故障机理深度关联的大型发电机保护新原理探讨  

Discussion on a new principle of large generator protection deeply associated with fault mechanisms

作　　者：尹项根[1,2] 王义凯 谭力铭 乔健[1,2] 卢庆辉 张春辉 YIN Xianggen;WANG Yikai;TAN Liming;QIAO Jian;LU Qinghui;ZHANG Chunhui(State Key Laboratory of Advanced Electromagnetic Engineering and Technology(Huazhong University of Science and Technology),Wuhan 430074,China;Hubei Electric Power Security and High Efficiency Key Laboratory(Huazhong University of Science and Technology),Wuhan 430074,China;Technology and Research Center,China Yangtze Power Co.,Ltd.,Yichang 443002,China)

机构地区：[1]强电磁工程与新技术国家重点实验室(华中科技大学),湖北武汉430074 [2]电力安全与高效湖北省重点实验室(华中科技大学),湖北武汉430074 [3]中国长江电力股份有限公司技术研究中心,湖北宜昌443002

出　　处：《电力系统保护与控制》2021年第22期1-7,共7页Power System Protection and Control

基　　金：国家自然科学基金项目资助(51877089)。

摘　　要：基于“碳达峰、碳中和”发展目标,新能源发电渗透率逐年提高,但其故障穿越能力差、不确定性强等问题愈发凸显。传统发电机组容量巨大,作为系统的主力支撑电源,其功率调节和安全支撑作用更为重要,增强其继电保护的性能和作用显得尤为紧迫。在配置和改进发电机保护原理时,应该与故障机理深度关联并提炼故障特征。对发电机零序横差保护不平衡电流的产生机理进行分析,得出零序横差不平衡电流与气隙电动势成正比的结论,并提出基于气隙电动势制动的零序横差保护判据,能够提高内部小匝差短路故障时保护的灵敏度。基于对定子单相接地故障风险的深度分析,利用接地故障电流反映故障风险,据此构建的定子接地保护方法能够通过发电机安全风险自适应选择出口方式。研究结果拟为基于故障机理的大型发电机组保护改进提供思路。Given a development goal of"carbon peak and carbon neutrality",the penetration of new energy power generation has been increasing year on year.However,problems such as poor fault ride-through capability and uncertain power output are increasingly prominent.Traditional generators have large capacity.As the main supporting power sources of the system,their power regulation and safety support effects are important,and it is particularly urgent to enhance the performance and function of their relay protection.To configure and improve the generator protection principle,it is necessary to deeply associate with the fault mechanism and extract the fault characteristics.In this paper,the unbalanced current’s generating mechanism of the generator zero-sequence transverse differential protection is analyzed.The conclusion is drawn that it is proportional to the main air gap Electromotive Force(EMF).Thus,a zero-sequence transverse differential protection criterion based on the air gap EMF brake is proposed.This can improve protection sensitivity under internal short-circuit faults with small turn-difference.Based on the in-depth analysis of the fault risk under single-phase stator ground faults,the ground fault current is used to reflect the fault risk.Then,a corresponding stator ground fault protection is proposed,one which can adaptively determine the tripping mode according to the security risk.Research results are intended to provide technical ideas for the improvement of large generator protection.

关 键 词：大型发电机保护 故障机理深度关联 零序横差保护 气隙电动势 定子接地保护 故障风险 

分 类 号：TM31[电气工程—电机] TM77