U.S. patent application number 16/436670 was filed with the patent office on 2019-09-26 for simulation of a maximum power output of a wind turbine.
The applicant listed for this patent is VESTAS WIND SYSTEMS A/S. Invention is credited to Kelvin HALES, Chris SPRUCE.
Application Number | 20190294741 16/436670 |
Document ID | / |
Family ID | 51224650 |
Filed Date | 2019-09-26 |
United States Patent
Application |
20190294741 |
Kind Code |
A1 |
SPRUCE; Chris ; et
al. |
September 26, 2019 |
SIMULATION OF A MAXIMUM POWER OUTPUT OF A WIND TURBINE
Abstract
A method is disclosed for determining an individual maximum
power level for one or more wind turbines in a wind power plant.
The method comprises storing a wind turbine type maximum power
level for one or more types of the one or more wind turbines,
storing one or more fatigue load values relating to a range of
power levels for each of the one or more types wind turbine, and
storing one or more parameters relating to site conditions at the
wind power plant. The method further comprises determining, based
on at least the stored one or more fatigue load values and the
stored one or more parameters, the individual maximum power level
for each wind turbine of at least a first type of the one or more
types.
Inventors: |
SPRUCE; Chris; (Leatherhead,
GB) ; HALES; Kelvin; (Surrey, GB) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
VESTAS WIND SYSTEMS A/S |
Aarhus N |
|
DK |
|
|
Family ID: |
51224650 |
Appl. No.: |
16/436670 |
Filed: |
June 10, 2019 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
14908949 |
Jan 29, 2016 |
10318666 |
|
|
PCT/DK2014/050224 |
Jul 16, 2014 |
|
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16436670 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F03D 9/255 20170201;
F05B 2270/802 20130101; Y02E 10/723 20130101; F05B 2260/84
20130101; F03D 9/25 20160501; Y02E 10/72 20130101; Y02E 10/725
20130101; F03D 7/0292 20130101; F03D 7/046 20130101; F03D 7/048
20130101; F05B 2270/332 20130101; G06F 30/20 20200101; F03D 7/028
20130101; G06F 30/23 20200101; F03D 17/00 20160501; F05B 2240/96
20130101; F05B 2270/1033 20130101 |
International
Class: |
G06F 17/50 20060101
G06F017/50; F03D 7/02 20060101 F03D007/02; F03D 7/04 20060101
F03D007/04; F03D 17/00 20060101 F03D017/00; F03D 9/25 20060101
F03D009/25 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 29, 2013 |
DK |
PA201370417 |
Claims
1. A method for determining an individual maximum power level for
one or more wind turbines in a wind power plant, the method
comprising: storing a wind turbine type maximum power level for one
or more types of the one or more wind turbines; storing one or more
fatigue load values relating to a range of power levels for each of
the one or more types; storing one or more parameters relating to
site conditions at the wind power plant; and determining, based on
at least the stored one or more fatigue load values and the stored
one or more parameters, the individual maximum power level for each
wind turbine of at least a first type of the one or more types.
2. The method as claimed in claim 1, wherein determining the
individual maximum power level for each wind turbine of at least a
first type of the one or more types further comprises: determining
whether each wind turbine can operate at a test power level based
on the one or more fatigue load values and the one or more
parameters, wherein the test power level is initially set as the
wind turbine type maximum power level for the one or more types,
and wherein the one or more parameters reflect site conditions at a
location of each wind turbine; when one or more wind turbines can
operate at the test power level, setting the test power level as
the individual maximum power level of the one or more wind
turbines; when one or more wind turbines cannot operate at the test
power level, generating a subsequent test power level by
decrementing the test power level by a predetermined value; and
iteratively performing the determination for each subsequent test
power levels until the individual maximum power level is set for
each wind turbine.
3. The method as claimed in claim 1, further comprising:
determining one or more fatigue load values for each power level in
the range of power levels by simulating one or more load cases
across a range of wind speeds and conditions.
4. The method as claimed in claim 1, further comprising:
determining that the one or more wind turbines have been in
operation; storing data relating to historical operation of the one
or more wind turbines; and altering the one or more fatigue load
values based on the data relating to the historical operation.
5. The method as claimed in claim 1, further comprising: setting
the individual maximum power level in the corresponding individual
wind turbine.
6. The method as claimed in claim 1, further comprising: setting a
lowest determined individual maximum power level in one or more
individual wind turbines.
7. The method as claimed in claim 1, wherein the individual maximum
power level includes one or more of: an individual maximum
generator torque, an individual maximum generator current, an
individual maximum generator speed, and an individual maximum rotor
speed.
8. An apparatus for determining an individual maximum power level
for one or more wind turbines in a wind power plant, the apparatus
comprising: a memory adapted to: store a wind turbine type maximum
power level for one or more types of the one or more wind turbines;
store one or more fatigue load values relating to a range of power
levels for each of the one or more types; and store one or more
parameters relating to site conditions at the wind power plant; and
one or more processors adapted to determine, based on at least the
stored one or more fatigue load values and the stored one or more
parameters, the individual maximum power level for each wind
turbine of at least a first type of the one or more types.
9. The apparatus as claimed in claim 8, wherein the one or more
processors are further adapted to: determine whether each wind
turbine can operate at a test power level based on the one or more
fatigue load values and the one or more parameters, wherein the
test power level is initially set as the wind turbine type maximum
power level for the one or more types, and wherein the one or more
parameters reflect site conditions at a location of each wind
turbine; when one or more wind turbines can operate at the test
power level, setting the test power level as the individual maximum
power level of the one or more wind turbines; when one or more wind
turbines cannot operate at the test power level, generate a
subsequent test power level by decrementing the test power level by
a predetermined value; and iteratively perform the determination
for each subsequent test power levels until the individual maximum
power level is set for each wind turbine.
10. The apparatus as claimed in claim 8, wherein the one or more
processors are further adapted to: determine one or more fatigue
load values for each power level in the range of power levels by
simulating one or more load cases across a range of wind speeds and
conditions.
11. The apparatus as claimed in claim 8, wherein the one or more
processors are further adapted to: determine that the one or more
wind turbines have been in operation, wherein the memory is further
adapted to store data relating to historical operation of the one
or more wind turbines; and alter the one or more fatigue load
values based on the data relating to the historical operation.
12. The apparatus as claimed in claim 8, wherein the one or more
processors are further adapted to: set the individual maximum power
level in the corresponding individual wind turbine.
13. The apparatus as claimed in claim 8, wherein the one or more
processors are further adapted to: set a lowest determined
individual maximum power level in one or more individual wind
turbines.
14. The apparatus as claimed in claim 8, wherein the individual
maximum power level includes one or more of an individual maximum
generator torque, an individual maximum generator current, an
individual maximum generator speed, and an individual maximum rotor
speed.
15. A computer program product comprising computer readable
executable code for implementing the method as claimed in claim
1.
16. A method comprising: simulating a load spectrum for two or more
test power levels to determine a respective load on a wind turbine
type for each test power level of the two or more test power
levels; comparing the determined load for each test power level
with a design load for the wind turbine type; setting a wind
turbine type maximum power level for the wind turbine type as a
maximum test power level of the two or more test power levels at
which the determined load does not exceed the design load for the
wind turbine type; storing one or more fatigue load values relating
to a range of power levels for the wind turbine type; storing one
or more parameters relating to site conditions at a wind power
plant; and determining, based on at least the stored one or more
fatigue load values and the stored one or more parameters, an
individual maximum power level for the wind turbine type.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of co-pending U.S. patent
application Ser. No. 14/908,949 filed on Jan. 29, 2016, which is a
national stage entry of PCT/DK2014/050224 filed on Jul. 16, 2014,
which claims priority to Danish Patent Application PA 2013 70417
filed on Jul. 29, 2013. Each of these applications is hereby
incorporated by reference in its entirety.
FIELD
[0002] The present invention relates to Maximum Power Levels for
wind turbines and, in particular, to setting a Wind Turbine Type
Maximum Power Level and an Individual Wind Turbine Maximum Power
Level for over-rating control.
BACKGROUND
[0003] Wind turbines generate electricity by converting kinetic
energy from wind into electrical energy via a generator. The amount
of electrical energy generated by a wind turbine is typically
determined by the nominal power rating or rated power level of the
wind turbine and the wind conditions at the site where the wind
turbine is located (e.g. terrain, wind speeds, etc.). Often
multiple wind turbines are co-located in a wind power plant in
order to generate a sufficient electrical energy to supply to a
grid.
