ASTM E1462-12(2018) Standard Test Methods for Insulation Integrity and Ground Path Continuity of Photovoltaic Modules.pdf

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1、Designation: E1462 12 (Reapproved 2018)Standard Test Methods forInsulation Integrity and Ground Path Continuity ofPhotovoltaic Modules1This standard is issued under the fixed designation E1462; the number immediately following the designation indicates the year oforiginal adoption or, in the case of

2、 revision, the 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 These test methods cover procedures for (1) testing forcurrent leakage between the electrical c

3、ircuit of a photovoltaicmodule and its external components while a user-specifiedvoltage is applied and (2) for testing for possible moduleinsulation breakdown (dielectric voltage withstand test).1.2 A procedure is described for measuring the insulationresistance between the electrical circuit of a

4、photovoltaicmodule and its external components (insulation resistance test).1.3 A procedure is provided for verifying that electricalcontinuity exists between the exposed external conductivesurfaces of the module, such as the frame, structural members,or edge closures, and its grounding point (groun

5、d path conti-nuity test).1.4 This test method does not establish pass or fail levels.The determination of acceptable or unacceptable results isbeyond the scope of this test method.1.5 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstand

6、ard.1.6 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-priate safety, health, and environmental practices and deter-mine the applicability of regulatory limitations prior to

7、 use.1.7 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recom-mendations issued by the World Trade Organization TechnicalBarrie

8、rs to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:2E772 Terminology of Solar Energy Conversion2.2 Underwriters Laboratories Standard:3ANSI/UL 1703 Standard for Safety for Flat-Plate Photovol-taic Modules and Panels3. Terminology3.1 DefinitionsDefinitions of terms used in this tes

9、tmethod may be found in Terminologies E772.3.2 Definitions of Terms Specific to This Standard:3.2.1 ground path continuity, nthe electrical continuitybetween the external and conductive surfaces of a photovoltaicmodule and the intended grounding point of the module.3.2.2 insulation resistance, nthe

10、electrical resistance of aphotovoltaic module insulation, measured at a specified ap-plied voltage between the module internal circuitry and itsgrounding point or mounting structure.4. Summary of Test Method4.1 Insulation IntegrityTwo procedures are provided fortesting the isolation of the electrica

11、lly active parts of themodule from the accessible conductive parts and the exposednonconductive surfaces. This isolation is necessary to providefor safe insulation, use, and service of a photovoltaic module orsystem.4.1.1 Dielectric Voltage Withstand ProcedureA rampedvoltage is applied between the p

12、hotovoltaic circuit and theaccessible parts and surfaces of the module outside of thephotovoltaic circuit while monitoring the current, or by deter-mining whether the leakage current exceeds a predeterminedlimit. The module is then inspected for evidence of possiblearcing.4.1.2 Insulation Resistance

13、 ProcedureThe insulation re-sistance is measured between the photovoltaic circuit and the1These test methods are under the jurisdiction of ASTM Committee E44 onSolar, Geothermal and Other Alternative Energy Sources and is the direct respon-sibility of Subcommittee E44.09 on Photovoltaic Electric Pow

14、er Conversion.Current edition approved Feb. 1, 2018. Published March 2018. Originallyapproved in 1992. Last previous edition approved in 2012 as E1462-12. DOI:10.1520/E1462-12R18.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org.

15、 For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Underwriters Laboratories Incorporated, Publication Stock, 333 PfingstenRoad, Northbrook, IL 60062.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocke

16、n, 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 Organizat

17、ion Technical Barriers to Trade (TBT) Committee.1accessible parts and surfaces of the module outside of thephotovoltaic circuit, using a high-impedance ohmmeter.4.2 Ground Path Continuity ProcedureThis procedure isintended for verification that electrical continuity exists be-tween all of the extern

18、al conductive components and themodule grounding point specified by the manufacturer. This isaccomplished by passing a current between the groundingterminal or lead and the conductive part in question andcalculating the resistance between these two points.5. Significance and Use5.1 The design of a p

19、hotovoltaic module or system intendedto provide safe conversion of the suns radiant energy intouseful electricity must take into consideration the possibility ofhazard should the user come into contact with the electricalpotential of the module. These test methods describe proce-dures for verifying

