Control strategy and placement of facts devices for damping of power system oscillations

Abstract

The modern power system is more complex due to change in the system configuration day to day, to meet the increasing demand in electrical energy by installing the new generating units, interconnection of transmission lines and extra high voltage tie line etc. The major problem is oscillations in system due to many sudden disturbances like faults, sudden changes in load and loss of line or addition of line etc. It may lead system to loose synchronism even when the system is being operated below its steady state limit. The invention of FACTS controllers achieved better results to dampen power system oscillations. Research is under progress for the invention of new controllers for damping of power system oscillations. Fuzzy logic power oscillation damping controller (FLPOD) is proposed along with PI voltage controller for shunt FACTS devices (SVC, STATCOM), along with PI power flow controller for series FACTS devices (TCSC, SSSC) and also for UPFC to damp power system oscillations. Simulate the power systems (3-machine 9-bus WSCC and 6-machine 30-bus IEEE power systems) with all FACTS devices and compare the performance of the proposed controller with PI conventional controller. The results show that the power system oscillations are dampens significantly with the proposed controller for FACTS devices. Optimum location of FACTS devices also influences the system performance. It is proposed to apply Extended Voltage Phasor Approach (EVPA) to find the optimum location of the FACTS devices. In this method Active power transmission paths (APTPs), Reactive power transmission paths (RPTPs) and Transmission path stability index (TPSI) will be determined and based on these indices, the optimum location for FACTS devices will be determined.