Leakage Current and Ground Fault Indicators Using ECD

Abstract

Leakage current indicators using ECD (Electric Chromic Display) are developed. These indicators are characterized by the following points.
(1) Coloration density of the indicator shows electric charge which is integration of leakage current.
(2) The coloration density is held even if input current is stopped.
Fundamental characteristics of ECD are measured. Methods which hold coloring density, compensate coloring density depending on temperature and set the threshold of coloration are described. Leakage and ground fault indicators are fabricated. Minimum charges which display in leakage and ground fault indicators are 4.2±0.8mC, 4.9±1.1C, respectively.
It was confirmed that the developed indicators were effective in electric power field.
Leakage current indicators help to determine the equipment in which insulation has broken down from lightning etc. and are useful in finding the equipment in which insulation is deteriorating.