Technical Report No.1258

No. 1258

Application Guide for Insulation Coordination in Non-effectively Grounded Systems and UHV Systems -Technical Explanation of JEC-0102-2010-

Collaborative Research Committee of Insulation Coordination for Non-effectively Grounded Systems and UHV Systems

Keyword :

Insulation Coordination, Revised edition of JEC-0102, Test voltage, Overvoltage

JEC-0102 "the standard for test voltages", which is a basic standard about the withstand voltage tests for electric power equipment, has been revised in 2010. This technical report describes the techniques and backgrounds that become the basis of the revised edition of JEC-0102. The points of the revision are as follows:
(1) addition of the lower level of the test voltages compared with the existing ones for 22kV systems
(2) addition of the lower level of the test voltages compared with the existing ones for gas-insulated substation in 66 to 154kVsystems
(3) establishment of the test voltages for UHV (Ultra High Voltage, 1000kV) systems
The test voltages are determined in consideration of both the various overvoltages applied to apparatus and the electrical insulation characteristics of apparatus. In addition, the insulation reliability of apparatus and the facilities configuration of substations are taken into consideration for determining the test voltage. In this technical report, the estimating process of overvoltages caused by various surge phenomena (lightning surge, switching surge, temporary overvoltage) and the determining process of the additional test voltages are mainly summarized. Moreover, the following key items are described: new knowledge about insulation properties such as the conversion coefficients, evaluation method of equivalent lightning surge waveform based on V-t characteristics, and evaluation of insulation reliability using Weibull distribution.
The Committee hopes this technical report can contribute to a better understanding of the JEC-0102-2010 and play a role of a reference book for future examination of insulation rationalization.