Fault Detection Algorithm for Multi-terminal LCC HVDC Interconnected Grid

The protection of Multi-terminal DC (MTDC) system is not straightforward. This paper proposes a novel protection technique for the proposed configuration topology of interconnection project between Egypt and Saudi Arabia. The proposed scheme depends on the second derivative of dc line current with the time which represents the acceleration of dc current with the time. A model of three-terminal Line Commutated Converter (LCC) MTDC with polarity reversing availability is used to study fault behavior and apply the proposed algorithm to detect and classify the fault. The proposed scheme is evaluated via an extensive simulation study for 500kV dc transmission network using Matlab©/Simulink©. The suggested algorithm detects a dc fault without communication link between the relays and can respond to different fault resistances and different fault distances in few milliseconds. (paper)