[0004] The Annual Energy Production (AEP) of a wind power plant
relates to the productivity of the wind turbines forming the wind
power plant and typically is dependent on the annual wind speeds at
the location of the wind power plant. The greater the AEP for a
given wind power plant the greater the profit for the operator of
the wind power plant and the greater the amount of electrical
energy supplied to the grid.
[0005] Thus, wind turbine manufacturers and wind power plant
operators are constantly attempting to increase the AEP for a given
wind power plant.
[0006] One such method may be to over-rate the wind turbines under
certain conditions, in other words, allow the wind turbines to
operate up to a power level that is above the rated or name-plate
power level of the wind turbines for a period of time, in order to
generate more electrical energy when winds are high and accordingly
increase the AEP of a wind power plant.
[0007] However, there are several problems and drawbacks associated
with over-rating wind turbines. Wind turbines are typically
designed to operate at a given nominal rated power level or
name-plate power level and to operate for a given number of years,
e.g. 20 years. Therefore, if the wind turbine is over-rated then
the lifetime of the wind turbine may be reduced.
[0008] The present invention seeks to address, at least in part,
some or all of the problems and drawbacks described
hereinabove.
SUMMARY
[0009] According to a first aspect of the present invention there
is provided a method for setting a Wind Turbine Type Maximum Power
Level for a type of wind turbine comprising: simulating a load
spectrum for two or more test power levels to determine a load on
the type of wind turbine for each of the two or more test power
levels; comparing the determined load for each test power level
with a design load for the type of wind turbine; and setting the
wind turbine type maximum power level for the type of wind turbine
as the maximum test power level at which the determined load does
not exceed the design load for the type of wind turbine.
[0010] Accordingly, a Wind Turbine Type Maximum Power Level can be
determined for one or more types of wind turbine.
[0011] A type of wind turbine may be understood as a wind turbine
with the same electrical system, mechanical system, generator,
gearbox, turbine blade, turbine blade length, hub height, and so
on. Accordingly, any difference to the main structure or components
of a wind turbine may effectively generate a new type of wind
turbine. For example, the same wind turbine except for different
hub heights (e.g. tower heights) may be considered two different
types of wind turbine. Similarly, the same wind turbine except of
different turbine blade lengths may also be considered two
different types of wind turbine. Also, a 50 Hz and 60 Hz wind
turbine may be considered different types of wind turbine, as are
cold climate and hot climate designed wind turbines.
[0012] The type of wind turbine therefore does not necessarily
correspond to the Electrotechnical Commission (IEC) class of wind
turbine as different types of turbine may be in the same IEC class
of wind turbine where each type of wind turbine may have a
different wind turbine type maximum power level based on the design
of and components in the wind turbine.
[0013] The wind turbine type maximum power level may be determined
by comparing the expected loads for a given power level with the
design loads for that the given type of wind turbine and
identifying the largest power level which does not cause loads on
the wind turbine that exceed the design loads. The loads may be the
mechanical loads, fatigue loads or any other loads that may be
determined for a wind turbine at a given power level.
[0014] Determining the load on the type of wind turbine may include
determining the load for one or more mechanical components of the
type of wind turbine. The loads may be determined for all the
mechanical components in the type of wind turbine or for one or
more of the main or critical mechanical components.
[0015] The method may further comprise setting a first test power
level, wherein the first test power level is greater than a nominal
name-plate power level for the type of wind turbine by a first
predetermined value; and incrementing each subsequent test power
level by a second predetermined value. The first test power level
may be initially set at a value higher than the nominal name-plate
rating, e.g. 5 KW, 10 KW, 15 KW, 20 KW, 30 KW, 50 KW, and so on, or
by a percentage of the nominal name-plate rating, e.g. 1%, 2%, 5%,
and so on. The incremental steps may be any suitable for the
purpose of identifying the wind turbine type maximum power level,
e.g. 5 KW, 10 KW, 15 KW, 20 KW, 30 KW, 50 KW, and so on, or
increase by a percentage of the test power level, e.g. 1%
increments, 2% increments, 5% increments, and so on.
[0016] The method may further comprise setting a first test power
level, wherein the first test power level is greater than a nominal
name-plate power level for the type of wind turbine by a third
predetermined value; and decrementing each subsequent test power
level by a fourth predetermined value. Therefore, the first test
power level may be initially set at a value substantially higher
than the nominal name-plate rating, e.g. 500 KW, 400 KW, 300 KW,
200 KW, 100 KW, 50 KW, and so on, or by a percentage of the nominal
name-plate rating, e.g. 20%, 15%, 10%, and so on. The decremented
steps may be any suitable for the purpose of identifying the wind
turbine type maximum power level, e.g. 5 KW, 10 KW, 15 KW, 20 KW,
30 KW, 50 KW, and so on, or decrease by a percentage of the test
power level, e.g. 1% increments, 2% increments, 5% increments, and
so on.
[0017] The step of simulating the load spectrum for the two or more
test power levels may be performed simultaneously, or may be
performed for each of the two or more test power levels in
turn.
[0018] The step of comparing the determined load for each of the
two or more test power levels with the design loads for the type of
wind turbine may be performed simultaneously, or may be performed
for each of the two or more test power levels in turn.
[0019] If the determined load exceeds the design load, then the
method may further comprise identifying one or more of the
mechanical components for which the determined load exceeded the
design load of the one or more mechanical components; and analyzing
the one or more mechanical components to identify whether the
design load for the one or more mechanical components can be
increased. There may be incorporated into the design of the given
type of wind turbine allowances or safety margins that may be
analyzed to see if they were conservative and therefore the design
limits of the mechanical components could be increased.
[0020] If the determined load exceeds the design load, the method
may further comprise identifying one or more of the mechanical
components for which the determined load exceeded the design load
of the one or more mechanical components; identifying control
and/or hardware to enable the one or more mechanical components to
operate at a load greater than the design load for the one or more
mechanical components; and implementing the identified control
and/or hardware in the type of wind turbine. Therefore, it may be
that the design limits of one or more mechanical components could
be increased by adding additional hardware/control software to the
wind turbine. For example, the control software could include
additional thresholds that could prevent over-rating under certain
conditions which would mean that for at least a period of time the
mechanical component could operate at higher that its design
limits. Hardware could include adding temperature sensors to the
mechanical component to measure the temperature and enable the
mechanical component to operate at higher than its design
limitations whilst the temperature is below a threshold. As will be
appreciated, there may be several different control and/or hardware
or a combination of the two which may enable the mechanical
components to operate at a power level greater than the design
limits for the mechanical components.
[0021] The method may further comprise determining for the wind
turbine type maximum power level whether one or more electrical
components of the type of wind turbine are within design limits.
The main electrical components may include, for example, the
generator, transformer, internal cables, contactors, or any other
electrical component in the type of wind turbine. Based on
simulations and/or calculations it may be determined whether the
main electrical components can operate at the previously determined
wind turbine type maximum power level.
[0022] If the design limits for one or more electrical components
are exceeded at the wind turbine type maximum power level, the
method may further comprise checking the determination for
conservatism to identify whether the design limits for the one or
more electrical components can be increased such that for the wind
turbine type maximum power level the one or more electrical
components are within the increased design limits. The design of
the electrical components may have incorporated conservatism,
allowances or safety margins which may be analyzed to check whether
the design limits for the electrical components can be increased
whilst still being able to operate safely. As over-rating may only
be performed at certain times and/or under certain conditions then
the electrical components may be able to operate at a higher power
level for a certain period of time enabling the design limits for
the purpose of over-rating to be increased.
[0023] If the design limits for one or more electrical components
are exceeded at the wind turbine type maximum power level, the
method may further comprise identifying control and/or hardware to
enable the one or more electrical components to operate at the wind
turbine type maximum power level; and implementing the identified
control and/or hardware in the type of wind turbine. For example,
if the temperature of the electrical component is key to its design
limit then additional temperature sensors could be implemented in
the wind turbine to ensure that the temperature does not exceed its
maximum whilst the wind turbine may be over-rated. Similarly,
additional control in terms of implementing additional thresholds
may be included, for example, to cancel or prevent over-rating if
the temperature increases to above a threshold, which may therefore
enable the electrical component to operate above its design limit
for at least a period of time. As will be appreciated, there may be
any suitable hardware, control software or any combination of the
two that may be implemented to enable one or more electrical
components to operate at a higher power level than the design
limit, for at least a period of time for over-rating.
