Effect of sampling rate on the location accuracy of measurements from radiated RF partial discharges signals

Partial discharges (PD) are electrical discharges which occur when the insulation system of electrical equipment under high voltage stress starts to break down. Radio frequency measurement methods can be employed to detect the radiated energy from the PD activity and therefore locate the PD source. Based on suitable arrangements of multiple antennas and measured time-differences-of-arrival (TDOA), the three dimensional location of the PD source may be determined using iterative or other triangulation algorithms. This paper evaluates the effect of sampling rate on the location accuracy of two different PD sources with two different energy and frequency contents using a locally customised “Y shaped” arrangement of four antenna positions. Based on sampling rate, the TDOAs are determined using both cross correlation and thresholding methods. The location is then determined through the application of an iterative standard least squares algorithm (SLS). The results demonstrate that the accuracy and the ability to determine the position of the two located PDs depend on the selected sampling rate, the nature of the signal as well as the TDOA method.