计及地线耦合的利用架空线路测量接地网接地阻抗的方法

在利用架空线路测量接地网接地阻抗时,未断开接地网与架空地线的连接构架会使通过接地网流入大地的电流小于实际注入电流,且经过地线的分流电流由于架空地线与相线间的电磁耦合效应会在线路中产生干扰电压。因此提出在测量接地网对地电压和实际注入电流时,同步测量地线电流以减小分流效应造成的误差;并通过多次测量的数据建立数学模型进行计算,以减小测量线路与地线的电磁耦合效应产生的感应电压对接地阻抗测量产生的影响。仿真结果表明,在电压极之前的杆塔与地线绝缘或者直接相连的杆塔数目较少的情况下,所提测量方法能有效减小用架空线路测量接地网接地阻抗时地线分流造成的接地阻抗测量误差。

Method for Measuring Grounding Resistance of Grounding Grid Considering the Influence of Earth Wire Coupling

When the overhead lines are used to measure the impedance of grounding grid,the current through grounding grid is less than actual injected if the ground grid is connected with the overhead ground lines.The current bypass the ground line will generate a coupling voltage on the circuit because of the electromagnetic coupling effect between ground line and conduct line.In order to reduce the measurement error caused by ground line shunt,this paper proposes that ground line shunt should be measured at the same time when the voltage of ground grid and actual injected current is measured.And a mathematical model is built by a few measurement data to reduce the influence of the electromagnetic coupling effect between ground line and conduct line.The simulation results show that if there are few towers connected with the ground lines,the proposed method can effectively reduce the measurement error caused by ground line shunt current when the overhead line is used to measure the grounding impedance.