Application and Validation of Peak Shaving to Improve Performance of a 100 kW Wind Turbine

Abstract

In this study, a peak shaving algorithm known as a control method to reduce peak mechanical loads in multi-megawatt wind turbines was designed and implemented to a medium capacity 100 kW wind turbine to solve overspeeding shutdown problem due to low moment of inertia of the rotor. The algorithm consists of a look-up table having an input of measured rotor speed and an output of blade pitch angle, and the output is added to the pitch command of the controller. The algorithm was firstly validated using a commercial aero-elastic simulation code, GH-Bladed, under low and high turbulence conditions. The simulation results clearly showed that the maximum rotor speed value causing an overspeed shutdown was reduced and that the mean power was slightly increased. In addition, the damage equivalent loads for the blade out-of-plane bending moment and tower fore-aft bending moment were reduced in the rated wind speed region. Field tests were also performed to confirm the validity of the simulation results. For the field test, the peak shaving algorithm was implemented to the original power control algorithm and it was uploaded to the programmable logic controller of the 100 kW wind turbine. It is concluded that applying the peak shaving method for multi-megawatt wind turbines to a medium capacity wind turbine with much lower rotor moment of inertia is effective in reducing overspeed shutdown problems and helps annual energy production as the result. In wind conditions where the average wind speed is 4.55% higher and the turbulence intensity is 11.81% higher, the maximum rotor speed and standard deviation causing an overspeed shutdown were reduced by − 2.06% and − 8.08%, respectively, with the proposed peak shaving algorithm. The results demonstrate convincingly that predicted improvement in simulation can be achieved in practice.