Experience with Carrier-Current Communication On a High-Tension Interconnected Transmission System

The paper gives a historical outline of the development of carrier-current communication on power systems. It discusses the principles of the various systems of carrier current developed to date and outlines the fundamentals of a carrier communication system over a transmission network. A description of the installations on a 132-kv. network having an extent of 2500 linear miles is given and the general experience with carrier, which is the sole means of communication operated and provided by the power companies on that system, is outlined. A carrier-current communication system is analyzed into its component parts and the experience with these various parts given. Extensive experience with various forms of couplings, various forms and makes of coupling capacitors is described. Experience with the protective system, the lead-in system, and the tuning used in connection with the coupling is given in detail. Detailed experience is given with the transmitting system and the receiving system of various makes of carrier employed. An outline of the experience with the various makes of power supply is given. A discussion of the operation of carrier on a large system such as the one described and the necessity for zoning and interzoning is given and experience in establishing and maintaining these zones is outlined. Definite data are cited as to cost, maintenance, reliability, traffic, and safety. A description of various types of portable sets developed and their use is given.