scholarly journals An Evaluation of Flicker Emissions from Small Wind Turbines

Energies ◽  
2021 ◽  
Vol 14 (21) ◽  
pp. 7263
Author(s):  
Junji Kondoh ◽  
Daisuke Kodaira
Keyword(s):  
Wind Power ◽  
Output Power ◽  
Wind Turbines ◽  
Distribution System ◽  
Low Voltage ◽  
Total Power ◽  
Total Output ◽  
Voltage Quality ◽  
Small Wind Turbines ◽  
Power Generation Systems

It is well known that the output power from small wind turbines (SWTs) fluctuates noticeably more when compared to that from other types of dispersed generators, such as residential photovoltaic (PV) power generation systems. Thus, the degradation of voltage quality, such as flicker emissions, when numerous SWTs are installed in a low-voltage distribution system is a particular concern. Nevertheless, practical examples of flicker emissions from small wind power facilities have not been made public. This paper aims to clarify the characteristics of flicker emissions by SWTs and their severity. The measurement results at the two selected sites indicate that the flicker emissions solely caused by variable-speed SWTs with a total power rating of ~20 kW are notably lower than the upper limit, and they are at their highest when the mean total output power is approximately 3/4 of the total power rating of small wind power facilities.

Total output power variation of several small wind turbines

2020 ◽  
pp. 0309524X2090798
Author(s):  
Kenta Kashiwaya ◽  
Junji Kondoh ◽  
Kakuru Funabashi
Keyword(s):  
Power Systems ◽  
Output Power ◽  
Wind Turbines ◽  
Low Voltage ◽  
Correlation Coefficients ◽  
Total Output ◽  
Smoothing Effect ◽  
Small Wind Turbines ◽  
Voltage Flicker ◽  
The Impact

There is a concern that connection of several small wind turbines may cause severe voltage fluctuation and voltage flicker in low-voltage distribution lines due to their output power variations. In this study, output power variations of four 5-kW-class small wind turbine systems were measured with an interval of 0.1 s at a site in Wakkanai, Hokkaido, and their correlations and smoothing effect in the frequency range from [Formula: see text] to 5 Hz were analyzed and compared with those of five residential photovoltaic power systems. The results indicate that a smoothing effect occurs more in small wind turbines than in photovoltaic systems, because of lower correlation coefficients in lower frequency ([Formula: see text] Hz) components. Voltage flicker at the point of common coupling was also measured and it was confirmed that the impact of small wind turbines on voltage flicker is low enough at the site. In addition, the upper limits of the installation number and/or the system resistance are estimated theoretically using the measured flicker values.

scholarly journals Inverter Performance for Small Wind Turbines When Connected In Paralled with the Low-Voltage Distribution System

2013 ◽  
Vol 1 (4) ◽  
pp. 9-16
Author(s):  
Jonathan Blackledge ◽  
◽  
Eugene Coyle ◽  
Derek Kearney ◽  
Eamonn Murphy ◽  
...  
Keyword(s):  
Wind Turbines ◽  
Distribution System ◽  
Low Voltage ◽  
Voltage Distribution ◽  
Small Wind Turbines

Power Quality Measurements of a Horizontal Axial Small Wind Turbine

2017 ◽  
Vol 870 ◽  
pp. 329-334
Author(s):  
Yu Jen Liu ◽  
Yen Chang Chen ◽  
Pei Hsiu Lan ◽  
Tsang Pin Chang
Keyword(s):  
Wind Turbine ◽  
Power Quality ◽  
Wind Turbines ◽  
Distribution System ◽  
Large Scale ◽  
Low Voltage ◽  
System Structure ◽  
System Level ◽  
Small Wind Turbines ◽  
Quality Measurements

As small wind turbines are increasingly used, the assessments of power quality may thus become paramount. Unlike the large-scale wind turbines which are optional required to perform power quality measurements during production certification stage; however the power quality measurements are often neglected in small wind turbines since they are not requested on the certain of national grid codes at low-voltage distribution system level. Considering the high penetrations of small wind turbines may be connected to the future urban electric network, the paper performs the power quality on-site measurements of a horizontal axle small wind turbines. The issues may include the discussion of measurement system structure, the description of measurement method, and the analysis of wind turbine power characteristic, voltage/current trends, harmonics and flicker phenomena. The measured data collected in the study will valuable for the further analysis of power systems connected with the small wind turbines.