[0024] If the design limits for one or more electrical components
are exceeded at the wind turbine type maximum power level, the
method may further comprise decrementing the wind turbine type
maximum power level by fifth predetermined value; determining for
the decremented wind turbine type maximum power level whether one
or more electrical components of the type of wind turbine are
within the design limits; and setting the wind turbine type maximum
power level at a first decremented wind turbine type maximum power
level for which the one or more electrical components of the type
of wind turbine are within the design limits.
[0025] Therefore, if there is no room for increasing the design
limit of one or more electrical components then a lower wind
turbine type maximum power level may be determined by decrementing
the wind turbine type maximum power level by a predetermined value
and then determining whether the electrical components can operate
within design limits at the decremented level. The predetermined
value that the wind turbine type maximum power level may be
decremented by may be any suitable for the purpose of identifying
the wind turbine type maximum power level, e.g. 5 KW, 10 KW, 15 KW,
20 KW, 30 KW, 50 KW, and so on, or by a percentage, e.g. 1%, 2%,
5%, and so on.
[0026] The method may further comprise determining an individual
maximum power level for one or more wind turbines based on the wind
turbine type maximum power level, wherein the individual maximum
power level is used in over-rating control of the one or more wind
turbines. Accordingly, the determined wind turbine type maximum
power level may then be used to determine an individual maximum
power level for a given wind turbine of the type of wind
turbine.
[0027] The wind turbine type maximum power level may be set for one
or more wind turbine types.
[0028] The method may further comprise applying a conservatism
factor to the wind turbine type maximum power level. Therefore, to
incorporate a safety margin for the wind turbine a conservatism
factor may be included, e.g. to reduce the wind turbine type
maximum power level by, e.g. 5 KW, 10 KW, 15 KW, 20 KW, 30 KW, 50
KW, and so on, or by a percentage, e.g. 1%, 2%, 5%, and so on.
[0029] The wind turbine type maximum power level may include, or
define, one or more of a maximum generator torque, a maximum
generator current, maximum generator speed, and maximum rotor
speed.
[0030] According to a second aspect of the present invention there
is provided an apparatus for setting a Wind Turbine Type Maximum
Power Level for a type of wind turbine comprising a first processor
adapted to simulate a load spectrum for two or more test power
levels to determine a load on the type of wind turbine for each of
the one or more test power levels; a second processor adapted to
compare the determined load for each test power level with a design
load for the type of wind turbine; and a third processor adapted to
set the wind turbine type maximum power level for the type of wind
turbine as the maximum test power level at which the determined
load does not exceed the design load for the type of wind
turbine.
[0031] According to a third aspect of the present invention there
is provided an apparatus for setting a Wind Turbine Type Maximum
Power Level for a type of wind turbine wherein the apparatus is
adapted or configured to simulate a load spectrum for two or more
test power levels to determine a load on the type of wind turbine
for each of the two or more test power levels; compare the
determined load for each test power level with a design load for
the type of wind turbine; and set the wind turbine type maximum
power level for the type of wind turbine as the maximum test power
level at which the determined load does not exceed the design load
for the type of wind turbine.
[0032] The first processor may be further adapted to determine the
load for one or more mechanical components of the type of wind
turbine.
[0033] The apparatus further comprise a fourth processor adapted to
set a first test power level, wherein the first test power level
may be greater than a nominal name-plate power level for the type
of wind turbine by a first predetermined value; and the fourth
processor may further adapted to increment each subsequent test
power level by a second predetermined value.
[0034] The apparatus may further comprise a fifth processor adapted
to set a first test power level, wherein the first test power level
may be greater than a nominal name-plate power level for the type
of wind turbine by a third predetermined value; and the fifth
processor may be further adapted to decrement each subsequent test
power level by a fourth predetermined value.
[0035] The first processor may be adapted to simulate the load
spectrum for the two or more test power levels simultaneously, or
may be adapted to simulate the load spectrum for each of the two or
more test power levels in turn.
[0036] The second processor may be adapted to compare the
determined load for each of the two or more test power levels with
the design loads for the type of wind turbine simultaneously, or
may be adapted to compare the determined load for each of the two
or more test power levels with the design loads for the type of
wind turbine in turn.
[0037] The apparatus may further comprise a sixth processor adapted
to identify one or more of the mechanical components for which the
determined load exceeded the design load of the one or more
mechanical components; and analyze the one or more mechanical
components to identify whether the design load for the one or more
mechanical components can be increased.
[0038] The apparatus may further comprise an eighth processor
adapted to identify one or more of the mechanical components for
which the determined load exceeded the design load of the one or
more mechanical components; and identify control and/or hardware to
enable the one or more mechanical components to operate at a load
greater than the design load for the one or more mechanical
components.
[0039] The apparatus may further comprise a ninth processor adapted
to determine for the wind turbine type maximum power level whether
one or more electrical components of the type of wind turbine are
within design limits.
[0040] If the ninth processor determines the design limits for one
or more electrical components are exceeded at the wind turbine type
maximum power level, then the ninth processor may be further
adapted to check the determination for conservatism to identify
whether the design limits for the one or more electrical components
can be increased such that for the wind turbine type maximum power
level the one or more electrical components are within the
increased design limits.
[0041] If the ninth processor determines the design limits for one
or more electrical components are exceeded at the wind turbine type
maximum power level, then the ninth processor may be further
adapted to identify control and/or hardware to enable the one or
more electrical components to operate at the wind turbine type
maximum power level; such that the identified control and/or
hardware can be implemented in the type of wind turbine.
[0042] If the ninth processor determines the design limits for one
or more electrical components are exceeded at the wind turbine type
maximum power level, then the ninth processor may be further
adapted to decrement the wind turbine type maximum power level by
fifth predetermined value; determine for the decremented wind
turbine type maximum power level whether one or more electrical
components of the type of wind turbine are within the design
limits; and set the wind turbine type maximum power level at a
first decremented wind turbine type maximum power level for which
the one or more electrical components of the type of wind turbine
are within the design limits.
[0043] The apparatus may further comprise a tenth processor adapted
to determine an individual maximum power level for one or more wind
turbines based on the wind turbine type maximum power level,
wherein the individual maximum power level may be used in
over-rating control of the one or more wind turbines.
[0044] The wind turbine type maximum power level may be set for one
or more wind turbine types.
[0045] The apparatus may further comprise an eleventh processor
adapted to apply a conservatism factor to the wind turbine type
maximum power level.
[0046] The wind turbine type maximum power level may include, or
define, one or more of a maximum generator torque, a maximum
generator current, maximum generator speed, and maximum rotor
speed.
[0047] The first processor through eleventh processor may be the
same processor, different processors, or any combination thereof.
The processor may include or be any one or more of a controller,
memory, inputs, outputs, and so on, to enable the processor to
perform the necessary functions or features of the aspect of the
invention.
[0048] The apparatus may be adapted, or configured, to perform the
functions and features of the aspect of the invention by hardware,
software, or any combination thereof.
[0049] According to a fourth aspect of the present invention there
is provided a computer program product comprising computer readable
executable code for implementing any one or all of the functions
and feature of the aspect of the present invention.
[0050] According to a fifth aspect of the present invention there
is provided a method for determining an individual maximum power
level for one or more wind turbines in a wind power plant,
comprising: storing a wind turbine type maximum power level for one
or more types of wind turbine; storing one or more fatigue load
values relating to a range of power levels for each of the one or
more types of wind turbine; storing one or more parameters relating
to site conditions for the site at which the wind power plant is
located; and determining for each wind turbine of a type of wind
turbine, based on at least the stored fatigue load levels for the
type of wind turbine and the stored parameters relating to the site
conditions, the individual maximum power level.
[0051] Accordingly, based on the wind turbine type maximum power
level, fatigue load levels and site conditions, an individual
maximum power level can be determined and set for each individual
wind turbine in a Wind Power Plant. This advantageously enables
each wind turbine to operate and/or over-rate to its maximum
potential at its location in a Wind Power Plant which may increase
the Annual Energy Production of the individual wind turbine and/or
the Wind Power Plant.
