ABSTRACT
Electric power distribution is the portion of the power delivery infrastructure that takes the electricity from the highly meshed, high-voltage transmission circuits and delivers it to customers. Primary distribution lines are “medium-voltage” circuits, normally thought of as 600 V to 35 kV. Distribution circuits are found along most secondary roads and streets. Several entities may own distribution systems: municipal governments, state agencies, federal agencies, rural cooperatives, or investor-owned utilities. Distribution planning is the study of future power delivery needs. Planning goals are to provide service at low cost and high reliability. Distribution circuits come in many different configurations and circuit lengths. There are several configurations of distribution systems. Most distribution circuits are radial. Radial circuits have many advantages over networked circuits including: easier fault current protection; lower fault currents over most of the circuit; and easier voltage control. Primary-loop systems are sometimes used on distribution systems for areas needing high reliability.
