Method to discard partial discharge pulses from neighboring high voltage equipment

On-line partial discharge (PD) diagnostics data are corrupted by various noise sources and this makes it more challenging to extract the PD signal contained in the raw data. Though the noise sources can be filtered out using signal processing techniques, PDs from neighboring cables and other high voltage equipment make the de-noising process more difficult due to the similar features of these signals with the PD signal of interest. Proposed in this paper is a double-ended partial discharge diagnostic system with dual sensors at each end which uses wireless time triggering using global time reference with the aid of global positioning system (GPS). Using the time of arrival method based on the velocity of propagation on the data, PD pulses originating from other sources can be discarded which reduces the volume of data to be stored and would eventually also reduce the hardware and software requirements of the denoising process thereby improving de-noising efficiency. System design, laboratory tests and on-site measurements are discussed.