Impact of Power Oscillation Damping and Control of Voltage Dip by Using FACTS Devices and Dual STATCOM Controller for DFIG

Abstract

In a power system, faults are inevitable. In this paper, Doubly Fed Induction Generator (DFIG) and Synchronous Generator (SG) are compared for fault performance and enhancement by using FACTS devices and dual STATCOM. If a symmetrical fault occurs in one of the line in dual path with fault resistance of 1 milli-ohm between phases and ground, the system behavior is studied. Surge currents will be formed and will flow in all lines, voltage decreases, oscillations in real power flow occurs and thereby overall stability decreases. The fault current so produced is diverted to the capacitor by using dual-STATCOM controller to mitigate voltage sag and current swell. It is aimed to verify the behavior of SG and DFIG due to the fault and also to find better FACTS device to mitigate the voltage sag and surge currents and to damp power oscillations.    Results proved that DFIG is more stubborn than SG and voltage is maintained by diverting surge currents, oscillations in real power flow from generator have damped and hence system stability and continuity of supply are enhanced. These disturbances are inherent and proposed STATCOM technique is having capability to maintain equilibrium during and post fault conditions. It is best suitable to maintain power system stability with uninterrupted power supply and to damp inter-area oscillations. The effectiveness of SG and DFIG based system was studied under four cases viz., case-1 without STATCOM, case-2 with single STATCOM, case-3 with SSSC, case-4 with UPFC and case-5 dual STATCOM. 

Impact of Power Oscillation Damping and Control of Voltage Dip by Using FACTS Devices and Dual STATCOM Controller for DFIG