摘要
某变电站发生1起母线差动保护误动事故,分析原因是故障线路L2相用于母差保护的二次回路电缆准确级绕组接错,当系统发生近端故障,短路电流较大时,在二次回路产生的电压作用下,测量级TA铁心磁通迅速增加而出现短时间内的反向饱和,励磁阻抗迅速减小,从而在该相上产生反向的异常电流,二次电流值无法正确反映故障电流情况,导致保护误动。同时通过故障录波图发现母差保护装置录波记录异常及所用TA抗饱和能力弱的问题。针对二次回路接线错误及TA饱和问题,提出校验电流二次回路正确性的方法及提高TA抗饱和能力的改进措施,可有效防止同类问题的再次发生。
In this paper, by case analysis of a substation bus differential protection misoperation, misoperation reason is concluded that TA measuring and protection winding secondary line reversed is happened on the bus differential protection. When the substation bus near fault occurs, short-circuit currents are larger than normal. In the role of the induced voltage on the secondary, current transformer measurement circuits reverse saturation short time and their magnetizing impedance decrease rapidly. Thereby reverse abnormal current appears on the fault phase. Since TA measuring and protection winding secondary line is reversed, abnormal currents of measurement windings play a malfunction. Fault record figures show abnormal record of bus differential protection device and weak anti-saturation capacity of TA in use. To solve the above problems, the verification methods for current secondary circuit and the improvement measures for TA anti-saturation capacity are presented, which can effectively prevent the recurrence of similar faults.
出处
《内蒙古电力技术》
2016年第3期38-41,共4页
Inner Mongolia Electric Power
关键词
变电站
母线差动保护
误动
测量用TA绕组
保护用TA绕组
饱和
transformer substation
bus differential protection
misoperation
measuring TA winding
protection TA winding
saturation
