Improving power smoothing and performance of pitch angle system for above rated speed range in wind power systems

2019 ◽  
Vol 13 (3) ◽  
pp. 409-416 ◽  
Author(s):  
Mehrdad Gholami ◽  
Seyed Hamid Fathi ◽  
Jafar Milimonfared ◽  
Zhe Chen
2018 ◽  
Vol 33 (11) ◽  
pp. 9599-9610 ◽  
Author(s):  
Ayoub Kavousi ◽  
Seyed Hamid Fathi ◽  
Jafar Milimonfared ◽  
Mohsen Nourbakhsh Soltani

Author(s):  
Shenghu Li

The induction generators (IGs) are basic to wind energy conversion. They produce the active power and consume the reactive power, with the voltage characteristics fragile compared with that of the synchronous generators and doubly-fed IGs. In the stressed system states, they may intensify var imbalance, yielding undesirable operation of zone 3 impedance relays.In this paper, the operation characteristics of the zone 3 relays in the wind power systems is studied. With the theoretical and load flow analysis, it is proved that the equivalent impedance of the IGs lies in the 2nd quadrature, possibly seen as the backward faults by the mho relays, i.e. the apparent impedance enters into the protection region from the left side. The undesirable operation may be caused by more wind power, larger load, less var compensation, and larger torque angle.


Processes ◽  
2021 ◽  
Vol 9 (5) ◽  
pp. 776
Author(s):  
Byunghui Kim ◽  
Sang-June Park ◽  
Seokyoung Ahn ◽  
Myung-Gon Kim ◽  
Hyung-Gun Yang ◽  
...  

Although mega-watt class onshore and offshore wind power systems are used to generate power due to their cost-effectiveness, small wind power systems are important for household usages. Researchers have focused on aerodynamic characteristics as a conceptual design from their previous studies on Archimedes spiral wind turbines. Here, we verified the design of a small wind turbine AWM-750D (100 W capacity) via both numerical simulation and experimentation. We used commercial code ANSYS CFX for numerical simulation and compared turbulence models and surface roughness for determining the performance. To obtain reliable and robust blades, we analyzed the effective manufacturing method with Moldflow. Through a test with an open-suction type atmospheric boundary layer wind tunnel, we varied wind speed from 4.0 m/s to the rated value of 12.5 m/s and obtained 106 W, equivalent to a power coefficient of 0.205. In addition, we compared the numerical and experimental power vs. rotational speed and found the former is 6.5% lower than the latter. In this study, we proved that numerical simulations can act as design verification methods to predict wind turbine performances and reliable manufacturing. Through our research, we provided the prototype of a small wind turbine with 100 W to act as an efficient electric power supplier for households and also the stable manufacturing process for complex spiral blades using injection molding.


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