基于回路阻抗测试的输电线路防范误操作方法

针对输电线路带地刀或临时接地线合闸误操作问题,提出了一种基于线路对地回路阻抗测试结果判定线路对地状态,从而避免误操作的方法。通过理论分析和数值计算,明确了线路末端有无接地点时回路阻抗的差异。基于仿真模型,计算了线路有无接地条件下的回路阻抗,并比较分析了信号源频率、长线路换位、杆塔接地电阻、土壤电阻率对回路阻抗检测结果的影响,最终提出了线路送电条件判据。在某110kV输电线路上,针对单相接地、三相接地、相间短路的回路阻抗进行了实测。实测结果与仿真计算结果吻合,验证了所提方法的可行性。

Research of Preventing Misoperation for Transmission Line Based on Loop Impedance Test

In order to solve the problem of transmission line with a grounding switch or temporary grounding switch closing fault misoperation, this paper put forward a method to avoid misoperation which was based on loop impedance test results of transmission line. The results could determine the status of transmission line to ground. Through theoretical analysis and numerical calculation, the difference of loop impedance between non grounding and grounding situation was specified. Based on the simulation model, non grounding and grounding conditions loop impedance of transmission line were calculated. The influence of the signal source frequency, long transmission line transposition, tower grounding resistance, soil resistivity on the loop impedance detection were compared. Finally, the transmission line energizing condition criterion was proposed. In a certain 110 kV transmission line, the situation of single phase grounding, three phase grounding and inter phase short loop impedance were tested. The measured results were in accordance coincide with the simulation results, which verifies the feasibility of the method.