雷击故障下的分布式故障监测装置定位精度测试方法

Location Accuracy Method of Distributed Fault Monitoring Device for Lightning Strike Fault

分布式故障监测装置广泛应用于输电线路的故障定位领域,而产品质量参差不齐,部分厂家仅通过行波电流或者工频电流的变化进行故障定位,定位精度存在较大问题。为此,该文提出了一种兼顾行波电流和工频电流模态变化的测试方法。首先,开展了行波电流和工频电流波形的时序逻辑设计,并提出了精度测试的方法。然后,基于仿真和试验方法,对电流探头进行了选型设计。最后,研制了分布式故障监测装置测试系统,并完成了测试精度的影响因素研究。研究结果表明:测试过程中,雷击故障过渡时长小于1个周波,基本实现雷击故障波形时序的复现;电流探头A621和TRCP3000可配合进行测试,基本满足10~1000A行波电流测量的要求;两路雷电流波前时间差范围为1~100μs,实现了故障点位置的随机设定;db1测试精度优于db4,db4小波系数的鲁棒性优于db1,当信噪比大于20dB时,即可满足测试标准的要求。该研究结果可为分布式故障监测装置雷击故障下的定位精度改善提供技术支撑。

Distributed fault monitoring devices have been widely applied to the field of fault location for power trans-mission lines.Nevertheless,the quality of these products varies,and certain manufacturers rely solely on changes in traveling wave currents or power-frequency currents for fault location,resulting in significant accuracy issues.In response to this challenge,this paper introduces a testing method that comprehensively considers changes in both traveling wave currents and power-frequency currents.Firstly,a time-sequenced logical design of traveling wave currents and pow-er-frequency currents is executed,and an accuracy testing method is proposed.Subsequently,based on simulation and experimental methods,the selection and design of current sensors are conducted.Finally,a testing system for distributed fault monitoring devices is developed,and research on factors affecting test accuracy is completed.The results demon-strate that,during the testing process,the transition duration of lightning-induced faults is shorter than one cycle,enabling the faithful replication of the timing of lightning-induced fault waveforms.Current sensors A621 and TRCP3000 can be effectively combined for testing,satisfying the requirements of measuring traveling wave currents ranging from 10 A to 1000 A.The time difference between the two lightning current wavefronts varies from 1 to 100μs,enabling the random configuration of fault point locations.Moreover,the testing accuracy of db1 surpasses that of db4,and robustness of the db4 is superior to that of db1.When the signal-to-noise ratio exceeds 20 dB,the testing standards can be met.These re-search findings offer technical supports for improving the accuracy of fault location in distributed fault monitoring devices for lightning strike fault.