Transmission Line Design for Individual Partial Discharge Waveshape Measurement

Measurement of transient phenomenon such as individual PD pulses requires fast, accurate, and noise-free circuits. The bandwidth of elements used in these circuits can affect the captured PD pulse waveshapes. Transmission lines, which couple the PD sources to data recording devices, are one the most important elements among various components in measurement systems. Therefore, transmission lines with wide bandwidths are necessary in building testbeds that capture individual PD pulses. This paper explains the requirements of an ideal Transmission line design that enables accurate individual PD pulse waveshape measurements. We comprehensively use finite element analysis (FEA) simulation to analyze the impact of PD testbed design on the PD pulse measurement performance. Based on the newly designed testbed with the proposed transmission line design, individual PD measurement performance is examined by the time-domain analysis of the FEA simulation. The results show the effect of transmission line parameters on its frequency responses. Also, the application of a narrow bandwidth transmission line for PD pulse measurement has been confirmed to deform its waveshape. Furthermore, the time-domain results confirmed the impact of transmission lines reflection and losses on captured waveshapes.