Hybrid fuzzy clustering neural networks to wind
power generation forecasting
Paulo Salgado
*
, Paulo Afonso
**
*
Universidade de Trás-os-Montes e Alto Douro/ECT-Departamento de Engenharias, Vila Real, Portugal
**
Universidade de Aveiro - Escola Superior de Tecnologia e Gestão de Águeda, Águeda, Portugal
psal@utad.pt ; pafnaa@ua.pt
Abstract— Wind power forecasting methods can be used to
plan unit commitment, scheduling and dispatch by system
operators and electricity traders. Because wind power is
weather dependent, and therefore, is variable and
intermittent over various time-scales, an accurate
forecasting of wind power is recognized as a major
contribution for a reliable large-scale wind power
integration taking profit of economics gains. This paper
explores a new approach using fuzzy clustering algorithms
for obtaining one day forecast for the characteristics curves
of speed wind. Moreover, a Feedforward Neural Networks
(FNN) provides an estimate of the average hourly wind
speed, for 24 hours horizon.
I. INTRODUCTION
Over the last decade there has been a rapid growth in
wind generated electricity. The worldwide installed wind
power capacity has increased from a total nameplate
capacity of 24.3 GW to 238,351 GW in 2011, and the
industry is set to grow by at least another 40 GW in 2012
[1]. The increased incidence of wind power in an energy
network causes an increase of the unpredictability factor
of energy production. Thus, it is difficult to predict the
wind power production value, as well as its maximal or
minimal values and their occurrence instants. The cause of
this problem is that the wind velocity and its orientation
are considered as one of the most difficult meteorological
parameters to forecast. This is a result of the complex
interactions between large scale forcing mechanisms such
as pressure and temperature differences, the rotation of the
earth, and local characteristics of the surface. The
forecasting technique employed depends on the available
information and the time scale in question.
However one of the shortcomings in the wide use of the
generation of electricity from the wind due to its
intermittency regime. This factor determines the extent to
which energy is produced from the wind turbine. This
problem is exacerbated by the fact that wind energy
cannot be stored and cannot be easily ramped up to meet
load requirements [2].
To address these problems, wind power forecasting
methods can be used to plan unit commitment, scheduling
and dispatch by system operators, and maximize profit by
electricity traders. Because wind power is weather
dependent, it is variable and intermittent over various
time-scales. This point makes very difficult to forecast the
power which will be injected in the distribution network,
which hinders the management of the networks of power
centrals, in the fragile energetic balance between the
production and the consumption of energy. There may
also be problems in energy transportation system that
connects wind farms, often placed far from the centers of
consumption. A good forecast of the produced power is,
therefore, very important. So, the accurate forecasting of
wind power is recognized as a major contribution for
reliable large-scale wind power integration. This demand
of prediction accuracy motivates researchers to propose
accurate short-term forecasting models of wind power.
The wind power forecast should be based on the actual
wind velocity forecast or on the output power of the wind
turbines. Huge research is being carried out for obtaining
good wind speed forecasting systems. Several
mathematical models which hybridize weather forecasting
models and statistical techniques have been proposed in
the literature [3-4]. Also, in many cases, these systems use
statistical down-scaling processes including auto-
regressive models [5], artificial neural networks [6] or
support vector machines [7], as a final step to improve the
wind speed forecasting of the system.
It may be agreed upon that wind power can be a more
viable prediction parameter than wind speed for power
generation purposes on the premise that predicting wind
speed and converting it to power output using power
curves or the following equation which relates the wind
turbine’s power output to wind speed:
3
1
2
P b w
P C Av (1)
where Cp is the coefficient of performance, is the air
density, Ab is the area swept by the blade and vw is the
wind speed at right angles to the turbine’s blades-face.
However, forecasting wind power has its limitations since
it can be linked to a particular machine design or
operation. Wind speed predictions is being a more logical
approach for understand wind forecasting techniques for
power generation. In addition, it is easier to obtain data
sets for wind speed than power output with better quality.
By using the power curves and equations in converting
wind speed to wind turbine power output can be made
through aggregate forecasting [8]. For these reasons in this
paper we present a wind speed forecasting.
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CINTI 2013 • 14th IEEE International Symposium on Computational Intelligence and Informatics • 19–21 November, 2013 • Budapest, Hungary
978-1-4799-0197-5/13/$31.00 ©2013 IEEE