Wide-Area Measurement-Based Adaptive Backup Protection for Shunt Compensation Environment

Abstract

In this paper, the localization issue associated with distance relay protecting a transmission line with static synchronous compensator (STATCOM) is discussed. Generally, distance relay is mal-operated due to the dynamic behaviour of STATCOM during its inductive and capacitive modes of operation. Because, STATCOM operation creates the problem of correct measurement of fault distance and is responsible of under-reach and over-reach of distance relay. Furthermore, high fault resistance is also the reason of under-reach along with STATCOM operation. To overcome aforementioned challenges, an adaptive wide-area backup protection scheme (WABPS) is addressed which compares the calculated impedance and referenced impedance. Calculated impedance is the difference between impedance measured by relay and impedance contributed by fault resistance. Referenced impedance is the sum of fault impedance and impedance contributed by STATCOM. If calculated impedance is less than referenced impedance, then the relay will generate a trip signal. Proposed WABPS is inherent directional and provides information about fault detection, fault distance, and fault resistance during dynamic operation of STATCOM. The performance of the proposed WABPS is evaluated using technology of synchronize phasor measurement and communication channel. A 230 kV, 50 Hz system with a 24-pulse STATCOM is simulated and validated using PSCAD/EMTDC software package.