Powering remote locations from central offices

The author describes a study examining the feasibility of powering remote locations (controlled environmental huts, underground enclosures, or remotely located equipment in commercial office buildings) from the central office by using existing outside plant distribution cables made surplus by the use of fiber-optic technology. The most common source in a central office, -48 V, although attractive from an availability point, cannot provide sufficient voltage to overcome the loop voltage drop in 12000 feet of 22-gauge, 1100-pair cable at 75 A. Voltages such as 130 V can supply sufficient voltage to overcome the loop voltage drop since the current would be less for the same power in the transmission path. However, the using location is designed to operate with a voltage of -48 V, and DC-to-DC converters are needed to convert the voltage to -48 V. It is concluded that these types of converters are technically feasible (130 V to -48 V at 75 A) and could be obtained from power supply manufacturers. However, other technical factors, raise some concerns as to the practicality of powering remote locations from the central office. In addition, it is shown that the estimated cost to provide the 130 V to -48 V conversion equipment at the remote location and the central office source makes the use of central office power as a source of power to remote locations economically unreasonable