Identification of the Terminal-to-Core Couplings in Filter Inductors by Using Double-Pulse-Test Setup

In this paper, the capacitive couplings between the terminals and the magnetic core of a medium-voltage (MV) filter inductor are identified by using the double-pulse-test setup under high-voltage and -current excitation, instead of using the traditional impedance analyzer, which performs frequency sweep at low-voltage and -current magnitudes. The time-domain current and voltage waveforms from the double-pulse-test setup are measured and further converted into the frequency-domain signals by using the Fourier Transformation. From this, the terminal-to-core impedance between the inductor terminals and the magnetic core of MV inductors under high-voltage and core saturation is obtained. The calculated impedance by using the measured data from DPT is compared with the measurements from an impedance analyzer, where the result indicates that the high-voltage and -current has almost no impacts on the change of the couplings between the inductor terminals and magnetic core of the studied MV filter inductors.