ASTM E1240-88(1996)
(Test Method)Test Method for Performance Testing of Wind Energy Conversion Systems (Withdrawn 2001)
Test Method for Performance Testing of Wind Energy Conversion Systems (Withdrawn 2001)
SCOPE
1.1 This test method covers a test method for determining and reporting performance characteristics of Wind Energy Conversion Systems (WECS). It is intended to provide consumers and other users with an equitable basis for comparing the energy production performance and operating characteristics of WECS available in the marketplace.
1.2 This test method is not limited to WECS that produce electricity.
1.3 These procedures and practices were specifically compiled for small WECS (SWECS), but the test method may be generally applicable to WECS of all sizes.
1.4 This test method does not address issues of reliability, durability, or economics.
1.5 For all ratings dependent upon wind speed, the wind is taken to be that which is experienced at the centerline height of the WECS rotor. No standard heights for either the WECS rotor or the anemometer are assumed.
1.6 The values stated in inch-pound units are to be regarded as the standard. The values given in parentheses are for information only.
1.7 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
General Information
Standards Content (Sample)
Designation: E 1240 – 88 (Reapproved 1996) An American National Standard
AMERICAN SOCIETY FOR TESTING AND MATERIALS
100 Barr Harbor Dr., West Conshohocken, PA 19428
Reprinted from the Annual Book of ASTM Standards. Copyright ASTM
Standard Test Method for
Performance Testing of Wind Energy Conversion Systems
This standard is issued under the fixed designation E 1240; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
INTRODUCTION
This test method describes a standard test method of determining and reporting primary
performance characteristics of wind energy conversion systems (WECS). It includes field test
procedures to determine the power production performance and other operating parameters for a
WECS; a field test procedure to determine noise levels associated with the WECS operation; and
procedures for deriving the WECS performance parameters and the manner in which these ratings
should be presented.
1. Scope S1.4 Specification for Sound Level Meters
1.1 This test method covers a test method for determining
3. Terminology
and reporting performance characteristics of Wind Energy
3.1 Definitions of Terms Specific to This Standard:
Conversion Systems (WECS). It is intended to provide con-
3.1.1 asynchronous WECS, n—wind energy conversion sys-
sumers and other users with an equitable basis for comparing
tem in which the rotor speed is more a function of wind speed
the energy production performance and operating characteris-
than of generator characteristics.
tics of WECS available in the marketplace.
3.1.2 average noise level, n—weighted average of the noise
1.2 This test method is not limited to WECS that produce
levels experimentally obtained for a WECS operating at
electricity.
various wind speeds.
1.3 These procedures and practices were specifically com-
3.1.3 AWEA (American Wind Energy Association) estimated
piled for small WECS (SWECS), but the test method may be
annual energy output (AEAEO), n—calculated total energy that
generally applicable to WECS of all sizes.
would be produced by a WECS during a one-year period,
1.4 This test method does not address issues of reliability,
assuming a Rayleigh wind speed distribution, based upon
durability, or economics.
yearly mean wind speed, and 100 % availability.
1.5 For all ratings dependent upon wind speed, the wind is
3.1.4 bin, n—wind speed interval used for test data group-
taken to be that which is experienced at the centerline height of
ing in the Method of Bins data reduction procedure.
the WECS rotor. No standard heights for either the WECS rotor
3.1.5 bin sort, n—bin-by-bin summary of the results of a
or the anemometer are assumed.
Method of Bins procedure.
1.6 The values stated in inch-pound units are to be regarded
3.1.6 bin width, n—size of a wind speed interval used in the
as the standard. The values given in parentheses are for
Method of Bins data reduction procedure (that is, a bin having
information only.
a span from 11.5 mph to 12.5 mph has a width of 1 mph).
1.7 This standard does not purport to address all of the
3.1.7 centerline height of the rotor, n—distance between the
safety concerns, if any, associated with its use. It is the
group and the vertical center of the rotor.
responsibility of the user of this standard to establish appro-
3.1.8 constant velocity test (CVT), n—wind energy conver-
priate safety and health practices and determine the applica-
sion system test in which a smooth steady airflow is maintained
bility of regulatory limitations prior to use.
either in a wind tunnel or by moving the WECS, relative to the
2. Referenced Documents ground, in calm air.
3.1.9 cut-in wind speed, n—lowest wind speed at which a
2.1 ANSI Standard:
WECS will begin to have power output.
3.1.10 cut-out wind speed, n—wind speed above which a
WECS will have, due to a control function, no power output.
3.1.11 downwind, n—relative orientation of two points
where A is downwind if the wind first passes B then A.
This test method is under the jurisdiction of ASTM Committee E-44 on Solar,
Geothermal, and Other Alternative Energy Sources and is the direct responsibility of
Subcommittee E44.90 on Geothermal Materials. Available from American National Standard Institute, 11 W. 42nd St., 13th
Current edition approved March 25, 1988. Published May 1988. Floor, New York, NY 10036.
