Wind Shear Profile Models Derived from the Kamchatka Peninsula Meteorological Masts Data

Abstract

The article describes two wind shear profile (WSP) models constructed in the form of empirical dependencies of the Hellman exponent mean values from the wind speed at the minimal met mast measurement height.

The WSP models were developed using the wind speed observation series with 10-min averaging intervals obtained for the minimum and maximum measurement heights from four met masts in the Kamchatka Peninsula, which were then subjected to generalization and putting in a systematic order. The empirical dependencies (WSP models) are applicable for modeling the average wind speed at any height up to 100 m for different source data averaging intervals (month, hour, 10 min) in territories similar to the four met mast sites on the Kamchatka Peninsula in physical and geographical conditions (terrain relief and roughness, and type of water surfaces: river, internal or external sea, etc.).

The second model seems to be of special value for further application due to its ability to model the average wind speed for short intervals of time (from 10 min to several hours) to any height, a feature that is of importance in designing wind power plants (WPPs) intended for operation in small local power systems (LPS). In developing this model, the wind turbulence was taken into account in addition to the terrain physical and geographical conditions. To this end, empirical and approximating dependences of the average turbulence intensity from the average wind speed in gradations (at 1 m/s steps) at the minimum measurement height of four met masts were developed.

The article describes the methods, verification and approximation criteria, and adopted assumptions based on which the WSP models were developed. The determinacy coefficient R2 was taken as the empirical dependence approximation validity indicator. The developed WSP models were verified in accordance with the criterion of relative deviation of the compared average wind speed values at the met mast maximum measurement height calculated from the actual series of data observed on met masts and using the modeled data, which should not exceed the permissible speed measurement error on the met mast (0.1 m/s) for the considered interval.

The effect the selected WSP model has on the design power output produced by a single WPP was analyzed only for one WPP site that coincides with the Ust Kamchatsk met mast site. Investigations for other met mast sites were not performed due to lack of WPP operational data. It is shown that the source data averaging interval should duly be taken into account in choosing the WSP model.