20、that the design and construction of themodule or system are capable of providing protection fromshock through normal installation and use. At no location onthe module should this electrical potential be accessible, withthe obvious exception of the intended output leads.5.2 These test methods describ

21、e procedures for determiningthe ability of the module to provide protection from electricalhazards.5.3 These procedures may be specified as part of a series ofqualification tests involving environmental exposure, mechani-cal stress, electrical overload, or accelerated life testing.5.4 These procedur

22、es are normally intended for use on drymodules; however, the test modules may be either wet or dry,as indicated by the appropriate protocol.5.5 These procedures may be used to verify module assem-bly on a production line.5.6 Insulation resistance and leakage current are strongfunctions of module dim

23、ensions, ambient relative humidity andabsorbed water vapor, and the ground path continuity proce-dure is strongly affected by the location of contacts and testleads to the module frame and grounding points.5.6.1 For these reasons, it is the responsibility of the user ofthese test methods to specify

24、the maximum acceptable leakagecurrent for the dielectric voltage withstand test, and themaximum acceptable resistance for the ground path continuityprocedure.5.6.2 Fifty A has been commonly used as the maximumacceptable leakage current (see ANSI/UL 1703, Section 26.1),and 0.1 has been commonly used

25、as the maximum accept-able resistance.5.7 Some module designs may not use any external metalliccomponents and thus lack a ground point designated by themodule manufacturer. In these cases, the ground path continu-ity test is not applicable.6. Apparatus6.1 Variable d-c Voltage Power SupplyFor the die

26、lectricvoltage withstand test, a d-c voltage power supply capable ofproviding the specified test voltage (see 5.6) in a gradual andsmooth manner is required. The application of voltage must notallow transients that may cause the instantaneous voltage toexceed the specified test voltage; nor may the

27、flow of capaci-tive current, due to charging, cause the test to indicate anerroneous leakage current.6.1.1 The power supply must include a means of indicatingthe test voltage that is applied to the module.6.1.2 The output voltage of the power supply must becontinuously adjustable and may have an aut

28、omatically con-trolled ramp rate.6.1.3 The power supply must be capable, as a minimum, ofdetecting a leakage current of 1 A.6.1.4 The power supply may, as an option, include a leakagecurrent limit set-point that will shut down the power supplywhen the leakage current exceeds the set-point. Audible o

29、rvisual alarms which indicate that the leakage current hasexceeded the set-point are also acceptable.6.2 Ground Path Continuity Tester, for measuring the resis-tance between any accessible conductive frame or supportelement and the module grounding point, with a minimumresolution of 0.01 .6.2.1 The

30、tester must be capable of passing a current oftwice the module short-circuit current through the moduleground path being tested.6.2.2 The tester must be able to limit the power applied to amodule ground path to 500 W.6.3 OhmmeterA high-impedance ohmmeter, or similardevice, capable of measuring a min

31、imum of 1000 M, and canprovide a voltage suitable for measuring high-resistances.6.4 Metallic Contact(s), aluminum or other metallic foil, ora rigid metallic plate, placed on the surfaces of moduleslacking a metallic frame. The metallic contact(s) function as asubstitute for a metallic frame.6.5 Tes

32、t Stand, for holding modules during testing.7. Procedures7.1 Procedure AInsulation Integrity, Dielectric VoltageWithstand:7.1.1 Mount the module to be tested on the test stand andensure that the module is not illuminated. This may beaccomplished by placing it face down on the test stand or byshading

33、 the face of the module with an appropriately sizedopaque material.7.1.2 Short the output leads of the module together.7.1.3 Ensure that the power supply is turned off before anyelectrical connections are made.7.1.4 Connect the high potential output of the power supplyto the module output leads.7.1.

