فهرست مطالب امیر نقی زاده گوگدره

One of the most important power quality aspects in wind farms is voltage fluctuation or flicker which should be investigated due to the nature of wind speed variations. These variations result in power and voltage fluctuations at the load bus. Moreover، the wind generation systems may be assumed as a harmonics source because of their power electronic converters. There are numerous factors that affect flicker and harmonic emission of grid-connected wind turbines during continuous operation، such as wind characteristics (e. g. mean wind speed، turbulence intensity)، type of generator and grid conditions (e. g. short circuit capacity، grid impedance angle). In this paper، an IEC based flickermeter is first modeled and then a variable speed wind turbine has been simulated by Matlab/Simulink software. The flicker and harmonics emissions of wind turbines equipped with DFIG during continuous operation and using output reactive control are investigated. The simulation results show that control of wind turbine output reactive power is an effective means for flicker mitigation during continuous operation. However، there should be a compromise between flicker reduction and harmonics level increase to enhance the whole power quality of wind turbine.

In this paper, derating factor of induction motors that are subjected to regular fluctuations (flicker) has been calculated. Voltage flicker is one of the most important phenomena in power systems study. The phenomenon may cause additional losses and decrease the efficiency of the induction motors. Due to huge amount of induction motors in the different industries, it is important to study the effect of voltage fluctuation on the induction motors behavior. The paper applies electrical, mechanical and thermal models of induction motors to estimate additional losses, temperature rise and derating factor.