Research On Distribution Network Planning Including Distributed Generation

With the decrease of global fossil energy, the energy sources and environment problem seem to stand out increasingly. Every country in the world is putting great effort to develop green energy resource. As a new type of power generation technology, the distributed generation has been well developed in recent years for advantages of energy saving, environmental protection, high efficiency and economical. It can cover the shortages of the traditional large-scale centralized power generation method, playing a crucial role in environment protection, the national energy strategy and the safe reliability of power system. However, there exists great influence on the node voltage and the line power flow of distribution network after massive DGs switch in the network. And the influence is closely related to the site and capacity of the distributed power, so that we have to carry scientific analysis on the influence brought out by the DGs switching in the network, and put rational planning on distribution. Based on this, my essay researchs the problem of distribution network planning including distributed generation, the main work and the chief research output are as follows:(1) It analyses the working principle and features of micro gas turbine, wind power generation, solar photovoltaic generation and fuel cell from technological type perspective.It also put forward an all-around induction and analysis of the influence brought by the DGs switching in the distribution network from6aspects that include the power flow, the transmission losses, the voltage, the relay protection, the quality and reliability of power.(2) It analyses PSO, PSO-w, PSO-cf and CLPSO from the principle, features, optimization effect, inducing and further analyzing several problems that need to be noticed in using the PSO to solve the planning problem.(3) It builds a model from the point of the power company that takes the minimum annual cost of distribution network as objective function through comprehensive consideration of the economy and the environmental protection. It optimizedly calculates the model using CLPSO algorithm and uses the IEEE33-bus system as simulation example. The result of simulation verifies that the CLPSO algorithm has good performance. The best planning program in simulation result reflects the transmission losses and general expenses are both declining, and the node voltages are rising to varying degrees. It gives the expression to the economical efficiency and the reliability of distribution network are rising obviously after the DGs switching in the distribution network, and also verifies the excellence of the planning program in this essay. Carrying out the analysis of the secondary index, it reflects the total capacity of DGs have great influence on the objective function at the beginning of the optimization process, and the indexes tend to be stable and become small after determining the total capacity of DGs. The later optimization mainly aims at the installation site of DGs and capacity of nodes in distribution network, the location difference of DGs directly influences the cost of installation and transmission losses, and this also reflects the influence of DGs switching in the network on system losses. It also uses the IEEE69-bus system as simulation example. The result of simulation shows that the model can be used in analyzing the IEEE69-bus system which has larger scale, and verifies the general applicability of the model.(4) It summarizes and analyses the power flow calculation models of wind power generation, photovoltaic power generation and fuel cell of DGs, and analyses the handling methods of corresponding PQ, PI, PV node type. A distribution network planning model is built that takes the minimum transmission losses of distribution network, and the fuel cell is processed as PV node type in power flow calculation, with the IEEE33-bus system being used as simulation example. The comparison of simulation results reflects the system losses drop further, and the node voltages are further improved. But the cost of fuel cell is high, and annual cost of distribution network goes up, so we should strive to develop the fuel cell as generation method in the future taking environmental benefits and energy saving into account.