Single-phase disconnection fault location of active distribution network based on negative-sequence differential impedance

Abstract

Accidents such as overvoltage, personal injury and motor damage caused by singlephase disconnection faults occur frequently in active distribution networks. In response to this problem, firstly, the negative-sequence differential impedance is defined and a protection method based on negative-sequence differential impedance is proposed, the method uses the amplitude of negative-sequence differential impedance as an action quantity and uses its phase to construct an adaptive braking threshold. Secondly, in case of protection failure under overload, the zero-sequence voltage amplitude difference is proposed as an auxiliary criterion, and the influence of different types of distributed generators on the zero-sequence voltage difference on both sides of the fault fracture is analyzed. Finally, it is verified by simulation that the method can be positioned reliably and is not affected by the neutral point grounding method, transition resistance, load and distributed generators.