[0052] Determining the individual maximum power level for each wind
turbine of one type of wind turbine may further comprise
determining for a test power level, wherein the test power level is
initially set at the wind turbine type maximum power level for the
type of wind turbine, whether each wind turbine can operate at the
test power level based on the fatigue load values and the
parameters relating to the site conditions at a location of each
wind turbine; if the determination is positive for one or more wind
turbines then setting the one or more wind turbines with an
individual maximum power level equal to the test power level; if
the determination is negative for one or more wind turbines then
generating a subsequent test power level by decrementing the test
power level by a predetermined value; and iteratively performing
the determination for each subsequent test power levels until the
individual maximum power level is set for each wind turbine.
[0053] Therefore, the power levels starting at the wind turbine
type maximum power level can be checked for each individual wind
turbine of that type of wind turbine to determine or identify,
based on the conditions at each individual wind turbine the maximum
power level that the individual wind turbine may be over-rated to.
The wind turbines may be over-rated to any power level up to the
maximum possible power level for each wind turbine which may
increase the effectiveness and annual energy production of the
individual wind turbine.
[0054] The method may further comprise determining the fatigue load
values for each power level in the range of power levels by
simulating one or more load cases across a range of wind speeds and
conditions.
[0055] The method may further comprise determining the one or more
wind turbines have been in operation; storing data relating to the
one or more wind turbines historical operation; and altering the
fatigue load values based on the data relating to the one or more
wind turbines historical operation.
[0056] If a wind turbine has been in operation then it may have
used up effective lifetime of the wind turbine meaning that it
cannot be over-rated to a higher power level that it could have
been. Similarly, if the wind turbine has been operating below
capacity then there may be spare capacity to over-rate to a higher
power level.
[0057] The method may further comprise setting the individual
maximum power level in the corresponding individual wind
turbine.
[0058] The method may further comprise setting a lowest determined
individual maximum power level in one or more individual wind
turbines.
[0059] The individual maximum power level may include, or define,
one or more of an individual maximum generator torque, an
individual maximum generator current, an individual maximum
generator speed, and an individual maximum rotor speed.
[0060] According to a sixth aspect of the present invention there
is provided an apparatus for determining an individual maximum
power level for one or more wind turbines in a wind power plant,
comprising: a memory adapted to store a wind turbine type maximum
power level for one or more types of wind turbine; the memory is
further adapted to store one or more fatigue load values relating
to a range of power levels for each of the one or more types of
wind turbine; the memory is further adapted to store one or more
parameters relating to site conditions for the site at which the
wind power plant is located; and a first processor adapted to
determine for each wind turbine of a type of wind turbine, based on
at least the stored fatigue load levels for the type of wind
turbine and the stored parameters relating to the site conditions,
the individual maximum power level.
[0061] According to a seventh aspect of the present invention there
is provided an apparatus adapted to, or configured to, store a wind
turbine type maximum power level for one or more types of wind
turbine; store one or more fatigue load values relating to a range
of power levels for each of the one or more types of wind turbine;
store one or more parameters relating to site conditions for the
site at which the wind power plant is located; and determine for
each wind turbine of a type of wind turbine, based on at least the
stored fatigue load levels for the type of wind turbine and the
stored parameters relating to the site conditions, the individual
maximum power level.
[0062] The first processor may be further adapted to determine for
a test power level, wherein the test power level is initially set
at the wind turbine type maximum power level for the type of wind
turbine, whether each wind turbine can operate at the test power
level based on the fatigue load values and the parameters relating
to the site conditions at a location of each wind turbine; if the
determination by the first processor is positive for one or more
wind turbines then a second processor is adapted to set the one or
more wind turbines with an individual maximum power level equal to
the test power level; if the determination by the first processor
is negative for one or more wind turbines then the first processor
is further adapted to generate a subsequent test power level by
decrementing the test power level by a predetermined value; and the
first processor is further adapted to iteratively perform the
determination for each subsequent test power levels until the
individual maximum power level is set for each wind turbine.
[0063] The apparatus may further comprise a third processor adapted
to determine the fatigue load values for each power level in the
range of power levels by simulating one or more load cases across a
range of wind speeds and conditions.
[0064] The apparatus may further comprise a fourth processor
adapted to determine the one or more wind turbines have been in
operation; the memory being further adapted to store data relating
to the one or more wind turbines historical operation; and a fifth
processor adapted to alter the fatigue load values based on the
data relating to the one or more wind turbines historical
operation.
[0065] The apparatus may further comprise a sixth processor adapted
to set the individual maximum power level in the corresponding
individual wind turbine.
[0066] The apparatus may further comprise a seventh processor
adapted to set a lowest determined individual maximum power level
in one or more individual wind turbines.
[0067] The individual maximum power level may include, or define,
one or more of an individual maximum generator torque, an
individual maximum generator current, an individual maximum
generator speed, and an individual maximum rotor speed.
[0068] The first processor through seventh processor may be the
same processor, different processors, or any combination thereof.
The processors may include one or more of controllers, memory,
inputs, outputs, and so on, to enable the processors to perform the
functions and features of the aspect of the invention.
[0069] The apparatus may be adapted, or configured, by hardware,
software, or any combination thereof.
[0070] According to an eighth aspect of the present invention there
is provided a computer program product comprising computer readable
executable code for implementing one or more of the functions or
features of the aspect of the present invention.
[0071] According to a ninth aspect of the present invention there
is provided a method comprising: simulating a load spectrum for two
or more test power levels to determine a load on a type of wind
turbine for each of the two or more test power levels; comparing
the determined load for each test power level with a design load
for the type of wind turbine; setting a wind turbine type maximum
power level for the type of wind turbine as the maximum test power
level at which the determined load does not exceed the design load
for the type of wind turbine; storing one or more fatigue load
values relating to a range of power levels for the type of wind
turbine; storing one or more parameters relating to site conditions
for the site at which a wind power plant is located; and
determining for each wind turbine of the type of wind turbine at
the wind power plant, based on at least the stored fatigue load
levels for the type of wind turbine and the stored parameters
relating to the site conditions, an individual maximum power
level.
[0072] The functions and features of the various aspects and
embodiments of the present invention may be separate or combined in
any manner to enable the present invention to be implemented and
performed.
BRIEF DESCRIPTION OF THE DRAWINGS
[0073] Embodiments of the present invention will now be described,
by way of example only, and with reference to the accompanying
drawings, in which:
[0074] FIG. 1 shows a schematic view of a wind turbine according to
many of the embodiments of the present invention.
[0075] FIG. 2 shows a schematic view of a wind power plant
according to many of the embodiments of the present invention.
[0076] FIG. 3 show a flow diagram according to many of the
embodiments of the present invention.
DESCRIPTION OF EMBODIMENTS
[0077] With reference to FIG. 1, a wind turbine 101 typically
includes foundations 102 to which a tower 103 is attached, in order
for the tower 103 to be securely and stably maintained at its
location. In the example wind turbine 101 shown in FIG. 1, the wind
turbine 101 is located onshore and as such the foundations 102 are
typically concrete foundations to secure the wind turbine 101 to
the Earth.
[0078] However, as will be appreciated, the foundations 102 may be
any suitable foundations to securely and stably maintain the wind
turbine 101 at its location. The foundations may therefore include
a platform, a floating platform for offshore wind turbines, anchor
cables, and so on.
[0079] On top of the tower 103 is located a nacelle 104, where the
nacelle typically houses many electrical systems, mechanical
systems, and hydraulic systems (not shown for ease of illustration)
to control the wind turbine 101 and enable the generation of
electrical energy.
[0080] A hub 105 is connected to the nacelle 104. The hub 105 is
typically attached to a drive shaft (not shown for ease of
illustration) which drives a generator (not shown for ease of
illustration) in the nacelle 104 to generate electrical energy.
[0081] Attached to the hub 105 is a number of turbine blades 106,
which rotate under the influence of the impacting wind to rotate
the drive shaft that is connected to the generator. In the example
shown in FIG. 1, the wind turbine 101 comprises three turbine
blades 106 but, as will be appreciated, there may be any number of
turbine blades suitable for the purpose of the wind turbine 101.
Furthermore, the wind turbine 101 example shown in FIG. 1 is a
Horizontal Axis Wind Turbine, but as will be appreciated, the wind
turbine 101 may be a Vertical Axis Wind Turbine.
[0082] With reference to FIG. 2, a schematic of a Wind Power Plant
(WPP) 201 is shown comprising five wind turbines 202. As will be
appreciated, there may be any number of wind turbines 202 in a WPP
201 depending on the required amount of electrical energy, the size
of the location of the WPP 201, and so on. There may be tens,
hundreds or even thousands of wind turbines 202 that may form a WPP
201.
