Analysis of partial discharge in solid sheet insulation using CIGRE-II method

Almost every electrical equipment is provided with insulation. The quality of insulation is very important factor in deciding the life of the equipment. Different methods had been used for assessing the quality of insulation under various conditions. Partial discharge (PD) test is one among the most important tests for assessment of insulation quality. In the paper, analysis of partial discharge is carried out for a void, inside the insulation with CIGRE-II method. A number of samples with different cavity dimensions have been prepared using circular Perspex disc. The analyses of these samples are done using MPD 540, which is a digital instrument, use for measurement of PD. By observations it is found that the inception voltage is almost 2.5 to 3.5 times the corresponding extinction voltage. By analyzing the graphs obtained for various parameters it is observed that the inception voltage decreases as diameter of cavity/cavity depth ratio or the diameter of cavity is increased, and it increases as cavity depth or sample thickness is increased.