Most of the generator stator winding faults are phase-to-ground faults. This is true
because the windings are always in close contact with steel slots that are at ground potential
and, in some designs, are not close to other phase conductors except for the end turns. Phase to-phase faults are less severe, in a sense, since the damage due to these faults can sometimes be
repaired by carefully taping the damaged insulation. This is not true for ground faults, which
often melt the steel laminations and may cause so much steel damage that the core laminations
will have to be rebuilt, resulting in a very long outage.