Improvement of voltage control using mitigation devices

opportunities for the power industry via utilization of the Flexible AC Transmission Systems (FACTS) devices. FACTS are based on power electronic controllers that enhance In recent years, the fast progress in the field of power opened new electronics has the capacity of the transmission lines. These controllers are fast and increase the stability operating limits of the transmission systems when their parameters are properly tuned. These devices offer an alternative means to mitigate power system oscillations and improve voltage profile by providing control of the power system through appropriate compensation of network parameters, such as line series impedance, line shunt impedance, line current, voltage, and real and reactive power. They help the operation of the power system network closer to its thermal limits. So they are operated synchronously with the transmission line and may be connected either in parallel producing controllable shunt reactive current for voltage regulation, or series with the line for controlling power flow on the transmission line.In this thesis the second generation of FACTS devices, Static Synchronous Compensator (STATCOM) and Static Synchronous Series Compensator (SSSC) devices will be installed with a SMIB power system. A robust control design of STATCOM and SSSC are proposed to improve the damping of power system oscillations and enhance voltage profile. An objective function based on eigenvalues is designed via Genetic Algorithm (GA) to tune the controller’s parameters and alleviate the negative damping effect due to the interaction of both AC and DC voltage regulators. Another optimization technique, which is Particle Swarm Optimization (PSO) is developed to ensure the optimal solution. Moreover, the applicability of GA STATCOM is discussed through online optimization process. A comparative study between GA STATCOM and GA SSSC is presented with and without the auxiliary stabilizing signal to show the superiority of one over the other and recommend it to be used in multimachine environment. The effectiveness and robustness of the suggested techniques in enhancing the inter area modes of oscillations and improving voltage profile over a wide range of operating conditions and system configurations is confirmed through eigenvalues analysis and time domain simulation results.