| Abstract: | Flexible ac transmission system (FACTS) controllers, especially the series-FACTS controllers, affect the operation
of distance relays and can lead to the relays under/over-reaching. This paper aims to demonstrate the effects of
static synchronous series compensator (SSSC) and series capacitive compensation (SCC), as two important series
compensators, on the distance protection using theoretical and computational methods. The results of the
investigation are used to develop a feasible and adequate method for eliminating the negative effects of these
devices on the distance relays. The developed method measures the voltages at terminals of the SSSC and SCC by
phasor measurement units (PMUs) which are then transmitted to the relay location by communication channels.
The transmitted signals are used to modify the voltage measured by the relay. Different operation types and
conditions of SSSC and SCC, and different faults such as phase-to-phase and phase-to-ground faults are
investigated in simulations. Since the modeled distance relay can measure the fault resistance, trip boundaries
are used to show the performance of the presented method. Results show that the presented method properly
eliminates the negative effects on the distance relays and prevents them from mal-operation under all fault
resistance conditions. |
