An Integrated Sensor With AE and UHF Methods for Partial Discharges Detection in Transformers Based on Oil Valve

According to the advantages and disadvantages of electromagnetic and acoustic partial discharges (PD) measurements shown in IEC TS 62478, a novel integrated sensor with acoustical emission (AE) and ultrahigh frequency (UHF) methods for PD detection in transformers is developed in this article. It is formed by placing an AE sensor inside the end part of a UHF probe, and can be mounted on the oil valve, pushed inside the transformer to measure the acoustic and electromagnetic PD signals simultaneously. The sensitivity and validity of the integrated sensor are proved by the experimental tests on a physical 110-kV transformer. This integrated PD detection sensor solves the problem that the structure-borne waves and amplitude attenuation of acoustic signals are reduced significantly for the AE sensor located inside the transformer tank with direct acoustic wave detection, which provides a novel mixed acoustic and electromagnetic method for PD detection in transformer.