Applying Hollow Blades for Small Wind Turbines Operating at High Altitudes

2015 ◽  
Author(s):  
Abolfazl Pourrajabian ◽  
Reza Ebrahimi ◽  
Masoud Mirzaei ◽  
Mehdi Ahmadizadeh ◽  
David Wood
Keyword(s):  
Objective Function ◽  
Output Power ◽  
Wind Turbines ◽  
Speed Ratio ◽  
High Altitudes ◽  
Horizontal Axis Wind Turbine ◽  
Lower Altitude ◽  
Starting Time ◽  
Design Variables ◽  
Small Wind Turbines

Since the air density reduces as the altitude increases, operation of Small Wind Turbines (SWTs) which usually have no pitch mechanism, remains as a challengeable task at high altitudes due largely to the reduction of starting aerodynamic torque. By reducing the blades moment of inertia through the use of hollow blades, the study aims to mitigate that issue and speed up the starting. A three-bladed, 2 m diameter small horizontal axis wind turbine with hollow cross-section was designed for operating at two sites with altitude of 500 and 3,000 m. The design variables consist of distribution of the chord, twist and shell thickness along the blade. The blade-element momentum theory was employed to calculate the output power and starting time and, the beam theory was used for the structural analysis to investigate whether the hollow blades could withstand the aerodynamic and centrifugal forces. A combination of the starting time and the output power was included in an objective function and then, the genetic algorithm was used to find a blade for which the output power and the starting performance, the goals of the objective function, are high while the stress limitation, the objective function constraint, is also met. While the resultant stresses remain below the allowable stress, results show that the performance of the hollow blades is far better than the solid ones such that their starting time is shorter than the solid blades by approximately 70%. However, in the presence of the generator resistive torque, the algorithm could not find the blade for the altitude near to 3000 m. To solve that problem, the tip speed ratio of the turbine was added to other design variables and another optimization process was done which led to the optimal blades not only for the lower altitude but also for the higher one.

scholarly journals Optimization of Power and Levelized Cost for Shrouded Small Wind Turbine

Inventions ◽  
2020 ◽  
Vol 5 (4) ◽  
pp. 59
Author(s):  
Hasanali Khojasteh ◽  
Younes Noorollahi ◽  
Mojtaba Tahani ◽  
Mehran Masdari
Keyword(s):  
Wind Energy ◽  
Objective Function ◽  
Wind Power ◽  
Wind Turbines ◽  
Power Plants ◽  
Large Scale ◽  
Renewable Energies ◽  
Levelized Cost ◽  
Small Wind Turbines ◽  
Input Parameters

Nowadays, by increasing energy demand and considering the importance of environmental issues in recent decades, the use of renewable energies is expanding. Among renewable energies, wind power and its technology are growing and evolving more rapidly. Resource assessment in Iran has revealed the significant potential of wind energy around the country. To further develop wind energy in the country and create large-scale wind power plants, the consideration of distributed power generation using small wind turbines for applications in agricultural and residential use is needed. Conventional small wind turbines and small wind lens turbines have been developed in recent years. In this research project, a small wind lens turbine is designed. The advantages of this turbine are an increased production capacity and reduced cut-in speed and noise pollution. In this study, a lens (or shroud) is added to a small turbine, and the maximized annual energy production (AEP) and minimization of the levelized cost of energy (LCOE) are modeled. We applied the NSGA-II algorithm for optimization to find the best answer. The input parameters in the objective function of the AEP are cut-in, cut-out, rated speeds, scale factor, and shape factor. Additionally, the input parameters in the objective function of the LCOE are the power production, initial capital cost, annual operating expenses, and balance of energy. The results indicate that installing a wind lens turbine in Kish Island led to an LCOE decrease of 56% on average, and we can see an 83% increase in the AEP. In the Firoozkooh area, an average reduction of 59% in the LCOE and 74% increase in the AEP for a wind lens turbine is observed.

