Qualitative Analysis of Contamination Severity between NaCl and CuSO4 for Outdoor Insulator

This paper presents a new criterion for insulator flashover condition prediction based on percentage 5
^th
to 3
^rd
harmonic component. These harmonics are extracted from leakage current of insulator employing FFT. In this context, a threshold limit of this ratio has been mentioned. To investigate experimentally, leakage current of an 11 kV glass disc insulator (contaminated at three different levels) has been recorded at different applied voltages. For contamination purpose two different types of salt are taken as contaminants, one is NaCl and other is CuSO
₄
. Above mentioned ratio has been calculated for both types of contamination separately and compared. Results show that contamination due to NaCl is more severe than that of CuSO
₄
.