An integrated approach for incorporation of voltage and transient stabilities into optimal power flow study

Abstract

Today's power systems are very likely to be stricken by the interference amongst different types of stability and associated control actions owing to their growing complexity resulted from expansion and interconnection. Taking control action into account with the aim of improving one stability phenomenon may deteriorate the others while their mutual interactions are omitted from a comprehensive study. In this paper, an integrated approach for incorporation of voltage and first-swing stabilities into optimal power flow study is proposed so as to not only preclude any potential inconsistency between such stability phenomena but also bring these two stabilities in harmony aiming to simultaneous improvement. During the exploration of an optimal operating point, the setpoint of voltage and power of generating units and other available VAr supporting sources like SVCs are adaptively adjusted whereby critical clearing time of fault (CCT) and network loadability limit (NLL) are maximized. Active power output and terminal voltage of generators along with injecting/absorbing reactive power of SVC constitute a vector of decision variables for solving the optimization problem through a powerful multi-objective evolutionary algorithm (MOEA), namely ISPEA2. The best compromise solution lying on Pareto front by which fulfilling all objective functions is determined by TOPSIS as a decision-making approach. The effectiveness of the proposed method is verified by its implementation in IEEE 39-bus test system using MATLAB software and the results demonstrate its applicability.