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Evaluation and development of normal year correction methodologies for icing climatology in wind farm applications

Klintström, Rebecka (2012)
Department of Energy Sciences
Abstract
Wind power developments in cold and icing conditions pose new challenges to the wind power industry. Icing
of wind turbines cause safety hazards, production losses and increased loads. This means that there is
a need to develop a technique to quantify the icing climatology and corresponding eects on wind turbines
to enable large scale wind power developments in the windy, sparesly populated areas of northern Sweden.
This thesis is focused on evaluating the possibilities to estimate the long term icing climatology using
mesoscale meteorological models in combination with existing ice models. The basis for the study
were long term, low resolution time series from WRF and COAMPS in combination with high resolution,
short term time... (More)
Wind power developments in cold and icing conditions pose new challenges to the wind power industry. Icing
of wind turbines cause safety hazards, production losses and increased loads. This means that there is
a need to develop a technique to quantify the icing climatology and corresponding eects on wind turbines
to enable large scale wind power developments in the windy, sparesly populated areas of northern Sweden.
This thesis is focused on evaluating the possibilities to estimate the long term icing climatology using
mesoscale meteorological models in combination with existing ice models. The basis for the study
were long term, low resolution time series from WRF and COAMPS in combination with high resolution,
short term time series for the same geographical area, with the aim to nd a method for normal year
correction of the icing climatology. A number of dierent methodologies for normal year correction of icing
climatology were developed and evaluated using a few criteria: plausibility of the results, site dependency,
sensitivity to data set used and sensitivity to the length of the time series used as reference. The ice modeling
was performed using an implementation of the Makkonen algorithm for ice accretion. The normal
year correction was performed using dierent theoretical reasoning and at dierent steps in the modeling.
Linear regression of time series of standard meteorological parameters as well as of active ice hours and
ice loads were tested. A method using iterative height adjustment of the parameters was developed as
well as a basic method directly relating the high resolution modeled ice load to the low resolution modeled
ice load. A method using averaged values for the dierent ice model input parameters was also tested.
The evaluation showed promising results for the linear regression method. The dierent implementations
showed feasible results and the outcome was not sensitive to the length of the correction basis. The
height adjustment method was dicult to evaluate and was sensitive to the time series used as correction
basis. The method using basic relations between high and low resolution parameters was extremely
sensitive to the correction basis and the method based on averaged values did not show feasible results.
Using active ice hours as basis for the normal year correction was shown to be preferable compared to
using ice load.
The conclusion drawn was that linear regression in combination with height adjustment to relate low
resolution modeled icing climatology to high resolution icing climatology may be a promising tool. Development
of the ice models used to estimate icing of wind turbines is needed, preferably a way to model ice
directly on the wind turbine blades compared to the standard cylinder used in the Makkonen algorithm.
Also, more reliable means to measure ice accretion are needed to enable further evaluation of the methods
compared to the real icing climatology. (Less)
Please use this url to cite or link to this publication:
author
Klintström, Rebecka
supervisor
organization
year
type
H1 - Master's Degree (One Year)
subject
keywords
ice modeling normal year correction icing of wind turbines mesoscale meteorological models
report number
5254
ISSN
0282-1990
language
English
id
3054826
date added to LUP
2012-09-20 14:50:49
date last changed
2012-09-20 14:50:49
@misc{3054826,
  abstract     = {Wind power developments in cold and icing conditions pose new challenges to the wind power industry. Icing
of wind turbines cause safety hazards, production losses and increased loads. This means that there is
a need to develop a technique to quantify the icing climatology and corresponding eects on wind turbines
to enable large scale wind power developments in the windy, sparesly populated areas of northern Sweden.
This thesis is focused on evaluating the possibilities to estimate the long term icing climatology using
mesoscale meteorological models in combination with existing ice models. The basis for the study
were long term, low resolution time series from WRF and COAMPS in combination with high resolution,
short term time series for the same geographical area, with the aim to nd a method for normal year
correction of the icing climatology. A number of dierent methodologies for normal year correction of icing
climatology were developed and evaluated using a few criteria: plausibility of the results, site dependency,
sensitivity to data set used and sensitivity to the length of the time series used as reference. The ice modeling
was performed using an implementation of the Makkonen algorithm for ice accretion. The normal
year correction was performed using dierent theoretical reasoning and at dierent steps in the modeling.
Linear regression of time series of standard meteorological parameters as well as of active ice hours and
ice loads were tested. A method using iterative height adjustment of the parameters was developed as
well as a basic method directly relating the high resolution modeled ice load to the low resolution modeled
ice load. A method using averaged values for the dierent ice model input parameters was also tested.
The evaluation showed promising results for the linear regression method. The dierent implementations
showed feasible results and the outcome was not sensitive to the length of the correction basis. The
height adjustment method was dicult to evaluate and was sensitive to the time series used as correction
basis. The method using basic relations between high and low resolution parameters was extremely
sensitive to the correction basis and the method based on averaged values did not show feasible results.
Using active ice hours as basis for the normal year correction was shown to be preferable compared to
using ice load.
The conclusion drawn was that linear regression in combination with height adjustment to relate low
resolution modeled icing climatology to high resolution icing climatology may be a promising tool. Development
of the ice models used to estimate icing of wind turbines is needed, preferably a way to model ice
directly on the wind turbine blades compared to the standard cylinder used in the Makkonen algorithm.
Also, more reliable means to measure ice accretion are needed to enable further evaluation of the methods
compared to the real icing climatology.},
  author       = {Klintström, Rebecka},
  issn         = {0282-1990},
  keyword      = {ice modeling normal year correction icing of wind turbines mesoscale meteorological models},
  language     = {eng},
  note         = {Student Paper},
  title        = {Evaluation and development of normal year correction methodologies for icing climatology in wind farm applications},
  year         = {2012},
}