1、Designation: E2848 13 (Reapproved 2018)Standard Test Method forReporting Photovoltaic Non-Concentrator SystemPerformance1This standard is issued under the fixed designation E2848; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the
2、 year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method provides measurement and analysisprocedures for determining the capacity of a specific photo
3、vol-taic system built in a particular place and in operation undernatural sunlight.1.2 This test method is used for the following purposes:1.2.1 acceptance testing of newly installed photovoltaicsystems,1.2.2 reporting of dc or ac system performance, and1.2.3 monitoring of photovoltaic system perfor
4、mance.1.3 This test method should not be used for:1.3.1 testing of individual photovoltaic modules for com-parison to nameplate power ratings,1.3.2 testing of individual photovoltaic modules or systemsfor comparison to other photovoltaic modules or systems,1.3.3 testing of photovoltaic systems for t
5、he purpose ofcomparing the performance of photovoltaic systems located indifferent places.1.4 In this test method, photovoltaic system power isreported with respect to a set of reporting conditions (RC)including: solar irradiance in the plane of the modules, ambienttemperature, and wind speed (see S
6、ection 6). Measurementsunder a variety of reporting conditions are allowed to facilitatetesting and comparison of results.1.5 This test method assumes that the solar cell temperatureis directly influenced by ambient temperature and wind speed;if not the regression results may be less meaningful.1.6
7、The capacity measured according to this test methodshould not be used to make representations about the energygeneration capabilities of the system.1.7 This test method is not applicable to concentratorphotovoltaic systems; as an alternative, Test Method E2527should be considered for such systems.1.
8、8 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.1.9 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-
9、priate safety, health, and environmental practices and deter-mine the applicability of regulatory limitations prior to use.1.10 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles for theDev
10、elopment of International Standards, Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:2D6176 Practice for Measuring Surface Atmospheric Tem-perature with Electrical Resistance Temperature SensorsE7
11、72 Terminology of Solar Energy ConversionE824 Test Method for Transfer of Calibration From Refer-ence to Field RadiometersE927 Specification for Solar Simulation for PhotovoltaicTestingE948 Test Method for Electrical Performance of Photovol-taic Cells Using Reference Cells Under Simulated Sun-lightE
12、973 Test Method for Determination of the Spectral Mis-match Parameter Between a Photovoltaic Device and aPhotovoltaic Reference CellE1036 Test Methods for Electrical Performance of Noncon-centrator Terrestrial Photovoltaic Modules and ArraysUsing Reference CellsE1040 Specification for Physical Chara
13、cteristics of Noncon-centrator Terrestrial Photovoltaic Reference CellsE1125 Test Method for Calibration of Primary Non-Concentrator Terrestrial Photovoltaic Reference Cells Us-ing a Tabular Spectrum1This test method is under the jurisdiction of ASTM Committee E44 on Solar,Geothermal and OtherAltern
14、ative Energy Sources, and is the direct responsibility ofSubcommittee E44.09 on Photovoltaic Electric Power Conversion.Current edition approved May 1, 2018. Published May 2018. Originallyapproved in 2011. Last previous edition approved in 2013 as E2848-13. DOI:10.1520/E2848-13R18.2For referenced AST
15、M standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohoc
16、ken, PA 19428-2959. United StatesThis international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recommendations issued by the World Trade Organiz
17、ation Technical Barriers to Trade (TBT) Committee.1E1362 Test Methods for Calibration of Non-ConcentratorPhotovoltaic Non-Primary Reference CellsE2527 Test Method for Electrical Performance of Concen-trator Terrestrial Photovoltaic Modules and Systems Un-der Natural SunlightG138 Test Method for Cali
18、bration of a SpectroradiometerUsing a Standard Source of IrradianceG167 Test Method for Calibration of a Pyranometer Using aPyrheliometerG173 Tables for Reference Solar Spectral Irradiances: DirectNormal and Hemispherical on 37 Tilted SurfaceG183 Practice for Field Use of Pyranometers, Pyrheliom-ete
19、rs and UV Radiometers2.2 IEEE Standards:IEEE 1526-2003 Recommended Practice for Testing thePerformance of Stand-Alone Photovoltaic SystemsIEEE 1547-2003 Standard for Interconnecting DistributedResources with Electric Power Systems2.3 International Standards Organization Standards:ISO/IEC Guide 98-1:
