提出了一种实时测量中性点不接地配电网电容电流的新方法——单频率测量法,即从电压互感器开口三角侧注入一个恒定的电流信号,测量开口三角侧电压和二次星形侧相电压。根据注入的电流信号和测出的电压信号,计算出配电网对地电容值和电容电流值。该方法完全避免了电压互感器短路阻抗和注入信号频率选取组合对测量结果的影响。经理论推导和模拟实验验证,该方法不影响配电网正常运行,具有安全、简捷、准确等优点。
A novel method of capacitive current measurement (injecting one frequency signal measurement) is proposed for insulated neutral distribution networks. With a constant current signal injected into the open-delta side of the voltage transformer, the voltage of the open-delta side and the phase voltage of the secondary star side are measured. The distribution network capacitance and capacitive current to ground can be calculated in accordance with the injected current signal and the measured voltage signals. The proposed method avoids the influence of short-circuit impedance of the voltage transformer and the injecting signal frequencies. The results of dynamic power system simulation show that the proposed method is with high precision, and can be used in real-time without power supply interrupting.