A wide area synchrophasor-based load shedding scheme to prevent voltage collapse

•This paper presents an optimal load shedding scheme to prevent voltage collapse.•The proposed method utilizes wide area voltage stability index.•Improved version of DICA is proposed and utilized in simulations.•The new method is tested on practical test case.•Results of various simulations prove the new method proficiency in preventing mid-term and long-term voltage collapse.

This paper presents a new method based on wide area voltage stability index for optimal load shedding to prevent voltage instability phenomena. Phasor Measurement Units (PMUs) have widely been used in recent years due to their great advantages in power systems wide area monitoring, protection and control. The purpose of this paper is to provide a new optimal load shedding method, which disconnects the least possible amount of load from optimum buses. Not only the system stability is considered as main goal in this research, but also minimum load shedding is taken into account. Moreover, the problem of optimal load shedding is applied using modified Discrete Imperialistic Competition Algorithm (DICA) in mid-term and long-term voltage instability scenarios. In all investigations, certain limitations are considered to obtain practical answers. In addition, some modifications are applied to the conventional ICA, which make it proper for solving the optimal load shedding problem. New modifications result in fast convergence characteristic and less run time, which are crucial in dealing with power system instability problems.