Performance Evaluation of TCSC and SVC on Voltage Stability Limit Improvement and Loss Minimization under Most Critical Line Outaged Condition

Due to the ever increasing demand for power, environmental constraints in expansion of transmission networks and the emerging scenario of restructuring of power system networks, the transmission lines are prone to be operated under heavily stressed conditions. In such a heavily stressed condition, there is a risk of line outage and the consequent voltage instability. This necessitates voltage stability limit improvement under probable line outage contingency conditions to keep the system under voltage secured conditions. Flexible Alternating Current Transmission System (FACTS) devices are found to be encouraging in improving voltage stability limit of power systems. In this paper, optimal location of TCSC and SVC are considered for reducing line losses and improving voltage stability limit. Amount of increased reactive power generation and line losses are taken as indicators of stressed conditions of a power system. The optimal location and sizing of TCSC and SVC are identified through Particle Swarm Optimization (PSO) algorithm. The proposed method is tested in IEEE 30 bus test system and results obtained are proving the validity of the work.