[0083] The wind turbines 202 are typically operatively connected to
a Wind Power Plant Controller (WPPC) 203. The WPPC 203 typically
controls the WPP, for example, the WPPC may selectively command
individual wind turbines to reduce their production of electricity,
or cease production completely, to regulate the total amount of
electricity being generated by the WPP. Each wind turbine 202
typically comprises a wind turbine controller (or suite of
controllers) to control the operation of the wind turbine 202, and
the WPPC 203 typically co-operates with wind turbine controllers
204 to manage and control the WPP 201.
[0084] The WPPC 203 may be co-located with the wind turbines 202 at
the WPP 201 or may be located externally to the WPP 201. The WPPC
203 may include a single controller/processor 206 to implement the
functionality of the WPPC, or may include two or more
controllers/processors 206 that co-operate to implement the
functionality if the WPPC 203.
[0085] There may be further control systems and/or computer systems
205, which may be associated with the WPP 201 or utilized to
control the WPP 201, plan and/or commission the WPP 201, or provide
any suitable support to the operation of the WPP 201. The further
control systems and computer systems 205 may include one or more
controllers/processors 207 for implementing the functionality of
the further control systems and/or computer systems 205.
[0086] With reference to FIG. 3, which shows a flow chart, the
control of over-rating according to many embodiments will be
described.
[0087] In step 301, a wind turbine type maximum power level for one
or more types of wind turbines is determined. In this example, an
offline computer system is utilized to determine the wind turbine
type maximum power level. However, as will be appreciated, the
functionality to determine the wind turbine type maximum power
level may be implemented by an online computer system, or any other
software and/or hardware associated with wind turbines and/or
WPP.
[0088] The wind turbine type maximum power level is the maximum
power level that a given type of wind turbine is allowed to produce
when the wind is suitably high if it is to be operated at the limit
of the design loads of the components of the wind turbine. The wind
turbine type maximum power level effectively applies for the design
lifetime of the turbine. Therefore, the wind turbine type maximum
power level will typically be higher than the nominal name-plate
rating for that type of wind turbine as the nominal name-plate
rating is typically a more conservative value.
[0089] A type of wind turbine, as used in the following examples
and embodiments, may be understood as a wind turbine with the same
electrical system, mechanical system, generator, gearbox, turbine
blade, turbine blade length, hub height, and so on. Accordingly,
any difference to the main structure or components of a wind
turbine effectively generates a new type of wind turbine, for the
purpose of the embodiments of the present invention. For example,
the same wind turbine except for different hub heights (e.g. tower
heights) would be two different types of wind turbine. Similarly,
the same wind turbine except of different turbine blade lengths
would also be considered two different types of wind turbine. Also,
a 50 Hz and 60 Hz wind turbine are considered different types of
wind turbine, as are cold climate and hot climate designed wind
turbines.
[0090] The type of wind turbine therefore does not necessarily
correspond to the Electrotechnical Commission (IEC) class of wind
turbine as different types of turbine may be in the same IEC class
of wind turbine where each type of wind turbine may have a
different wind turbine type maximum power level based on the design
of and components in the wind turbine.
[0091] In the following example, the wind turbine is rated at a
nominal plate rating power level of 1.65 MW (1650 KW), with a hub
height of 78 metres and designed for service in the conditions of a
specific IEC Wind Class.
[0092] The wind turbine type maximum power level may then be
determined for this type of wind turbine by simulating a load
spectrum for a first test over-rate power level to identify the
loads on the type of wind turbine for that first power level. The
loads may be mechanical loads, fatigue loads, any other loads that
may be experienced by the wind turbine, or any combination of the
different loads. In this example, the mechanical loads are
considered however, as will be appreciated, other loads, e.g.
fatigue loads could also be taken into account. The process of
simulating the load spectrum may also include or be an
extrapolation or other form of analysis that may be performed to
determine the load on the type of wind turbine.
[0093] A load spectrum typically includes a range of different test
cases which may be run in a computer simulation of a wind turbine.
For example, the load spectrum may include test cases for winds at
8 m/s for duration of 10 minutes, for 10 m/s for 10 minutes, for
different wind directions, for different wind turbulences, for
startup of the wind turbine, for shutdown of the wind turbine, and
so on. As will be appreciated, there are many different wind
speeds, wind conditions, wind turbine operating conditions, and/or
fault conditions for which there are test cases to be run in the
wind turbine simulation of the load spectrum. The test cases may
include real, actual data or artificial data (e.g. for 50 year
gusts that are defined in the standards relating to wind turbines).
The simulation of the load spectrum may determine the forces and
loads affecting the wind turbine for all test cases in the load
spectrum. This simulation may also estimate or determine the number
of times that the test case event may occur, for example, a test
case of 10 m/s wind for a duration of 10 minutes may be expected to
occur 2000 times during the 20 year lifetime of the wind turbine
and therefore the fatigue on the wind turbine for the lifetime of
the wind turbine can be calculated. The simulation may also
calculate or determine the fatigue damage or load that could be
incurred by the various components in the wind turbine based on the
determined loads affecting the wind turbine.
[0094] In this example, the first test power level may be 1700 KW
as this is higher than the nominal name-plate rating power level
for the type of wind turbine being considered in this example. The
load spectrum may then be simulated for the given type of wind
turbine in order to determine whether the type of wind turbine can
operate at that first test power level without exceeding the
ultimate design loads of the mechanical components of the type of
wind turbine. If the simulation identifies that the type of wind
turbine can operate at the first test power level then the same
process may be repeated for a second test power level. For example,
the second test power level, in this example, may be 1725 KW. The
load spectrum is then simulated for the given type of wind turbine
to identify whether that type of wind turbine can operate at that
second test power level without exceeding the ultimate design loads
of the mechanical components.
[0095] If the ultimate design loads of the mechanical components
are not exceeded then the process of simulating the load spectrum
for further test power levels can be iteratively performed. In this
example, the test power levels are incremented at steps of 25 KW
however, as will be appreciated, the incremental steps may be any
suitable for the purpose of identifying the wind turbine type
maximum power level, e.g. 5 KW, 10 KW, 15 KW, 20 KW, 30 KW, 50 KW,
and so on, or increase by a percentage of the test power level,
e.g. 1% increments, 2% increments, 5% increments, and so on.
Alternatively, the process start at a high first test power level
and for each iteration decrements the test power level by a
suitable amount until the wind turbine type maximum power level is
identified, i.e. the first test power level at which the type of
wind turbine can operate without exceeding ultimate design
limitations.
[0096] In this example, the given type of wind turbine is
identified as being able to operate at further test power levels of
1750 KW, 1775 KW and 1800 KW before a design limitation of one or
more mechanical components is exceeded at 1825 KW.
[0097] Thus, the process identifies that the wind turbine type
maximum power level for this type of turbine is 1800 KW.
[0098] In further embodiments, as the type of wind turbine did not
exceed the ultimate design loads for the mechanical components at
1800 KW but did exceed the ultimate design loads for the mechanical
components at 1825 KW then the process could further iteratively
increment the test power levels by smaller increments, e.g. 5 KW to
identify whether the wind turbine could operate without exceeding
the mechanical ultimate design loads at a power level between 1800
KW and 1825 KW. However, in the current example, the power level of
1800 KW is taken as the wind turbine type maximum power level for
this type of wind turbine.
[0099] In further embodiments, additional analysis could be
performed once a test power level is reached at which the type of
wind turbine exceeds the ultimate design loads of one or more of
the mechanical components. For example, if the mechanical component
for which the ultimate design load was exceeded at a given test
power level is, e.g. a gearbox, then an analysis of the mechanical
component, e.g. gearbox, could be performed. For example, if the
gearbox ultimate torque exceeded the design limitations then an
analysis could be performed on the specific components of the
gearbox to identify the weak spots. The weak spots in this case may
be, e.g. the casing and the torque arms, and therefore by analyzing
those weak spots it may be identified that the increased loads at
the test power level would not in fact increase the loads on the
weak spots beyond the ultimate design load of the components in the
identified weak spots, due to the safety factors present in those
components. Therefore, after analyzing the components of the
gearbox it may be identified that in fact the gearbox could operate
at the given test power level. Additionally, Finite Element (FE)
analysis could also be performed on the one or more components that
exceeded the ultimate design loads.