20、2009 Uncertainty of measurementPart 1: Introduction to the expression of uncertainty inmeasurementISO/IEC Guide 98-3:2008 Uncertainty of measurementPart 3: Guide to the expression of uncertainty in measure-ment (GUM:1995)2.4 World Meteorological Organization (WMO) Standard:WMO-No. 8 Guide to Meteoro
21、logical Instruments andMethods of Observation, Seventh Ed., 20083. Terminology3.1 DefinitionsDefinitions of terms used in this testmethod may be found in Terminology E772, IEEE 1547-2003,and ISO/IEC Guide 98-1:2009 and ISO/IEC Guide 98-3:2008.3.2 Definitions of Terms Specific to This Standard:3.2.1
22、averaging interval, nthe time interval over whichdata are averaged to obtain one data point. The performancetest uses these averaged data.3.2.2 data collection period, nthe period of time definedby the user of this test method during which system outputpower, irradiance, ambient temperature, and win
23、d speed aremeasured and recorded for the purposes of a single regressionanalysis.3.2.3 plane-of-array irradiance, POA, nsee solarirradiance, hemispherical in Tables G173.3.2.4 reporting conditions, RC, nan agreed-upon set ofconditions including the plane-of-array irradiance, ambienttemperature, and
24、wind speed conditions to which photovoltaicsystem performance are reported. The reporting conditionsmust also state the type of radiometer used to measure theplane-of-array irradiance. In the case where this test method isto be used for acceptance testing of a photovoltaic system orreporting of phot
25、ovoltaic system performance for contractualpurposes, RC, or the method that will be used to derive the RC,shall be stated in the contract or agreed upon in writing by theparties to the acceptance testing and reporting prior to the startof the test.3.2.5 sampling interval, nthe elapsed time between s
26、cansof the sensors used to measure power, irradiance, ambienttemperature and wind speed. Individual data points used for theperformance test are averages of the values recorded in thesescans. There are multiple sampling intervals in each averaginginterval.3.2.6 utility grid, nsee electric power syst
27、em in IEEE1547-2003.3.3 Symbols: The following symbols and units are used inthis test method:3.3.1 reference cell ISCtemperature coefficient, C13.3.2 a1,a2,a3,a4linear regression coefficients, arbitrary3.3.3 a, b, c, dspectral mismatch factor calibrationconstants, arbitrary3.3.4 Creference cell cali
28、bration constant, Am2W13.3.5 Coreference cell calibration constant at SRC,Am2W13.3.6 Eplane-of-array irradiance, W/m23.3.7 Eoirradiance at SRC, plane-of-array, W/m23.3.8 Eo()reference spectral irradiance distribution,Wm2nm13.3.9 ERCRC rating irradiance, plane-of-array, W/m23.3.10 ERC()spectral irrad
29、iance distribution at RC, Wm2nm13.3.11 ET()spectral irradiance distribution, test lightsource, Wm2nm13.3.12 Ffractional error in short-circuit current, dimen-sionless3.3.13 ISCshort-circuit current, A3.3.14 Mspectral mismatch factor, dimensionless3.3.15 pp-value, dimensionless quantity used to deter
30、-mine the significance of an individual regression coefficient tothe overall rating result3.3.16 Pphotovoltaic system power, ac or dc, W3.3.17 PRCphotovoltaic system power at RC, ac or dc, W3.3.18 RCreporting conditions3.3.19 RR()reference cell spectral responsivity, A/W3.3.20 RT()test device spectr
31、al responsivity, A/W3.3.21 SRCstandard reporting conditions3.3.22 SEstandard error, W3.3.23 Taambient temperature, C3.3.24 TRCRC rating temperature, C3.3.25 U95expanded uncertainty with a 95 % coverageprobability of photovoltaic system power at RC, W3.3.26 wavelength, nm3.3.27 vwind speed, m/s3.3.28
32、 vRCRC rating wind speed, m/sE2848 13 (2018)24. Summary of Test Method4.1 Photovoltaic system power, solar irradiance, ambienttemperature, and wind speed data are collected over a definedperiod of time using a data acquisition system.4.2 Multiple linear regression is then used to fit the collectedda
33、ta to the performance equation (Eq 1) and thereby calculatethe regression coefficients a1, a2, a3, and a4.P 5 Ea11a2 E1a3 Ta1a4 v! (1)4.3 Substitution of the RC values Eo, To, and vointo Eq 1then gives the ac or dc power at the reporting conditions.PRC5 ERCa11a2 ERC1a3 TRC1a4 vRC! (2)4.4 The collect
34、ed input data and the performance at thereporting conditions are then reported.5. Significance and Use5.1 Because there are a number of choices in this testmethod that depend on different applications and systemconfigurations, it is the responsibility of the user of this testmethod to specify the de
