scholarly journals Experimental Investigation on Power Output in Aged Wind Turbines

2012 ◽  
Vol 4 ◽  
pp. 380986 ◽  
Author(s):  
N. Murugan ◽  
M. Umamaheswari ◽  
SI. Vimal ◽  
P. Sivashanmugam
Keyword(s):  
Experimental Investigation ◽  
Wind Turbines ◽  
Power Output

scholarly journals Performance Enhancement of Proposed Namaacha Wind Farm by Minimising Losses Due to the Wake Effect: A Mozambican Case Study

Energies ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 4291
Author(s):  
Paxis Marques João Roque ◽  
Shyama Pada Chowdhury ◽  
Zhongjie Huan
Keyword(s):  
Wind Speed ◽  
Wind Power ◽  
Wind Turbines ◽  
Power Output ◽  
Wind Farm ◽  
Wind Farms ◽  
Operating Conditions ◽  
Wake Effect ◽  
Wind Generators ◽  
Wind Potential

District of Namaacha in Maputo Province of Mozambique presents a high wind potential, with an average wind speed of around 7.5 m/s and huge open fields that are favourable to the installation of wind farms. However, in order to make better use of the wind potential, it is necessary to evaluate the operating conditions of the turbines and guide the independent power producers (IPPs) on how to efficiently use wind power. The investigation of the wind farm operating conditions is justified by the fact that the implementation of wind power systems is quite expensive, and therefore, it is imperative to find alternatives to reduce power losses and improve energy production. Taking into account the power needs in Mozambique, this project applied hybrid optimisation of multiple energy resources (HOMER) to size the capacity of the wind farm and the number of turbines that guarantee an adequate supply of power. Moreover, considering the topographic conditions of the site and the operational parameters of the turbines, the system advisor model (SAM) was applied to evaluate the performance of the Vestas V82-1.65 horizontal axis turbines and the system’s power output as a result of the wake effect. For any wind farm, it is evident that wind turbines’ wake effects significantly reduce the performance of wind farms. The paper seeks to design and examine the proper layout for practical placements of wind generators. Firstly, a survey on the Namaacha’s electricity demand was carried out in order to obtain the district’s daily load profile required to size the wind farm’s capacity. Secondly, with the previous knowledge that the operation of wind farms is affected by wake losses, different wake effect models applied by SAM were examined and the Eddy–Viscosity model was selected to perform the analysis. Three distinct layouts result from SAM optimisation, and the best one is recommended for wind turbines installation for maximising wind to energy generation. Although it is understood that the wake effect occurs on any wind farm, it is observed that wake losses can be minimised through the proper design of the wind generators’ placement layout. Therefore, any wind farm project should, from its layout, examine the optimal wind farm arrangement, which will depend on the wind speed, wind direction, turbine hub height, and other topographical characteristics of the area. In that context, considering the topographic and climate features of Mozambique, the study brings novelty in the way wind farms should be placed in the district and wake losses minimised. The study is based on a real assumption that the project can be implemented in the district, and thus, considering the wind farm’s capacity, the district’s energy needs could be met. The optimal transversal and longitudinal distances between turbines recommended are 8Do and 10Do, respectively, arranged according to layout 1, with wake losses of about 1.7%, land utilisation of about 6.46 Km2, and power output estimated at 71.844 GWh per year.

Experimental Investigation of Hydraulic-Pneumatic Regenerative Braking System

2015 ◽  
Author(s):  
A. G. Agwu Nnanna ◽  
Erik Rolfs ◽  
James Taylor ◽  
Karla Ariadny Freitas Ferreira
Keyword(s):  
Experimental Investigation ◽  
Kinetic Energy ◽  
Power Output ◽  
Energy Recovery ◽  
Scale Model ◽  
Regenerative Braking ◽  
Gear Pump ◽  
Braking System ◽  
Light Duty ◽  
Overall Efficiency

