Instantaneous Active Power Based Integral Differential Protection for AC Lines at Receiving End of LCC-HVDC System

Commutation failure is an unavoidable phenomenon for Line Commutated Converter based High Voltage Direct Current system (LCC-HVDC). Some conventional protection schemes for AC transmission line will be affected by this kind of commutation failure when the line is connected to the inverter station. To solve this problem, this paper proposes an integral differential protection scheme using instantaneous active power. The adopting of active power is to avoid the influence of reactive compensation in principle. The use of instantaneous value is for the quick response of protection criterion. And the reliability is able to be improved, benefiting from integral algorithm. In addition, feasibility of the proposed protection scheme is verified by the simulation model from actual HVDC engineering project.