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.

The manuscript addresses a robust three-dimensional fuzzy-PID controller (Fuzzy-3D PID) to control frequency of a diverse energy source integrated hybrid power system under various loadings. In order to obtain stability over system frequency under any disturbances, a secondary control loop called load frequency control (LFC) loop is required in the system. LFC tries to monitor power generation irrespective of load demand. Further, a novel hybridized harmony search and random search (hyHS-RS) algorithm is proposed to optimally design the suggested Fuzzy-3D PID controller. The proposed hybrid network is incorporated with integration of different diverse energy sources such as wind-plant (WP), solar-plant (SP), diesel-generator (DEG), and micro-turbine (MT) along with conventional power-generating sources like thermal system, hydro system, and nuclear power plant. The wind-plant and solar-plant exhibit large dynamics and low inertia which degrades the system frequency seriously. The proposed Fuzzy-3D PID controller makes necessary control actions over disturbed frequency and trying to amend steady nominal frequency in the system. It has been observed the percentage improvement in ITAE with proposed hyHS-RS over basic harmony search (HS) and random search (RS) are 54.5% and 201.6% respectively. Finally, proposed hyHS-RS designed Fuzzy-3D PID controller justifies its superiority through different comparative studies.