Novel wind turbine control techs open for commercialisation

New technologies for fast frequency support and forced oscillation control in wind turbines have been developed at the University of Birmingham, UK.

The technologies, which can be integrated into existing wind turbine control systems, are aimed to address the two major issues identified with the rapid growth of wind farms globally – namely power system frequency control and forced oscillations, which can cause widespread disruption over entire power grids.

While details about the technologies are limited, patent applications have been filed and the University is seeking commercial partners for licensing, collaboration or co-development.

“With increasing high penetration of renewable energy generation moving towards 100%, exploitation of future control potential from wind turbines becomes inevitable,” says Professor Xiao-Ping Zhang, chair in Electrical Power Systems at the University of Birmingham, who has led the development of the wind turbine control technologies.

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“These two technologies make the most of this potential, to benefit both the grid and wind farm operators, and ultimately energy users who need an uninterrupted energy supply and hence bring significant added values to wind turbines and power grids.”

Grid frequency events are caused by shifts in supply and demand, with the frequency dropping with a potentially protracted settling process when demand exceeds supply.

The new method is designed to quicken this recovery and eliminate the risk of a frequency second dip, with minimal – less than 1% – loss of wind power capture.

In particular, the technology was developed for use in variable speed wind turbine systems, which have emerged as the dominant type and usually operate at maximum power point tracking mode to extract the greatest amount of energy and so do not regulate their active power to support the grid when its frequency deviates from its usual value.

The second technology addresses the issue of forced oscillations, which occur when external disturbances produce oscillations that are close or equal to the natural oscillations in a power system – in the context of wind farms triggered by factors such as wind shear, wind turbulence or upstream turbine wakes and in the context of power grids by malfunctioning equipment.

The new control system suppresses and isolates forced oscillations originating either from the grid or from the turbine itself by releasing or absorbing power that is opposite to the oscillating power.

A university statement says that both systems have been verified in simulations with a range of different wind scenarios.