[0100] In further embodiments, once the wind turbine type maximum
power level for a given type of wind turbine has been determined it
may be suitable to apply a conservative factor to the wind turbine
type maximum power level. For example, the wind turbine type
maximum power level determined may be reduced by a predetermined
amount, e.g. 1%, 2%, 5%, 10 KW, 25 KW, 50 KW, and so on, as the
conservative factor. This conservative factor may be applied to
ensure that the absolute wind turbine type maximum power level
cannot be exceeded in any circumstances.
[0101] However, in the present embodiment such additional analysis
is not performed nor is a conservative factor applied and the wind
turbine type maximum power level is identified or determined as
1800 KW from the incremental test power level process described
hereinabove.
[0102] The process of determining the wind turbine type maximum
power level may then be performed for any further types of wind
turbine that are to be analyzed.
[0103] In step 302 of FIG. 3, the design limitations for the
electrical components in the type of wind turbine may be considered
or evaluated for the previously determined wind turbine type
maximum power level. As described hereinabove, the wind turbine
type maximum power level for the type of wind turbine being
analyzed in this embodiment was determined hereinabove as 1800 KW
in relation to its mechanical components.
[0104] Therefore, in step 302, the main electrical components are
considered to ensure that the determined wind turbine type maximum
power level does not exceed the design limitations of the main
electrical components of the type of wind turbine being analyzed.
The main electrical components may include, for example, the
generator, transformer, internal cables, contactors, or any other
electrical component in the type of wind turbine.
[0105] Based on simulations and/or calculations it is then
determined whether the main electrical components can operate at
the previously determined wind turbine type maximum power level.
For example, operation at the determined wind turbine type maximum
power level may cause a temperature of one or more electrical
cables inside the wind turbine to increase and so reduce the
electrical current carrying capability of the electrical cables,
which is determined by the size of cable conductor and the
conditions for thermal dissipation. Therefore, the current carrying
capacity would be calculated for the new temperature conditions in
order to determine if the electrical cables are able to operate at
power levels up to the wind turbine type maximum power level.
Similar considerations may be taken into account for other
electrical components, e.g. the temperature of the components,
capacity of the components and so on, to identify whether the
electrical components can operate at power levels up to the wind
turbine type maximum power level
[0106] If it is determined or identified that the main electrical
components can operate at the previously determined wind turbine
type maximum power level in relation to the mechanical components
then, in step 303 of FIG. 3, for the given type of wind turbine
then the wind turbine type maximum power level is set or recorded
as the maximum power level for the given type of wind turbine.
[0107] However, if one or more the electrical components are unable
to operate at the previously determined wind turbine type maximum
power level then one or more of three options may be followed.
[0108] First, the calculations or simulations utilized to identify
the one or more electrical components that are unable to operate at
the previously determined wind turbine type maximum power level may
be analyzed to identify whether any conservatism was incorporated
into the calculations/simulations. Based on the analysis, it may be
identified that the one or more electrical components may, in fact,
be able to operate at the previously determined wind turbine type
maximum power level due to the conservatism of the
calculations/simulations used. If so, then in step 303 of FIG. 3,
the maximum power level for the given type of wind turbine can be
set at the previously determined wind turbine type maximum power
level. For example, the electrical current that would result from
the previously determined wind turbine type maximum power level may
depend upon, at least in part, the voltage on the grid to which the
WPP is connected. At some wind power sites the voltage on the grid
may be less stable and vary more than at other wind sites. Where it
can be determined that the voltage variation on a given individual
wind site will be less than the variation for which the electrical
components have been designed then the turbine may be allowed to
operate at higher power.
[0109] Second, the design of the electrical components and/or
mechanical components to which the electrical components may be
associated, can be analyzed to identify whether a software control
and/or hardware control solution may be implemented to enable the
given type of wind turbine to operate at the previously determined
wind turbine type maximum power level. For example, the control
solution (in hardware and/or software) may allow the wind turbine
to operate at the wind turbine type maximum power level for a
period of time before preventing or cancelling the operation of the
wind turbine at the wind turbine type maximum power level until it
is able to do so again. An example of this may be that the
calculations/simulations indicate that an electrical component,
e.g. the generator terminal box, may overheat at the wind turbine
type maximum power level. However, on analysis of that electrical
component it may be identified that additional sensors, e.g.
temperature sensors, could be implemented at or near to the
electrical component such that the wind turbine operation can be
controlled to cancel or prevent the operation at wind turbine type
maximum power level if the temperature measurements from the
temperature sensors is greater than a threshold. If the condition
that may cause the calculation/simulation of the electrical
components to fail can be solved or compensated for via software
and/or hardware control then in step 303 of FIG. 3, the maximum
power level for the given type of wind turbine may be set at or
recorded as the previously determined wind turbine type maximum
power level.
[0110] Third, if the calculations/simulations identify one or more
electrical components as being unable to operate at the previously
determined wind turbine type maximum power level and a solution to
the failure for the one or more electrical components is not
possible then a new wind turbine type maximum power level for the
given wind turbine type may then be determined. For example, the
previously determined wind turbine type maximum power level may be
decremented by a predefined amount (e.g. 25 KW, 50 KW, 1%, 2%, and
so on), and the calculations/simulations performed again on the
electrical components. The calculations/simulations are performed
at decrementing test power levels until a test power level is
determined at which the design capabilities of the electrical
components are not exceeded. The newly determined test power level
may then, in step 303 of FIG. 3, be set or recorded as the wind
turbine type maximum power level for that given type of wind
turbine.
[0111] In this embodiment, it is determined from the analysis of
the electrical components that, for the given type of wind turbine,
the electrical components are able to operate at the previously
determined wind turbine type maximum power level of 1800 KW. Thus,
in step 303 of FIG. 3, the wind turbine type maximum power level
for this type of wind turbine is set at or recorded as 1800 KW.
[0112] In the above described embodiments, the steps of identifying
the wind turbine type maximum power level that the main mechanical
components and the main electrical components of a given type of
wind turbine are able to operate at are performed separately.
However, as will be appreciated, the steps could be performed
together, e.g. a combined mechanical component and electrical
component analysis. In the above described embodiments the main
mechanical components are analyzed prior to the main electrical
components however, as will be appreciated, those steps are
inter-changeable in order to determine the wind turbine type
maximum power level for the given type of wind turbine.
[0113] The above described process may then be performed for
further types of wind turbines, such that a wind turbine type
maximum power level is determined and recorded for all different
types of wind turbines.
[0114] Once the wind turbine type maximum power level has been
determined for each type of wind turbine then this parameter may be
utilized in order to determine or identify the maximum power level
at which a wind turbine could be over-rated under certain
conditions and at its location in a WPP. As described hereinabove,
the wind turbine type maximum power level determined for a given
type of wind turbine is the maximum power level that the type of
wind turbine could be over-rated to, or able to operate at, without
exceeding the ultimate design loads and/or limitations of the given
type of wind turbine.
[0115] However, conditions at the WPP location or site may prevent
the type of wind turbine being able to over-rate to the determined
wind turbine type maximum power level. Or, the conditions facing
some of the wind turbines at the WPP may prevent those wind
turbines from being over-rated to the determined wind turbine type
maximum power level for that type of wind turbine.
[0116] Therefore, it is preferable that an individual maximum power
level e.g. the maximum over-rating power level, is determined for
each wind turbine in a WPP, or a WPP maximum power level, e.g. the
maximum over-rating power level, is determined for a WPP as a
whole.
[0117] Individual maximum power levels for each wind turbine in a
WPP are advantageous as the conditions in a WPP may vary across the
site of the WPP. Therefore, it may be the case that a wind turbine
in one location in the WPP may face different conditions to another
wind turbine of the same type at a different location in the WPP.
Accordingly, the two wind turbines of the same type may require
different individual maximum power levels, or the lowest individual
maximum power level may be applied to all wind turbines of that
type in the WPP depending on the preferred implementation.
[0118] In this embodiment an individual wind turbine specific
individual maximum power level will be determined. Accordingly, the
WPP is analyzed in order to determine or identify the individual
maximum power level for each wind turbine in the WPP, where the WPP
may include one or more different types of wind turbine.
