大型发电机组非全相保护存在问题及对策  

Problems and Solutions of Open-phase Protection for Large Generator-transformer Unit

作　　者：卫琳 张健康 粟小华 牛拴保 WEI Lin;ZHANG Jiankang;SU Xiaohua;NIU Shuanbao(Northwest Electric Power Dispatching and Control Sub-center,Xi’an 710048,Shaanxi Province,China)

机构地区：[1]国家电网西北电力调控分中心,陕西省西安市710048

出　　处：《电网技术》2020年第6期2336-2342,共7页Power System Technology

摘　　要：通过分析2起发电机非全相运行造成继电保护动作范围扩大的案例,指出非全相保护能够以较短时限可靠切除非全相运行,不仅可以降低负序电流对发电机设备的损伤,更关键的是,它能避免非全相运行期间产生的零序电流造成电网零序电流保护越级跳闸,是重要的涉网保护,其拒动的后果比较严重。详细分析了目前非全相保护在实际应用中存在的问题,包括功能配置缺失、回路不完整、保护未正确投入等,讨论了其对机组设备和电网运行的危害,并从工程应用角度提出了解决措施,提高了非全相保护的运行可靠性。最后分析了非全相保护在定值整定、启动失灵保护、与电网保护配合等方面需关注的问题。该方案目前已在西北电网大型发电机组中获得应用,提高了发电机设备和电网运行的安全性。Based on the analysis of two cases in which the operation range of relay protection is enlarged due to the open-phase operation of the generators,it is pointed out that the open-phase protection can remove the open-phase operation reliably in a short time.It can not only reduce the damage of the negative-sequence current to the generator equipment;but also,more importantly,avoid the zero-sequence current during the open-phase operation,which leads to over-step tripping of zero-sequence current protection in power network.It is an important network-related protection,and the consequences of its rejection are serious.This paper analyzes in detail the problems exiting in the application of open-phase protection at present,including the absence of the function configuration,the incomplete circuit,the incorrect input of protection,etc.It discusses its harms to the operation of the generator unit equipment and the power network.From the point of view of engineering application,the solutions are put forward to improve the operational reliability of open-phase protection.Finally,the problems of value setting,circuit breaker failure protection starting and power network protection cooperating are analyzed.The scheme has been applied to the large units in Northwest China Power Grid and improved the safety of the unit equipment and the power grid operation.

关 键 词：非全相保护 负序电流 零序电流 失灵保护 整定计算 

分 类 号：TM721[电气工程—电力系统及自动化]