A universal power-law model for wind speed uncertainty

Abstract

The uncertainty is a significant characteristic of wind speed in wind engineering field. Especially, it has brought much more problems to the grid in safe and efficient utilization of large scale wind power. And there is urgent need of systematic and perfect models that can describe windspeed uncertainty in grid scheduling and controlling. In this paper, a universal power-law model is proposed for properly depicting the uncertainty of both wind speed and wind power. According to the turbulence nature of wind uncertainty, the uncertainty model of wind speed is firstly obtained by using wavelet multi-scale transform algorithm for its tight supporting characteristic, which is more reasonable than the traditional algorithm of getting the mean valve and the variance valve of the time series. And the turbulent intensity model is further improved by a power-law model, which is suitable for much more kinds of turbulence on complex geographical conditions than that proposed in current international IEC standard with the sufficient actual data. In physically speaking, the model improvement with three parameters is consistent with turbulence development mechanism. Moreover, the uncertainty modeling method of wind power is developed based on the universal power-law model, which is not only suitable for the power of single wind turbine, but also suitable for the power of whole wind farm. It’s very importance that the wind speed uncertainty model is extended to model the power uncertainty of wind turbine and farm, in especial its or their power output is usually limited for human adjustment control. It has a certain significance to the real-time dispatch and optimal control of the renewable energy power system.