GB/T 16935.1-2023 English PDF (GBT16935.1-2023)

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GB/T 16935.1-2023: Insulation coordination for equipment within low-voltage supply systems - Part 1: Principles, requirements and tests
GB/T 16935.1-2023
GB
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 29.080.30
CCS K 30
GB/T 16935.1-2023 / IEC 60664-1:2020
Replacing GB/T 16935.1-2008
Insulation coordination for equipment within low-voltage
supply systems - Part 1: Principles, requirements and tests
(IEC 60664-1:2020, IDT)
ISSUED ON: SEPTEMBER 07, 2023
IMPLEMENTED ON: APRIL 01, 2024
Issued by: State Administration for Market Regulation;
Standardization Administration of the People’s Republic of China.
Table of Contents
Foreword ... 4
Introduction ... 6
1 Scope ... 7
2 Normative references ... 8
3 Terms, definitions and abbreviated terms ... 8
3.1 Terms and definitions ... 8
3.2 Abbreviated terms ... 18
4 Basic technical characteristics for insulation coordination ... 18
4.1 General requirements ... 18
4.2 Voltages ... 19
4.3 Overvoltage categories... 22
4.4 Frequency ... 24
4.5 Pollution ... 24
4.6 Insulating material ... 25
4.7 Environmental aspects ... 28
4.8 Duration of voltage stress ... 30
4.9 Electrical field distribution ... 30
5 Design for insulation coordination ... 30
5.1 General requirements ... 30
5.2 Dimensioning of clearances ... 31
5.3 Dimensioning of creepage distances ... 35
5.4 Requirements for design of solid insulation ... 40
6 Tests and measurements ... 43
6.1 General requirements ... 43
6.2 Verification of clearances ... 43
6.3 Verification of creepage distances ... 47
6.4 Verification of solid insulation ... 47
6.5 Performing dielectric tests on complete equipment ... 54
6.6 Other tests ... 56
6.7 Measurement of the attenuation of the transient overvoltages... 57
6.8 Measurement of clearances and creepage distances ... 57
Annex A (Informative) Basic data on withstand characteristics of clearances ... 64
Annex B (Informative) Nominal voltages of mains supply for different modes of
overvoltage control ... 69
Annex C (Normative) Partial discharge test methods ... 71
C.1 Test circuits ... 71
C.2 Test parameters ... 73
C.3 Requirements for measuring instruments ... 73
C.4 Calibration ... 75
Annex D (Informative) Additional information on partial discharge test methods ... 78
D.1 Measurement of partial discharge (PD), PD inception and extinction voltage ... 78
D.2 Description of PD test circuits (Figure D.1) ... 78
D.3 Precautions for reduction of noise ... 79
D.4 Application of multiplying factors for test voltages ... 80
Annex E (Informative) Comparison of creepage distances specified in Table F.5 and
clearances in Table A.1 ... 82
Annex F (Normative) Tables ... 83
Annex G (Informative) Determination of clearance distances according to 5.2 ... 92
Annex H (Informative) Determination of creepage distances according to 5.3 ... 94
Bibliography ... 96
Foreword
This document was drafted in accordance with the rules provided in GB/T 1.1-2020
Directives for standardization - Part 1: Rules for the structure and drafting of
standardizing documents.
This document is Part 1 of GB/T 16935, Insulation coordination for equipment within
low-voltage supply systems. The following parts have been issued for GB/T 16935:
-- Part 1: Principles, requirements and tests;
-- Part 2-1: Application guide - Explanation of the application of the GB/T 16935
series, dimensioning example and dielectric testing;
-- Part 2 -2: Interface considerations - Application guide;
-- Part 3: Use of coating, potting or moulding for protection against pollution;
-- Part 4: Consideration of high-frequency voltage stress;
-- Part 5: Comprehensive method for determining clearances and creepage distances
equal to or less than 2 mm.
This document replaces GB/T 16935.1-2008, Insulation coordination for equipment
within low-voltage systems - Part 1: Principles requirements and tests. Compared with
GB/T 16935.1-2008, except for structural adjustment and editorial changes, the main
technical changes are as follows:
-- CHANGE the scope (see Clause 1; Clause 1 of the 2008 edition);
-- ADD terms such as “low-voltage supply system”, “mains supply” and “steady-
state working voltage” (see 3.1.1, 3.1.2, 3.1.8, etc.), CHANGE terms such as
“working overvoltage”, “flashover” and “electrical breakdown” (see 3.1.7, 3.1.46,
3.1.44, etc.; 3.7.2, 3.20.2, 3.20, etc. of the 2008 edition), and DELETE terms such
as “switching overvoltage”, “lightning overvoltage” and “functional overvoltage”
(see 3.7.3, 3.7.4, 3.7.5, etc. of the 2008 edition);
-- ADD 1500 V DC to tables in Annex B and Annex F;
-- CHANGE the correction factor at an altitude of 1 000 m from 0.844 to 0.884 (see
Table F.10; Table F.8 of the 2008 edition).
This document is identical to IEC 60664-1:2020, Insulation coordination for equipment
within low-voltage supply systems - Part 1: Principles, requirements and tests.
The following minimal editorial changes are made to this document:
Insulation coordination for equipment within low-voltage
supply systems - Part 1: Principles, requirements and tests
1 Scope
This document deals with insulation coordination for equipment having a rated voltage
up to AC 1 000 V or DC 1 500 V connected to low-voltage supply systems.
This document applies to frequencies up to 30 kHz.
Note 1: Requirements for insulation coordination for equipment within low-voltage
supply systems with rated frequencies above 30 kHz are given in IEC 60664-
4.
Note 2: Higher voltages can exist in internal circuits of the equipment.
This document applies to equipment for use up to 2 000 m above sea level and provides
guidance for use at higher altitudes (See 5.2.3.4).
This document provides requirements for technical committees to determine clearances,
creepage distances and criteria for solid insulation. It includes methods of electrical
testing with respect to insulation coordination.
The minimum clearances specified in this document do not apply where ionized gases
are present. Special requirements for such situations can be specified at the discretion
of the relevant technical committee.
This document does not deal with distances:
-- through liquid insulation;
-- through gases other than air;
-- through compressed air.
This basic safety publication focusing on safety essential requirements is primarily
intended for use by technical committees in the preparation of standards in accordance
with the principles laid down in IEC Guide 104 and ISO/IEC Guide 51.
One of the responsibilities of a technical committee is, wherever applicable, to make
use of basic safety publications in the preparation of its publications.
For the equipment likely to generate an overvoltage that is higher than the transients
expected to come into the equipment, for example due to switching devices, the
required impulse voltage shall take into account the transient generated in the
equipment. The value of these transient overvoltages generated internally in the
equipment shall be used without considering the preferred list in 4.2.2.1.
4.2.2.5 Attenuation of transient overvoltage levels
Equipment or parts of equipment may be used under conditions where the transients are
reduced. Various technology of component exists such as surge protective device (SPD),
transformer, capacitance, resistance, and can have different behaviour regarding the
transient overvoltage attenuation. These various technologies shall be verified and the
method of propagation measurement shall be defined based on their relevant product
standard. <...