Measurement-based dynamic equivalent modeling for small and medium hydropower generator group

Abstract

With the scale of small and medium hydropower increasing gradually, it is difficult to establish a detailed model because the parameters of each generating unit can barely be obtained. To build a dynamic equivalent model of the hydropower generator group, this paper presents an estimation-based equivalent method, which will keep the dynamic responses and the transient stability consistent before and after the equivalence. A 3rd order generator and a parallel static characteristic ZIP load model are selected as the dynamic equivalent model of hydropower generator group. Based on phasor measurements in the tie line which connects to the modeled hydropower generator group, the self-adaptive control parameters modified differential evolution (SACPMDE) algorithm is used to obtain the parameters of equivalent model. The proposed method is verified in the small and medium hydropower generator group with simulation in an actual power grid of China. The results show that the proposed equivalent model has highly precision on the dynamic responses and the parameters identification method is stable. The proposed method can be used for modeling a group of small and medium hydropower generators whose structures and parameters are unknown.