|
|
||||||||||||||||||
GB/T 9535-1998 PDF EnglishUS$350.00 · In stock · Download in 9 seconds
GB/T 9535-1998: Crystalline silicon terrestrial photovoltaic(PV) modules-design qualification and type approval Delivery: 9 seconds. True-PDF full-copy in English & invoice will be downloaded + auto-delivered via email. See step-by-step procedure GB/T 9535: Evolution and historical versions
Excerpted PDFsFull copy of true-PDF will be delivered in 9 seconds upon purchase: GB/T 9535-1998Similar standardsGB/T 19964 GB/T 33589 GB/T 33599 GB/T 6424GB/T 9535-1998: Crystalline silicon terrestrial photovoltaic(PV) modules-design qualification and type approval---This is an excerpt. Full copy of true-PDF in English version (including equations, symbols, images, flow-chart, tables, and figures etc.), auto-downloaded/delivered in 9 seconds, can be purchased online: https://www.ChineseStandard.net/PDF.aspx/GBT9535-1998 GB NATIONAL STANDARD OF THE PEOPLE’S REPUBLIC OF CHINA ICS 27.160;31.260 F 12 eqv IEC 1215:1993 Replacing GB/T 9535-1988 Replacing GB/T 14007-1992 Replacing GB/T 14009-1992 Crystalline Silicon Terrestrial Photovoltaic (PV) Modules-Design Qualification and Type Approval ISSUED ON: NOVEMBER 17, 1998 IMPLEMENTED ON: JUNE 1, 1999 Issued by: State Bureau of Quality and Technical Supervision Table of ContentsForeword ... 3 IEC Foreword ... 4 1 Scope and object ... 5 2 Normative References ... 5 3 Sampling ... 6 4 Marking ... 6 5 Testing ... 7 6 Pass Criteria ... 7 7 Major Visual Defects ... 8 8 Report ... 10 9 Modifications ... 11 10 Test Procedures ... 11 10. 1 Visual inspection ... 11 10.2 Performance at STC ... 12 10.3 Insulation test ... 12 10.4 Measurement of temperature coefficients ... 13 10.5 Measurement of nominal operating cell temperature (NOCT) ... 14 10.6 Performance at NOCT... 21 10.7 Performance at low irradiance ... 21 10.8 Outdoor exposure test ... 24 10.9 Hot-spot endurance test ... 24 10.10 UV test ... 31 10.11 Thermal cycling test ... 31 10.12 Humidity-freeze test ... 33 10.13 Damp-heat test ... 35 10.14 Robustness of terminations test ... 36 10.15 Twist test ... 38 10.16 Mechanical load test... 39 10.17 Hail test ... 40 Crystalline Silicon Terrestrial Photovoltaic (PV) Modules-Design Qualification and Type Approval1 Scope and objectThis International Standard lays down IEC requirements for the design qualification and type approval of terrestrial photovoltaic modules suitable for long-term operation in general open-air climates, as defined in GB/T 4797.1. It applies only to crystalline silicon types. Standards for thin- film modules and other environments, such as marine or equator conditions, are under consideration. This standard does not apply to modules used with concentrators. The object of this test sequence is to determine the electrical and thermal characteristics of the module and to show, as far as is possible within reasonable constraints of cost and time, that the module is capable of withstanding prolonged exposure in climates described in the scope. The actual lifetime expectancy of modules so qualified will depend on their design, their environment and the conditions under which they are operated.2 Normative ReferencesThe provisions in following documents become the essential provisions of this Document through reference in this Document. For the dated documents, only the versions with the dates indicated are applicable to this Document; for the undated documents, only the latest version (including all the amendments) is applicable to this Document. GB/T 2421-1989 Basic environmental testing procedures for electric and electronic products - General and guidance (eqv IEC 68-1:1988) GB/T 2423.3-1993 Basic environmental testing procedures for electric and electronic products - Test Ca: Damp heat, steady state (eqv IEC 68-2-3:1984) GB/T 2423.29-1982 Basic environmental testing procedures for electric and electronic products -Test U: robustness of terminations and integral mounting devices (eqv IEC 68-2- 21:1980) GB/T 2828-1987 Sampling procedures and tables for lot-by-lot inspection by attributes (Apply to inspection of successive lots or batches) GB/T 4797.1-1984 Environmental conditions appearing in nature of electric and electronic products; Temperature and humidity GB/T 6495.1-1996 Photovoltaic devices - Part 1: Measurement of photovoltaic current-voltage characteristics (idt IEC 904-1:1987) GB/T 6495.3-1996 Photovoltaic devices - Part 3: Measurement principles for terrestrial photovoltaic (PV) solar devices with reference spectral irradiance data (idt IEC 904-3:1989) GB/T 6495.4-1996 Procedures for temperature and irradiance corrections to measured I-V - characteristics of crystalline silicon photovoltaic devices (idt IEC 891:1987) Amendment