34、5 Connect the grounded output of the power supply tothe module grounding point or specific component beingtested.7.1.5.1 The module may contain separate and unconnectedmetallic components; if so, the procedure must be repeated foreach metallic component. For example, a junction box notconnected to t

35、he frame must be tested separately.7.1.5.2 Any connections to metallic components must bemade to uninsulated points for the procedure to be valid. ForE1462 12 (2018)2example, an anodized aluminum frame would not qualifyunless the anodization was removed at the test point.7.1.5.3 If the module lacks

36、any exterior metalliccomponents, the leakage current connection must be made toan insulating surface such as a nonmetallic module frame. Ametallic contact (see 6.4) must be placed in contact with thesurface, and connection is then made to the metallic contact.The contact must be at least the same si

37、ze as the surface beingtested. The sponsor or user of this procedure must specifyacceptable connections in these cases.7.1.6 Determine the test voltage for the dielectric voltagewithstand test. The maximum system voltage (see TerminologyE772) for which a module is suitable must be specified by themo

38、dule manufacturer. The test voltage shall be twice themaximum system voltage plus 1000 V. For a module with amaximum system voltage of 30 volts or less, the test voltageshall be 500 volts.7.1.7 Increase the voltage, not to exceed a rate of 200 V/s,until the test voltage is achieved.NOTE 1The capacit

39、ance of modules may be large enough to causelarge currents to flow while the insulation capacitance is charging. Theoperator must be aware of such conditions and allow time for the currentto stabilize.7.1.8 Hold the power supply voltage at the test voltage for1 min.7.1.9 Record the maximum leakage c

40、urrent, or the voltageat which the leakage current set-point was exceeded.7.1.9.1 If the equipment has the current limit set-pointcapability described in 6.1.4 and the power supply shuts downor the alarms are triggered, the maximum current leakage hasbeen exceeded.7.1.10 Observe and listen to the mo

41、dule during the test forevidence of arcing or flash-over.7.1.11 Turn off the power supply.7.1.12 Reverse the power supply-to-module connection po-larity (see 7.1.4 and 7.1.5) and repeat 7.1.7 through 7.1.11.7.1.13 Disconnect the test module.7.1.14 Inspect the module for any visual evidence of arcing

42、or flash-over.7.2 Procedure BInsulation Integrity, Insulation Resis-tance:7.2.1 Mount the module as specified in 7.1.1 and 7.1.2.7.2.2 Connect the ohmmeter to the module as specified in7.1.3 7.1.5 with references to the power supply replaced withthe ohmmeter.7.2.3 Measure and record the insulation r

43、esistance indicatedby the ohmmeter.7.3 Procedure CGround Path Continuity:7.3.1 Determine the necessary current to pass through anymodule ground paths. This current is equal to twice the moduleshort-circuit current.7.3.2 Determine the location of the grounding point and allaccessible conductive parts

44、 of the module. Establish thecontact size, location, and attachment method necessary toperform the ground path continuity test.7.3.2.1 A conductive part is considered accessible unless itis insulated with a material that has been evaluated for itsinsulation properties in the intended application or

45、it isphysically inaccessible according to the definition in ANSI/UL1703, Section 14.7.3.2.2 If the module has more than one accessible conduc-tive part, each must be tested separately.7.3.3 Connect the grounded lead of the continuity tester tothe module grounding point identified by the module manu-

46、facturer.7.3.4 Connect the the high potential lead of the continuitytester to an accessible conductive part of the module.7.3.5 Increase the voltage applied by the continuity testerfrom zero until a current of twice the module short-circuitcurrent is passing through the grounding path under test, or

47、until the maximum wattage indicated in 6.2.2 is reached.7.3.6 Compute and record the resistance from the voltagedrop across the continuity tester leads at the points at whichthey connect to the module.7.3.7 Repeat 7.3.4 7.3.6 for each ground path identified in7.3.2.8. Report8.1 Report the following

48、items at the minimum:8.1.1 The manufacturer and a complete test specimenidentification,8.1.2 A description of the module construction,8.1.3 A description of the measurement equipment andmeasurement conditions or parameters,8.1.4 A description of any apparent changes due to testing,with any sketches

49、or photographs providing clarification,8.1.5 The actual maximum leakage current observed (7.1.9)or the applied voltage at which the maximum current leakagewas exceeded (7.1.9.1),8.1.6 Observations or indications of arcing or flash-over,8.1.7 The insulation resistance recorded in 7.2.3,8.1.8 Results of the ground path continuity procedure from7.3.6, and8.1.9 Any deviation from the procedures.9. Precision and Bias9.1 Several factors make a determination of the precisionand bias from results of an interlaboratory study not practicablefor these procedures