EN 60904-10:1998
(Main)Photovoltaic devices - Part 10: Methods of linearity measurement
Photovoltaic devices - Part 10: Methods of linearity measurement
Describes procedures used to determine the degree of linearity of any photovoltaic device parameter with respect to a test parameter.
Photovoltaische Einrichtungen - Teil 10: Meßverfahren für die Linearität
Dispositifs photovoltaïques - Partie 10: Méthodes de mesure de la linéarité
Décrit des procédures pour déterminer le degré de linéarité d'un quelconque paramère d'essai du dispositif photovoltaïque par rapport à un paramètre d'essai.
Fotonapetostne naprave – 10. del: Metode merjenja linearnosti
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2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.Fotonapetostne naprave – 10. del: Metode merjenja linearnostiPhotovoltaische Einrichtungen -- Teil 10: Meßverfahren für die LinearitätDispositifs photovoltaïques -- Partie 10: Méthodes de mesure de la linéaritéPhotovoltaic devices -- Part 10: Methods of linearity measurement27.160Solar energy engineeringICS:Ta slovenski standard je istoveten z:EN 60904-10:1998SIST EN 60904-10:2001en01-september-2001SIST EN 60904-10:2001SLOVENSKI
STANDARD
NORMEINTERNATIONALECEIIECINTERNATIONALSTANDARD60904-10Première éditionFirst edition1998-02Dispositifs photovoltaïques –Partie 10:Méthodes de mesure de la linéaritéPhotovoltaic devices –Part 10:Methods of linearity measurement Commission Electrotechnique Internationale International Electrotechnical
CommissionPour prix, voir catalogue en vigueurFor price, see current
catalogueÓ IEC 1998
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http: //www.iec.chCODE PRIXPRICE CODEMSIST EN 60904-10:2001
60904-10 © IEC:1998– 3 –CONTENTSPageFOREWORD. 5Clause1Scope and object. 72Normative references. 93Apparatus. 113.1Test apparatus. 113.2Specimen apparatus. 114Procedure for current and voltage linearity test. 114.1Procedure in natural sunlight. 114.2Procedure with a solar simulator.
155Procedure for spectral response linearity test.175.1Special considerations.175.2General procedure.196Linearity calculation.196.1Slope linearity determination .196.2Determination of spectral response linearity.236.3Linearity requirements .23SIST EN 60904-10:2001
60904-10 © IEC:1998– 5 –INTERNATIONAL ELECTROTECHNICAL COMMISSION___________PHOTOVOLTAIC DEVICES –Part 10: Methods of linearity measurementFOREWORD1)The IEC (International Electrotechnical Commission) is a worldwide organization for standardization comprisingall national electrotechnical committees (IEC National Committees). The object of the IEC is to promoteinternational co-operation on all questions concerning standardization in the electrical and electronic fields. Tothis end and in addition to other activities, the IEC publishes International Standards. Their preparation isentrusted to technical committees; any IEC National Committee interested in the subject dealt with mayparticipate in this preparatory work. International, governmental and non-governmental organizations liaisingwith the IEC also participate in this preparation. The IEC collaborates closely with the International Organizationfor Standardization (ISO) in accordance with conditions determined by agreement between the twoorganizations.2)The formal decisions or agreements of the IEC on technical matters express, as nearly as possible, aninternational consensus of opinion on the relevant subjects since each technical committee has representationfrom all interested National Committees.3)The documents produced have the form of recommendations for international use and are published in the formof standards, technical reports or guides and they are accepted by the National Committees in that sense.4)In order to promote international unification, IEC National Committees undertake to apply IEC InternationalStandards transparently to the maximum extent possible in their national and regional standards. Anydivergence between the IEC Standard and the corresponding national or regional standard shall be clearlyindicated in the latter.5)The IEC provides no marking procedure to indicate its approval and cannot be rendered responsible for anyequipment declared to be in conformity with one of its standards.6)Attention is drawn to the possibility that some of the elements of this International Standard may be the subjectof patent rights. The IEC shall not be held responsible for identifying any or all such patent rights.International Standard IEC 60904-10 has been prepared by IEC technical committee 82: Solarphotovoltaic energy systems.The text of this standard is based on the following documents:FDISReport on voting82/186/FDIS82/193/RVDFull information on the voting for the approval of this standard can be found in the report onvoting indicated in the above table.SIST EN 60904-10:2001
