不接地系统跨线两点相继接地故障多级保护技术  

Multi-level protection technology for cross-line two-point successive grounding fault in isolated neutral

作　　者：刘勇 刘大鹏 穆勇 李振成 王顺 卢泽钰 LIU Yong;LIU Dapeng;MU Yong;LI Zhencheng;WANG Shun;LU Zeyu(Tangshan Power Supply Company of North Hebei Electric Power Co.,Ltd.,Tangshan 063000,China)

机构地区：[1]国网冀北电力有限公司唐山供电公司,河北唐山063000

出　　处：《供用电》2024年第5期56-63,共8页Distribution & Utilization

基　　金：国家电网有限公司科技项目(52010320019K)。

摘　　要：针对配电网单点接地故障保护问题已经进行了大量研究,但对于跨线两点相继接地故障保护问题研究甚少。首先,基于不接地系统的后发接地故障暂态等值电路,推导了第二次接地故障时,各线路零序电流和母线零序电压暂态量的表达式,分析了欠阻尼和过阻尼情况下,故障线路与健全线路暂态功率分布差异,发现暂态功率方向法对于两点相继接地故障具有良好的适用性。然后,分析了基于暂态功率方向的相继接地故障多级保护技术在单端供电单回线配电网和两端供电配电网中的应用与整定,进一步对保护级差和两条故障线路相互影响进行了分析。最后,通过仿真验证了该方法的真实性和有效性。该方法算法简单,由馈线终端单独完成,不依赖主站及通信,可以较好地解决不接地系统相继接地故障多级保护问题。At present,a lot of research has been done on single-point grounding fault protection of distribution networks,but there is little research on cross-line two-point successive grounding fault protection.Firstly,based on the transient equivalent circuit of an ungrounded system,the expression of the zero-sequence current of each outlet and zero-sequence voltage of the bus during the second grounding fault is derived.The difference of the transient power distribution between the faulty line and the sound line under underdamped and overdamped conditions is analyzed.It is found that the transient power direction method has good applicability for two-point successive grounding faults.Then,the application and setting of multistage protection technology based on transient power direction for successive ground faults in the single-terminal power distribution network and two-terminal power distribution network are analyzed,and the protection level difference and interaction between the two fault lines are further analyzed.Finally,the authenticity and effectiveness of the method were verified through simulation.The algorithm of this method is simple,which is completed by the feeder terminal alone,independent of the main station and communication,and can better solve the problem of multistage protection of successive grounding faults in ungrounded systems.

关 键 词：不接地系统 跨线故障 两点相继接地 暂态特征 暂态检测 多级保护技术 

分 类 号：TM72[电气工程—电力系统及自动化]