Lightning Protection of 230-kV Stations by Pipe Gaps

The impulse, switching surge, and 60-cycle breakdown characteristics of a pipe gap with an effective length of 18 feet and 36-inch spacing have been determined and the predischarge current for impulse surges measured. Superior protective characteristics of pipe gaps as compared with rod gaps for protecting 230 kV transformers against steep lightning surges are demonstrated. A pipe gap, developed for Ontario Hydro-Electric 230-kV stations, to be used in conjunction with the conventional rod gap, is described.