New England Electric´s 39 years of experience with resonant neutral grounding of unit-connected generators

Since 1951 all unit connected generators of the New England Electric System Companies have been grounded using ground fault neutralizers (GFNs). This grounding method permits protection against phase-to-ground faults on the generator bus that is more sensitive than with resistor grounded units. In addition, the fault current is limited to such a low value that the possibility of stator iron burning is practically eliminated. Also, because of the limited fault current, overvoltage due to arcing is not possible. These advantages of ground-fault neutralizer generator protection are illustrated through discussion of actual operating experience and by calculations for a typical generator