Growing Share of Wind Power in the Power System and its Impacts on Frequency Regulation

The share of wind energy in the power grid is growing at a very fast rate. As a result, there is a proportional drop in the share of traditional generators. Synchronous machines, which constitute the backbone of the AC grid, possess many important capabilities such as inertia, speed droop and short term overloading capability. These features are essential for balancing the frequency after every system event. Since grid connection of wind turbines (WTs) is done through power electronic converters, the natural linking between these machines and the system will be missing. Thus, the growing share of wind power in the grid will reduce the system inertia and increase the droop. In an interconnected system, the impact will be a drop in the area control error (ACE) leading to a reduced tieline flow from the renewable energy (RE) dominated area. The result of all these eventually leads to increased frequency deviations and larger rate of change of frequency (ROCOF) coupled with longer recovery periods for frequency after system events. In this work, these aspects are analysed and their impacts on frequency regulation capability is demonstrated through simulations.