| Distributed Generation (DG) analysis is becoming more and more popular in power system research. DG is defined as a power source of small scale and compatible with environment, whose output power is between several kW and 50 MW. With the advantages of saving investment, reducing energy consumption and improving reliability of the system, the DG technologies will be the trends in power industry.The introduction of DG makes the distribution network become multi-source served from single source served, which will greatly affects the power flow, bus voltage, short circuit level and relay protection. Firstly, this thesis introduces the models of different DGs connecting to the network, including wind turbine, photovoltaic battery, fuel cell and micro-turbine, also it makes a research to the energy-storing battery. It gives out the suitable models in power flow calculation and short circuit calculation.Then, the thesis analyses the difference among the DG models of different principles about their impact on the distribution network. The paper also explores the handling of nodes in different types of DG, that is taking the wind turbines as PQU nodes, photovoltaic cells and fuel cells as PQ nodes, micro-turbines as PV nodes, and thus it realizes the power flow calculation of the distribution network with multiple DGs. And then a power flow simulation and analysis is made to show the characteristics of the grid with DG connected.The thesis also studies the effect on short circuit analysis. It declares and realizes the improved node impedance matrix method to calculating the short circuit. DG will increase the short circuit at short node, and will differently affect the protection for the position of DG installed, fault position and DG capacity.Finally the thesis carries out the power flow and short circuit calculation through IEEE 36 nodes distribution system and a factual 10kV system. The results prove the methods and calculation effective in the distribution network.
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