No.1 (1992) IEC 904-9:1996 Photovoltaic device – Part 9: Solar simulator performance requirements QC 001 002:1986 Rules of Procedure of the IEC Quality Assessment System for Electronic Components (IECQ) Amendment No.1(1992)3 SamplingEight modules for qualification testing (plus spares as desired) shall be taken at random from a production batch or batches, in accordance with the procedure given in GB/T 2828. The modules shall have been manufactured from specified materials and components in accordance with the relevant drawings and process sheets and have been subjected to the manufacturer's normal inspection, quality control and production acceptance procedures. The modules shall be complete in every detail and shall be accompanied by the manufacturer's handling, mounting and connection instructions, including the maximum permissible system voltage. When the modules to be tested are prototypes of a new design and not from production, this fact shall be noted in the test report (see Clause 8).4 MarkingEach module shall carry the following clear and indelible markings: - name, monogram or symbol of manufacturer; - type or model number; - serial number; - polarity of terminals or leads (color coding is permissible); - maximum system voltage for which the module is suitable. The date and place of manufacture shall be marked on the module or be traceable from the serial number.5 TestingThe modules shall be divided into groups and subjected to the qualification test sequences in Figure 1, carried out in the order laid down. Each box refers to the corresponding subclause in this standard. Test procedures and severities, including initial and final measurements where necessary, are detailed in Clause 10. NOTE: Where the final measurements for one test serve as the initial measurements for the next test in the sequence, they need not be repeated. In these cases, the initial measurements are omitted from the test. In carrying out the tests, the tester shall strictly observe the manufacturer's handling, mounting and connection instructions. Test given in 10.4 may be omitted if the temperature coefficients α and β are already known. Test conditions are summarized in Table 1.6 Pass CriteriaA module design shall be judged to have passed the qualification tests, and therefore to be IEC type approved, if each test sample meets all the following criteria: a) the degradation of maximum output power at standard test conditions (STC) does not exceed the prescribed limit after each test nor 8 % after each test sequence; b) no sample has exhibited any open-circuit or ground fault during the tests; c) there is no visual evidence of a major defect, as defined in Clause 7; d) the insulation test requirements are met after the tests. If two or more modules do not meet these test criteria, the design shall be deemed not to have met the qualification requirements. Should one module fail any test, another two modules meeting the requirements of Clause 3 shall be subjected to the whole of the relevant test sequence from the beginning. If one or both of these modules also fail, the design shall be deemed not to have met the qualification requirements. If, however, both modules pass the test sequence, the design shall be judged to have met the qualification requirements. 10.2 Performance at STC 10.2.1 Purpose To determine how the electrical performance of the module varies with load at STC (cell temperature: 25°C±2°C, irradiance: 1000 W•m-2, standard solar spectral irradiance distribution conforms to the provisions of GB/T 6495.3) using natural sunlight or a class A simulator conforming to the requirements of GB/T 6495.1. 10.2.2 Procedure Determine the current-voltage characteristic of the module at STC, in accordance with GB/T 6495.1. When necessary, make temperature and irradiance corrections in accordance with GB/T 6495.4. 10.3 Insulation test 10.3.1 Purpose To determine whether or not the module is sufficiently well insulated between current carrying parts and the frame. 10.3.2 Test conditions The test shall be made on modules at ambient temperature of the surrounding atmosphere (see GB/T 2421) and in a relative humidity not exceeding 75 %. 10.3.3 Procedure a) Connect the shorted output terminals of the module to the positive terminal of a D.C. insulation tester with a current limitation. b) Connect the exposed metal parts of the module to the negative terminal of the tester. If the module has no frame or if the frame is a poor electrical conductor, mount the module on a metallic simulated support structure, which is to be connected to the negative terminal of the tester. c) Increase the voltage applied by the tester at a rate not exceeding 500 V•s-1 to a maximum equal to 1 000 V plus twice the maximum system voltage (i.e., the open-circuit voltage of the system at STC). Maintain the voltage at this level for 1 min. If the maximum system voltage does not exceed 50 V, the applied voltage shall be 500 V. d) Reduce the applied voltage to zero and short-circuit the terminals of the tester for 5 min, while still connected to the module. e) Remove the short circuit. f) Apply a D.C. voltage of not less than 500 V to the module, with the tester connected as in steps a) and b). Determine the insulation resistance. 