[0119] The analysis may be performed using a computer system that
is online or offline in relation to the operation and control of
the WPP. The tool to perform this analysis may be the same as or
different to the system utilized to determine the wind turbine type
maximum power level for each type of wind turbine, as described
hereinabove. In the following example, an offline Site Check (SC)
tool separate to the one used to determine the wind turbine type
maximum power level is utilized to analyses the WPP and to
determine the individual maximum power level for each wind
turbine/the WPP.
[0120] Firstly, the SC tool is configured or set up in order to be
able to determine an individual maximum power level for each wind
turbine in a given WPP.
[0121] In step 304 of FIG. 3, the SC tool is populated with the
previously determined wind turbine type maximum power level for
each type of wind turbine and further populated with fatigue load
values for a range of different power levels for each type of wind
turbine in the WPP.
[0122] The fatigue load values may be calculated offline and may be
calculated by the SC tool or by the offline system that determined
the wind turbine type maximum power level for each type of wind
turbine. In this embodiment, the offline system that determined the
wind turbine type maximum power level calculates the fatigue load
values for each type of wind turbine.
[0123] The range of power levels for which the fatigue load values
are calculated is dependent on the type of wind turbine and its
wind turbine type maximum power level, previously determined or
identified. In the above described example, the type of wind
turbine being analyzed had a nominal name-plate rating of 1650 KW
and was determined as having a wind turbine type maximum power
level of 1800 KW. Therefore, the range of power levels for which
the fatigue load values are calculated may be from the nominal
name-plate rating of 1650 KW to the wind turbine type maximum power
level of 1800 KW. The range of power levels may therefore start at
1650 KW and increment in steps of 20 KW, 25 KW, 40 KW, 50 KW, and
so on, or in percentage terms, e.g. 1%, 2%, 5%, and so on, up until
the wind turbine type maximum power level for the given type of
wind turbine is reached.
[0124] As will be appreciated, different types of wind turbine will
have different nominal name-plate ratings and different determined
wind turbine type maximum power levels.
[0125] It may also be useful to consider the fatigue load values
for de-rated power levels of the type of wind turbine or for each
individual wind turbine. For example, in this case where the type
of wind turbine has a nominal plate rating of 1650 KW then the
range of power levels for which fatigue load values are calculated
may instead start at, for example, 1400 KW up to the wind turbine
type maximum power level in order to include the de-rated power
levels for the wind turbine.
[0126] The advantage of including de-rated power levels is that, on
average, a higher individual maximum power level can be achieved,
because the expected or actual de-rating of the wind turbine will
provide more spare fatigue capacity in the components.
[0127] The fatigue-load values are used for the whole spectrum of
operating conditions and power level ranges, since the fatigue
damage accumulates in all operating conditions and power levels,
but at different rates. Accordingly it may be beneficial to utilize
in the calculation the expected or actual time that a wind turbine
may spend at each power-level of operation, including both
over-rated and non-over-rated power levels, to determine the amount
of fatigue and/or damage to the components of the wind turbine.
[0128] However, in this embodiment the fatigue load values will
only be calculated for each type of wind turbine from nominal
name-plate rating up to the determined wind turbine type maximum
power level.
[0129] The offline system determines the fatigue load values for
each power level in the range by running or simulating load cases
across a range of wind speeds (e.g. 4 m/s to 20 m/s) of 5 or 10
minute durations. Accordingly, a significant number of fatigue load
levels for each power level in the range of power levels are
calculated and generated. Simulating the load cases may also
include extrapolation or any other analysis that could be performed
in order to calculate or generate the fatigue load levels.
[0130] Additionally, the offline system may also calculate fatigue
load values based on one or more ranges of other variables, such as
wind-speed, turbulence, air density, and so on.
[0131] The SC tool is populated with at least the calculated
fatigue load values relevant to the type or types of wind turbines
in a given WPP that is being analyzed.
[0132] In step 305 of FIG. 3, the SC tool is further populated with
information or parameters relating to the given WPP site
topography, terrain, wind conditions, and so on. The topography and
terrain information may be provided by site surveys and/or from
knowledge of the WPP site, which may include details of slopes,
cliffs, inflow angles to each turbine in the WPP, and so on. Wind
conditions, e.g. wind-speeds (seasonal, annual, etc.), turbulence
intensity (seasonal, annual, etc.), air density (seasonal, annual,
etc.), temperature (seasonal, annual, etc.), and so on, may be
provided from Met Mast data and/or from wind conditions experienced
and logged by the wind turbines and/or WPPC in location at the
WPP.
[0133] The SC tool may comprise one or more memory, database, or
other data structure, to store and maintain the fatigue load values
for each type of wind turbine, wind turbine type maximum power
levels for each type of wind turbine, and information and/or
parameters relating to the WPP site conditions.
[0134] Once the SC tool has been populated with the relevant data
then the over-rating power level for each wind turbine can be
determined.
[0135] In step 306 of FIG. 3, it may be identified whether the
process for determining the Wind Turbine specific individual
maximum power level (or WPP specific) over-rating power level is
being applied to an existing WPP (e.g. as a retrofit) or is being
applied to a new, or recently installed WPP.
[0136] In the case that the determination of Wind Turbine specific
individual maximum power level (e.g. the maximum possible
over-rating power level for the individual wind turbine) is being
applied to an existing WPP that has been in operation for a period
of time (e.g. one year or more) then the method may move to step
307 of FIG. 3. Alternatively, any historical operation of the WPP
and/or the Wind Turbines could be ignored and the existing WPP
effectively be considered a new WPP for the purpose of determining
the individual maximum power level for each specific Wind
Turbine/the WPP. In this case, the process would proceed to step
308 of FIG. 3.
[0137] In the case that the determination of Wind Turbine specific
individual maximum power level is being applied to a new WPP or a
WPP that has been in operation for a short period of time (e.g.
less than one year) then the method of the embodiments moves to
step 308 of FIG. 3.
[0138] Returning to step 307, in the case that the process is being
applied to an existing WPP, the SC tool may be further populated
with historical information or data relating to the WPP's operation
and/or each wind turbine's operation to-date. The historical data
may include, for example, the number of years operation to date,
the operating levels of the wind turbines, temperatures and other
conditions measured in the turbine that could potentially cause the
control system to limit the over-rating if such conditions were to
occur in future operation, and so on.
[0139] By utilizing existing or historical data on the operation of
the WPP and/or for each of the wind turbines then a more effective
individual maximum power level can be determined. For example, if
the historical operational data shows that the wind conditions have
been below the design regime for the wind turbine(s) then there
could effectively be additional "spare capacity" in component
fatigue. In other words, if the WPP has seen lower wind speeds than
expected then the wind turbines will not have been operated to
their fullest capacity and as such will not have been subject to as
much component fatigue as expected and therefore could permit a
higher level of over-rating to be achieved. Similarly, if the WPP
has seen greater wind speeds than expected then the level of
over-rating could be reduced to ensure that the wind turbine
components reach their expected lifetime (typically 20 years).
[0140] The historical data relating to the operation of the WPP
and/or Wind Turbines in the WPP may be used to alter or correct the
fatigue load values calculated in the previous step, so that the
historical operation data is taken into account when determining
the over-rating power level for each specific Wind Turbine.
[0141] For example it may be necessary to limit the over-rating on
hot days when critical temperatures approach their operating limits
even though high wind conditions would otherwise allow more power
to be generated. The historical data will allow the duration of
such periods to be estimated and used to correct the wind-based
predictions of how much over-rated operation is likely to occur in
future. By taking into account periods of restriction on
over-rating that arise from conditions other than the availability
of suitable wind conditions a lower estimate of future fatigue load
will result than would otherwise be calculated thus enabling a
higher upper-limit on over-rated power, and therefore individual
maximum power level to be calculated.
[0142] The process may then continue to step 308 of FIG. 3 in order
to determine the specific individual maximum power levels for each
wind turbine in the WPP.
[0143] In step 308 of FIG. 3, the Wind Turbine specific individual
maximum power levels can be determined by the SC tool based on, at
least some, of the information and data the SC tool has been
populated with in the preceding steps described hereinabove.
[0144] The SC tool may consider each Wind Turbine in turn, may
consider all Wind Turbines in the WPP of each type of Wind Turbine
in turn, or may consider all Wind Turbines of all types in the WPP
together in order to determine the wind turbine specific individual
maximum power level for each Wind Turbine in the WPP.
[0145] In this embodiment, the SC tool will consider all Wind
Turbines in the WPP of the same type in turn.
