A New Index to Evaluate the Severity of Discharges Based on Energy Calculation

摘要

Discharges in the transformer are important symptoms to assess degration of its insulating structure. The indexes of q, Φ, n and dissolved gases have been used for many years for diagnosis discharges of oil filled transformers. In this paper, one discharge experiment for needle -plate model is performed. To investigate the difference of indexes to evaluate the severity of discharges, a new energy index is proposed and all the indexes including maximum apparent discharge (Qmax), average apparent discharge (Qave), frequency of apparent discharge (Qfre), phase position of apparent discharge (Qpha), total hydrocarbon concentration (THC) and the new energy index are analysed. It is found that the best performance of all these indexes to evaluate the severity of discharges is W which rises with discharge process and increase rapidly in the end.