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A Stochastic Model for Wind Turbine Power Quality using a Levy Index Analysis of Wind Velocity Data (2011)

Blackledge, Jonathan; Coyle, Eugene; Kearney, Derek

A Stochastic Model for Wind Turbine Power Quality using a Levy Index Analysis of Wind Velocity Data (2011)

Blackledge, Jonathan; Coyle, Eugene; Kearney, Derek

Abstract:

The power quality of a wind turbine is determined by many factors but time-dependent variation in the wind velocity are arguably the most important. After a brief review of the statistics of typical wind speed data, a non- Gaussian model for the wind velocity is introduced that is based on a Levy distribution. It is shown how this distribution can be used to derive a stochastic fractional diusion equation for the wind velocity as a function of time whose solution is characterised by the Levy index. A Levy index numerical analysis is then performed on wind velocity data for both rural and urban areas where, in the latter case, the index has a larger value. Finally, an empirical relationship is derived for the power output from a wind turbine in terms of the Levy index using Betz law.

https://arrow.dit.ie/engscheleart/146

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Analysis of Wind Velocity and the Quantification of Wind Turbulence in Rural and Urban Environments Using the Levy Index and Fractal Dimension (2012)

Blackledge, Jonathan; Coyle, Eugene; McCoy, Niall; Kearney, Derek; Sunderland, Keith; W...

Analysis of Wind Velocity and the Quantification of Wind Turbulence in Rural and Urban Environments Using the Levy Index and Fractal Dimension (2012)

Blackledge, Jonathan; Coyle, Eugene; McCoy, Niall; Kearney, Derek; Sunderland, Keith; Woolmington, Thomas

Abstract:

This paper is concerned with a quantitative and comparative analysis of wind velocities in urban and rural environments. It is undertaken to provide a route to the classification of wind energy in a rural and urban setting. This is a common problem and the basis of a significant focus of research into wind energy. In this paper, we use a non-Gaussian statistical model to undertake this task, and, through a further modification of the data analysis algorithms used, extend the model to study the effect of wind turbulence, thereby introducing a new metric for this effect that is arguably superior to a more commonly used and qualitatively derived measure known as the Turbulence Intensity. Starting from Einstein’s evolution equation for an elastic scattering process, we consider a stochastic model for the wind velocity that is based on the Generalised Kolmogorov Feller Equation. For a specific ‘memory function’ - the Mittag-Leffler function - it is shown that, under specified conditions,...

https://arrow.dit.ie/engscheleart2/67

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Analysis of Wind Velocity Signals for Estimating the Wave Power Density of Ireland's Coastal Resource (2012)

Blackledge, Jonathan; Coyle, Eugene; Kearney, Derek; McGuirk, Ronan

Analysis of Wind Velocity Signals for Estimating the Wave Power Density of Ireland's Coastal Resource (2012)

Blackledge, Jonathan; Coyle, Eugene; Kearney, Derek; McGuirk, Ronan

Abstract:

The aim of this paper is to report on a possible correlation between the Lévy index for the wind velocity and the mean Energy Density of sea surface waves in the same location. The result is based on data obtained from six buoys located around the coast of Ireland and maintained by the Marine Institute of Ireland. These buoys provide signals on the wind velocity, wave height and wave period as well as other data on an hourly interval. Using this data, we consider the relationship between a stochastic model for the time variations in wave height that, in turn, is based on a non-Gaussian model for the wind force characterized by the Lévy index. Although the results presented in this paper can not be said to statistically significant due to the limited amount of data that is available (i.e. the Marine Institute of Ireland only maintains six buoys around the coast of Ireland) they indicate the possibility of developing a method of accurately estimating the energy and power densities of ...

https://arrow.dit.ie/engscheleart2/49

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Energy Commodities Trading Using a Phase Signal Derived from the Levy Index of Price and Volatility (2012)

Blackledge, Jonathan; Kearney, Derek; Farrell, Claire; Kearney, Grace

Energy Commodities Trading Using a Phase Signal Derived from the Levy Index of Price and Volatility (2012)

