架空线路电压反演的电场测量法研究

Research on the Electric Field Measurement Method for Voltage Inversion of Overhead Line

研究目的:电力系统中架空输电线路的电压检测主要以电压互感器为主,而传统互感器存在体积大、难以移动、需断电安装、可能引发铁磁谐振等缺点,使得地形不便地区的高压输电线的电压监测难度较大。针对该问题,本文基于电磁场镜像法建立110 kV三相架空输电线路的电场计算模型,研究其电场分布特点,接着论证电场测量用于架空线路电压反演计算的可行性,提出基于电场传感器阵列测量导线三相电场的电压反演算法,实现缩比架空线路模型的电压反演。研究结论:(1)基于电磁场镜像法建立了架空线路的电场计算模型,理论分析了110 kV三相架空线路的电场分布特点,结果表明,架空线路下方地面的场强幅值分布呈“双峰”形;(2)基于对110 kV三相架空线路的电场分布特点的研究,提出基于三相电场测量的架空线电压反演算法,理论分析证明,通过测量三相导线下方的垂直方向三相电场,可以进行架空线三相电压的反演计算;(3)基于电压反演算法的研究,在实验室内搭建了110 kV三相输电线路的比例微缩模型,实验验证了算法的准确性,实验结果表明,对于所建立的实验模型,电压反演算法的幅值误差在3.31%以内,相角误差在2°以内;(4)本研究成果可为架空线电压监测提供理论依据。

Research purposes:The voltage detection of overhead transmission lines in the power system is mainly based on voltage transformers,while the traditional transformers have the disadvantages of large volume,difficulty in moving,need to be installed without power,and possible ferromagnetic resonance,which makes the voltage monitoring of high-voltage transmission lines in areas with inconvenient terrain more difficult.Based on the electromagnetic field mirror method,this paper establishes the electric field calculation model of 110 kV three-phase overhead transmission line,and studies its electric field distribution characteristics.Then the feasibility of electric field measurement for overhead line voltage inversion calculation is demonstrated and a voltage inversion algorithm based on electric field sensor array is put forward,which can measure the three-phase electric field of wire.The voltage inversion of the scaled overhead line model is realized.Research conclusions:(1)Based on the electromagnetic field mirror method,the electric field calculation model of overhead line is established,and the electric field distribution characteristics of 110 kV three-phase overhead line are theoretically analyzed,and the results show that the field strength amplitude distribution of the ground below the overhead line is"bimodal".(2)Based on the research on the electric field distribution characteristics of 110 kV three-phase overhead lines,an overhead line voltage inversion algorithm based on three-phase electric field measurement is proposed,and theoretical analysis proves that by measuring the vertical three-phase electric field under the three-phase wire,the inversion calculation of the three-phase voltage of the overhead line can be carried out.(3)Based on the research of voltage inversion algorithm,a scaled model of 110 kV three-phase transmission line is built in the laboratory,and the accuracy of the algorithm is verified by experiments.The experimental results show that the amplitude error of the voltage inversion algorithm is within 3.31%and the phase angle error is within 2°for the established experimental model.(4)This research result can provide a theoretical basis for overhead line voltage monitoring.