A new algorithm of wide-area backup protection based on fault charge comparison

A new method of wide-area backup protection is proposed based on fault charge comparisons according to the wide-area fault charge information of power grid. The node Intelligent Electronic Device (IED) associated domain is defined in the method, and the relationship of positive sequence fault charges for associated domain boundaries is sought. Then conceptions of the calculational charge and the reference charge for a node IED associated domain are given. A state matrix of nodes and associated branches is established based on size comparisons of those two charges which are send to the wide-area decision-making centre station by Node IEDs, then actual failure element can be determined by searching for matrix elements. Simulations show that the algorithm is simple and could be set conveniently with no influences from grounding resistances and the fault type.