60904-10 © IEC:1998– 7 –PHOTOVOLTAIC DEVICES –Part 10: Methods of linearity measurement1 Scope and objectThis part of IEC 60904 describes procedures used to determine the degree of linearity of anyphotovoltaic device parameter with respect to a test parameter. It is primarily intended for useby calibration laboratories, module manufacturers and system designers.Photovoltaic (PV) module and system performance evaluations, and performance translationsfrom one set of temperature and irradiance conditions to another frequently rely on the use oflinear equations (see IEC 60891 and IEC 61829). This standard lays down the linearityrequirements and test methods to ensure that these linear equations will give satisfactoryresults. Indirectly, these requirements dictate the range of the temperature and irradiancevariables over which the equations can be used.The methods of measurement described in this standard apply to all PV devices and areintended to be carried out on a sample or on a comparable device of identical technology. Theyshould be performed prior to all measurement and correction procedures that require a lineardevice. The methodology used in this standard is similar to that specified in IEC 60891 in whicha linear (straight-line) function is fitted to a set of data points using a least-squares fitcalculation routine. The variation of the data from this function is also calculated, and thedefinition of linearity is expressed as an allowable variation percentage.A device is considered linear when the following conditions are met over the temperature andirradiance range of interest. Typically, this range of temperature is 25 °C to 60 °C minimum,and the irradiance range of 700 W×m–2 to 1 000 W×m–2 minimum.a)For the curve of short-circuit current versus irradiance, the normalized standard deviation ofthe slope (ss/m) should be less than 0,02.b)For the curve of open-circuit voltage versus the logarithm of irradiance, the normalizedstandard deviation of the slope (ss/m) should be less than 0,05.c)For the curve of open-circuit voltage and short-circuit current versus temperature, thenormalized standard deviation of the slope (ss/m) should be less than 0,1.d)The variation of relative spectral response at a specified voltage is less than 5 % for thewavelength band.NOTE 1 – Many of the IEC PV standards require spectral mismatch corrections which in turn require spectralresponse measurements. Therefore, the linearity of spectral response with respect to temperature and irradiance isimportant. It can also be significant for new technologies such as photochemical cells.NOTE 2 – Because the relative spectral response of some devices such as amorphous silicon varies considerablywith voltage, it is important that the linearity determination be performed at a fixed voltage. The voltage selected isgoverned by the ultimate usage. Vmax may be selected if the maximum power regime is the area of interest, and forcalibration zero bias voltage might be more appropriate.SIST EN 60904-10:2001
60904-10 © IEC:1998– 9 –NOTE 3 – It should be noted that the relative spectral response of some devices varies with temperature andirradiance. Some of these effects may be accounted for as changes in the items a) and c) short-circuit current non-linearity, but some may not be. The item d) requirement accounts for these non-linearities.General procedures for determining the degree of linearity for these and any other performanceparameter are described in clauses 4 through 6.2 Normative referencesThe following normative documents contain provisions which, through reference in this text,constitute provisions of this part of IEC 60904. At the time of publication, the editions indicatedwere valid. All normative documents are subject to revision, and parties to agreements basedon this part of IEC 60904 are encouraged to investigate the possibility of applying the mostrecent editions of the normative documents indicated below. Members of IEC and ISO maintainregisters of currently valid International Standards.IEC 60891:1987, Procedures for temperature and irradiance corrections to measured I-Vcharacteristics of crystalline silicon photovoltaic devicesAmendment 1 (1992)IEC 60904-2:1989, Photovoltaic devices – Part 2: Requirements for reference solar cellsIEC 60904-3:1989, Photovoltaic devices – Part 3: Measurement principles for terrestrialphotovoltaic solar devices with reference spectral irradiance dataIEC 60904-6:1994, Photovoltaic devices – Part 6: Requirements for reference solar modulesIEC 60904-7:1995, Photovoltaic devices – Part 7: Computation of spectral mismatch errorintroduced in the testing of a photovoltaic device (English only)IEC 60904-8:1995, Photovoltaic devices – Part 8: Guidance for measurement of spectralresponse of a photovoltaic (PV) device (English only)IEC 60904-9:1995, Photovoltaic devices – Part 9: Solar simulator performance requirements(English only)IEC 61215:1993, Crystalline silicon terrestrial photovoltaic (PV) modules – Design qualificationand type approvalIEC 61646:1996, Thin-film terrestrial photovoltaic (PV) modules – Design qualification and typeapprovalIEC 61829:1995, Crystalline silicon photovoltaic (PV) array – On-site measurement of I-VcharacteristicsSIST EN 60904-10:2001
60904-10 © IEC:1998– 11 –3 Apparatus3.1 Test apparatusThe following apparatus is required to control and measure the test conditions:a)a radiant source (natural sunlight or solar simulator, class B or better in accordance withIEC 60904-9) of the type to be used in subsequent tests;b)any equipment necessary to change the irradiance over the range of interest withoutaffecting the relative spectral irradiance distribution and the spatial uniformity, such asmesh filters or neutral density filters;NOTE – The equipment and procedure used to change the irradiance are to be verified with a radiometer. Thechange in relative spectral irradiance distribution should not result in more than 0,5 % change in the short-circuitcurrent of the device (see IEC 60904-7 and IEC 60904-8). Mesh filters are believed to be the best method for largesurfaces.c)a PV reference device having a known short-circuit current versus irradiance characteristicdetermined by calibrating against an absolute radiometer in accordance with the relevantIEC standard;d)any equipment necessary to change the temperature of the test specimen over the range ofinterest;e)a means for controlling the temperature of the test specimen and reference device, or aremovable shade;f)a suitable mount for supporting the test specimen and the reference device in the sameplane normal to the radiant beam;g)a means for monitoring the temperature of the test specimen and reference device to anaccuracy of ±1 °C, and repeatability of ±0,5 °C.3.2 Specimen apparatusDepending on the performance parameter for which the linearity determination is being made,one or more of the following apparatus items may be required:a)equipment for measuring the current of the test specimen and reference device to anaccuracy of ±0,2 % of the reading;b)equipment for measuring the voltage of the test specimen and reference device to anaccuracy of ±0,2 % of the reading;c)equipment for measuring the relative spectral response of the test specimen (or arepresentative sample equivalent to the test specimen) in accordance with IEC 60904-7 toan accuracy of ±2 % of the reading.NOTE – IEC 60904-7 provides methods for the computation of spectral mismatch error introduced in the testing ofphotovoltaic devices, and IEC 60904-8 provides guidance for spectral measurement.4 Procedure for current and voltage linearity testThere are two acceptable procedures for performing the linearity test of short-circuit currentand open-circuit voltage with respect to temperature and irradiance.4.1 Procedure in natural sunlight4.1.1
Measurement in natural sunlight shall only be made when–the total irradiance is at least as high as the upper limit of the range of interest;–the irradiance variation caused by short-term oscillations (clouds, haze, or smoke) is lessthan ±2 % of the total irradiance as measured by the reference device; and–the wind speed is less than 2 m×s–1.SIST EN 60904-10:2001
60904-10 © IEC:1998– 13 –4.1.2
Mount the reference device co-planar with the test specimen so that both are normal tothe direct solar beam within ±1°. Connect to the necessary instrumentation.NOTE – The measurements described in the following subclauses should be made as expeditiously as possiblewithin a few hours on the same day to minimize the effect of changes in the spectral conditions. If not, spectralcorrections may be required.4.1.3
If the test specimen and reference device are equipped with temperature controls, setthe controls a
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