TRANSIENT CHARACTERISTICS OF WIND ENERGY CONVERSION SYSTEM (WECS)

Abstract

A theoretical and experimental study on steady and transient state performance of variable speed horizontal axis wind turbine due to sudden change of wind speed is presented. A steady state model is presented for the prediction of performance of a wind turbine based on the blade element and momentum theories with inclusion of the tip losses and the effect of Reynolds number, and a computer program has been developed. A comparison between theoretical and experimental results is made. A simple perturbation model using a quasilinear first order system is developed to study the transient state performance of wind turbine. In this theoretical model, it is assumed that the instantaneous aerodynamic characteristics of the turbine is same as that of the steady state performance at the same wind speed and tip speed ratio. A computer program has been developed and the effects of rate of change of wind speed, number of blades i.e. two and three blade rotors, inertia of the system and the load coefficient K (i.e. type of load) are studied by computer simulation. For some cases, where experimental simulations are possible, the theoretical predictions have been verified with experimental investigations for two and three blade turbine models of one meter diameter by testing in a wind tunnel. Resonable agreement has been found between the theoretical and experimental results.