35、tails and protocol of an individualsystem power measurement prior to the beginning of a mea-surement.5.2 Unlike device-level measurements that report perfor-mance at a fixed device temperature of 25C, such as TestMethods E1036, this test method uses regression to a referenceambient air temperature.5
36、.2.1 System power values calculated using this test methodare therefore much more indicative of the power a systemactually produces compared with reporting performance at arelatively cold device temperature such as 25C.5.2.2 Using ambient temperature reduces the complexity ofthe data acquisition and
37、 analysis by avoiding the issuesassociated with defining and measuring the device temperatureof an entire photovoltaic system.5.2.3 The user of this test method must select the timeperiod over which system data are collected, and the averaginginterval for the data collection within the constraints o
38、f 8.3.5.2.4 It is assumed that the system performance does notdegrade or change during the data collection time period. Thisassumption influences the selection of the data collectionperiod because system performance can have seasonal varia-tions.5.3 The irradiance shall be measured in the plane of t
39、hemodules under test. If multiple planes exist (particularly in thecase of rolling terrain), then the plane or planes in whichirradiance measurement will occur must be reported with thetest results. In the case where this test method is to be used foracceptance testing of a photovoltaic system or re
40、porting ofphotovoltaic system performance for contractual purposes, theplane or planes in which irradiance measurement will occurmust be agreed upon by the parties to the test prior to the startof the test.NOTE 1In general, the irradiance measurement should occur in theplane in which the majority of
41、 modules are oriented. Placing themeasurement device in a plane with a larger tilt than the majority willcause apparent under-performance in the winter and over-performance inthe summer.5.3.1 The linear regression results will be most reliablewhen the measured irradiance, ambient temperature, and wi
42、ndspeed data during the data collection period are distributedaround the reporting conditions. When this is not the case, thereported power will be an extrapolation to the reportingconditions.5.4 Accumulation of dirt (soiling) on the photovoltaic mod-ules can have a significant impact on the system
43、rating. Theuser of this test may want to eliminate or quantify the level ofsoiling on the modules prior to conducting the test.5.5 Repeated regression calculations on the same system tothe same RC and using the same type of irradiance measure-ment device over successive data collection periods can b
44、eused to monitor performance changes as a function of time.5.6 Capacity determinations are power measurements andare adequate to demonstrate system completeness. However, asingle capacity measurement does not provide sufficient infor-mation to project the energy generation potential of the systemove
45、r time. Factors that may affect energy generation over timeinclude: module power degradation, inverter clipping andoverloading, shading, backtracking, extreme orientations, andfiltering criteria.6. Reporting Conditions6.1 The user of this test method shall select appropriate RC.In the case where thi
46、s test method is to be used for acceptancetesting of a photovoltaic system or reporting of photovoltaicsystem performance for contractual purposes, the RC, or themethod that will be used to derive the RC, must be agreed uponby the parties to the test.6.1.1 Reporting conditions may be selected either
47、 on thebasis of expected conditions or actual conditions during thedata collection period. Choose RC irradiance and ambient airtemperature values that are representative of the POA irradi-ance and ambient air temperature for the system location for aclear day in the data collection period. When the
48、selection isbased on expected conditions, irradiance can be evaluated froma year-long hourly dataset of projected POA values calculatedfrom historical data measured directly on the system site or ata nearby site. Ambient temperatures can be evaluated by areview of historical data from the site or a
49、nearby location.Reporting conditions should be chosen such that the system isnot subject to frequent shading, inverter clipping or othernon-linear operation at or around the RC. For instance, inlarger photovoltaic systems, the ratio of installed DC capacitytoAC inverter capacity may be such that the inverter limits theproduction of the modules under certain conditions. If this isthe case, care should be taken to choose a reference within thenormal operating range of the inverters.NOTE 2There are many publicly-availab
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