IMPROVEMENT OF VOLTAGE STABILITY BY USING SVC WITH CASCADE PIDPOD CONTROLLER (CASE STUDY AREA: SEBETA-II SUBSTATION)

Abstract

In order to improve the quality and transfer capability of the electrical power system regulation of voltage within acceptable range is very crucial in modern power system networks. The voltage stability is determined by magnitude of production and consumption of reactive power. The major cause of voltage instability is un-regulated reactive power. Static Var Compensators (SVCs) can provide or consume the reactive power which is necessary to control the dynamic voltage to get stable and improve voltage stability. Modeling of SVC with controller to improve the bus voltage stability at Sebeta-II substation network is presented in this thesis work. The line to ground (LG) fault is considered in this thesis as more than seventy percent occurrence of fault in the electrical power system network is the LG fault. In this thesis the proposed SVC controller is a cascade of Proportional Integral Derivative (PID) and Power Oscillation Damping (POD) which is a suitable for SVC controller. According to the results obtained from the simulation by using Matlab Simulink software, the Static VAR compensator has an ability to improve the voltage stability of buses at the substation network. From the result, injecting PID-POD controlled SVC of 107MVAR rating at 230kV bus in the network is significantly improve the voltage stability with shorter time during a phase faulted condition at Sebeta-II substation. It also observed that the voltage magnitude at buses is increased and with standard range in all buses after installing SVC with PID-POD controller. From the results for generator connected with PID-POD controlled SVC, the magnitude voltage of the weakest bus is increased from SVC to and generator rotor speed deviation is decreased from to