Abstract :
THE Hog Island Shipyard, near Philadelphia, Pennsylvania, constructed as a war measure, and which is known all over the world as one of the largest shipyards in existence, is operated throughout by electrical power purchased from the Philadelphia Electric Company and transmitted over a double-circuit, 66,000-volt stranded copper No. 00 tranmission line. There is also another single-circuit line operating at 13,000 volts. Both are three-phase circuits. At the main substation (shown in an accompanying illustration) there are twelve General Electric transformers with a capacity of 2000 kv-a. each. The frequency throughout the system is 60 cycles per second. The primaries of the transformers are delta-connected, and the secondaries are Y-connected. Their temperatures were 55 deg. cent, when the writer was at the station in March, 1920. They are purely oil-cooled. Monthly tests are made of the oil in the transformers, and if the oil is below the 28,000 point it is filtered by a filter which is located on the interior of the substation. It too, is a standard G. E. type.
