Ground-Fault Protection of Four-Pole Generators With Two Parallel Branches in Phase Winding

An analysis of the operating conditions of a third harmonic ground-fault protection system for a four-pole generator with two parallel branches in the phase winding was carried out. The voltage exciting the measuring element of the protection system for various neutral grounding configurations was determined. The influence of the neutral grounding configurations on the exciting voltage was examined through simulations. The operating conditions of the protection system were determined taking into account the actual third harmonic distribution along the stator winding, the to-ground capacitances of the generator breakers, and the real ground-fault arc resistance