基于谐振频率预测模型的配电网电容电流测量方法

Capacitive Current Measuring Method for Distribution Networks Based on Resonant Frequency Prediction Model

现有配电网电容电流测量的信号注入法在测量精度和速度上暂不能达到平衡,为更适应测量系统快速跟踪变化的要求,提出了一种谐振频率预测模型。该模型直接根据波形波峰间的时间差进行谐振频率的计算,能够快速确定电容电流大小,大大缩短测量时间。为有效消除具有一定频率偏差的工频信号干扰,设计了级联陷波器对中性点电压信号进行处理。多组仿真实验证明,该模型测量方法可有效消除工频信号干扰,计算简便,测量精度高、速度快。

The existing signal injection method for measuring the capacitive current in the distribution network is still unable to reach the equilibrium between the measuring accuracy and the measuring speed. To better meet the fast tracking requirement of the measuring system, a resonant frequency prediction model is proposed. In this model, the resonant frequency is calculated according to the time difference between the peaks of the waveform, and the capacitive current value is quickly determined,which greatly reduces the measurement time. To effectively eliminate interference of the power frequency signal with a frequency deviation, a cascaded notch filter is designed to process the neutral voltage. Multiple simulation results show that the proposed method is able to ef{ectively inhibit the power frequency interference with simple calculation and high measuring accuracy and speed.