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GB/T 7251.2-2023 English PDF (GBT7251.2-2023)

GB/T 7251.2-2023 English PDF (GBT7251.2-2023)

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GB/T 7251.2-2023: Low-voltage switchgear and controlgear assemblies - Part 2: Power switchgear and controlgear assemblies
GB/T 7251.2-2023
GB
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 29.130.20
CCS K 31
GB/T 7251.2-2023 / IEC 61439-2:2020
Replacing GB/T 7251.12-2013
Low-Voltage Switchgear and Controlgear Assemblies
– Part 2: Power Switchgear and Controlgear Assemblies
(IEC 61439-2:2020, IDT)
ISSUED ON: AUGUST 6, 2023
IMPLEMENTED ON: MARCH 1, 2024
Issued by: State Administration for Market Regulation;
Standardization Administration of the People’s Republic of China.
Table of Contents
Foreword ... 3
Introduction ... 7
1 Scope ... 8
2 Normative References ... 9
3 Terms and Definitions ... 10
4 Symbols and Abbreviations ... 13
5 Interface Characteristics ... 13
6 Information ... 15
7 Service Conditions ... 15
8 Constructional Requirements ... 15
9 Performance Requirements ... 20
10 Design Verification ... 20
11 Routine Verification ... 25
Annexes ... 28
Annex AA (Informative) Items Subject to Agreement between the PSC-Assembly Manufacturer and the User ... 29
Annex BB (Informative) Forms of Internal Separation (see 8.101) ... 33
Annex CC (Informative) Determining Power Loss by Measurement for Circuits Exceeding 1600 A in a Reference Design ... 39
Annex DD (Informative) Assemblies for Use in Photovoltaic Installations ... 41 Annex EE (Informative) Items Subject to Agreement between the Photovoltaic Assembly (PVA) Manufacturer and the User ... 52
Annex FF (Informative) Design Verification (PVA Only) ... 56
Annex GG (Informative) List of Notes Concerning Certain Countries ... 58 Bibliography ... 59
Foreword
This Document was drafted as per the rules specified in GB/T 1.1-2020 Directives for Standardization – Part 1: Rules for the Structure and Drafting of Standardizing Documents. This Document is Part 2 of GB/T 7251 Low-Voltage Switchgear and Controlgear Assemblies. GB/T 7251 has published the following parts:
--- Part 1: General rules;
--- Part 2: Power switchgear and controlgear assemblies;
--- Part 3: Distribution boards intended to be operated by ordinary persons (DBO); --- Part 4: Particular requirements for assemblies for construction sites (ACS); --- Part 5: Particular requirements for assemblies for power distribution in public networks; --- Part 6: Busbar trunking systems (busways);
--- Part 7: Assemblies for specific applications such as marinas, camping sites, market squares, electric vehicles charging stations;
--- Part 8: General technical requirements for intelligent assembly;
--- Part 10: Guidance to specifying assemblies.
This Document replaced GB/T 7251.12-2013 Low-Voltage Switchgear and Controlgear Assemblies - Part 2: Power Switchgear and Controlgear Assemblies. Compared with GB/T 7251.12-2013, the technical changes of this Document are as follows besides the structural adjustments and editorial modifications:
--- Add requirements for photovoltaic installation assemblies (see Annexes DD, EE and FF of this Edition);
--- Change the requirements for the internal isolation form. When the isolation form is greater than 1, when the functional unit is turned off, the protection level of all still running components between the functional units shall be at least IPXXB (see 8.101 of this Edition; 8.101 of 2013 Edition);
--- Add the verification method in the verification and evaluation method of temperature rise (i) Verify the temperature rise of assemblies with natural cooling and circuits with rated currents above 1600A through comparison with reference designs and calculations; (ii) Verify the temperature rise for assemblies with active cooling and rated current not exceeding 1600A. (See 10.10.4.101, 10.10.4.102 of this Edition);
Low-Voltage Switchgear and Controlgear Assemblies
– Part 2: Power Switchgear and Controlgear Assemblies
1 Scope
This Document defines the specific requirements for the power switchgear and controlgear assembly (abbreviated ‘PSC-assembly’ throughout this Document see 3.1.101) as follows: --- assemblies for which the rated voltage does not exceed 1 000 V AC or 1 500 V DC; --- assemblies designed for a nominal frequency of the incoming supply or supplies not exceeding 1 000 Hz;
NOTE 1: Frequencies above 1 kHz are considered as high frequencies, see also GB/T 16935.1- 2008, 5.3.3.2.5 to take into account additional constraints to insulation coordination. --- assemblies intended for indoor and outdoor applications;
--- stationary or movable assemblies with or without enclosures;
--- assemblies intended for use in connection with the generation, transmission, distribution and conversion of electrical energy, and for the control of equipment consuming electrical energy and for associated data processing;
--- assemblies designed for use under special service conditions, for example in ships and in rail vehicles, provided that the other relevant specific requirements are complied with; NOTE 2: Supplementary requirements for assemblies in ships are covered by IEC 60092-302-2. This Document also applies to assemblies for use in photovoltaic installations, designated as photovoltaic assemblies (PVA). The particular characteristics, specific service conditions and the requirements for PVA’s are included in Annexes DD, EE and FF.
This Document provides supplementary requirements for PSC-assemblies intended for use as part of the electrical equipment of machines and can be applied in addition to the requirements given in IEC 60204-1.
This Document applies to all assemblies whether they are designed, manufactured and verified on a one-off basis or fully standardized and manufactured in quantity.
The manufacture and/or assembly can be carried out by an entity other than the original manufacturer (see 3.10.1 of GB/T 7251.1-2023).
test position (see 3.2.102), or a test situation (see 3.1.102). They shall be distinctly located in these positions. These positions shall be clearly discernible.
In PSC-assemblies with withdrawable parts all live parts shall be protected in such a manner that they cannot unintentionally be touched when the door, if any, is open and the withdrawable part is withdrawn from the connected position or removed. Where an obstacle or shutter is used they shall meet the requirements of 8.4.6.2.1 of GB/T 7251.1-2023.
For the electrical conditions associated with the different positions of withdrawable parts, see Table 103.
8.5.2.102 Interlocking and padlocking of removable and withdrawable parts A removable or withdrawable part shall be fitted with a device that ensures that it can only be removed and inserted after its main circuit has been switched off from the load. In order to prevent unauthorized operation, the removable and withdrawable parts or their associated assembly location may be provided with a lockable means to secure them in one or more of their positions.
8.5.3 Selection of switching devices and components
Addition:
NOTE 2: The standards with which components can comply, include, for example, IEC 60947 (all parts), IEC 60269 (all parts), IEC 60898 (all parts), IEC 61008 (all parts), IEC 61009 (all parts), IEC 62423, IEC 61800-5-1, IEC 61010-2-201.
Additional subclauses:
8.5.101 Description of the types of electrical connections of functional units A functional unit can have the same or different types of electrical connection for incoming and outgoing supplies; for example, a withdrawable connection can be used for the incoming and fixed or disconnectable for the outgoing.
NOTE 1: Particularly when multiple supplies are involved, the specifier carries out an assessment in order to choose the most appropriate connection.
The types of electrical connections of functional units within PSC-assemblies or parts of PSC- assemblies can be denoted by a three-letter code:
– the first letter denotes the type of electrical connection of the main incoming circuit; – the second letter denotes the type of electrical connection of the main outgoing circuit; – the third letter denotes the type of electrical connection of the auxiliary circuits.
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