Research On Coordinated Power Supply Model Of Distribution System

At present, urban distribution system planning has already been recognited bymany power supply enterprises. However, there were the problem that the reliabilityand equipment effectiveness of our distribution network are more lower than that ofdeveloped country. Moreover, the research showed that vacant equipments cannotplay an important role on reliability improving. Therefore, it should be significant thatthe methods are studied based on actuality of our distribution sytem to enhanceequipment effectiveness under the premise of reliability ensuring. To resolve it, PowerSupply Capability(PSC) algorithm and distribution system coordinated theory andmethod are deeply researched to receive many results in the paper.(1) Because it was difficult to describe harmony of distribution network, the PSCindex is defined and its actual algorithm is analyzed. Taking the cause intoconsideration, this paper proposes a method to correct the load rate matrix ofinterconnection schemes that is based on the advantages of the former method. Firstly,the minimum load rate of each interconnection scheme is searched and recorded,according to which the same column are corrected. Secondly, the margins produced inthe former step are distributed to each main transformer of the same interconnectionscheme according to the N-1guideline. The method completes after the traversal ofload rate matrix. Finally, it is demonstrated that this method obtains a more accurateresult by the calculation of practical example.(2) Based on the improved algorithm to calculate PSC of MV distribution system,the theory of all levels power network harmony is proposed. Moreover, MVdistribution network coordinated planning method between substation and feeder ispresented with the analysis on power supply and transfer. As a result, typicaldistribution system coordinated planning principles are received.(3) Power Supply Model(PSM) of MV distribution system is presented to resolvethe problem that conventional analysis only gave regards to feeder connection modeso as to neglect coordination power supply with multiply voltage levels. First, PowerSupply Framework(PSF) indicated interconnection structure of substation isestablished according with landform and load density; next, integrated PSM is formedby the analysis of PSF and connection mode; last, the attribute and externalcharacteristic of PSM is gained with quantity of power supply unit and power supplycapability. The proposed PSM could reflect coordination power supply with substation and MV feeder in whole, which can play an important guidance role on thetheoritic analysis and actual design of power supply project.(4) Based that the integrated assessment index system and its key indicescalculation is presented for established PSM of MV distribution system, thecharacteristics of all models are assessed which is convenient for PSM selection. Inaddition, in order to guide the planning selection and, the transition projects areproposed based on that of PSF and connection mode with different developmentstages of urban load.