Estimation of Cut-In and Shut-Down Wind Speed for a Grid Connected Wind Turbine

The Gazelle 22 kW wind turbine is grid connected with an induction generator used as a motor at cut-in. Unnecessary cut-ins reduces net power generation. Development of the control system of the grid connected Gazelle wind turbine highlighted a problem when values of the measured local wind speed were used to disconnect and reconnect the turbine. The measured wind speed at shut down is less than when the blades are stationary, as related to the induction factor. Experiments were performed to investigate this difference, allowing the results to be used within the design of the turbine controller. This gave improved net power generation.