At higher frequencies, VT resonance becomes the most
important feature to represent. Typically, as nominal voltage
increases, the first resonance experienced by a VT occurs at a
lower frequency. This resonant frequency is related to the
transformer turns ratio [10], and inductive VTs used at
distribution voltages typically have a wider bandwidth than
those at higher transmission voltages. The frequency response
of a 200kV VT [10] is shown in Figure 4. It can be seen that a
peak in VT gain occurs at around 1.3 kHz. When the primary
voltage of this VT was subjected to an impulse, the measured
waveform on the secondary winding had a similar impulse
waveform, with a ripple introduced at 1.3 kHz.