ASTM E1036-02

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Designation:E1036–02
Standard Test Methods for
Electrical Performance of Nonconcentrator Terrestrial
Photovoltaic Modules and Arrays Using Reference Cells
This standard is issued under the fixed designation E1036; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
1. Scope E 1039 Test Method for Calibration of Silicon Non-
Concentrator Photovoltaic Primary Reference Cells Under
1.1 These test methods cover the electrical performance of
Global Irradiation
photovoltaic modules and arrays under natural or simulated
E1040 Specification for Physical Characteristics of Non-
sunlight using a calibrated reference cell.
concentrator Terrestrial Photovoltaic Reference Cells
1.2 Measurements under a variety of conditions are al-
E1125 TestMethodforCalibrationofPrimaryNonconcen-
lowed; results are reported under a select set of reporting
trator Terrestrial Photovoltaic Reference Cells Using a
conditions (RC) to facilitate comparison of results.
Tabular Spectrum
1.3 These test methods apply only to nonconcentrator ter-
E1328 Terminology Relating to Photovoltaic Solar Energy
restrial modules and arrays.
Conversion
1.4 The performance parameters determined by these test
E1362 Test Method for Calibration of Nonconcentrator
methodsapplyonlyatthetimeofthetest,andimplynopastor
Photovoltaic Secondary Reference Cells
future performance level.
G159 TablesforReferencesSolarSpectralIrradianceatAir
1.5 There is no similar or equivalent ISO standard.
Mass 1.5: Direct Normal and Hemispherical for a 37°
1.6 This standard does not purport to address all of the
Tilted Surface
safety concerns, if any, associated with its use. It is the
responsibility of the user of this standard to establish appro-
3. Terminology
priate safety and health practices and determine the applica-
3.1 Definitions—Definitions of terms used in these test
bility of regulatory limitations prior to use.
methodsmaybefoundinTerminologyE772andTerminology
2. Referenced Documents E1328.
3.2 Definitions of Terms Specific to This Standard:
2.1 ASTM Standards:
3.2.1 nominal operating cell temperature, NOCT, n—the
E691 Practice for Conducting an Interlaboratory Study to
temperature of a solar cell inside a module operating at an
Determine the Precision of a Test Method
−2
3 ambient temperature of 20°C, an irradiance of 800 Wm , and
E772 Terminology Relating to Solar Energy Conversion
−1
an average wind speed of 1 ms .
E927 Specification for Solar Simulation for Terrestrial
3 3.2.2 reporting conditions, RC, n—the device temperature,
Photovoltaic Testing
total irradiance, and reference spectral irradiance conditions
E941 Test Method for Calibration of Reference Pyranom-
2 that module or array performance data are corrected to.
eters With Axis Tilted by the Shading Method
3.3 Symbols:
E948 Test Method for Electrical Performance of Photovol-
3.3.1 Thefollowingsymbolsandunitsareusedinthesetest
taic Cells Using Reference Cells Under Simulated Sun-
methods:
light
−1
a —temperature coefficient of reference cell I ,°C ,
r SC
E973 Test Method for Determination of the Spectral Mis-
a—current temperature coefficient of device under test,
match Parameter Between a Photovoltaic Device and a
−1
°C ,
Photovoltaic Reference Cell
b(E)—voltage temperature function of device under test,
E1021 Test Methods for Measuring the Spectral Response
−1
°C ,
of Photovoltaic Cells
2 −1
C—calibration constant of reference cell, Am W ,
C8—adjusted calibration constant of reference cell,
2 −1
These test methods are under the jurisdiction of ASTM Committee E44 on
Am W ,
Solar, Geothermal, and Other Alternative Energy Sources and are the direct
C—NOCT Correction factor,°C,
f
responsibility of Subcommittee E44.09 on Photovoltaic Electric Power Conversion.
Current edition approved Oct. 10, 2002. Published October 2002. Originally
published as E1036–85. Last previous edition E1036–96.
Annual Book of ASTM Standards, Vol 14.02.
3 4
Annual Book of ASTM Standards, Vol 12.02. Annual Book of ASTM Standards, Vol 14.04.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
E1036–02
d(T)—voltageirradiancecorrectionfunctionofdeviceunder 4.5.1 Ifapulsedsolarsimulatorisusedasalightsource,the
test, dimensionless, transient responses of the module or array and the reference
DT—NOCT cell-ambient temperature difference, °C, cell must be compatible with the test equipment.
