Online partial discharge detection and location techniques for condition monitoring of power transformers: A review

Partial discharge (PD) is an important indicator of insulation condition in a power transformer. The PD phenomenon is exhibited in various observable forms such as electrical, mechanical, optical and electromagnetic energy. Many modern systems use a combination of these techniques, because electrical detection is a proven technology, combining it with modern techniques gives the conformity and the advantage of modern digital signal processing. This paper discusses the evolution of various techniques in partial discharge measurement as a condition monitoring tool available for online measurement of field transformers. This paper also discusses the recent techniques used for partial discharge analysis with its advantages and suitability over conventional method for proper condition monitoring of large power transformers.