Blackledge, Jonathan; Kearney, Derek; Farrell, Claire; Kearney, Grace

Abstract:

Energy traders need to decide what markets and commodities to trade in, when to open and close trades and how to maximize profits. In this paper we consider an approach for analyzing energy commodity price data based on the Lévy index in order to develop a new short-term predictive trend indicator for the price. This is achieved by computing the unwrapped phase signal generated from the Lévy index of both the Stochastic Volatility and price and is evaluated using data from the Irish Energy Market, namely, time series for the price of Electricity, Gas and Oil. The initial results show the predictive hypothesis holds true and algorithms are developed for implementation on an open source trading platform (Alpari MetaTrader4) which includes a range of energy commodities. This is used to demonstrate the potential of the approach in support of energy commodities trading compounded in a set of prototype MetaQuotes Language 4 (MQL4) Apps which can be downloaded and evaluated further by inte...

https://arrow.dit.ie/engscheleart2/61

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Estimation of Wave Energy from Wind Velocity (2013)

Blackledge, Jonathan; Coyle, Eugene; Kearney, Derek; McGuirk, Ronan; Norton, Brian

Estimation of Wave Energy from Wind Velocity (2013)

Blackledge, Jonathan; Coyle, Eugene; Kearney, Derek; McGuirk, Ronan; Norton, Brian

Abstract:

The aim of this paper is to report on a possible correlation between the Levy index for wind velocity and the mean Energy Density of sea surface waves in the same location. The result is based on data obtained from 6 buoys located around the coast of Ireland and maintained by the Marine Institute of Ireland and a further 144 buoys located at various locations off the coast of the United States of America and maintained by the National Data Buoy Centre. These buoys provide historical data on the wind velocity, wave height and wave period as well as other data on an hourly interval. Using this data, we consider the relationship between a stochastic model for the time variations in wave height that in turn, is based on a non-Gaussian model for the wind force characterised by the Ĺevy index. The results presented in this paper indicate the possibility of developing a method of estimating the energy and power densities of sea waves from knowledge of the wind velocity alone.

https://arrow.dit.ie/engscheleart2/64

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How Profitable are Wind Turbine Projects? An Empirical Analysis of a 3.5 MW Wind Farm In Ireland (2015)

Kealy, Tony; Barrett, Martin; Kearney, Derek

How Profitable are Wind Turbine Projects? An Empirical Analysis of a 3.5 MW Wind Farm In Ireland (2015)

Kealy, Tony; Barrett, Martin; Kearney, Derek

Abstract:

With many electricity markets worldwide deregulated or in the process of deregulation, the opportunity for smaller independent generators to provide power to their local power system has increased. For smaller independent wind developers assessing the feasibility of a large scale wind farm project is vitally important due to significant risk associated with the investment. This paper presents a longitudinal case study of a 3.5 MW wind farm situated in the North East of Ireland utilising multiple sources of empirical data obtained over a three year period following commissioning. The findings suggest that an average yearly capacity factor of 34% was recorded from the turbines providing for a simple payback period of 6.7 years. It would appear from this case study that site selection, electricity market conditions, the quality of the control system and the competencies of the design/installation/commissioning company all contributed to the satisfactory results.

https://arrow.dit.ie/engscheleart2/86

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Inverter Performance for Small Wind Turbines When Connected in Paralled with the Low-Voltage Distribution System (2013)

Blackledge, Jonathan; Coyle, Eugene; Kearney, Derek; Murphy, Eamonn

Inverter Performance for Small Wind Turbines When Connected in Paralled with the Low-Voltage Distribution System (2013)

Blackledge, Jonathan; Coyle, Eugene; Kearney, Derek; Murphy, Eamonn

Abstract:

