Adaptability Analysis of Fault Component Directional Component in AC/DC Multi-terminal Infeed System

Abstract

There is a problem of adaptability of fault component directional element in AC/DC multi-terminal infeed system, and there is no corresponding analysis method at present. In this paper, the principle of the fault component directional element is analyzed; the corresponding operation conditions are studied; and the relationship between the operation range of the feeder directional element and the equivalent back impedance fluctuation region of the converter in the AC/DC multi-terminal infeed system is theoretically derived. Combined with the fault response characteristics of the converter system, the equivalent sequence impedance characteristics of the converter in different fault scenarios are studied, and the fluctuation range of the sequence impedance of the converter is deduced. The applicable conditions of the fault component directional element in AC/DC hybrid system are given, and the influencing factors of applicable conditions are analyzed. Finally, the correctness of the theoretical analysis is verified by PSCAD simulation, which provides a theoretical basis for the application of the fault component directional element in nonlinear power grids.