Electric distribution systems

Electric distribution systems

Systems that comprise those parts of an electric power system between the subtransmission system and the consumers' service switches. It includes distribution substations; primary distribution feeders; distribution transformers; secondary circuits, including the services to the consumer; and appropriate protective and control devices. Sometimes, the subtransmission system is also included in the definition.

The subtransmission circuits of a typical distribution system (see illustration) deliver electric power from bulk power sources to the distribution substations. The subtransmission voltage is usually between 34.5 and 138 kV. The distribution substation, which is made up of power transformers together with the necessary voltage-regulating apparatus, bus-bars, and switchgear, reduces the subtransmission voltage to a lower primary system voltage for local distribution. The three-phase primary feeder, which usually operates at voltages from 4.16 to 34.5 kV, distributes electric power from the low-voltage bus of the substation to its load center, where it branches into three-phase subfeeders and three-phase and occasionally single-phase laterals. Most of the three-phase distribution system lines consist of three-phase conductors and a common or neutral conductor, making a total of four wires. Single-phase branches (made up of two wires) supplied from the three-phase mains provide power to residences, small stores, and farms. Loads are connected in parallel to common power-supply circuits. See Alternating current, Electric power transmission

Overview of the power system from generation to consumer's switchenlarge picture
Overview of the power system from generation to consumer's switch
References in periodicals archive ?
The district accounts for its production and electric distribution systems separately.
In addition to restoring electric service interruptions, Consumers Energy's electric line crews perform tasks such as upgrading and constructing electric distribution systems.
The reliability of electric distribution systems is critically important for both utilities and customers.
Its primary function is replacement of conventional overhead line reclosers in medium-voltage electric distribution systems.
A unique combination of theory and practice for designing, operating, and optimizing electric distribution systems.
This month, the National Rural Utilities Cooperative Finance Corporation (NRUCFC) released the results of its 2006 Key Ratio Trend Analysis (KRTA) to electric distribution systems across the country.
LIPA is one of the largest municipal electric distribution systems in the country, with over 1.
MJMEUC's interest in the Plum Point Project will be used to meet its commitments under unit power purchaser contracts, providing power to seven of its retail electric distribution systems in Missouri (four) and Arkansas (three).
At the same time, major investments are needed in PSE's aging natural gas and electric distribution systems to maintain their structural integrity, meet stricter safety requirements, and serve a steadily growing customer base.
CURRENT(TM) Smart Grid Services enable utilities to improve the operation and efficiency of their electric distribution systems with capabilities such as:
The rating also recognizes that the city has chosen ENCO, a former Edison affiliate that operates municipal electric distribution systems in California and Arizona, to operate the Winter Park system.
It provides real-time, predictive power measurement tools that can automate intelligence as well as predictive analytical tools for the prevention or containment/isolation of diverse electric distribution systems failures or black-outs.

Full browser ?