摘要
通过对一起110kV变电站主变压器35kV侧复合电压闭锁过电流保护拒动事故的调查分析,得出事故的原因是:当35kV线路远端发生三相短路时,变电站35kV母线残压高于变压器后备保护中低电压元件的整定值,低电压元件将后备保护闭锁。指出了在现有变压器中、低压侧后备保护中,低电压元件存在对线路远端三相短路故障灵敏度不足的问题。为防止类似事故的发生,提出了在变压器后备保护中增设一段不带电压闭锁的纯过电流保护的策略,并用定量计算的方法分析了其对现有变压器后备保护的改善效果。
A 35 kV side compound voltage blocking over-current protection operation failure accident occurred on main transformer in a 110 kV substation.According to the on-site survey and analysis,the cause of the accident is that backup-protection did not act because the bus residual voltage was higher than the low-voltage element setting value of backup-protection of the transformer when three-phase short circuit fault occurred in distant end of 35 kV line.It points out that the device voltage sensitivity of transformer backup-protection on middle and low voltage side is not enough when the three-phase short circuit occurred in distant end of lines.In order to prevent occurrence of similar accidents,a countermeasure is put forward.That means to add a segment over-current protection without voltage blocking to the transformer backup-protection.The quantitative analysis is used to show the improvement of the transformer backup-protection.
出处
《电力系统自动化》
EI
CSCD
北大核心
2013年第3期129-133,共5页
Automation of Electric Power Systems
关键词
变压器
后备保护
复合电压闭锁
过电流保护
低电压元件
拒动
灵敏度
transformer
backup-protection
compound voltage blocking
over-current protection
low-voltage components
operation failure
sensitivity
