The Analysis Of The Impact Of Distributed Generation On Transmission Network Dispatching

With the deterioration of the global environment, research and application of renewable energy attract more and more attention. Wind farm and photovoltaic developed quickly in recent years. In the UK, renewable source contributes4.6%of the total energy in2006, but the goal in2008is15%. In China, the total capacity of renewable energy generation reached to282GW by2011. In the year of2011, there are11409wind power generation systems were installed in the mainland of China. The increased capacity was17630.9MW and the increasing rate reached to39.4%. Most renewable source will be connected to the grid as DG (distributed generation). The greatest characteristic of DG is that it is connected to the distribution system directly. Therefore, it has the different impact on the grid compared with traditional generation.There are many resources regarding the impact of DG on the distribution system recently. This effect is vast and direct since it is connected to the distribution system directly. However, for transmission network, the effect is unknown. This project focuses on the DG impact on the demand at transmission level, especially under the different situation of DG types, penetration, location and line capacity. IEEE30bus system is chosen as the test system. All the power flow analysis and curve fitting are realised in Matpower, which is software based on Matlab.The first chapter introduces the background and significance of this project and summarises the definition, characteristics and categories of DG. Chapter two introduces some categories of DG, including wind power generation, solar power generation, micro turbine generation, garbage power generation and small hydro and so on, and analyses their equivalent model in power flow analysis. It presents methods to calculating the output power of DG. In this essay we choose F factors for calculation according to protocol P2/6. Chapter three summarises the impact of DG on distributed system from the perspective of power flow, line loss, network planning, power quality and protection. In chapter four, nine scenarios are implemented on IEEE30buses system. Among them, wind farm is connected to distributed system as DG generation in five scenarios, for calculating and exploring the impact of penetration, location and line capacity in both ideal situation and practical situation. CHP (Combined Heat and Power) is used as DG generation connected to the system in four scenarios. It calculates and explores the impact of penetration and line capacity in both ideal situation and practical situation, and analyses a special situation which is the impact of units’number when they have the same capacity. Programming, simulation results and analysis including qualitative and quantitative analysis are shown in chapter five,. In chapter six we discuss results and analyse the impact on transmission network dispatching. The final chapter of this essay is conclusion and further work.