An Improved Protective Relaying Technique for Transmission Line Connected with UPFC and DFIG-Based Wind Farm

Nowadays, wind energy is one of the cleanest and most economically affordable generating sources and there is an increasing trend towards doubly fed induction generator (DFIG)-based wind farms integrated with power grids through unified power flow controller (UPFC) devices for extracting large amounts of electrical power. The conventional protective relaying scheme used in transmission lines (TLs) is mostly affected by the nonlinear variation of output power due to the fluctuation of wind speed and power control mode operation of UPFC. Therefore, a novel approach of fast discrete S-transform assisted gradient boosting ensemble method for fault detection and classification scheme is proposed in this article to overcome the problem of such TL relaying scheme. The proposed method requires only grid-side current information to process the intelligent relaying scheme for this UPFC-compensated line connecting the DFIG-based wind farm. The performance of the proposed method is tested with different cases through the MATLAB/Simulink platform for different wind speeds. The proposed method has a low computational burden as it requires only three-phase current information. The performance of the proposed method is further tested on a larger network, the modified IEEE 39-bus New England system with a wind farm. Finally, the results of comparative analysis with some earlier established techniques justify the efficacy of the proposed method for fault detection and classification tasks. The proposed method has 100% accuracy for fault detection and 99.86% accuracy for fault classification.