Wake-Effect Minimising Optimal Control of Wind Farms, with Load Reduction

A power generating wind turbine causes a speed reduction and an added turbulence to the wind. Wind turbines in wind farms are often caught in these wakes and are found to have a higher structural load than non affected wind turbines. This article investigates the possibility of designing a control strategy which optimizes the power production, while minimizing the effect of the wakes in the wind farm. A generic wind farm model which is able to calculate the wind turbines influence on each other is developed. Models for the reduction in wind speed as well as turbulence in the wake effects are developed in order to simulate the wake effects. The models are of low complexity, making the wind farm model suitable for control purposes. A model predictive wind farm controller (MPC) is developed and compared to a classical wind farm controller. The MPC is developed, with the ability to minimize the wake effects in the farm, while maintaining optimal power output. A feature which enables the MPC to spare certain turbines, while maintaining the power output is also implemented. The MPC controller is able to minimize the wake effect in the wind farm, when the power demand is not using the full potential of the wind farm.