ANALYSIS OF SYSTEM STABILITY OF GRID INTEGRATED WITH RENEWABLE ENERGY SOURCES

Abstract

The global electricity market and network is changing with integration of large shares of renewable energy sources in the conventional electrical grid. The shift from conventional sources of electricity to renewable sources is due to the increasing prices of conventional fossil fuel-based thermal power plants which uses mainly petroleum and coal; direct pollution and carbon emissions. Although nuclear powered thermal power plants have the capability to power the world; the radiation hazards and complex operational safety requirements makes it unsuitable. With increasing concern over global warming, efforts are made to increase penetration levels of renewable energy sources in the conventional electricity grid. Of all the renewable energy sources (RES) wind and solar photovoltaic are the most mature technologies which are operated extensively all around the world, especially in Europe and USA. The intrinsic nature and variable generation from RES pose challenges to integrate them with the grid and maintain stable electrical power system. Due to increasing penetration level of RES, voltage and frequency stability has emerged in an AC grid mainly due to the power electronics used in RES technologies and withdrawal of large inrush current in induction generators in wind power plants while starting. This dissertation aims to analyze the system stability issues of grid integrated with renewable energy sources with load flow analysis and steady state analysis. An extensive literature review is carried out on system stability issues of grid integrated RES and research gaps identified. Bhutan’s power grid is chosen for the analysis of system stability with renewables. Renewable energy resource potential mainly, wind and solar power potential is estimated using measured data and also NREL’s data. The modeling of the grid, wind energy conversion systems, solar PV systems and system stability analysis are carried out using MATLAB Simulink. The results from load flow shows that voltage profile is improved with integration of wind and solar energy sources. Further, financial analysis with LCOE for wind and solar PV systems are also carried out and discussed and presented in this dissertation report