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A Hardware in the loop simulator development for wind energy conversion systems

Pourkeivannour, Siamak
In this thesis a wind turbine emulator is developed to replicate the mechanical and electrical behavior of a real wind energy conversion system. A scaling down algorithm is developed to scale down the mechanical behavior of a real wind energy conversion system to a laboratory scale wind turbine emulator. A user interface software is developed to be used as a supervisory control and data acquisition system for the wind turbine emulator in LABVIEW environment. The accuracy of the scaling down algorithm is verified using a MATLAB simulation environment and comparing the simulation and experimental results. Next, a microgrid is developed both in simulation and experimental environments. The developed microgrid is capable of operating in grid-connected and islanded mode. Then the developed microgrid is used to investigate the voltage and frequency deviations in the islanding event transition period using three control methods; the DC-braking resistance, the pitch angle control method and the load shedding method. To verify the accuracy of the developed system, the transients caused by the islanding event is compared for the simulation and experimental environments. Different load consumption and power generation scenarios are investigated in the islanding transition event. Finally, the transient results for the voltage and frequency of the microgrid are analyzed and discussed based on the grid regulation codes prepared by Turkey electrical grid distributor, TEİAŞ, given in chapter 5. It is found out that when the turbine produces more power than the microgrid consumption the frequency and voltage oscillation magnitudes get larger as the difference between the two is larger during transition to islanding mode. It is also found that the oscillation magnitudes get larger as the power factor becomes smaller than unity. In addition, while the oscillation magnitude of the voltage and frequency increases the settling time for the corresponding variable rises. The results indicate that for the scenarios in which the power generation is higher than the load consumption in the microgrid with the value of 0.6 p.u. or higher, the microgrid frequency oscillations overpasses the grid regulation limitations. While the voltage of the microgrid exceeds the voltage ride through regulation limits, which is plotted in chapter 6, when the generation in the microgrid is higher than the consumption value of 0.7 p.u. or higher. On the other side the power factor of the loads in the microgrid affects the islanding transition oscillations. In the future, other control methods will be investigated for the scenarios which their oscillations are beyond the grid regulation limits.