Detecting instant of multiple faults on the transmission line and its types using time-frequency analysis

Abstract

In a complex interconnected network, due to dynamic interaction between the AC networks, during occurrences of faults, the successful relay operation is threatened. For security and reliability of the power system network, a fast and accurate protection scheme is of great importance. This study presents a protection scheme for multiple fault detection at bus/line and its type in a wide area network. If a fault occurs on a line, followed by another fault at the same/different line, before the clearance of former fault, the proposed scheme is capable of detecting such multiple fault events. The scheme applies processed signal information for its time-frequency representation using Smoothed Pseudo Wigner-Ville distribution, followed by Hilbert transform and calculation of indices to interpret the fault events. It is shown that faulted bus, faulted line, time instant, and types of faults can be easily identified with low computational burden. The scheme is validated on the signals simulated on Kundur's model, IEEE 39 bus system and verified with signals on real-time digital simulator for different fault conditions; fault resistance and fault location on the line. The scheme can be successfully applied on signals available from phasor measurement units for wide area network protection.