A new shunt capacitor protection principle based on model identification is proposed compared the capacitance deviation of in-zone and out-zone faults calculated with the capacitor modal equation
the fault type can be determined. The method is immune from non-periodic component and high-frequency component due to the essential dependence on the differential algorithm on network parameter distinguishing. This judgement scheme can also be used as capacitors protection. When in-zone inter-phase faults or longitudinal faults occur
the protection works. Otherwise
it gets locked. ATP simulations show the scheme enables to determine fault direction within 5ms and enhance the rate and reliability greatly.
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