A Protection Scheme for Cross-Country Faults and Transforming Faults in Dual-Circuit Transmission Line Using Real-Time Digital Simulator: A Case Study of Chhattisgarh State Transmission Utility

摘要

This paper presents a protection scheme for cross-country faults and transforming faults in a dual-circuit transmission line of 400-kV Indian transmission network of Chhattisgarh state. An intelligent relaying scheme is designed for fault detection and classification of cross-country faults and transforming faults in a mutually coupled dual-circuit transmission line. The proposed scheme is a hybrid framework of discrete wavelet transform and artificial neural network (DWT-ANN) which is used to detect the fault, distinguish the faulty phase(s), and identify the type of fault in a dual-circuit transmission line. The cross-country faults and transforming faults are difficult to detect by the conventional scheme because the first involves faults at two different locations and the latter involves a change in the type of fault after a few cycles. A practical 400-kV power transmission network of Chhattisgarh state has been modeled and simulated in real-time digital simulator (RTDS) environment to reproduce real-time fault events and further analysis is carried out in MATLAB software. To examine the efficacy of the proposed protection scheme, a wide range of case studies have been done thereby varying different fault parameters, power system operating parameters, and typical fault scenarios. The results described that the proposed protection scheme based on the DWT-ANN algorithm is reliable and extremely responsive to various types of cross-country and transforming faults which are more complex in nature. The distinct advantage of the proposed protection scheme is that it accurately detects all types of cross-country faults and transforming faults in a dual-circuit transmission line by employing single-end data only.