A heuristic linearized line outage contingency ranking of integrated multiterminal AC-DC power systems

Abstract

This paper presents an efficient noniterative algorithm for the line outage contingency ranking of integrated multiterminal AC-DC systems. The proposed method can be used to obtain the contingency ranking based on the real power overload performance index. The proposed method uses the converter real and reactive powers, obtained by the base-case solution of AC-DC load flow, to transform the original AC-DC system to an equivalent AC system. The post-contingency voltages and angles of the transformed system are obtained either by a hybrid method or by using the first iteration 1 P - 1 Q of the AC fast decoupled load flow method. The hybrid method is based on an improved linearized method and the sensitivity relationship of the equivalent AC power system. The proposed hybrid method was tested on 5-bus, 14-bus and 30-bus AC-DC test systems having a DC link and DC mesh connections. For all the test systems, contingency rankings based on the real power overload performance index and the voltage deviation performance index were obtained by the proposed method and compared with the results obtained by the full sequential AC-DC load flow algorithm. The capture ratios obtained by the proposed method are excellent.