Scenario-based line switching for enhancing static voltage stability with uncertainty of renewables and loads

Abstract

The fast-growing renewables, such as wind power and photovoltaic, introduce a large number of uncertainties into the power grid. The uncertainty of renewables, coupled with that of load, increases the complexity of the analysis of static voltage stability of power systems. In this paper, the nonlinear impact of the uncertainties from both renewables and loads on static voltage stability (limited by two types of typical bifurcations, i.e., saddle-node bifurcation and structure-induced bifurcation) is investigated and illustrated. To model the uncertainties, a scenario-based scenario construction method is presented to obtain the representative scenarios tailored for the static voltage stability problem which can avoid the mis-elimination of the extreme scenarios. Then, a stochastic line switching problem is formulated to maximize the load margin to the static voltage stability of the look-ahead power system. To fast identify the line solutions, a three-stage methodology, including a scenario construction stage, the identification stage, and the evaluation stage, is proposed to balance the speed and accuracy. Finally, the computational results based on the IEEE 118-bus power system, 1648-bus power system, and 3120-bus power system demonstrate the efficiency of the proposed methodology.