Study on Selective Leakage Protection System of Mine High Voltage Grid Based on Harmonic Phase Comparison

摘要

As for the wide application of arc suppression coil to the grounding in neutral point of mine high voltage grid,grid leakage fault rules and harmonic characteristics of the neutral point grounding system through arc suppression coilare analyzed, the selective leakage protection program “zero-sequence voltage starts, fifth harmonics of grid zerosequencevoltage and zero-sequence current are extracted for phase comparison” is proposed, and corresponding fifthharmonic extraction circuit and power direction discrimination circuit are designed. The experimental results show thatthe protective principle applies not only to the neutral point insulated power supply system, but also to the power supplysystem in which neutral point passes arc suppression coil, which can solve selective leakage protection problems underdifferent neutral grounding ways, improving the reliability of selective leakage and guaranteeing the stability of the actionvalue.