Voltage Stability Improvement Using Voltage Stability Index Optimization

Voltage stability improvement using line voltage stability index based on optimal power flow (OPF) in power systems is presented in this work. Line voltage stability index (LVSI) traditionally adopted to identify the most critical line in the system where its value is in the range of 0 (no load) and 1 (voltage collapse) has been applied as part of the constraints to prevent the system from the voltage collapse. LVSI has also been adopted as the objective function to enhance system stability. The OPF problems have been solved by using salp swarm optimization (SSO). The voltage stability improvement has been investigated in the IEEE 30-bus system. Two conditions consisting of stressed load condition where the load demand is raised and line outage contingency condition where the most critical line is considered for outage have been considered to evaluate the performance of the voltage stability improvement. The simulation results of considering LVSI as part of the constraints and objective function are compared with the base case where fuel cost is the objective function. The results express that the system stability can be significantly improved.