“…The reason for this is that the total harmonic distortion (1) does not take into account the phase angles of the individual voltage harmonic components [2]. In [3] two examples of the dependence of the number of partial discharge pulses on the phase angle of the 5th order voltage harmonic are shown. In the first case, in gas cavity, the same number of partial discharges occurs during a period, as with a pure sinusoidal voltage, but in the second case, the number of partial discharges is greater.…”