STABILZATION OF FREQUENCY OSCILLATIONS USING POWER MODULATION CONTROLLER OF HVDC LINK IN A PARALLEL AC-DC INTERCONNECTED SYSTEM

Abstract

Power systems have many control areas which are interconnected to each other .In such a system if any sudden change of load occurs in any area this will lead to change of system frequency of all area and also tie line powers. By the implementation of Automatic Generation Control (AGC) we can maintain nominal frequency and keep tie line power at scheduled value even after the step load is subjected to any area. To implement this Automatic generation control it takes help of Area Control Error signal. This signal is fed to integral controller for achieving desired response of frequency. Though system described above attained nominal frequency with help Area Control error signal but still before frequency reached its nominal value after disturbance its response is oscillatory with large overshoot and settling time. With the objective of stabilizing such frequency oscillation and simultaneously reducing both overshoot and settling time. In this project we are using a interconnection of HVDC in parallel to AC tie line. As gain of closed loop system plays an important role in its dynamic performance so gain is optimized to obtain best response. To attain the above objective a power modulation controller is designed to damp out inter-area oscillation. Simulation study response corroborates significant outcome of the designed control.