The Comparative Study of PD Detecting in Power Transformer Model According to Acoustic Emission and IEC270 Standard Method

This paper presents a comparative study of partial discharge (PD) detection technique of power transformer model. The acoustic emission (AE) method was applied to detect the signal from PD-origin in a model of the power transformer tank according to IEEE standard C57.127. The Time Difference of Arrival (TDOA) technique was additionally applied. In the experiment, a simulated PD-origin was set up inside the transformer tank. Four acoustic sensors were installed on the tank surface, which were used to detect and provide the signal to a signal amplifier and data recorder. Multifunction Compact NI-DAQ 9223 was used together with 1 slot Chassis model 9191 in order to transfer the data to computer by using LAN or wireless system. The AE signal of PD-origin was then collected and analyzed with the Lab View program to identify the location of PD-origin. All physical dimensions of power transformer such as width, length and height and position of each acoustic sensor (in centimeters) were loaded into the main program. Then, the pattern of PD-origin was simulated at different positions in oil-filled transformer tank model. Finally, the localization result was displayed in a graphic user-interface screen. The acquired signal from this method was subsequently compared with the conventional PD detection method using IEC60270 standard in order to observe the PD. The experimental results were satisfactory and could be applied practically.