Abstract: Through the analysis on two DC power transmission line faults, it is discovered that the characteristics of the dynamic response of coal-fired power plants to primary frequency regulation are generally poor, and the dynamic characteristics of large frequency deviation are completely different from those of small or medium frequency deviation of the power grid. Based on the identification of large frequency deviation model, the primary frequency regulation strategy is optimized, and the experiments of large frequency deviation are conducted with the results being analyzed to estimate the risks of the loading conditions and evaluate the performance of the primary frequency regulation with large frequency deviation for coal-fired power plants so as to effectively improve the primary frequency regulation performance on the premise of ensuring the unit safe operation, which benefits both the power grid and the generating units.

Key words: coal-fired power generation unit, large frequency deviation, primary frequency regulation, model identification, control strategy, optimization, risk evaluation