Study On The Fault Analysis And Control Of Distribution System With Distributed Generators

With urbanization speeding up and economy improving,citizens demand a highly reliable electricity supply and traditional unrenewable energy bring the environmental problem.So,distribution generation(DG)has been made in great progress.The installed capacity and the capacity access to grid are increased annually.However,the grid structure has changed and the direction of power supply system has shown a large uncertainty after DG connects to the grid.Based on this reason,researching fault-locating algorithm of power supply network with DG has an important influence on the popularity and application of DG.Not only that,what is a vital measure to further improve the reliability of power supply is to quickly restore the power supply at the fault section and to minimize the power-off time.To begin with,this dissertation analyzes the impact that distributed power access has influence on fault-locating.It main focuses on the effect of short circuit current on the contact switch.And simulation analyse the effect of DG access point on short circuit current.In the meantime,it proves that the bigger capacity of DG,the lower sensibility of Feeder Terminal Unit(FTU).Against the decline of the sensibility of FTU,the traditional fault-locating algorithm have its the limitations.So some scientists put forward the improved matrix algorithm for distribution network with DG.This algorithm links the fault reported by FTU to supervisory control and data acquisition(SCADA)system.Finally,it rapidly isolates the fault section of the power supply network through fault-locating algorithm.This matrix only needs operate the product and the positioning principle is very simple and intuitional.It also can be applied into complex network with multiple branch bus points.After the fault-locating of power supply network,power supply system will return to work.Firstly,this thesis take into full consideration the network feature of real power supply network,and then it raises the theory which combine islanding rules with binary particle swarm algorithm.Through the this way,it can make sure the real-time updating and guiding of particles reinforce the convergence of algorithm.Finally,the algorithm is realized by programming.The examples analysis shows that the algorithm can effectively solve the problem of power recovery after power failure.And it also have those advantages which are good convergence,high speed and tendency to reach the optimal solution.