常运行时毋需触及的外壳和盖板，如果公众不可触及，则其温升极限可增加10K。
5.6 额定短时耐受电流
对于额定短时耐受电流Ik和Ike，GB/T 11022—2011的4.6适用并做如下补充：
——主回路额定短时耐受电流Ik；
注1：原则上，主回路的额定短时耐受电流不能超过其串联元件中最薄弱元件的相应额定值。但是，对于高压隔室或每一个回路，可以采用限制短路电流的器件，如限流熔断器、电抗器等。
——接地回路额定短时耐受电流Ike：
该值可以不同于主回路的数值。
注2：接地回路适用的短路电流额定值取决于所用在的系统中性点的接地类型。见9.105。