Research On Partial Discharge Location Method Of Transformer Based On Optical Fiber FP Sensor

Partial discharge detection is an important step in monitoring the insulation condition of high voltage equipment in power system.With the aging of high-voltage devices,insulation may be due to mechanical,thermal and electrical stress and breakdown,leading to catastrophic failure of the device.Therefore,the power system to detect the sector,how to accurately determine the location of the transformer partial discharge is critical.In this paper,a method for PD location in transformer based on optical fiber FP sensor is proposed.First a 2 × 2 EFPI ultrasonic sensor array is designed,which can be placed in the oil to detect PD ultrasonic signal.Then according to the SRP(steered response power)sound source localization theory to locate PD.Finally SRP and MUSIC(multiple signal classification)algorithms are used to process the experimental signals and compared.The results show that the EFPI sensor array can detect the partial discharge signal with high SNR in the oil;The SRP algorithm has less error than the MUSIC algorithm and can locate PD according to a single measurement,but the positioning accuracy should be further improved.Analysis shows that the PD location error is mainly caused by the deviation of the position of the array element from its theoretical value.Therefore,an array element position error correction method that combines MUSICwith TCT(two-sided correlation transformation)is proposed.The method corrects the position error of the array elements by the DOA of the assisting PD source.Simulation and experiment verify the effectiveness of this method.For ultrasonic multipath propagation,a direct wave extraction method based on CS(compressive sensing)theory is proposed.Experimental study on PD location in the presence of a copper baffle is performed.