scholarly journals Wind power of small wind turbines in turbulent open jets

2012 ◽  
Vol 19 (2) ◽  
pp. 272-281 ◽  
Author(s):  
A. Sedaghat ◽  
X. Liu ◽  
J. Whitty ◽  
X. Tang
Keyword(s):  
Wind Power ◽  
Wind Turbines ◽  
Small Wind Turbines

scholarly journals DFIG use with combined strategy in case of failure of wind farm

2020 ◽  
Vol 10 (3) ◽  
pp. 2221
Author(s):  
Azeddine Loulijat ◽  
Najib Ababssi ◽  
Mohammed Makhad
Keyword(s):  
Wind Power ◽  
Wind Turbines ◽  
Wind Farm ◽  
Reactive Power ◽  
Low Voltage ◽  
Voltage Drop ◽  
Optimal Solution ◽  
Wind Farms ◽  
Electrical Networks ◽  
Constant Frequency

In the wind power area, Doubly Fed Induction Generator (DFIG) has many advantages due to its ability to provide power to voltage and constant frequency during rotor speed changes, which provides better wind capture as compared to fixed speed wind turbines (WTs). The high sensitivity of the DFIG towards electrical faults brings up many challenges in terms of compliance with requirements imposed by the operators of electrical networks. Indeed, in case of a fault in the network, wind power stations are switched off automatically to avoid damage in wind turbines, but now the network connection requirements impose stricter regulations on wind farms in particular in terms of Low Voltage Ride through (LVRT), and network support capabilities. In order to comply with these codes, it is crucial for wind turbines to redesign advanced control, for which wind turbines must, when detecting an abnormal voltage, stay connected to provide reactive power ensuring a safe and reliable operation of the network during and after the fault. The objective of this work is to offer solutions that enable wind turbines remain connected generators, after such a significant voltage drop. We managed to make an improvement of classical control, whose effectiveness has been verified for low voltage dips. For voltage descents, we proposed protection devices as the Stator Damping Resistance (SDR) and the CROWBAR. Finally, we developed a strategy of combining the solutions, and depending on the depth of the sag, the choice of the optimal solution is performed.

scholarly journals Modelling Types 1 and 2 Wind Turbines Based on IEC 61400-27-1: Transient Response under Voltage Dips

Energies ◽  
2020 ◽  
Vol 13 (16) ◽  
pp. 4078 ◽  
Author(s):  
Tania García-Sánchez ◽  
Irene Muñoz-Benavente ◽  
Emilio Gómez-Lázaro ◽  
Ana Fernández-Guillamón
Keyword(s):  
Wind Turbine ◽  
Wind Power ◽  
Wind Turbines ◽  
Distribution System ◽  
Power Plants ◽  
Short Circuit ◽  
Energy Resource ◽  
Weather Conditions ◽  
International Electrotechnical Commission ◽  
Voltage Dips

Wind power plants depend greatly on weather conditions, thus being considered intermittent, uncertain and non-dispatchable. Due to the massive integration of this energy resource in the recent decades, it is important that transmission and distribution system operators are able to model their electrical behaviour in terms of steady-state power flow, transient dynamic stability, and short-circuit currents. Consequently, in 2015, the International Electrotechnical Commission published Standard IEC 61400-27-1, which includes generic models for wind power generation in order to estimate the electrical characteristics of wind turbines at the connection point. This paper presents, describes and details the models for wind turbine topologies Types 1 and 2 following IEC 61400-27-1 for electrical simulation purposes, including the values for the parameters for the different subsystems. A hardware-in-the-loop combined with a real-time simulator is also used to analyse the response of such wind turbine topologies under voltage dips. The evolution of active and reactive powers is discussed, together with the wind turbine rotor and generator rotational speeds.

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