Generation rejection scheme based on a combinational rotor angle trajectory prediction

This paper presents a response-based Generation Rejection Scheme (GRS) based on angular stability prediction logic to initiate the outage of accelerated generating units while saving the rest of generating units from the loss of synchronism. First, trigonometric, polynomial, and hybrid models of rotor angle trajectory based on reasonable assumptions were validated. Then, in the prediction step, through maximum use of measured data based on defined Forecast Horizon (FH) and data window with an incremental length, the stability /instability of generating units was separately predicted. Next, the status of the tripping signal based on the combinational logic of the output results for the angular stability prediction method was determined. In the developed logic, if at least two models out of the three designated models yielded the same response about the unit stability status, the tripping signal was accordingly fired or blocked. The proposed method was employed to investigate the one-machine infinite bus and the WSCC standard test bed under different operations and fault scenarios. The obtained results demonstrated that besides simplicity, low computational burden, and very short processing time, the proposed combinatorial method outperformed the existing ones working with individual prediction models. (C) 2021 Sharif University of Technology. All rights reserved.