Abstract：In order to solve the misoperation problem of bypass pair overload protection in hybrid cascade UHVDC transmission system, the current loop and protection misoperation mechanism after fault are analyzed and studied, and a protection criterion based on the measured currents at the high and low voltage sides of the converter is proposed. Aiming at the action of bypass pair overload protection in inverter station when pole bloking is performed under the interruption of station communication, the strategy of line commutated converter (LCC) closing bypass switch (BPS) in inverter station is proposed, and the corresponding protection setting method is studied. Real time digital simulation (RTDS) test shows that the proposed scheme is simple and feasible, which avoids the misoperation of bypass pair overload protection and improves the reliability of UHVDC transmission system.
2022, Vol. 23 
