An optimization-based approach for load modelling dependent voltage stability analysis

Abstract

A voltage stability index that considers voltage dependent load models is proposed in this paper for the detection of critical buses. The proposed index uses sensitivities provided from the solution of the maximum loadability problem based on an optimization model, to evaluate the voltage stability condition of power system under stress conditions caused by bus loading. The proposed index provides an accurate indication of voltage stability, by considering the difference between the maximum power transfer point and maximum loadability point using voltage dependent loads such as ZIP and exponential models. Validation tests carried out in a two-bus and the IEEE 30-bus test systems show an adequate response of the proposed approach. In first power system, the proposed index is compared to other indices and methods for voltage stability analysis, including L-index and modal analysis. Finally in the last power system, the proposed index is additional compared the extended L-index GEM.