10.3.4 Test requirements - no dielectric breakdown (less than 50μA) or surface cracking during step c); - insulation resistance not less than 50 MΩ. 10.4 Measurement of temperature coefficients 10.4.1 Purpose To determine the temperature coefficients of current (α) and voltage (β) from module measurements. The coefficients so determined are valid at the irradiance at which the measurements were made. For linear modules, they are also valid over an irradiance range of ±30 % of this level. This procedure supplements that in GB/T 6495.4 for measuring these coefficients from a representative set of single cells. 10.4.2 Apparatus a) Solar simulator (class B or better), conforming to future standard IEC 904-9. Means to measure irradiance, short-circuit current and open-circuit voltage in accordance with Clause 2 of GB/T 6495.1-1996. NOTE: The use of a pulsed solar simulator is preferred, since it creates little additional heat that could affect the module during the measurement. If a steady-state simulator is used, it should be equipped with a shutter or equivalent means to minimize the period of irradiance to 0.5 s or less. b) Means to measure the surface or cell temperature of the module to an accuracy of ±0.5°C. c) A chamber capable of accommodating the module, equipped with a transparent window and means for evenly heating and cooling the contents over the temperature range of interest. 10.4.3 Procedure a) Determine the short-circuit current of the module at the desired irradiance at room temperature, in accordance with GB/T 6495.1. b) Mount the test module in the chamber and a suitable irradiance monitor outside the chamber within the simulator beam. Connect to the instrumentation. c) Close the chamber and· set the irradiance so that the test module produces the short-circuit current determined in item a). Use the irradiance monitor to maintain this irradiance setting throughout the test... the equilibrium mean solar cell junction temperature in the SRE, with the module mounted as recommended by the manufacturer. The second, called "the reference-plate method", is faster but is applicable only to PV modules of the type which respond to changes of ambient temperature (within restricted ranges of wind speed and irradiance) in the same way as the reference plates used in the measurement. Crystalline silicon modules with a glass front and plastic back are in this category. The reference plates are calibrated using the same procedure as in the primary method. 10.5.3 Primary method 10.5.3.1 Principle This method is based on gathering actual measured cell temperature data under a range of environmental conditions including the SRE. The data are presented in a way that allows accurate and repeatable interpolation of the NOCT. The temperature of the solar cell junction (TJ) is primarily a function of the ambient temperature (Tamb), the average wind speed (v) and the total solar irradiance (G) incident on the active surface of the module. The temperature difference (TJ - Tamb) is largely independent of the ambient temperature and is essentially linearly proportional to the irradiance at levels above 400 W·m-2. The procedure calls for plotting (TJ - Tamb) against G for a period when wind conditions are favorable. A preliminary NOCT value is then determined by adding 20 °C to the value of (TJ - Tamb) interpolated at the SRE irradiance of 800 W·m-2. Finally, a correction factor, dependent on the average temperature and wind speed during the test period, is added to the preliminary NOCT to correct it to 20°C and 1 m·s-1. 