Modeling of grid connected PV generator for power flow assessment

The power distribution systems are continuously expanding due to the rise in world population and its migration to urban areas. But consuming the non-renewable resources to generate the electric power, the carbon emissions have made a serious call to global warming so, during the last decade, the electric power systems have seen the penetration of renewable energy resources. This phenomenon has given flexibility to the power grid but also its complexity has increased. In order to successfully integrate the distribution generation of the renewable energy resources, the power grid demands modern power electronic equipment and state-of-the-art techniques, control approach and simulation tools to assess the practical like conditions of the systems. In this continuous struggle to modernize and advance state-of-the-art power grid, this master research thesis investigates the two-stage converter topology for the grid-connected photovoltaic generator using the Newton Raphson iterative method in MATLAB programming. The reason to choose the photovoltaic generator is the rapid growth of such systems and the Newton Raphson method has the advantage of being fast in convergence and robust. The analytical tool for this research thesis is MATLAB coding. The maximum power point tracking of the photovoltaic generator was applied in MATLAB coding to always extract the maximum power from the photovoltaic panels. Later on the admittance matrix, nodal voltages, linearized system of equations of the dc converter are constructed. Then this system of equations is incorporated into the linearized system of equations of the voltage source converter. To implement this scenario in power flows the dc converter implementation in power flows is also represented. The results of different test cases indicate that the two-stage converter topology, involving dc/dc and voltage source converter, for the distribution generation improves the voltage profile significantly at each bus of the system and inject the active power into the nodes generated by the DG units