摘要
大型机组启动备用变断路器发生非全相时,产生负序电流,依据产生负序电流的大小对接于其上的负载造成不同程度损伤、同时对系统产生影响,必须及时切除。分析了变压器非全相运行时的相序电流和相序电压与故障前负载电流的关系。启动备用变在轻载时,负序电流非常小,传统电流保护不易判断,提出了负序电流比例增量保护思路,设计出采用负序电流比例增量判据的非全相保护逻辑图。结合实例分析了现行启动备用变非全相保护存在的问题,给出详细配置方案以及在不同情况下的启失灵方案。
When the breaker of the starting-standby transformer runs with open-phase, it will produce negative sequence current that will damage the loads which-connect to the transformer to different degree depending on its magnitude, at the same time it will influence the power system, which should be promptly removed. This paper analyses the relationship between the phase sequence current and voltage in open-phase condition and the normal load current. When the standby transformer is in small load, the negative sequence current is so small that the traditional protection relay can＇t identify it easily. New scheme of the negative sequence proportion increment and the diagram of open-phase protection are presented. It analyses the problem of current open-phase protection of the standby transformer through the actual example. Detailed configuration scheme and the starting of the breaker malfunction in different cases are described.
出处
《电力系统保护与控制》
EI
CSCD
北大核心
2011年第17期139-143,共5页
Power System Protection and Control
关键词
启动备用变
非全相
负序电流比例增量
保护配置
失灵
standby transformer
open-phase
negative sequence proportion increment
protection allocation
malfunction
