并阻尼谐振接地系统对地参数测量与高阻故障选线新方法

针对谐振接地系统对地参数测量不准确以及高阻接地故障选线困难的问题，提出了并阻尼谐振接地系统对地参数测量与高阻故障选线新方法。基于消弧线圈并联阻尼电阻的投切特性，利用投切阻尼电阻前后零序电压幅值与相位的变化关系，测量系统对地电导与电容参数。在系统正常运行时，通过调整并联阻尼电阻值大小，测量各馈线零序导纳值。在发生接地故障后退出阻尼电阻，测量故障后各馈线零序导纳值，可消除系统参数不对称、互感器采样不同步的影响，主动构造故障前后各馈线的零序导纳相角差，实现故障线路的准确判别。在PSCAD仿真环境下对所提方法进行验证，结果表明：所提方法能够精确测量对地电导与电容参数，测量相对误差不高于0.6%；在不同馈线、不同过渡电阻下发生接地故障时，能准确判别故障线路，耐过渡电阻能力达10 kΩ。

A new method for measuring ground parameters and selecting high resistance fault linesin parallel damping resonant grounding systems

There are problems of inaccurate measurement of ground parameters and difficulty in selecting high resistance grounding fault lines in resonant grounding systems. Thus this paper proposes a new method for measuring ground parameters and selecting high resistance fault lines in parallel damping resonant grounding systems. Based on the switching characteristics of parallel damping resistance of an arc suppression coil, the system’s ground conductance and capacitance parameters are measured by using the relationship between the zero-sequence voltage amplitude and phase change before and after switching the damping resistor. During normal operation of the system, the zero sequence admittance value of each feeder line is measured by adjusting the parallel damping resistance value. After a ground fault occurs, the damping resistance is exited and the zero sequence admittance value of each feeder after the fault is measured. This can eliminate the influence of system parameter asymmetry and asynchronous transformer sampling, actively construct the zero sequence admittance phase difference of each feeder before and after the fault, and achieve accurate identification of the faulty line. The proposed method is validated in the PSCAD simulation environment, and the results show that it can accurately measure the ground conductivity and capacitance parameters, with a relative measurement error of no more than 0.6%; when grounding faults occur in different feeders and transition resistors, the fault line can be accurately identified, and the resistance to transition resistance can reach 10 k.