Automatic substations

In this paper the description of an automatic synchronous converter substation is prefaced by the mention of a number of more familiar instances of automatic operation, in which electric motors or generators operate without regular attendance. The paper then describes the Detroit automatic substation, in which a 60-cycle, 500-kw. synchronous converter supplying current to a 125/250-volt, three-wire d-c. lighting system is operated entirely from a distant station. An interesting feature of this installation is the absence of control wires, as the three-conductor, 4400-volt cable carrying the a-c. supply current to the station is used in connection with the automatic devices in the station to start, load and stop the machine. and the automatic devices furnish protection.