Grounding Transformer

A grounding transformer, also called an earthing transformer, is an auxiliary transformer used in three-phase electric power systems to provide a ground path to either an ungrounded wye or a delta-connected system. Grounding transformers maintain system neutrals at ground potential, restrict voltage surges during ground faults, supply ground fault current when line-to-ground faults occur, and enable the connection of phase-to-neutral loads in delta-connected systems. Most use a zigzag winding configuration, though delta-wye designs are occasionally used, and they are particularly common in power plants and wind farms for neutral grounding on generators.