Research on Analytic Method of Power System Frequency Response Characteristics under Large Power Disturbance

Frequency is one of the important indicators to measure the power quality of the power grid. Based on the characteristics of primary frequency regulation limit of the current universal electro-hydraulic governor, the output of the electro-hydraulic control system is simplified to a step response under the case of large frequency deviation. Considering the influence of the system inertia, the damping coefficient and the frequency regulation of load, an analytical model of single-system considering the governor limit of unit under large power disturbance is proposed. The analytical description of the frequency after the disturbance of large-power fault is deduced, and the influence of each key factor on the maximum frequency deviation is quantified. This analytical method enables rapid evaluation of the frequency response characteristics of the system under large power disturbances. And the validity of this analytical method is verified by the evaluation results of East China Grid after bipolar locking of Jin-Su DC transmission line.