Design and development of energy efficient vehicles is of paramount importance to the automobile industry. Energy efficiency can be enhanced through recovery of the kinetic energy lost in the form of waste heat during braking. The kinetic energy could be converted into a reusable energy source and aid in acceleration, hence the braking system would contribute to improving the overall efficiency of a vehicle. Hydraulic-Pneumatic Regenerative Braking (HPRB) systems are a hybrid drive system that works in tandem with a vehicle’s engine and drivetrain to improve efficiency and fuel-economy. A HPRB system functions by recovering the energy typically lost to heat during vehicle braking, and storing this energy as a reusable source that can propel a vehicle from a stop. The major advantages of a HPRB system are that a vehicle would not require its engine to run during braking to stop, nor would the engine be required to accelerate the vehicle initially from a stop. The benefit realized by this system is an increase in fuel-efficiency, reduced vehicle emissions, and overall financial savings. An HPRB system aids in slowing a vehicle by creating a drag on the driveline as it recovers and stores energy during braking. Therefore, HPRB system operation reduces wear by minimizing the amount of work performed by the brake pads and rotors. An experimental investigation of Hydraulic-Pneumatic Regenerative Braking (HPRB) system was conducted to measure the system’s overall efficiency and available power output. The HPRB in this study is a 1/10th lab-scale model of a light-duty four wheel vehicle. The design/size was based on a 3500 lbs light-duty four wheel vehicle with an estimated passenger weight of 500 lbs. It was assumed that the vehicle can accelerate from 0–15 mph in 2 seconds. The aim of this work is to examine the effect of heat losses due to irreversibility on energy recovery. The experimental facility consisted of a hydraulic pump, two hydraulic-pneumatic accumulators, solenoid and relief valves, and data acquisition system. The HPRB system did not include any driveline components necessary to attach this system onto a vehicle’s chassis rather an electric motor was used to drive the pump and simulate the power input to the system from a spinning drive shaft. Pressure transducers, Hall effects sensor, and thermocouples were installed at suction and discharge sections of the hydraulic and pneumatic components to measure hydrodynamic and thermos-physical properties. The measured data were used to determine the system’s energy recovery and power delivery efficiency. Results showed that the HPRB system is capable of recovering 47% of the energy input to the system during charging, and 64% efficient in power output during discharging with an input and output of 0.33 and 0.21 horsepower respectively. Inefficiencies during operation were attributed to heat generation from the gear pump but especially due to the piston accumulator, where heat loss attributed to a 12% reduction in energy potential alone.

scholarly journals Wind turbine icing characteristics and icing-induced power losses to utility-scale wind turbines

2021 ◽  
Vol 118 (42) ◽  
pp. e2111461118
Author(s):  
Linyue Gao ◽  
Hui Hu
Keyword(s):  
Wind Turbines ◽  
Power Output ◽  
Turbine Blades ◽  
Digital Camera ◽  
Unmanned Aircraft ◽  
Ice Accretion ◽  
Power Losses ◽  
Field Campaign ◽  
Output Losses ◽  
Utility Scale

A field campaign was carried out to investigate ice accretion features on large turbine blades (50 m in length) and to assess power output losses of utility-scale wind turbines induced by ice accretion. After a 30-h icing incident, a high-resolution digital camera carried by an unmanned aircraft system was used to capture photographs of iced turbine blades. Based on the obtained pictures of the frozen blades, the ice layer thickness accreted along the blades’ leading edges was determined quantitatively. While ice was found to accumulate over whole blade spans, outboard blades had more ice structures, with ice layers reaching up to 0.3 m thick toward the blade tips. With the turbine operating data provided by the turbines’ supervisory control and data acquisition systems, icing-induced power output losses were investigated systematically. Despite the high wind, frozen turbines were discovered to rotate substantially slower and even shut down from time to time, resulting in up to 80% of icing-induced turbine power losses during the icing event. The research presented here is a comprehensive field campaign to characterize ice accretion features on full-scaled turbine blades and systematically analyze detrimental impacts of ice accumulation on the power generation of utility-scale wind turbines. The research findings are very useful in bridging the gaps between fundamental icing physics research carried out in highly idealized laboratory settings and the realistic icing phenomena observed on utility-scale wind turbines operating in harsh natural icing conditions.

scholarly journals Correlations of power output fluctuations in an offshore wind farm using high-resolution SCADA data

2021 ◽  
Vol 6 (4) ◽  
pp. 997-1014
Author(s):  
Janna Kristina Seifert ◽  
Martin Kraft ◽  
Martin Kühn ◽  
Laura J. Lukassen
Keyword(s):  
Wind Turbine ◽  
Wind Turbines ◽  
Power Output ◽  
Wind Farm ◽  
Offshore Wind ◽  
Offshore Wind Farm ◽  
Flow Conditions ◽  
Output Fluctuations ◽  
Power Difference ◽  
Time Correlations

