Performance of PCCC in presence of mercaptans in transformer oil using Ø-t-N technique

Paper-oil insulation is widely used in transformers. The reactive sulphur forms copper sulfide and dispersing in oil causes the reduction in insulation of the transformer. It is reported that during life cycle of transformer, paper and pressboard insulation undergoes deterioration mainly because of increase in sulphur content in transformer oil. The Ø-t-N distribution is a popular choice for PD representation as the discharge magnitude is associated with the state of insulation. Representations based on the charge magnitude are susceptible to influence of the measuring system, discharge and equivalent characteristics. On the other hand, the Ø-t-N representation offers much flexibility.