ENHANCING STABILITY FOR POWER SYSTEMS USING FACTS CONTROLLERS AND FUZZY PI APPROACH

Abstract

With the rapid development of power electronics, Flexible AC Transmission Systems (FACTS) devices have been proposed and implemented in power systems. The recent development of power electronics introduces the use of FACTS controllers in power system. FACTS technology provides the opportunity to increase loading capacity of transmission lines, prevent blackouts, improve generation productivity, reduce circulating reactive power, improves system stability limit, reduce voltage flicker, reduce system damping and oscillations, control power flow so that it flows through the designated routes and congestion management. FACTS devices can be used to control power flow and enhance system stability. There is an increasing interest in using FACTS devices in the operation and control of power systems. However, their coordination with the conventional damping controllers in the aiding of power system oscillation damping is still an open problem. Therefore, it is essential to investigate the coordinated control of FACTS devices, traditional power system controllers in large scale power systems and different aspects of voltage stability and the related basic concepts. We have seen that voltage stability and collapse are a dynamic phenomenon of large magnitude. Various methods aimed at increasing the voltage stability limit of the power system with reactive power compensation were also presented. In this thesis, we are concerned with modeling and enhancement stability of the power system network based on its V-I characteristics, considering the power flow constraints. Such a system can be controlled using advanced techniques like novel controller consists of fuzzy additional to PI, basic measured data and data computed by numerical field analysis. Recently, many control techniques have been proposed where's a numerical technique for solving problems and fuzzy logic controller (FLC) based on proportional integral control (PIC) is used to control the firing angle of FACTS inverter. Since, the controllers have several attractive advantages like: high speed response, good transient performance, insensitivity to a variety of system parameters and external disturbances, simplicity of realization and robust to control nonlinear systems. The proposed controller is called “fuzzy PI controller” new controller. The simulation of FACTS model power system network under the proposed technique is carried out. Also, the simulation is verified, which consists of designing and constructing the FACTS devices, building IGBT inverter H bridge and associative drive gate with its control circuit. The simulation is varied, Its results with the proposed algorithm show that, the system performance is improved significantly in the presence of load disturbance and insensitive to system parameter variations.