Thesis - Open Access
Master of Science (MS)
Department / School
Electrical Engineering and Computer Science
Photovoltaic-hydro microgrids can provide reliable clean energy in remote areas that do not have an electric grid. Higher photovoltaic penetration can cause large frequency deviations at a high rate of change of frequency in the system. Virtual synchronous machines have been used to enhance performance of a diesel hybrid minigrid but no studies have been performed to account for dynamics of a hydro system. A method is needed to improve the transient stability of photovoltaic-hydro microgrid systems while allowing high photovoltaic penetration. The objective of this thesis was to study the feasibility of using virtual synchronous machines to improve transient stability of photovoltaic-hydro microgrid systems. A virtual synchronous machine is a short term energy storage device with power electronics and a dispatching algorithm that provides inertia to the grid. Transient analysis of a 25 kWp-39 kW photovoltaic–hydro benchmark system was performed using a MATLAB\Simulink simulation with and without the virtual synchronous machine. The virtual synchronous machine was modeled using directquadrature axis based current control techniques, and software in the loop simulations were performed in Opal-RT real time digital simulator. Large frequency deviations and rate of change of frequency were observed when the virtual synchronous machine was not included. When the virtual synchronous machine was used, frequency deviations and the rate of change of frequency were reduced to within limits. The energy use was minimal and comparable to small lead acid or NiMH batteries. Hence, virtual synchronous machines can improve the transient stability of photovoltaic-hydro systems while allowing high photovoltaic penetration.
Library of Congress Subject Headings
Electric power transmission -- Reliability Electric machinery, Synchronous Microgrids (Smart power grids)
Includes bibliographical references (pages 103-106)
Number of Pages
South Dakota State University
Tamraker, Ujjwol, "Improvement of Transient Stability of Photovoltaic-hydro Microgrids Using Virtual Synchronous Machines" (2015). Electronic Theses and Dissertations. 1892.