基于变电阻电压扰动的配电网对地参数精确测量新方法

摘要

为了获得配电网精确对地参数，提出基于变电阻电压扰动法的电网对地参数测量方法。对于中性点不接地系统、中性点经消弧线圈接地系统，由于系统正常运行时参数的不平衡，将在中性点产生一定的电压偏移。通过在中性点投入不同阻值的电阻，引起中性点电压的改变，测量改变前后的电压幅值，由电压幅值和其他已知参数通过一定的运算可先计算出配电网对地电导，将电导代入再求出系统对地电容精确值。Matlab仿真分析和实验模拟网测试结果表明该方法具有很高的精确度，且该方法简单、安全、适用范围广、可操作性强。同时指出实际现场测量时，应选用适当阻值电阻，以减小测量误差。%In order to obtain accurate grounded parameter of distribution network, a method of measuring grounded parameter of power grid based on variable resistor voltage disturbance is put forward. Due to the unbalanced parameters during system normal operation, voltage will deviated in the neutral point for neutral point grounding system and neutral point via arc suppression coil grounded system. By adding resistors with different resistance in the neutral point to change the neutral point’s voltage, this paper measures the voltage amplitude before and after the change, uses the voltage amplitude and other known parameters by certain operations to calculate the distribution network grounded conductance, and substitutes conductance into the equation to obtain accurate grounded capacitance. Matlab simulation analysis and experimental test results show that the method is highly accurate, simple, safe and has wide application and operability. It also points out that appropriate resistance values should be chosen in actual measurement to reduce the measurement error.