Implementation and Experimental Analysis of Finding Partial Discharge Source between a Transformer and its Peripheral High Voltage Devices using Several Heterogeneous PD Sensors

Monitoring the transformer’s condition and fault diagnosis are essential to maintain the reliable operation of the transformer and maximize its lifespan. Usually, detecting PD signal from UHF PD sensor installed in a transformer is a method for monitoring the transformer conditions. However, the PD The PD signals leaked from Transformer will be detected by PD sensors due to peripheral high voltage. And it could be mistaken for as PD signal occurred in the transformer. In this paper, through experimental analysis, we propose a technology that installs several heterogeneous PD sensors in a transformer and a peripheral high voltage device and processes PD signals simultaneously to distinguish between PD signals generated inside a transformer and PD signals generated in peripheral high voltage devices. Several heterogeneous PD sensors, such as UHF sensors, TEV sensors, and HFCT sensors, are installed in transformers and peripheral high voltage devices, and the normalized amplitude of PD signals received from each sensor are compared and analyzed on a synchronized time and phase axis. For example, if the PD signals detected by the transformer and the peripheral high voltage device are on the same time and phase axis, and the normalized amplitude of PD signal from transformer is larger than the normalized amplitude of PD signal from the peripheral high voltage device. At this time, this PD signal is determined to have occurred inside the transformer. Whereas, if the normalized amplitude of the PD signal introduced from peripheral high voltage devices is larger than the normalized amplitude of the PD signal introduced from the transformer, it is determined to be PD signal introduced from the peripheral high voltage devices. With the results of experimental analysis, this technology can be effectively used to determine whether the detected PD signal from transformer PD sensor is originated from inside of the transformer or from peripheral high voltage device.