Novel time synchronization method based on duo-satellite triggering for double-ended PD location in MV cables

Recent years, double-ended techniques for PD location in MV cables emerged in large numbers. Nevertheless, great majority of the methods face the challenge of the time-synchronization between the two cable terminals because of the satellite invisibility and atmospheric condition problems in the global positioning system (GPS) receiver. Conventional methods adopt free running 1PPS to synchronize system clock, which in addition generates large volume of datasets and increases the hardware cost. Based on IEEE 1588, this paper therefore proposes a Round-Trip Communication (RTC) algorithm implemented in two portable cost-effective PD location devices developed specially for double-end measurement system based on the combination of both GPS and BeiDou Navigation Satellite (BDS) signals. A particular 1PPS is adopted as transfer signal between the two devices on considering the time margin and communication delay so that the starting record time could be synchronized. The performance of this proposed technique is evaluated via laboratory tests, and the results indicate that the average error of time offset is reduced to great extent. Key points of future research work are highlighted at the end of paper.