−2
E—irradiance, Wm , 4.6 The data from the measurements are translated to a set
−2
of reporting conditions (see 5.3) selected by the user of these
E —irradiance at RC, Wm ,
o
test methods. The actual test conditions, the test data (if
FF—fill factor, dimensionless,
available), and the translated data are then reported.
I—current, A,
I —current at maximum power, A,
mp
5. Significance and Use
I —current at RC, A,
o
I —short-circuit current of reference cell, A,
5.1 Itistheintentoftheseprocedurestoproviderecognized
r
I —short-circuit current, A, methods for testing and reporting the electrical performance of
sc
M—spectral mismatch parameter, dimensionless, photovoltaic modules and arrays.
P—electrical power, W, 5.2 The test results may be used for comparison of different
P —maximum power, W, modulesorarraysamongagroupofsimilaritemsthatmightbe
m
encountered in testing a group of modules or arrays from a
T—temperature, °C,
T —ambient temperature, °C, single source. They also may be used to compare diverse
a
designs, such as products from different manufacturers. Re-
T —temperature of cell in module, °C,
c
peatedmeasurementsofthesamemoduleorarraymaybeused
T —temperature at RC, °C,
o
for the study of changes in device performance.
T —temperature of reference cell, °C,
r
−1
5.3 Measurements may be made over a range of test
n—wind speed, ms ,
conditions. The measurement data are numerically translated
V—voltage, V,
(see Section 8) from the test conditions to SRC, to nominal
V —voltage at maximum power, V,
mp
operating conditions, or to optional user-specified reporting
V —voltage at RC, V, and
o
conditions. The SRC are defined in Table 1.
V —open-circuit voltage, V.
oc
5.4 These test methods are based on two requirements.
5.4.1 First, the reference cell is selected so that its spectral
4. Summary of Test Methods
response is considered to be close to the module or array to be
4.1 Measurement of the performance of a photovoltaic
tested.
module or array illuminated by a light source consists of
5.4.2 Second, the spectral response of a representative cell
determining at least the following electrical characteristics:
and the spectral distribution of the irradiance source must be
short-circuit current, open-circuit voltage, maximum power,
known. The calibration constant of the reference cell is then
and voltage at maximum power.
corrected to account for the difference between the actual and
4.2 Theseparametersarederivedbyapplyingtheprocedure
thereferencespectralirradiancedistributionsusingthespectral
in Section 8 to a set of current-voltage data pairs (I-V data)
mismatch parameter, which is defined in Test Method E973.
recorded with the test module or array operating in the
5.5 Terrestrial reference cells are calibrated with respect to
power-producing quadrant.
areferencespectralirradiancedistribution,forexample,Tables
4.3 Testing the performance of a photovoltaic device in-
G159.
volves the use of a calibrated photovoltaic reference cell to
5.6 Areference cell made and calibrated as described in 4.3
determine the total irradiance.
will indicate the total irradiance incident on a module or array
4.3.1 The reference cell is chosen according to the spectral
whose spectral response is close to that of the reference cell.
distributionoftheirradianceunderwhichitwascalibrated,for
5.7 With the performance data determined in accordance
example, the direct normal or global spectrum. These spectra
with these test methods, it becomes possible to predict module
are defined by Tables G159 . The reference cell therefore
or array performance from measurements under any test light
determines to which spectrum the test module or array perfor-
source in terms of any reference spectral irradiance distribu-
mance is referred.
tion.
4.3.2 The reference cell must match the device under test
5.8 These test methods are valid for the range of tempera-
such that the spectral mismatch parameter is 1.00 6 0.05, as
tureandirradianceconditionsoverwhichthecorrectionfactors
determined in accordance with Test Method E973.
(definedinAnnexA2)weredetermined.Devicesforwhichthe
4.3.3 Recommended physical characteristics of reference
correction factors cannot be determined or are unavailable will
cells are described in Specification E1040.
have to be measured at temperature and irradiance conditions
4.4 The spectral response of the module or array is usually
as close to the desired reporting conditions as possible.
taken to be that of a representative cell from the module or
array tested in accordance with Test Method E1021. The
representative cell should be packaged such that the optical
TABLE 1 Reporting Conditions
properties of the module or array packaging and the represen-
Device
Total Irradiance, Spectral
tative cell package are similar.
Temperature,
−2
Wm Irradiance
°C
4.5 Thetestsareperformedusingeithernaturalorsimulated
Standard reporting conditions 1000 G 159 25
sunlight. Solar simulation requirements are stated in Specifi-
Nominal operating conditions 800 . NOCT
cation E927.
