Dielectric and partial discharge investigations on ceramic insulator contaminated with condensable hydrocarbons

This paper investigates on understanding the influence of condensable hydrocarbons (collectively known as tar) over the dielectric condition of ceramic insulators. Multiple dielectric and diagnostic test methods over a wide frequency range are employed for this purpose. Initially, experiments are conducted on chosen clean and contaminated insulator samples. The influence of tar contaminations on the surface of the chosen samples are quantified through surface dielectric properties such as insulation resistance, loss factor or dissipation factor, impedance and so on. In addition, the partial discharge (PD) that arises over the contaminated surface of the insulator sample is measured and the respective phase resolved PD pattern is analyzed. The recorded PD signals are de-convoluted in frequency domain. Following this, similar experiments are conducted on test insulators contaminated under laboratory condition. The findings of the clean and contaminated samples are experimentally cross-verified on test insulators and later validated on an actual electrostatic precipitator unit. In summary, it is believed that such an investigation might provide an opportunity to gain more knowledge about the electrical characteristics of condensable hydrocarbons.