10.5.3.2 Apparatus The following apparatus is required: a) An open rack to support the test module(s) and pyranometer. in the specified manner (see 10.5.3.3). The rack shall be designed to minimize heat conduction from the modules and to interfere as little as possible with the free radiation of heat from their front and back surfaces. NOTE: In the case of modules not designed for open-rack mounting, the test module(s) should be mounted as recommended by the manufacturer. b) A pyranometer, mounted in the plane of the module(s) and within 0.3 m of the test array. c) Instruments to measure wind speed down to 0.25 m·s-1 and wind direction, installed approximately 0.7 m above the top of the module(s) and 1.2 m to the east or west. d) An ambient temperature sensor, with a time constant approaching that of the module(s), installed in a shaded enclosure with good ventilation near the wind sensors. e) Cell temperature sensors, attached by solder or thermally conductive adhesive to the backs of two solar cells near the middle of each test module, or other equipment necessary for IEC-approved measurement of cell temperature. f) A data acquisition system to record the following parameters within an interval of no more than 60s: irradiance; ambient temperature; cell temperature; wind speed; wind direction. Accuracy: the total accuracy of NOCT shall be ±1K. 10.5.3.3 Test module mounting Tilt angle: the test module(s) shall be positioned so that it is normal to the direct solar beam (within ±5°) at local solar noon. Height: the bottom edge of the test module(s) shall be 0.6 m or more above the local horizontal plane or ground level. Configuration: to simulate the thermal boundary conditions of modules installed in an array, the test module(s) shall be mounted within a planar surface that extends at least 0.6 m beyond the module(s) in all directions. For modules designed for free-standing, open-back installations, black aluminum plates or other modules of the same design shall be used to fill out the remaining open area of the planar surface. Surrounding area: there shall be no obstructions to prevent full irradiance of the test module(s) during the period from 4 h before local solar noon to 4 h after local solar noon. The ground surrounding the module(s) shall not have an abnormally high solar reflectance and shall be flat and level or sloping away from the test fixture in all directions. Grass, other types of vegetation, black asphalt or dirt are acceptable for the local surrounding area. 10.5.3.4 Procedure a) Set up the apparatus with the test module(s), as described in 10.5.3.3. Ensure that the test module(s) are open-circuited. b) On a suitable, clear, sunny day with little wind, record, as a function of time, the cell temperature, the ambient temperature, the irradiance, wind speed and wind direction. The reference plates shall be made of hard aluminum alloy to the dimensions shown in Figure 3. The front surface shall be painted matt black and the back surface gloss white. Means shall be provided for measuring the temperature of the reference plates to the required accuracy. One method employing two thermocouples is shown in Figure 3. One thermocouple is cemented into each branch of the milled groove with thermally conductive and electrically insulating adhesive, after removing any insulation for a distance of 25 mm from the junction. The remainder of the thermocouple wires are finally cemented into the groove with aluminum putty. At least three reference plates shall be made and calibrated, using the primary method described in 10.5.3. The steady-state temperatures so determined shall be within the range 46°C to 50°C and shall differ by no more than 1°C. One of the reference plates shall be kept unused as a control. Before making a NOCT measurement, the steady-state temperatures of the reference plates shall be checked against that of the control plate under the acceptable conditions indicated in item c) of 10.5.3.4 c) to detect any change in their thermal properties. If the measured temperatures of the reference plates differ by more than 1°C, the reason for this shall be investigated and necessary corrective action taken before proceeding with the test. 10.5.4.3 Test site Select a flat test site with negligible wind disturbance from buildings, trees and topographical features. Non-uniform reflections from the ground and objects behind the test lane shall be avoided. 10.5.4.4 Apparatus The following apparatus is required (see Figure 4). a) A number of reference plates, as described in 10.5.4.2 (one more than the number of modules to be tested simultaneously). b) A pyranometer or a PV reference device. c) An open rack to support the test module(s), reference plates and pyranometer so that they are normal to the direct solar beam (within ±5°) at local solar noon. Each module shall be closely flanked by two references plates, with the lower edge of the module (s) approximately 1 m above the ground. The rack shall be designed to minimize heat conduction from the module(s) and plates and to interfere as little as possible with the free radiation of heat from their front and back surfaces. d) Instruments to measure wind speed down to 0.25 m·s-1 and wind direction, installed approximately 0.7 m above the top of the module(s) and 1.2 m to the east or west, as shown in Figure 4. e) An ambient temperature sensor with a time constant approaching that of the modules, installed in a shaded enclosure with good ventilation near the wind sensors. 