This 2.6 kHz oscillation can be explained by looking at the
VT frequency response, shown in Figure 10. It can clearly be
seen that the VT experiences resonance and has maximum
gain at 2.6 kHz. The instantaneous change in voltage
presented by the voltage waveform on the primary winding,
shown in Figure 8a, has a very high frequency content. This
results in a 2.6 kHz oscillation being seen on the secondary
winding. A similar 2.6 kHz oscillation was apparent in both
the measured and simulated VT impulse response [13].