A Fast Local Bus Current-Based Primary Relaying Algorithm for HVDC Grids

This paper proposes a fast, selective, reliable, and local bus primary relaying algorithm for high-voltage direct current (HVDC) grids. The proposed relaying algorithm only uses measurements obtained from current sensors to detect faults and identify their locations. This algorithm is local and requires only communication at the bus level rather than the system level. Furthermore, the algorithm is not sensitive to the system configuration and operating point and can be employed during line or converter outages with limited retuning and adjustments. The proposed algorithm is applied to a four-terminal HVDC grid. Study results show that the proposed algorithm 1) detects faults on both transmission lines and DC buses; 2) identifies the faulted bus or transmission line; 3) requires insignificant computation capacity; 4) distinguishes between faults and other system transients to prevent erroneous circuit-breaker trips; and 5) is not sensitive to measurement noise.