Abstract

This study presents a comprehensive control framework to ensure desired loading margin (LM) while minimising the corresponding control cost. The proposed framework is divided into corrective control (CC) and preventive control (PC) subproblems. The CC subproblem deals with the condition that a power system encounters voltage instability as a result of severe contingencies. This control is merely devised to restore system stability. The PC subproblem is brought up when the system operates in a stable region but its LM is insufficient. In this manner, the system-operating point is changed such that the desired LM is achieved. One of the features of the proposed methodology is to consider participation of demand-side resources as an effective control facility that reduces control costs considerably. Active and reactive redispatch of generating units and involuntary load curtailment (ILC) are employed along with voluntary demand-side participation as control facilities in CC and PC subproblems. The proposed control framework is examined through case studies conducted on the IEEE 14- bus and the IEEE 118-bus test systems. The results presented demonstrate the effectiveness and efficiency of the proposed framework.