Power system dynamic stability enhancenent using facts devices

Abstract

The continuously increasing power demand requires construction of new generating plants and transmission lines; this is more restrictive due to economic and environmental impacts, the conventional power transfer control devices with fixed or mechanically switchable components have low speed and others associated disadvantages, therefore, faster control devices need to be developed in order to increase the power transfer capacity by utilizing existing generating units and loading transmission lines closer to their thermal limits even in contingency conditions. In prevailing scenario, Flexible AC Transmission System (FACTS) devices are the best sought after alternatives. The Unified Power Flow Controller (UPFC) is one of the most versatile FACTS devices, it has unique capability to control simultaneously or independently, all the parameters affecting power flow in the transmission line which are voltage, impedance, and phase angle, it can independently control both the real and reactive power flow in the transmission line and regulate the voltage at the bus where it is connected, this device creates a tremendous quality impact on power system stability. These features become more significant as the UPFC can allow loading of transmission lines close to their thermal limits, forcing the power to flow through the desired paths, this will give the power system operators much needed flexibility in order to satisfy the demands that the deregulated power system will impose. newlineThe objective of this thesis is to investigate the power system dynamic stability enhancement via UPFC based POD controller installed with Multi-Machine power system. The present thesis summaries the basic configuration and operation principle of UPFC; a typical UPFC consists of two three-phase voltage sourced converters, one is connected in shunt and other in series with transmission line, they are operated from a common DC-link consisting of a DC-storage capacitor. The series device injects a controllable magnitude and phase voltage source via series