Analysis Of The Effects Of Distributed Generation On Distribution System

Distributed generation is a new trend in new century in prospect of power sourcestechnique. The developments of distributed generation have a great influence on thetraditional power system and bring about electrical technology notable advancement. Inorder to utilize disperse energy resources and improve utility system reliability,distributed generations are applied in power system more and more widely. But thenumber of distributed generation increasing brings about some technical problems: thedirectional change of power flow in distribution system brings problem to voltageregulation; DG raising short circuit level makes protection setting and breakersoperation difficulty.Most distribution systems especially rural systems are operated in a radialconfiguration. The main reason for this structure is the simplicity of operation andeconomy of the overcurrent protection system. The voltage regulation and protection ofdistribution systems are based on radial configuration. When distributed generation ispresent, meshed distribution networks are in place of radial systems. Most conflicts overoperation with DG arise from this structure, which brings new challenge to voltageregulation and protection.The author classifies the distributed generation and discusses four populardistributed generation techniques, introduces the voltage level and basic distributionnetwork configuration. Distribution systems model with load model and DG model arebuilt. According to the size and location and power factor of DG the author discussesthe effects of DG on distribution systems and draws a conclusion. All kinds of methodsof voltage regulation are discussed including generator, SVC, transformer and networkparameter changes. Based on the discussion a new voltage regulation method isproposed. The SVC model is built and the simulation shows the method is feasiblewhether DG is in or out of the distribution systems.The function and request of protection are introduced and some kinds of protectionof distribution systems are discussed. The author details the theory and setting principleof three sections current protection. Typical distribution systems model and DG modelare built. According to the size and location of DG the author discusses the influence ofDG on protection and draws a conclusion. Base on the discussion a new voltageregulation method is proposed.