Adaptive distance protection scheme for shunt FACTS compensated line connecting wind farm
To improve the performance of the conventional distance protection scheme for compensated lines with high resistance faults, an adaptive distance protection scheme is proposed. This study presents an analytical approach for finding the possible impacts of shunt connected flexible AC transmission systems (FACTS) devices such as static synchronous compensator/static volt ampere reactive (VAR) compensator (SVC) integrated with off shore wind farm (WF) on distance relay characteristics. Analytical results are presented and verified on simulation platform compares under reach phenomena in presence of both FACTS devices and it is found that under reach is more severe for SVC connected system. Moreover, presence of SVC changes the line characteristic presented to relay even for bolted faults. It is also seen that type of coupling transformer has a considerable effect on apparent impedance. Furthermore, the reach setting of the relay is significantly affected as the relay end voltage and power fluctuates continuously (due to non linear relationship with speed) when off shore WFs are connected to power transmission systems. Thus, adaptive tripping characteristics for high resistance line to ground fault with shunt FACTS devices considering appropriate operating conditions is a demanding concern and the same has been addressed in the proposed research work.