基于电压相量差的发电机GCB失灵保护新原理  

Novel principle of generator circuit breaker failure protection based on voltage phasor difference

作　　者：王义凯 谭力铭 尹项根[1,2] 洪心 田兴 乔健[1,2] 徐雯 WANG Yikai;TAN Liming;YIN Xianggen;HONG Xin;TIAN Xing;QIAO Jian;XU Wen(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;Three Gorges Cascade Dispatch&Communication Center,Yichang 443113,China)

机构地区：[1]华中科技大学强电磁工程与新技术国家重点实验室,湖北武汉430074 [2]华中科技大学电力安全与高效湖北省重点实验室,湖北武汉430074 [3]三峡梯调通信中心,湖北宜昌443133

出　　处：《电力自动化设备》2022年第3期182-188,共7页Electric Power Automation Equipment

基　　金：国家自然科学基金资助项目(51877089);乌东德电站发变组保护整定计算项目。

摘　　要：大型发电厂普遍安装发电机出口断路器(GCB),当发电机出现内部故障或异常工况时,依照相关规定对应的保护需通过GCB切除发电机,并同时启动GCB失灵保护。由于此时发电机电气量的特殊性及切机方式的多样性,目前工程中采用基于电流判据(相电流、负序电流判据)的GCB失灵保护无法有效检测部分GCB失灵故障。为提高GCB失灵保护动作性能,通过对称分量法构建故障复合序网分析不同GCB失灵故障情况下的电气量特征,在计及发电机灭磁过程的前提下,得出正确动作相GCB两侧基波电压相量差较大,拒动相GCB两侧基波电压相量差为0的结论。基于GCB两侧基波电压相量差的差异,构造基于基波电压相量差的GCB失灵保护判据。为提高轻载情况下GCB失灵保护的可靠性,引入3次谐波电压相量差辅助判据。仿真结果表明,所提保护新原理在不同GCB失灵故障情况下均具有较高灵敏度。GCB(Generator Circuit Breaker)is generally installed in large power plants.When the generator has internal faults or abnormal working conditions,the corresponding protection trips the generator by GCB according to relevant regulations,and the GCB failure protection is started at the same time.Due to the particularity of generator electrical quantity and the diversity of generator tripping modes,GCB failure protection based on current criterion(phase current and negative-sequence current criterion)used in current engineering cannot effectively detect some GCB failure faults.To improve the performance of the GCB failure protection,the electrical quantity characteristics of different GCB failure faults are analyzed by constructing fault composite sequence network using symmetrical component method.Considering the de-excitation process of generator,the conclusion is get that the fundamental voltage phasor difference between the two sides of GCB in the correct operation phase is large,while the fundamental voltage phasor difference between the two sides of GCB in the phase which fails to operate is nearly zero.Based on the difference of fundamental voltage phasor between two sides of GCB,the GCB failure protection criterion based on the fundamental voltage phasor difference is constructed.In order to improve the reliability of GCB failure protection under light load,the auxiliary criterion of third harmonic voltage phasor difference is introduced.Simulative results show that the proposed protection principle has high sensitivity under different GCB failure conditions.

关 键 词：发电机 GCB失灵保护 对称分量法 基波电压相量差 3次谐波电压相量差 

分 类 号：TM77[电气工程—电力系统及自动化]