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 effectively inhibit the power frequency interference with simple calculation and high measuring accuracy and speed.