Abstract. Space–time correlations of power output fluctuations of wind turbine pairs provide information on the flow conditions within a wind farm and the interactions of wind turbines. Such information can play an essential role in controlling wind turbines and short-term load or power forecasting. However, the challenges of analysing correlations of power output fluctuations in a wind farm are the highly varying flow conditions. Here, we present an approach to investigate space–time correlations of power output fluctuations of streamwise-aligned wind turbine pairs based on high-resolution supervisory control and data acquisition (SCADA) data. The proposed approach overcomes the challenge of spatially variable and temporally variable flow conditions within the wind farm. We analyse the influences of the different statistics of the power output of wind turbines on the correlations of power output fluctuations based on 8 months of measurements from an offshore wind farm with 80 wind turbines. First, we assess the effect of the wind direction on the correlations of power output fluctuations of wind turbine pairs. We show that the correlations are highest for the streamwise-aligned wind turbine pairs and decrease when the mean wind direction changes its angle to be more perpendicular to the pair. Further, we show that the correlations for streamwise-aligned wind turbine pairs depend on the location of the wind turbines within the wind farm and on their inflow conditions (free stream or wake). Our primary result is that the standard deviations of the power output fluctuations and the normalised power difference of the wind turbines in a pair can characterise the correlations of power output fluctuations of streamwise-aligned wind turbine pairs. Further, we show that clustering can be used to identify different correlation curves. For this, we employ the data-driven k-means clustering algorithm to cluster the standard deviations of the power output fluctuations of the wind turbines and the normalised power difference of the wind turbines in a pair. Thereby, wind turbine pairs with similar power output fluctuation correlations are clustered independently from their location. With this, we account for the highly variable flow conditions inside a wind farm, which unpredictably influence the correlations.

scholarly journals Wind Turbines with Truncated Blades May Be a Possibility for Dense Wind Farms

Energies ◽  
2020 ◽  
Vol 13 (7) ◽  
pp. 1810 ◽  
Author(s):  
Shyuan Cheng ◽  
Yaqing Jin ◽  
Leonardo P. Chamorro
Keyword(s):  
Wind Turbines ◽  
Power Output ◽  
Large Scale ◽  
Outer Region ◽  
Wind Farms ◽  
Mixing Enhancement ◽  
Incoming Flow ◽  
Economic Optimization ◽  
Blade Length ◽  
The Impact

We experimentally explored the impact of a wind turbine with truncated blades on the power output and wake recovery, and its effects within 2 × 3 arrays of standard units. The blades of the truncated turbine covered a fraction of the outer region of the rotor span and replaced with a zero-lift structure around the hub, where aerodynamic torque is comparatively low. This way, the incoming flow around the hub may be used as a mixing enhancement mechanism and, consequently, to reduce the flow deficit in the wake. Particle image velocimetry was used to characterize the incoming flow and wake of various truncated turbines with a variety of blade length ratios L / R = 0.6 , 0.7, and 1, where L is the length of the working section of the blade of radius R. Power output was obtained at high frequency in each of the truncated turbines, and also at downwind units within 2 × 3 arrays with streamwise spacing of Δ x / d T = 4 , 5, and 6, with d T being the turbine diameter. Results show that the enhanced flow around the axis of the rotor induced large-scale instability and mixing that led to substantial power enhancement of wind turbines placed 4 d T downwind of the L / R = 0.6 truncated units; this additional power is still relevant at 6 d T . Overall, the competing factors defined by the expected power reduction of truncated turbines due to the decrease in the effective blade length, the need for reduced components of the truncated units, and enhanced power output of downwind standard turbines suggest a techno-economic optimization study for potential implementation.

scholarly journals Improving wind farm power output through deactivating selected wind turbines

2019 ◽  
Vol 187 ◽  
pp. 407-422 ◽  
Author(s):  
Francisco Haces-Fernandez ◽  
Hua Li ◽  
David Ramirez
Keyword(s):  
Wind Turbines ◽  
Power Output ◽  
Wind Farm
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