Study on Characteristic Parameters and Influencing Factors of Leakage Current of Polluted Porcelain Insulators

Abstract

The characteristic values of the leakage current, such as the effective value of the leakage current, the number of pulses, etc., can effectively reflect the contamination of the surface of the insulator. In this paper, a three-piece U70BP porcelain insulator is used as a test sample. The insulator is subjected to artificial contamination test through a mist chamber to extract the characteristic value of leakage current, and compared with salt density and relative humidity. The test results show that the leakage current waveform is more severe with the salt density of the insulator surface and the relative humidity of the environment. The effective value of the leakage current increases with the increase of relative humidity and salt density, the leakage current obtained by simulating the salt component with NaCl is a power function relationship with the salt density, and the leakage current obtained by simulating the contaminated salt component with CaSO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</sub> is small, and the effective value does not change much when the relative humidity is 85% to 90%. The leakage current of the two salt components is about 5 times different at 100% relative humidity. The leakage current pulse is mainly concentrated in the 0-1 mA interval, the leakage current pulse number decreases with the increase of relative humidity, and the leakage current pulse time domain entropy and humidity satisfy the exponential function. In the frequency domain, the third harmonic and the fifth harmonic of the leakage current are the main harmonics, and the amplitude of each harmonic increases with the increase of salt density. The ratio of the high frequency to the low frequency energy of the leakage current increases as the salt density increases.