Figure 18. Waveforms under internal fault (taking CT saturation into account): ( a ) i self0 and i n0 ; ( b ) Figure 18. Waveforms under internal fault (taking CT saturation into account): ( a ) i self0 and i n0 ; Figure 18. Waveforms under internal fault (taking CT saturation into account): ( a ) i self0 and i n0 ; ( b ) zero-sequence differential current. ( b ) zero-sequence di ff erential current. zero-sequence differential current.