Development of techniques for accurate assessment of wind power potential at a site and optimum site matching of wind turbine generators are of vital importance. Performance of wind energy systems depends on factors like variation of wind speed frequency distribution, turbine speed characteristics viz. Cut-in velocity, rated velocity, cut-out velocity and hub height. Once the details of the wind resource is known for potential wind power site, efficient design of a wind energy systems demand optimum site matching of wind turbines to the potential wind site to obtain higher energy production at higher capacity factor.|
The research work contributes to the following problems in the area of assessment of wind power potential and optimum site matching of wind turbine generators:
Development of a methodology for accurate assessment of wind power potential at a site: Wind speed distributions are parameterized by arithmetic mean, root mean square and cubic mean cuberoot and statistically modeled using Weibul & Rayleigh probability distributions. Actual wind speed data available from a site and the characteristic speeds of the installed wind turbines are used to compute the capacity factors. Kappadagudda wind power station, located in Karnataka, is take up as a case study to validate the analytical results obtained form statistical models. Actual capacity factors from Kappadagudda wind farm are compared with analytical capacity factors to arrive at a salient conclusion that the capacity factors estimated using cubic means and Weibul model prove to be very close.
Based on the above conclusion, a systematic methodology for performance evaluation of various commercially available wind turbines at different potential wind sites is developed. As many as 54 potential wind sites, geographically distributed, in India are studied. Salient conclusions are drawn for performance of different turbines at,
(a) different sites,
(b) same site, and
(c) sites with same cubic mean wind velocity.
A novel method for matching wind turbines to a site based on Turbine Performance Index is developed. The methodology involves identifying the optimum wind turbine speed parameters from turbine performance index curve, which is in-turn obtained from normalized power and capacity factor curves, so as to yield higher energy production at higher capacity factor. Mathematical expressions for normalized power and capacity factors entirely expressed in normalized rated speed are derived.
Wind turbine performance is a newly introduced concept in this research work. It is shown that there exists a unique TPI curve for every site from which speed parameters of a turbine that will optimally match a site can be obtained. The three curves are expected to be of great utility in determining,
(a) Optimum wind turbine parameters for a site,
(b) TPI of various commercial available wind turbines, and
(c) to rank them in order of performance for installation at the site.
Two illustrative case studies have been taken up.
A simple method for estimating the capacity factors, when new wind turbines are installed as a replacement for older or obsolete machines at a site is developed.
A user-friendly interactive software package for optimum site matching of wind turbine generators is developed and tested. A database consisting of wind frequency distributions of 54 Indian sites and specification of various commercially available wind turbine generators is created.