E 1240
3.1.12 dwell time, n—number of samples in a bin divided by tem in which the rotor speed is more a function of generator
the sampling rate (in samples per second). characteristics than of wind speed.
3.1.13 field test, n—performance test that is carried out 3.1.32 tower, n—subsystem of a WECS that supports the
under naturally occurring atmospheric conditions. rotor, or other collection device, above the ground.
3.1.14 HAWT, n—horizontal axis wind turbine. 3.1.33 upwind, adj—relative orientation of two points
3.1.15 master bin sort, n—compilation of bin sorts. where A is upwind of B if the wind first passes A then B.
3.1.16 maximum design wind speed, n—maximum wind 3.1.34 utility interconnection, n—electrical connection be-
speed a WECS in automatic, unattended operation, but not tween a WECS and a utility grid in which energy can be
necessarily generating, has been designed to sustain without transferred from the WECS to that utility grid.
damage to structural components or loss of ability to function 3.1.35 VAWT, n—vertical axis wind turbine.
normally. 3.1.36 WECS, n—wind energy conversion system.
3.1.17 maximum power, n—maximum power output a 3.1.37 wind shear, n—variation of wind velocity with
WECS, in normal steady state operation, will produce. respect to spatial variation in a plane normal to the wind
3.1.18 maximum tested wind speed, n—maximum wind direction, usually in the vertical direction.
speed a WECS in automatic, unattended operation, but not
4. Significance and Use
necessarily generating, has sustained without damage to struc-
4.1 This test method is intended to provide consumers and
tural components or loss of ability to function normally.
other users with an equitable basis for comparing the energy
3.1.19 Method of Bins, n—data reduction procedure by
production performance and operating characteristics of
which test data are grouped into wind speed intervals (bins).
WECS available in the marketplace.
3.1.20 Discussion—For each bin, the number of samples
and the sum of the samples are recorded, allowing the average
5. Apparatus
parameter value to be evaluated.
5.1 Test Machine:
3.1.21 overspeed control, n—action of a control system, or
5.1.1 The manufacturer, or other testing entity, may not
part of such system, that prevents excessive rotor speed.
modify or adjust any component of the WECS in order to
3.1.22 power curve, n—characteristic of WECS power out-
enhance its performance beyond that of a regular production
put versus steady-state wind speed.
machine operating in a typical user installation.
3.1.23 power form, n—physical characteristics that describe
5.1.2 If a manufacturer institutes a model change or a
the form in which power produced by the WECS is made
modification that can be expected to produce a detrimental
deliverable to the load.
change amounting to more than 10 % of an established rating,
3.1.24 power output, n—useful power delivered by a WECS
then a retest for the affected parameter(s) and an amended test
at a stated steady state wind speed.
report are required. In the case of power output performance, a
3.1.25 rated rotor speed, n—nominal rotational speed of a
10 % degradation at any wind speed in the range from 12 to 35
WECS rotor when it is producing power.
mph (5.4 to 15.6 m/s) will necessitate retesting.
3.1.26 Rayleigh wind speed distribution, n—mathematical
5.1.3 On WECS that can be either electronically adjusted or
idealization giving a ratio of time the wind blows within a
mechanically outfitted to match operational capabilities or
given wind speed band, probability interval of V to V + dV,to
characteristics to a specific site, the test machine should be set
the total time under consideration. This is a Weibull wind speed
up assuming a 12 mph (5.4 m/s) or 16 mph (7.2 m/s) average
distribution with a constant of two and depends only on mean
wind speed and a Rayleigh distribution of wind speed prob-
wind speed, defined as follows:
ability density. The manufacturer has the option of setting-up
V p p V
¯
V 2
for 10 mph (4.5 m/s) or 14 mph (6.3 m/s) or 18 mph (8.0 m/s),
F V dV 5 EXP 2 dV (1)
~ !
2 F S D G
2 ¯ 4 ¯
V V
or combination thereof, average wind speeds, performing
separate tests to arrive at separate power curves, and using the
where:
¯
V
results to calculate the AWEA estimated annual energy output
F (V) 5 Rayleigh frequency distribution as a function of
at these averages. In this case, however, the manufacturer must
V,
specify, in all literature containing these ratings, that this option
¯
V 5 mean wind speed,
was exercised.
V 5 instantaneous wind speed, and
5.2 Instrumentation:
dV 5 wind speed probability interval.
5.2.1 Anemometry—The accuracy of the test anemometer
3.1.27 rotor, n—system of rotating aerodynamic elements
should not be less than 61 mph (0.4 m/s) over a range of 7 to
attached to a single shaft that converts the kinetic energy in the
45 mph (3.1 to 20.1 m/s). The test anemometer should be
wind into mechanical shaft energy.
calibrated within a period of 6 months prior to the test. This
3.1.28 rotor diameter, n—twice the distance from the rotor
calibration is to be U.S. National Institute of Standards and
axis to the outermost point on the blade.
