Comprehensive voltage control scheme considering CO₂ emission and fuel cost

Recently, as power system loads are located farther away from power plants and are more unevenly distributed, reactive power losses have tended to increase due to heavier power flows with high load growth and long distance transmission. Therefore, concerns over voltage instability phenomena have grown as significant voltage drops and voltage collapse have been experienced. Thus, preventive voltage control schemes using voltage stability indices have been brought to attention in a considerable number of studies. However, there are some cases in which bus voltages exceed the upper limits when the preventive voltage controls are conducted in a system with long distance transmission lines. Therefore, in this paper, we propose a comprehensive voltage control scheme in steady and emergency states with the voltage stability index VIPI (Voltage Instability Proximity Index), VMPI (Voltage Margin Proximity Index), an optimizing method PSO (Particle Swarm Optimization) and the ellipse fitting P-V curves. We also consider added values such as transmission losses, CO ₂ emissions and fuel costs in the steady state. Simulations are run using the IEEJ west 30 machine 115 bus system to verify the effectiveness of the proposed method.