Fault Indicator Three-Phase Synchronization Method Based on Fault Instant

Abstract

The fault indicator with the "two remote" (remote signaling and telemetering) function needs synchronous measurement of three-phase current when uploading zero-sequence current information. Based on the zero-sequence current detection method of the fault indicator, this paper proposes a three-phase synchronization method based on the fault instant. Firstly, the fault instant is found out by detecting the fault phase current. The non-fault phase is awakened and the recorded wave data are sampled on this basis. Secondly, the starting point of the three-phase fault can be traced back to the normal operation section with the same cycle wave number. Then the Fourier algorithm is used to calculate the three-phase current phasor to obtain the time synchronization error between fault phase and non-fault phase. Finally by adjusting the synchronization deviation between the fault phase and the non-fault phase, the alignment of the three-phase current sampling value after the fault is realized to obtain the zero sequence current. This method uses fault information to achieve synchronous measurement, which avoids the additional GPS module and reduces the cost. The simulation results show that the proposed method has feasibility and high accuracy.