10.8 Outdoor exposure test 10.8.1 Purpose To make a preliminary assessment of the ability of the module to withstand exposure to outdoor coi;1ditions and to reveal any synergistic degradation effects which may not be detected by laboratory tests. NOTE: Caution should be taken in making absolute judgements about module life on the basis of passing this test because of the shortness of the test and the environmental variability of the test conditions. This test should only be used as a guide or indicator of possible problems. 10.8.2 Apparatus a) a solar irradiation monitor, accurate to ±10 %; b) means to mount the module, as recommended by the manufacturer, co-planar with the irradiation monitor. 10.8.3 Procedure a) Short-circuit the module and mount it outdoors, as recommended by the manufacturer, co-planar with the irradiation monitor. Any hot-spot protective devices recommended by the manufacturer shall be installed before the module is tested. b) Subject the module to an irradiation totaling 60 kW·h·m-2, as measured by the monitor, under conditions conforming to general open-air climates, as defined in GB/T 4797.1. 10.8.4 Final measurements Repeat tests 10.1, 10.2 and 10.3. 10.8.5 Requirements - no evidence of major visual defects, as defined in clause 7; - the degradation of maximum output power at STC shall not exceed 5 % of the value measured before the test; - insulation resistance shall meet the same requirements as for the initial measurements. 10.9 Hot-spot endurance test 10.9.1 Purpose To determine the ability of the module to withstand hot-spot heating effects, e.g., solder melting or deterioration of the encapsulation. This defect could be provoked by cracked or mismatched cells, interconnect failures, partial shadowing or soiling. 10.9.2 Hot-spot effect Hot-spot heating occurs in a module when its operating current exceeds the reduced short- circuit current of a shadowed or faulty cell or group of cells within it. When such a condition occurs, the affected cell or group of cells is forced into reverse bias and must dissipate power, which can cause overheating. Figure 6 illustrates the hot-spot effect in a module consisting of a series string of cells, one of which, cell Y, is partially shadowed. The amount of power dissipated in Y is equal to the product of the module current and the reverse voltage developed across Y. For any irradiance level, maximum power is dissipated in the short-circuit condition, when the reverse voltage across Y is equal to the voltage generated by the remaining (S - 1) cells in the module. This is shown in Figure 6 by the hatched rectangle constructed at the intersection of the reverse I-V characteristic of Y with the image of the forward I-V characteristic of the (S - 1) cells. Because the reverse characteristic can vary considerably from cell to cell, it is necessary to classify cells as voltage-limited (type A) or current-limited (type B), according to how the reverse characteristic intersects the "test limit zone" shown in Figure 7. The maximum power consumption situation of a damaged or shaded cell shown in Figure 6 belongs to Type-A. This situation occurs when the reverse curve and the image of the forward I-V curve of (S-1) cells intersect at the maximum power point. In contrast, Figure 8 shows that the maximum dissipation in a type B cell occurs when it is fully shadowed. But it should be noted that, in this case, the dissipated power may be only a fraction of the total power available from the module. 10.9.3 Classification of cell interconnection Solar cells in a PV module are connected in one of the following ways: Case S: series connection of s cells in a single string (Figure 6); Case SP: series-parallel connection, i.e., a parallel connection of P strings, each with S cells in series (Figure 9); Case SPS: Series-parallel-series connection, i.e., a series connection of B blocks, where each block consists of a parallel connection of P strings, each with S cells in series (Figure 10). By-pass diodes, if present, limit the reverse voltage of the enclosed cells and therefore define the part of the circuit to be tested. Each configuration requires a particular hot-spot testing procedure. The maximum internal power dissipation occurs with the module short-circuited. 10.9.4 Apparatus a) Radiant source 1. Steady-state solar simulator or natural sunlight capable of an irradiance of not less than 700 W·m-2 with a non-uniformity not more than ±2 % and a temporal ......Source: Above contents are excerpted from the full-copy PDF -- translated/reviewed by: www.ChineseStandard.net / Wayne Zheng et al. |
