Six years´ experience with factory-built unit-type substations

THE Iowa-Illinois Gas and Electric Company installed its first unit-type substations late in 1939. At the present time, there are installed in the various operating districts of the company nine unit-type substations. We are outlining the reasons for the choice of this type of substation and the distribution system into which the substations are being fitted. This paper will cover our operating experience with six of this type of substation located in the quad-city area of Davenport, Iowa; Rock Island, Moline, and East Moline, Ill. The reasons given for the selection of this type of substation, the design of the distribution system served by the substation, and operating experience so far encountered are typical also of the other districts in which the additional three substations are located.