摘要
通过分析相关电网事故,阐述了微机绝缘监测装置的工作原理及对直流电压波动和偏移的影响,从检测的灵敏度和安全性考虑分析了平衡桥电阻和切换桥电阻的选取原则。通过继电器动作电压的理论计算和变电站现场电容测试、安全性试验,得出当绝缘监测装置引起直流对地电压偏移至10%时,发生直流一点接地可引起保护继电器误动作并导致开关跳闸的结论。最后提出通过降低直流对地电压偏移和提高二次回路抗干扰能力等措施以避免保护误动作。
Through analyzing the correlated grid accident,the paper researches the principle of insulation detection and the influence to fluctuation and excursion for DC voltage.It also analyzes the choosing principle of balance bridge resistance and switch bridge resistance.Through calculating relay voltage and testing capacitance and safety of DC system,it finds out when the DC voltage excurse to 10%,a point-grounding can lead relay mis-action and breaker-tripping.The reasonable measures such as reducing the excursion of DC voltage and enhancing the ability of con-disturb are put forward to avoid protection missing-action in the end.
出处
《电测与仪表》
北大核心
2010年第8期45-47,共3页
Electrical Measurement & Instrumentation
关键词
绝缘监测
一点接地
平衡桥
偏移
防跳回路
insulation detection
a point-grounding
balance bridge
excursion
avoid-jumping loop
