Response characteristics of partial discharge pulses according to the length of the signal lines

The signal transmission system from the sensor to the PD detector should be fully understood to avoid the measuring error due to the sensor resonance, the impedance and the length of communication cables and the connection status of terminals, etc. In this paper, the effect of the signal line length on PD pulse wave shape was investigated. For the purpose, wave shapes and frequency characteristics of PD pulses were analyzed and compared in different lengths of RG 58 and RG 174 cables using PD calibration pulses and on-site PD measurement. As a result, high frequency components in RG 174 cables were more attenuated than those in RG 58 cables, and the cable length more than 3m would not be adequate for the analysis of PD pulse wave shapes. These results could decrease errors in separating noises from PD signals for the PD pulse wave shape analysis.