Study of acoustic emission (AE) caused by high voltage insulators

Acoustic emission (AE) study based on the acoustic signal ranges from 30MHz to 300MHz has been performed to diagnose the deterioration of insulation level in outdoor ceramic insulator. Different weather conditions combining with artificially created pollution were produced in laboratory and measurements were recorded over a fixed period of time. Pollution due to fine dust particles has been created according to IEC standard under wet and dry conditions. Samples that exhibit internal cracks and fracture were used in this study. The collected AE signals were sampled and analysed using fractal theory. The results of this study have clearly demonstrated the prospect of using AE technique to monitor the working condition of outdoor insulator.

Emission-based condition monitoring technique for ZnO surge arrester

In this paper, electromagnetic emission at the frequency range of 30MHz to 300MHz is used to detect physical defects on the 22kV outdoor zinc-oxide (ZnO) surge arresters. Different weather conditions combining with artificially created pollution were produced in a laboratory environment and measurements were recorded over a fixed period of time. Pollution due to fine dust particles has been created according to IEC standard under both wet and dry conditions. The aim is to detect the defects (bushing damage) when the surge arrester is subjected to various weather and surface condition. The collected electromagnetic signals were sampled and analyzed using analysis tools such as the autocorrelation coefficient and Wigner-Ville distribution. The results from the present paper indicate that electromagnetic radiation from the defects on surge arrester combining with the adequate analysis tools can be used as a valuable diagnostic tool for power system operator.