if less than 1, current flows up the neutral. Although the current can be up or down the neutral
for a high-side fault, in practice, with the usual system and transformer parameters, the current is
always up the neutral for low-voltage faults.5
Figure 4.19 shows the connections for a variety of transformer installations. Either potential or
current polarization may be used, or both simultaneously. However, since the zero-sequence voltage
always has its maximum magnitude at the fault and decreases from the fault point to the grounded
system neutral, it is possible that there will not be sufficient zero-sequence voltage at the station to
give adequate polarizing. It is therefore generally recommended to use current polarizing at stations
where transformer banks are solidly grounded.