A new technique to diagnose the oil-filled transformers based on the condensing analysis for very small decomposed products in insulating oil

Analysis of gases dissolved in insulating oil offers the most important and efficient diagnostic method to detect the faults in oil-filled transformers. We carried out a survey of decomposed products from various kind of solid-materials through simplified model tests and current using model tests. The gas chromatography-mass spectrometer and the purge/trap gas extraction equipment are employed to condense and analyze very small decomposed products. As a result, we found out effective decomposed products for diagnosis. This paper describes the new technique for diagnosis based on the decomposed products utilizing the condensing analysis with a view to early detection and location of abnormal part in oil-filled transformers.