New techniques for secure power system operation

Abstract

This paper describes a security algorithm that incorporates load flows, contingency selection, AC outage studies and security control. The load flow method is based on the superdecoupled load flow method of Haley and Ayres, which gives rapid and exact load flow solutions. Separate contingency selection methods for real power flow and voltage security analyses have been developed. For real power analysis the line overload contingency selection technique of Stott et al. has been adopted, but for voltage security analysis a new voltage contingency selection technique has been developed. Critical outages selected from the contingency selection functions are analysed in detail with AC outage simulations of line and generator outages. For security control a range of feasible corrective actions are provided which inclued phase shifter control, generation rescheduling and/or load shedding to alleviate the line overload problem and transformer taps to adjust the bus voltage deviations. New and fast line overload alleviation techniques have been developed by using injections at the terminating buses of the overloaded line without having to compute the sensitivity and Jacobian line flow matrices. The proposed security algorithm has been validated by testing on several standard test systems.