Small wind turbines have been installed in urban and turbulent locations with surprisingly poor performance and this has been backed up by data from a trial at the Dublin Institute of Technology. In order to develop the small wind turbine industry a careful examination of assessment methods for the wind resource is required. Small wind turbines connected in parallel with the grid use inverters. As the wind turbine is not always at max output, a Weighted Average Efficiency for wind inverters is proposed. Pitfalls associated with developing an accurate weighted average efficiency for an inverter are identified and this will enable a more accurate sizing of the inverter for the turbine. The methodology for determining the performance of inverters and small wind turbines can be applied to any location.

https://arrow.dit.ie/engscheleart2/65

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Non-Gaussian Analysis of Wind Velocity Data for the Determination of Power Quality Control (2011)

Blackledge, Jonathan; Coyle, Eugene; Kearney, Derek

Non-Gaussian Analysis of Wind Velocity Data for the Determination of Power Quality Control (2011)

Blackledge, Jonathan; Coyle, Eugene; Kearney, Derek

Abstract:

The quality of power (i.e. the sustainable power output as a function time) of any wind dependent energy converter (including wind turbines and wave energy converters) is determined by many design and environmental factors but timedependent variations in the wind speed are arguably the most important. In this paper we consider a non-Gaussian model for analysing and then simulating wind velocity data. In particular, we consider a Lévy distribution for the statistical characteristics of wind velocity and show how this distribution can be used to derive a stochastic fractional diffusion equation for the wind velocity as a function of time whose solution is characterised by the L´evy index. A L´evy index based numerical analysis is then performed on wind velocity data for both rural and urban areas where, in the latter case, the index is shown to have a larger value. Finally, an empirical relationship is derived for the power output from a wind turbine in terms of the L´evy index using ...

https://arrow.dit.ie/engscheleart2/51

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Nonlinear Behaviour of Sea Surface Waves Based on Low-Gradient Phase-Only Scattering Effects (2011)

Blackledge, Jonathan; Coyle, Eugene; Kearney, Derek

Nonlinear Behaviour of Sea Surface Waves Based on Low-Gradient Phase-Only Scattering Effects (2011)

Blackledge, Jonathan; Coyle, Eugene; Kearney, Derek

Abstract:

Nonlinear sea waves generated by the wind, including freak waves, are considered to be phenomena that can be modelled using the nonlinear (cubic) Schrodinger equation, for example. However, there is a problem with this approach which is that sea surface waves, driven by wind speeds of varying strength, must be considered to be composed of two distinct types, namely, linear waves and nonlinear waves. In this paper, we consider a different approach to modelling ‘nonlinear’ waves that is based on a solution to the linear wave equation under a low-gradient, phase-only condition. This approach is entirely compatible with the fluid equations of motion (the Navier-Stokes equations) and is thereby not based on a phenomenological model such as the nonlinear Schr¨odinger equation.

https://arrow.dit.ie/engscheleart/149

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Wind Resource in the Urban Environment (2012)

Blackledge, Jonathan; Coyle, Eugene; Kearney, Derek; Murphy, Eamonn; Rivas Duartes, Mar...

Wind Resource in the Urban Environment (2012)

Blackledge, Jonathan; Coyle, Eugene; Kearney, Derek; Murphy, Eamonn; Rivas Duartes, Maria-Jose

Abstract:

The World Meteorological Organization (WMO) Commission for Instruments and Methods of Observation recognized the need to include in the 1996 WMO Guide to Instruments and Methods of Observation, WMO No. 8 a new chapter on Urban Observations (Oke 2006). There is an increasing demand for meteorological data to support building and urban design, energy conservation, micro -wind turbine installation, air quality, pollution control, insurance, wind engineering, etc. Over the last six years instrumentation has been installed at the Dublin Ins titute of Technology (DIT) in two separate locations to monitor the wind. Research has shown that the wind resource will vary quite considerably on a given site and this is due to local variations in topography, and other factors associated with wind and turbulence in the built environment.

https://arrow.dit.ie/engscheleart2/66

Displaying Results 1 - 10 of 10 on page 1 of 1