China Electric Power Research Institute, Beijing 100192, China

Because the dynamic gain of excitation systems has a significant impact on the dynamic stability of salient-pole generators, it is often necessary to adjust the dynamic gain and then configure the power system stabilizer (PSS) in order to improve the damping of the power system. However, there are some unclear understandings about the impact of dynamic gain on the dynamic stability of generators. Firstly, the impact of dynamic gain of excitation systems on the dynamic damping is analyzed. Then, the impact of dynamic gain of excitation systems on the damping torque, damping ratio of salient-pole generators and the frequency response characteristics of excitation systems is calculated and analyzed with typical unit parameters and operation conditions. The simulation is carried out in the single-machine infinite system, two-machine system and real system. The calculated results are consistent with the simulation results. Finally, the experiments are carried out in the laboratory and the engineering field, and the correctness of the simulation and calculation results is verified, namely the larger the dynamic gain of excitation system is, the weaker the dynamic damping of salient-pole generator is. In order to improve the dynamic damping of salient-pole generators (such as hydrogenerator), the dynamic excitation gain should be smaller on the premise of meeting the requirements of relevant standards, and the system damping should be further improved by configuring corresponding PSS.