Separation of sources in radiofrequency measurements of partial discharges using time-power ratio maps

- Several sources of ultra-high frequency pulses are measured with an antenna.
- The spectral power share in bands of frequency are used to parameterize the pulses.
- The pulse duration separates sources with similar spectral power distribution.
- Several known electromagnetic disturbance sources are previously characterized.
- This method allows to separate simultaneous events and infer which are PD.

Partial discharges measurement is one of the most useful tools for condition monitoring of high-voltage (HV) equipment. These phenomena can be measured on-line in radiofrequency (RF) with sensors such as the Vivaldi antenna, used in this paper, which improves the signal-to-noise ratio by rejecting FM and low-frequency TV bands. Additionally, the power ratios (PR), a signal-processing technique based on the power distribution of the incoming signals in frequency bands, are used to characterize different sources of PD and electromagnetic noise (EMN). The calculation of the time length of the pulses is introduced to separate signals where the PR alone do not give a conclusive solution. Thus, if several EM sources could be previously calibrated, it is possible to detect pulses corresponding to PD activity.