Chapter 18 - A reliable decision-making algorithm for fault during power swing in 400 kV double-circuit transmission line: a case study of Chhattisgarh state power system network

Abstract

The adverse effect of power swing (PS) led to blackout situation in Indian power network during July 30 and 31, 2012. During PS, the decision-making property of distance relay is greatly affected. To avoid this, modern distance relay is equipped with a PSB element that is used to prevent the false tripping imposed by PS. But in case of occurrence of fault followed to PS condition, the fault remains undetected due to PSB element. Therefore a reliable decision-making algorithm is required to overcome such type of problem. Furthermore, in case of a fault during PS in a double-circuit transmission line (DCTL), transient disturbances are also imposed in the voltage and current signals of similar phases of the healthy circuit due to the effect of mutual coupling between the two circuits. To resolve such protection challenges, this chapter proposes an intelligent technique based on bagged decision tree (BDT) algorithm for fault during PS detection and classification in a DCTL using wavelet packet energy (WPE) of voltage and current signals. All type of shunt faults are simulated and preprocessed to design an input data set to erudite the proposed intelligent scheme and concurrently tested with new faulty cases. Moreover, immunity of the proposed scheme has been analyzed for capacitor coupling voltage transformer transients as well as the current transformer saturation condition. The main advantage of the proposed scheme is that it is independent of the threshold setting, zero sequence mutual compensation factor, and remote-end data. It is also not influenced by variation in different fault parameters and power system operating parameters such as power flow angle and source impedance ratio. The proposed scheme is validated on an existing 400kV, 50Hz, double-circuit line of Chhattisgarh state power transmission network using MATLAB/Simulink software. Further, to validate the proposed scheme in real time, the experimental studies are carried out using the real-time digital simulator setup.