|XIAO Xiangtao,HAO Liangliang,WANG Zemin,HE Peng.Analytical calculation of short circuit fault of phase compound excitation generator in control rod power system of nuclear power plant[J].Electric Power Automation Equipment,2023,43(11):124-132
|关键词: 核电站控制棒电源系统 相复励 发电机短路故障 故障解析
|Analytical calculation of short circuit fault of phase compound excitation generator in control rod power system of nuclear power plant
XIAO Xiangtao1, HAO Liangliang1, WANG Zemin1, HE Peng2
1.School of Electrical Engineering, Beijing Jiaotong University, Beijing 100044, China;2.Liaoning Hongyanhe Nuclear Power Co.,Ltd.,Dalian 116001, China
|For the control rod power supply system of nuclear power plant, the existing protection only uses the fixed time overcurrent protection with rated current as the backup protection for short circuit fault, which has led to several events of overcurrent protection preemptive action and mismatch with loss of excitation protection in this system. The key to solve the protection mismatch problem is to accurately analyze the short circuit fault current of generator in the control rod power supply system. The key point of the analysis is to consider the influence of the phase compound brushless excitation mode actually adopted by generator on the fault current, and the phase compound excitation current is composed of the excitation components corresponding to the shunt excitation voltage component and the compound excitation current. Through the reasonable assumption and model simplification, combined with the basic equations of the generator and the mathematical model of the excitation system, the three-phase short circuit current under the shunt excitation voltage component is derived. The compound excitation current component is introduced to modify the short circuit current according to the variation of excitation current, and the time-domain analytical expression of three-phase short circuit current of phase compound excitation generator including transient component and steady-state component is obtained. The time-domain analytical expression of two-phase short circuit current is obtained by extending the positive sequence equivalent rule. The electromagnetic transient model of the control rod power supply system is established based on PSCAD/EMTDC platform to verify the theoretical analysis results, and the protection optimization method is further discussed.
|Key words: nuclear power plant control rod power system phase compound excitation short circuit fault of generator fault analysis