An equivalent modeling for small and medium-sized hydropower generator group considering excitation and governor system

Building an equivalent model of small and mediumsized hydropower generator group is a practical method carried out for dynamic analysis of water electricity grid. Excitation and governor system have prominent influences on the precision of the equivalent model. This paper presents a method to build a dynamic equivalent model of hydropower generator units containing excitation and governing system, the method uses traditional equivalent model of hydropower generator group which is based on homology method as the foundation, and considers the equivalence of excitation and governor system. It uses PLPF method to get the equivalent parameters of excitation system and weighted average method to get the equivalent parameters of prime mover and speed governor. Numerical examples show that deviation of the method in dynamic process is smaller, and it can improve the simulation accuracy. On this basis, further simulations are made to analyze the effect of excitation and governor system on dynamic characteristics.