Design Of Four-supply-one-backup Electric Wiring Plan For A Distribution System

With the rapid development of social economy,the living standard of the residents has improved significantly.The demand for power supply and reliability of distribution network is higher and higher.Smart grid is a great change in the power industry,representing the development direction of the future power grid.Through the comprehensive transformation of existing power grid and equipment,smart grid relies on advanced communication and control technology to achieve the harmonious development of power grid and environment,energy,economy and security.Self healing control is the inevitable trend of the future distribution network development.It is an inevitable trend to use self-healing technology to build high reliability demonstration zones.This paper first analyzes the typical wiring modes and characteristics of the traditional distribution system.The typical connection modes of medium voltage cable network in China mainly include single-shot,single-loop,double-loop,Three-supply-one-backup Connection Mode.This paper mainly compares the reliability of power supply,customer experience,economy,technical performance and line utilization.The urban area with high load density and high reliability requires Three-supply-one-backup or double loop connection modes.At the same time,the distribution network should be upgraded intelligently.The smart distribution network with self healing function is built.Then,the demand analysis of the distribution system in a central city is carried out.This paper expounds the load distribution,importance,power supply reliability and other power supply requirements of a downtown system.This paper analyzes the problems and construction goals of central distribution network.This paper explains the necessity of transformation of the distribution system in the central area of a city.Conventional central district power grid selects Three-supply-one-backup or double loop network connection mode.This paper puts forward the design of the Four-supply-one-backup plan in a central city.This paper introduces three kinds of Four-supply-one-backup connection schemes: full circuit breaker type,load switch + circuit breaker type and full load switch type.It includes the one and two equipment configuration,typical wiring action analysis,protection and self healing function configuration.Finally,the connection matrix method is used to evaluate the three kinds of Four-supply-one-backup connection schemes.This paper evaluates the reliability of power supply,customer experience,economy,"N-1" security? operational flexibility and line utilization rate and concludes that the best scheme is the Four-supply-one-backup connection scheme.Combined with the actual distribution network high reliability demonstration area project,this article carries on the transformation plan research and the design.It will have a strong reference for future smart distribution network transformation and design.