Economic optimisation of a wind power plant for isolated locations

A wind power plant model for isolated locations is composed of a vertical axis wind turbine connected to a self-excited induction generator operating at constant voltage and frequency. Also included in the system are a back-up diesel generator and a battery system. Constant voltage and frequency are only obtained by controlling the generator appropriately. The control system is supposed to be optimized so that the system operates at the highest efficiency. In order to further improve the total efficiency, a gear-box is considered to vary the gear transmission ratio between the turbine and the generator. A ‘Monte Carlo’ type simulation has been used to analyse the operation of that system over a one-year period. The basis of the model is a probability density function of the wind speed derived by statistical data concerning a given location and on the probabilistic curve of the load required by an isolated location. The cost per kW h for different dimensions of the main components has been evaluated and the optimum configuration identified.