关键词: 大容量水轮发电机;中性点接地装置;接地故障电流;暂态过电压;

Abstract: The parameter configuration of neutral point grounding equipment of large-capacity hydro-generator needs to consider the grounding fault current, transient overvoltage, neutral point displacement voltage, stator injection protection configuration strategy, etc. In this paper, the grounding fault current and transient overvoltage were analyzed. Based on the finite element analysis, the core ablation under different grounding fault current was calculated, and the limit value of grounding fault current under different control conditions was obtained. Then based on the electromagnetic transient analysis technology, the grounding transient overvoltage under different parameter configurations was calculated, and the suggestions for the selection of grounding device configuration were given. Through the research on the limit value of grounding fault current and transient overvoltage, the control boundary conditions for the selection and configuration of neutral point grounding device of large-capacity hydro-generator were clarified. Finally, it is recommended to use the series connection method to configure the neutral point grounding equipment.

Key words: neutral point grounding equipment; grounding fault current; transient overvoltage; large-capacity hydro-generator