Review of Frequency Stability Control Schemes in the Presence of Wind Energy Sources

Renewable energy sources have become a major area of interest for governments and utilities world-wide. They not only promote use of clean energy but also ensure a friendly and healthy living environment. As a result, large integration of renewable energy into the grid has become common and is growing fast. However, this rapid development has realized drastic and insurmountable challenges. The stability of the power system is compromised because renewable energy sources do not provide system inertia. The inadequacy or lack of system inertia lead to increased system frequency excursions and henceforth frequency instability. Wind energy resource development has seen unprecedented scales of growth and has also been adversely affected by frequency instability especially in isolated power systems. Research has shown that isolated or weak grids not supported by system inertia experience more instability. Most researchers therefore concentrated on finding solutions to the isolated power systems. However, large scale integration of renewables imply conventional sources of energy will be displaced and frequency instability problems would also occur in the grid. There are many frequency control methods utilized at different levels to stabilize the power system. The three levels are inertia, primary and secondary frequency response based on time of the response. This research paper investigates frequency stability with wind energy sources using IEEE 39 bus test system. It is modelled in MATLAB/Simulink and simulated by power system analysis toolbox. The results show huge power system losses and power mismatch values. In conclusion the toolbox is not sufficient to simulate and analyze the grid with the provided IEEE 39 bus data.