GB/T 21697-2022Insulation coordination of lightning overvoltage for low-voltage distribution wiring and electronic systems (English PDF)

Foreword

This document is in accordance with the provisions of GB/T 1.1-2020 "Guidelines for Standardization Work Part 1: Structure and Drafting Rules of Standardization Documents" drafted.

This document replaces GB/T 21697-2008 "Lightning Overvoltage Insulation Coordination for Low-Voltage Power Lines and Electronic Equipment Systems", and Compared with GB/T 21697-2008, in addition to structural adjustment and editorial changes, the main technical changes are as follows.

a) The standard name is changed to "Insulation coordination of lightning overvoltage in low-voltage distribution lines and electronic systems";

b) Modified the scope (see Chapter 1, Chapter 1 of the 2008 edition);

c) Added terms such as "self-recovery insulation" (see Chapter 3), deleted terms such as "electrical clearance" (see Chapter 3 of the 2008 edition), - Modified terms such as "insulation coordination" (see Chapter 3, Chapter 3 of the 2008 edition);

d) Deleted "normal use conditions" (see 4.2 of the 2008 edition);

e) Added "Lightning current and lightning overvoltage" (see Chapter 4);

f) Added "Classification of Insulation" (see 5.1.1);

g) Modified "Insulation coordination method" (see 5.1.2, 5.4 of the 2008 edition);

h) Modified "equipment with protective device" (see 5.3.1, 5.5.1 of the 2008 edition);

i) MODIFY "Equipment powered directly from the distribution network" (see 5.4.1, 6.1.1 of the 2008 edition);

j) Modified "Preferred value of lightning impulse withstand voltage" (see 5.4.3, 6.2 of the 2008 edition);

k) Modified "Insulation Test", merged 8.1 of the 2008 edition into 6.1 (see 6.1, 8.1 of the 2008 edition);

l) Added "Test Requirements" (see 6.2);

m) Added "Atmospheric Condition Correction" and "Altitude Correction" (see 6.3.2, 6.3.3);

n) Deleted "Lightning arrester or SPD protection level" (see Chapter 7 of the 2008 edition);

o) Added "Selection and Application of Lightning Protection Measures" (see Chapter 7);

p) Added Appendix A "Main Lightning Parameters", Appendix B "Lightning Overvoltage", Appendix C "Low Voltage Equipment Immunity Criteria" and Appendix D "Insulation coordination and selection requirements for SPD".

1 Scope

This document specifies the lightning current and lightning overvoltage, insulation coordination and insulation level, insulation test and its requirements, selection and application of lightning protection measures.

This document is applicable to low-voltage distribution lines and electronic circuits with rated AC voltage not greater than 1000V and DC rated voltage not greater than 1500V system.

2 Normative references

The contents of the following documents constitute essential provisions of this document through normative references in the text. Among them, dated citations documents, only the version corresponding to that date applies to this document; for undated references, the latest edition (including all amendments) applies to this document.

GB/T 16927.1-2011 High Voltage Test Technology Part 1: General Definition and Test Requirements

GB/T 21714.3 Lightning Protection Part 3: Physical Damage to Buildings and Danger to Life

GB/T 33588.2 Lightning Protection System Components (LPSC) Part 2: Requirements for air terminals, down conductors and earth electrodes

3 Terms and Definitions

The following terms and definitions apply to this document.