Condition Assessment of Instrument Transformer by Partial Discharge Analysis: A Comprehensive Approach

This paper presents results of partial discharge tests that have been carried out on high voltage instrument transformers. The goal is to develop diagnostic tools that, starting from partial discharge measurements, can provide indications on the degradation state of the paper/oil transformer insulation systems. Preliminary results indicate the PD source recognition is a fundamental tool to assess the condition of the transformer being monitored, while relying only upon partial discharge repetition rate and magnitude can provide misleading indications