Partial Discharge Measurement for Power Cable Using Crosstalk-Free FDM-DAS

A crosstalk-free frequency division multiplexing distributed acoustic sensing (CFFDM-DAS) technology for partial discharge (PD) measurement in power cable is proposed in this article. The multicarrier crosstalk-free probe pulse, along with raised cosine roll-off (RCR) processing, is constructed and implemented to avoid interchannel crosstalk between the different frequency, significantly increasing multiplexing density. In this way, the CFFDM-DAS is modeled and established with an increased crosstalk suppression ratio of 61.39 dB compared to traditional multiplexing techniques. As a result, the frequency bandwidth of the proposed method is extended to 100 kHz using ten-channel multiplexing with a 5-km sensing range. Validation experiments confirm that the sensing system exhibits an excellent wideband response and reliable acoustic signal reconstruction capabilities. Discharge experiments on a 10-kV cross linked polyethylene (XLPE) power cable with void insulation defect are conducted. The measurement of PD with the proposed system demonstrates its capacity for detecting discharges with a minimal apparent charge of approximately 31 pC and effectively capturing most PD events. The proposed CFFDM-DAS system presents a promising approach for the reliable and continuous monitoring of PD activity.