Abstract :
The Pennsylvania Water and Power Company, since it started operation of its hydroelectric plant at Holtwood, Pennsylvania, has kept a careful record of all operating events. In the following paper this record is given for the four years 1911–1914, as far as the high-tension transmission line, Holtwood to Baltimore, is concerned. The record deals essentially with certain observations made on lightning flash-overs, deterioration of insulators, sleet on cables, and the various means adopted to prevent disturbances to operation from these causes.