[0146] As described hereinabove, the SC tool is populated with the
wind turbine type maximum power level for each type of wind
turbine, fatigue load values for each type of wind turbine for at
least a range of power levels (which may or may not have been
corrected or altered by historical operational data if the WPP has
been in operation for one year or more), and the WPP site
conditions (which may include the terrain and conditions that may
affect each wind turbine in the WPP).
[0147] In the examples given hereinabove, one type of wind turbine
was considered and the maximum power level was determined as 1800
KW. Therefore, in this example the SC tool may determine a wind
turbine specific individual maximum power level for each of the
wind turbines of this type.
[0148] The SC tool may start at the wind turbine type maximum power
level for the type of wind turbine, e.g. 1800 KW in this example,
and check the fatigue load values for each turbine based on one or
more of the conditions faced by each of the wind turbines at their
specific location or position in the WPP.
[0149] If a specific Wind Turbine of the given type of wind turbine
is able to operate at 1800 KW, based on the fatigue load values
determined for the 1800 KW power level and given the site
conditions facing that Wind Turbine (e.g. expected wind conditions,
terrain conditions, etc.) then the individual maximum power level
for over-rating of that particular Wind Turbine can be set at 1800
KW.
[0150] All the Wind Turbines of the given type are checked in
relation to whether they are able to operate at 1800 KW at their
location in the WPP. All the Wind Turbines that are able to operate
at 1800 KW are recorded or marked as having an individual maximum
power level of 1800 KW.
[0151] If there are Wind Turbines of the given type of wind turbine
that are not able to operate at 1800 KW, due to the site conditions
at their location in the WPP, then the SC tool checks to see which
of the remaining wind turbines of the given type are able to
operate at a lower or decremented power level. The amount that the
power level is decremented relates to the power level range for
which the fatigue load levels were previously calculated. In this
example, the SC tool will check whether the remaining wind turbines
of the given type are able to operate at 1780 KW.
[0152] Therefore, for each of the remaining wind turbines or the
given type of wind turbine it is checked whether each specific wind
turbine, based on the fatigue load levels for 1780 KW and the site
conditions expected for each of the remaining wind turbines, it is
determined or identified which of the remaining wind turbines are
able to operate at an over-rating power level of 1780 KW. Those
wind turbines that are able to operate at 1780 KW are then recorded
or marked as having an individual maximum power level of 1780
KW.
[0153] The process is iteratively repeated for all subsequent
decremented power levels until an individual maximum power level is
identified or recorded for all wind turbines of the given type in
the WPP.
[0154] The same process is then repeated for all other types of
wind turbine that are present in the WPP so that an individual
maximum power level is identified or recorded for all wind turbines
present in the WPP.
[0155] Accordingly, at the end of step 308 of FIG. 3, an individual
maximum power level that is wind turbine specific will have been
identified or recorded for all wind turbines present in the
WPP.
[0156] In the above example, the process determined an individual
maximum power level for each wind turbine of a given type by
identifying which wind turbines are able to operate at the wind
turbine type maximum power level determined previously and then
subsequently decrementing the power level until all wind turbines
of the given type had an individual maximum power level.
[0157] Alternatively, the process could have started at the nominal
name-plate rating power level and increment the power levels until
an individual maximum power level for each individual wind turbine
is identified and recorded.
[0158] As a further alternative, a single WPP maximum power level
could have been identified as the lowest individual maximum power
level for any one wind turbine, either using an incrementing or
decrementing power level process.
[0159] It has been identified that even if the wind turbine is able
to operate at a particular determined individual maximum power
level there may be other limitations, for example, due to external
cabling, grid requirements, operator requirements, customer
requirements, and so on. Therefore, in step 309 of FIG. 3, it may
be checked whether any other limitations that may prevent the wind
turbine from operating at its determined individual maximum power
level exist.
[0160] If any additional limitations exist which may affect the
individual maximum power level for one or more wind turbines in the
WPP then the individual maximum power level for those wind turbines
may be adjusted accordingly.
[0161] In step 310 of FIG. 3, each wind turbine is set at its
individual maximum power level. The WPPC may inform or set the
individual maximum power levels in each individual wind turbine or
any other system may communicate the individual maximum power
levels to each of the wind turbines in the WPP.
[0162] As an alternative, in step 311 of FIG. 3, a single WPP
maximum power level for the WPP or one maximum power level for a
given type of wind turbine (e.g. the lowest individual maximum
power level identified for the WPP or the lowest individual maximum
power level identified for a given type of wind turbine in the WPP)
is used and each wind turbine is set at the appropriate individual
maximum power level.
[0163] Accordingly, each wind turbine is then able to operate at
one or more power levels up to its individually set individual
maximum power level.
[0164] Accordingly, the embodiments described hereinabove
advantageously enables an individual maximum power level to be
determined for and set in the control system of each individual
wind turbine in a WPP. The individual maximum power level
determination may take into consideration the determined wind
turbine type maximum power level along with one or more of various
factors and conditions that may affect, or have affected, the
individual wind turbines, for example, the wind conditions at the
WPP site, the terrain conditions and topography, and so on. This
ensures a more efficient and effective ability to control the
over-rating of the individual wind turbines and ensure the most
efficient Annual Energy Production (AEP) for each WPP.
[0165] In the above embodiments and examples, a single individual
maximum power level was determined for each wind turbine in a WPP.
Alternatively or additionally, individual wind sector maximum power
levels may be determined for over-rating control for different
wind-direction sectors for each wind turbine. Typically, the 360
degree horizon of a wind turbine is divided into 12 sectors, each
of 30 degrees, and therefore an individual sector maximum power
level may be determined for each of the 12 sectors for each of the
wind turbines. This may provide a greater AEP as one sector may be
a low turbulence sector and as such may have a greater scope for
over-rating and thus a greater individual first sector maximum
power level than one or more other sectors. Similarly a high
turbulence sector may have a lower scope for over-rating and thus a
lower individual second sector power level than one or more other
sectors.
[0166] In order to determine the individual wind sector maximum
power level for over-rating control in each sector for each wind
turbine then step 308 of FIG. 3 may further include determining the
individual sector maximum power level for each sector based on the
wind and/or site conditions corresponding or relating to each
sector of each wind turbine in the WPP. For example, in step 308
instead of determining an individual maximum power level for a
specific wind turbine of a given type, the process may determine an
individual sector maximum power level for each sector of each wind
turbine based on the fatigue load levels and the wind/site
conditions in each sector. In order to enable a sector based
over-rating power level then the SC tool may be further populated
with sector based data for each wind turbine. Alternatively, or
additionally, an optimization algorithm could adjust the maximum
power levels in each sector, with the aim being the highest
possible estimated AEP from the turbine, subject to a constraint
that wind turbine lifetime must not be less than design life.
[0167] In the above examples and embodiments, the different maximum
power levels for over-rating control were determined and
subsequently used to control the operation of each individual wind
turbine. However, alternatively or additionally the maximum powers
levels (for type of wind turbine and/or individual wind turbine)
may, in one or more of the embodiments or in alternative
embodiments, include, indicate or define one or more of a maximum
rotor speed, a maximum generator speed, a maximum generator torque,
and a maximum generator current demand. For example, one or more of
a maximum rotor speed, a maximum generator speed, a maximum
generator torque, and a maximum generator current demand may be
determined for each type of wind turbine and then subsequently one
or more of a maximum rotor speed, a maximum generator speed, a
maximum generator torque, and a maximum generator current demand
could be determined for each wind turbine of that type of wind
turbine and use to control the operation of the over-rating in each
wind turbine in the WPP. The process would be very similar to that
described hereinabove in relation to the determination of the
over-rating maximum power levels.
[0168] For example, an optimization algorithm could be used to
determine the values of maximum rotor speed and/or the maximum
generator current for a given turbine that would give the maximum
AEP subject to the turbine lifetime not being less than the design
lifetime.
[0169] The above described embodiments are not exclusive and one or
more of the features can be combined or cooperate in order to
achieve the improved over-rating control via setting maximum power
levels for each wind turbine in a Wind Power Plant that takes into
account the environmental and site conditions facing or affecting
the wind turbine.
[0170] While embodiments of the invention have been shown and
described, it will be understood that such embodiments are
described by way of example only. Numerous variations, changes and
substitutions will occur to those skilled in the art without
departing from the scope of the present invention as defined by the
appended claims. Accordingly, it is intended that the following
claims cover all such variations or equivalents as fall within the
spirit and the scope of the invention.
* * * * *