Technology (NIST) traceable. The manufacturer, or other
3.1.29 rotor speed, n—angular velocity of a WECS rotor
testing entity, should determine the best type of anemometer to
about its rotational axis.
be used for the test.
3.1.30 steady-state wind speed, n—condition where a con-
stant wind speed continues until dynamic transients in WECS
NOTE 1—Use of a secondary calibration source (anemometer manufac-
behavior have subsided.
turer, laboratory, etc.) is acceptable so long as NIST traceability is
3.1.31 synchronous WECS, n—wind energy conversion sys- maintained.
E 1240
NOTE 2—Anemometers that display significant hysteresis effects
produce sound levels in excess of those produced by the test
should be avoided, since they can distort the outcome of a Method of Bins
WECS.
procedure.
7.2 Installation of Apparatus:
NOTE 3—It is preferable to use an anemometer that can respond rapidly
7.2.1 It is recommended that the centerline height of the
to changes in wind speed and direction.
rotor be at least 25 ft (7.6 m) above the ground.
5.2.2 Power Monitoring—The power monitoring instru-
7.2.2 The tower, load, and wiring, or its equivalent, should
mentation used for the test shall have a cumulative accuracy
be representative of typical customer installations.
within 3 % over a range of 5 to 125 % of the WECS maximum
7.2.3 The load should be large enough to ensure that the
power. Each component of this instrumentation should be
WECS output quantities that determine energy transfer capa-
calibrated within a period of 6 months prior to the test. This
bility (voltage, pressure, torque, etc.) will be maintained within
calibration is to be NIST traceable. For WECS that have a
generally recognized operating limits during the course of the
power form of alternating current (AC) electricity the instru-
test.
mentation shall provide a true root-mean-square (RMS) read-
NOTE 6—If lead-acid batteries constitute the load, then the battery
ing of real power.
storage system should be large enough to maintain the individual cells
below 2.35 V.
NOTE 4—Use of a wattmeter is strongly recommended.
NOTE 7—Wind energy conversion systems intended for utility-
5.2.3 Temperature Monitoring—The thermometer or other
interconnected operation should be connected to motor-generators for this
temperature indicator shall be accurate to within 61°F
test method only if the motor-generator has sufficient capacity to maintain
(60.6°C) over the range of temperatures experienced during the WECS output within accepted utility industry standards for voltage
and frequency.
the test. The thermometer or other temperature indicator shall
have a least count of 1°F (0.6°C) or less.
7.2.4 The test anemometer is to be located at a height within
5.2.4 Atmospheric Pressure Monitoring—The barometer
63 ft (0.9 m) or ⁄10of the rotor diameter, whichever is greater,
used to measure atmospheric pressure shall have an accuracy
of the rotor centerline height. Shear corrections, such as the
of 63 % over the range of pressures experienced during the
“ ⁄7power law,” are not allowed under this test method.
test. The barometer shall have a least count of 2.5 mm Hg or
7.2.5 The test anemometer should not be closer than 1.5
less.
rotor diameters from the horizontal center of the rotor on a
5.2.5 Tachometer—The tachometer or other device used to
horizontal-axis wind turbine (HAWT) and 2 rotor diameters on
measure rotor speed shall have an accuracy within 2 % over the
a vertical-axis wind turbine (VAWT).
WECS operating range. The tachometer shall have a least
7.2.6 The test anemometer should be within six rotor
count not greater than 2 % of the WECS maximum operating
diameters of the center of the rotor.
speed.
7.2.7 During the course of the test, the test anemometer
5.2.6 Sound Level Meter—The sound level meter shall be in
must never be in the wake of any portion of the WECS rotor or
accordance with ANSI S1.4 for Type 2 instruments. The sound
structure.
level meter shall be set to the A-weighting network and, where
NOTE 8—If the distance requirements set forth in 7.2.5 of this section
possible, “slow meter response.” A wind screen should be
are met, the upwind wake is assumed negligible.
placed on the microphone used in the test.
7.2.8 Power monitoring instrumentation shall be placed in
6. Sampling Rates the WECS power circuit, or its equivalent, in a manner that
ensures that only power delivered to the load is measured.
6.1 Wind Speed/Power Output:
6.1.1 The minimum sampling rate shall be one data point
NOTE 9—All internal WECS losses due to excitation, friction, or
every 30 s. controls must be supplied from the WECS side of the power monitoring
instrumentation or deducted from the gross power measurements.
NOTE 5—There is no maximum sampling rate.
7.2.9 Air temperature shall be monitored at the base of the
6.2 Air Temperature and Atmospheric Pressure:
WECS tower, or equivalent structure.
6.2.1 Readings should be taken at the beginning and end of
NOTE 10—A height of 5 ft (1.5 m) is recommended.
a test period and once per hour in between.
6.2.2 The average of these readings for each test period,
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