一种新型的直流系统绝缘互窜检测方法

直流电源系统是站用电源系统的重要组成部分,相当于变电站的"心脏",其绝缘水平直接影响到变电站的安全运行[1]。因此,准确监测直流系统绝缘故障是提高电网运行可靠性的关键。直流互窜现象也称为环网故障,是直流系统中一种常见且危害性较大的故障。传统用测量仪表测试直流系统各项工作参数的方法很难及时检测和判定故障点,而现有绝缘检测装置又存在缺少直流互窜检测功能、故障误报、互窜检测过程中干扰直流系统正常运行等缺陷。针对上述问题,文章首先对变电站直流互窜故障产生原因、危害及类型进行阐述分析,提出一种新型的直流互窜检测方法。该方法采用互窜检测桥,对两套直流系统母线之间直流互窜故障进行实时监控、精准定位、计算互窜电阻,并以在220kV变电站的实际应用检测数据验证该方法的有效性。

DC power supply system is very important in substations,it is equivalent to the"heart"of substation.The insulation level directly affects the safe operation of substation.Therefore,accurately monitoring the insulation fault of DC system is the key to improve the reliability of power grid.DC inter-connect is a common and harmful fault in DC system.The traditional instruments which measure the parameters of DC system can't easily detect faults,and the existing insulation detection devices have some defects such as lack of DC inter-connect detection function,false alarm and interference with the normal operation of DC system when detecting inter-connect.For the above problems,this paper first analyses the cause,hazards and types of DC inter-connect faults in substations,and then proposes a new DC inter-connect detection method.Based on the inter-connect bridge,this method monitors,locates accurately and calculates the inter-connect resistance between two sets of DC system,and the effect is verified by the application in 220 kV substation.