E1036–02
6. Apparatus 6.6.1 The variable load should be capable of operating the
device to be tested at an I-V point where the voltage is within
6.1 Photovoltaic Reference Cell—A calibrated reference
1%of V in the power-producing quadrant.
oc
cell is used to determine the total irradiance during the
6.6.2 The variable load should be capable of operating the
electrical performance measurement.
device to be tested at an I-V point where the current is within
6.1.1 The reference cell shall be matched in its spectral
1%of I in the power-producing quadrant.
sc
response to a representative cell of the test module or array
6.6.3 The variable load should allow the device output
such that the spectral mismatch parameter as determined by
power (the product of device current and device voltage) to be
Test Method E973 is 1.00 6 0.05.
variedinincrementsassmallas0.2%ofthemaximumpower.
6.1.2 Specification E1040 provides recommended physical
6.6.4 The electrical response time of the variable load
characteristics of reference cells.
should be fast enough to sweep the required range of I-V
6.1.3 Reference cells may be calibrated in accordance with
operating points during the measurement period. It is possible
Test Methods E1039, E1125, or E1362, as appropriate for a
that the response time of the device under test may limit how
particular application.
fast the range of I-V points can be swept, especially when
6.1.4 A current measurement instrument (see 6.7) shall be
pulsedsimulatorsareused.Forthesecases,itmaybenecessary
usedtodeterminetheI ofthereferencecellwhenilluminated
sc
to make multiple measurements over smaller portions of the
with the light source (see 6.4).
I-V curve to obtain the entire recommended range.
6.2 Test Fixture— The device to be tested is mounted on a
6.7 Current Measurement Equipment—The instrument or
test fixture that facilitates temperature measurement and four-
instruments used to measure the current through the device
wire current-voltage measurements (Kelvin probe, see 6.3).
under test and the I of the reference cell shall have a
sc
The design of the test fixture shall prevent any increase or
resolution of at least 0.02% of the maximum current encoun-
decrease of the device output due to reflections or shadowing.
tered, and shall have a total error of less than 0.1% of the
Arrays installed in the field shall be tested as installed. See
maximum current encountered.
7.2.3 for additional restrictions and reporting requirements.
6.8 Voltage Measurement Equipment—The instrument or
6.3 KelvinProbe—Anarrangementofcontactsthatconsists
instruments used to measure the voltage across the device
oftwopairsofwiresattachedtothetwooutputterminalsofthe
under test shall have a resolution of at least 0.02% of the
device under test. One pair of wires is used to conduct the
maximum voltage encountered, and shall have a total error of
currentflowingthroughthedevice,andtheotherpairisusedto
less than 0.1% of the maximum voltage encountered.
measure the voltage across the device.Aschematic diagram of
an I-Vmeasurement using a Kelvin Probe is given in Fig. 1 of
7. Procedures
Test Method E948.
7.1 Momentary Illumination Technique:
6.4 Light Source— The light source shall be either natural
7.1.1 This technique is valid for use with pulsed solar
sunlight or a solar simulator providing Class A, B, or C
simulators, shuttered continuous solar simulators, or shuttered
simulation as specified in Specification E927.
sunlight. For testing under continuous illumination see 7.2.
6.5 Temperature Measurement Equipment—The instrument
7.1.2 Determine the spectral mismatch parameter, M, using
or instruments used to measure the temperature of both the
Test Method E973.
reference cell and the device under test shall have a resolution
7.1.3 Mountthereferencecellandthedevicetobetestedin
of at least 0.1°C, and shall have a total error of less than 61°C
the test fixture coplanar within 62°, and normal to the
of reading.
illumination source within 610°. If an array or module cannot
6.5.1 Temperature sensors, such as thermocouples or ther-
be aligned to within 610°, the solar angle of incidence, the
mistors, suitable for the test temperature range shall be
device orientation and its tilt angle must be reported with the
attached in a manner that allows measurement of the device
data.
temperature. Because module and array temperatures can vary
7.1.4 Connect the four-wire Kelvin probe to the module or
spacially under continuous illumination, multiple sensors dis-
array output terminals.
tributed over the device should be used, and the results
7.1.5 Expose the module or array to the light source.
averaged to obtain the device temperature.
7.1.6 If the temporal instability of the light source (as
6.5.2 When testing modules or arrays for which direct
defined in Specification E927) is less than 0.1%, the total
measurement of the cell temperature inside the package is not
irradiance may be determined with the reference cell prior to
feasible,sensorscanbeattachedtotherearsideofthedevices.
the performa
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