Electrical equivalent circuit of ceramics insulators with RTV Silicone Rubber coated and computer simulation of leakage current

During operation, high voltage insulators may severe a certain degree of pollution which may reduce their performances such as surface resistance and flash over voltages. Under these conditions a large leakage current (LC) may flow on the surface and degradation may take place. The LC waveforms are normally non-pure sinusoidal. This is due to the non linear behaviour of insulator surface and in particular condition, electrical discharges take place which distort the leakage current waveform. The magnitude and the waveform of the leakage current correlate with the surface condition of outdoor insulators. The parameters were proposed as diagnostics tools for ceramic outdoor insulators with RTV silicone rubber coating. In order to improve the diagnostic tool and to deeply understand the behaviour of the leakage current on the outdoor insulators, it is important to investigate the parameters affect the leakage current. To understand the correlation between leakage current waveforms and electrical circuit parameter, we will, in this paper, proposed an equivalent electrical circuit model for modelling leakage current phenomenon on ceramic outdoor insulator with RTV silicone rubber coating under various environmental conditions. Proposed equivalent electrical circuit model consists of capacitor(s), non-linear resistor(s), and arc model(s). These three parameters will be used to simulate the LC waveforms of ceramic insulator with RTV silicone rubber coating under various environmental conditions using ATP/EMTP software package. The results showed the similarity between experimental and simulated LC waveforms. The simulated environmental conditions were clean sample.