GB/T 16895.32-2021 English PDFUS$1104.00 · In stock
Delivery: <= 7 days. True-PDF full-copy in English will be manually translated and delivered via email. GB/T 16895.32-2021: Low voltage electrical installations - Part 7-712: Requirements for special installations or locations - Solar photovoltaic (PV) power supply systems Status: Valid GB/T 16895.32: Historical versions
Basic dataStandard ID: GB/T 16895.32-2021 (GB/T16895.32-2021)Description (Translated English): Low voltage electrical installations - Part 7-712: Requirements for special installations or locations - Solar photovoltaic (PV) power supply systems Sector / Industry: National Standard (Recommended) Classification of Chinese Standard: F12;P63 Word Count Estimation: 58,563 Issuing agency(ies): State Administration for Market Regulation, China National Standardization Administration GB/T 16895.32-2021: Low voltage electrical installations - Part 7-712: Requirements for special installations or locations - Solar photovoltaic (PV) power supply systems---This is a DRAFT version for illustration, not a final translation. Full copy of true-PDF in English version (including equations, symbols, images, flow-chart, tables, and figures etc.) will be manually/carefully translated upon your order. Low voltage electrical installations-Part 7-712.Requirements for special installations or locations-Solar photovoltaic (PV) power supply systems ICS 27.160;29.020;91.140.50 F12;P63 National Standards of People's Republic of China Replace GB/T 16895.32-2008 Part 7-712 of low-voltage electrical installations. Requirements for special installations or places Solar photovoltaic (PV) power system (IEC 60364-7-712.2017, IDT) Released on 2021-04-30 2021-11-01 implementation State Administration of Market Supervision and Administration Issued by the National Standardization Management Committee Table of contentsPreface Ⅴ Introduction Ⅶ 712 Solar Photovoltaic (PV) Power Supply Unit 1 712.1 Scope 1 712.2 Normative references 1 712.3 Terms and Definitions 3 712.31 Purpose, power supply and structure 7 712.4 Safety protection 14 712.41 Protection against electric shock 14 712.410 Introduction 14 712.412 Protective measures. double or reinforced insulation 14 712.414 Protective measures. use SELV and PELV extra low voltage 14 712.42 Protection against thermal effects 15 712.421 Protection against fire caused by electrical equipment 15 712.43 Protection against overcurrent 16 712.432 Protection of electrical characteristics 16 712.433 Protection against overload 16 712.434 Protection against short-circuit current 20 712.44 Protection against voltage interference and electromagnetic interference 20 712.443 Protection against atmospheric or operating transient overvoltage 20 712.444 Measures to prevent electromagnetic influence 21 712.5 Selection and installation of electrical equipment 21 712.51 General rules 21 712.511 Compliance with standards 21 712.512 Working conditions and external influences 21 712.513 Ease of maintenance 22 712.514 Identification 22 712.515 Prevention of mutual adverse effects 24 712.52 Wiring system 25 712.521 Wiring system type 25 712.522 Selection and installation of cabling systems involving external influences 27 712.523 current carrying capacity 27 712.524 Cross-sectional area of conductor 28 712.525 Voltage drop in user device 29 712.526 Electrical connection 29 712.527 Selection and installation of wiring systems to reduce the spread of fire 30 712.528 Distance between wiring system and other service facilities 30 712.529 Wiring system selection and installation involving maintainability (including cleaning) 30 712.530 Isolation, switching and control 30 712.531 Prevent indirect contact (fault protection) electrical appliances with automatic cut-off of power supply 30 712.532 Appliances to prevent thermal effects 33 712.533 Protective appliances to prevent overcurrent 33 712.534 Protective appliances to prevent transient overvoltage 34 712.536 Isolation and switch 36 712.54 Grounding configuration and protective conductor 37 712.542 Grounding configuration 37 712.55 Other equipment 37 712.6 Inspection and Testing 38 Appendix A (informative appendix) PV installation information 39 Appendix B (Normative Appendix) Calculation of UOCMAX and ISCMAX 42 Appendix C (informative appendix) Examples of marking 43 Appendix D (informative appendix) Isolating diode 44 Appendix E (informative appendix) Arc fault detection and interruption in PV square array 47 References 48 Figure 712.1 General functional configuration of PV installation 7 Figure 712.2 PV square matrix diagram---single string example 8 Figure 712.3 PV square matrix diagram---multi-group series-parallel example 9 Figure 712.4 PV square matrix diagram---several sub-square arrays that make up the square matrix are multiple sets of series and parallel connections 10 Figure 712.5 Use PV square matrix 11 with multiple MPPT DC input PCE Figure 712.6 Use a PV square array with multiple DC inputs PCE (each input is connected in parallel on the common DC bus inside the PCE) Figure 712.7 Example of PV array where strings are grouped and each group is protected by an overload protection appliance 18 Figure 712.8 An example of a logo indicating the presence of PV installations on a building 23 Figure 712.9 Example of a cable with reinforced protection 25 Figure 712.10 PV string wiring with minimum loop area 27 Figure A.712.1 Single string PV square array 39 Figure A.712.2 Multi-group series-parallel PV square array 40 Figure A.712.3 The ungrounded PV array is connected to the AC side through a PCE with a built-in transformer 41 Figure A.712.4 The ungrounded PV array is connected to the AC side through a PCE without a transformer 41 Figure A.712.5 The grounded PV square array is connected to the AC side through the PCE containing the transformer 41 Figure A.712.6 The grounded PV array is connected to the AC side through a PCE without a transformer and a separate transformer 41 Figure C.712.1 Example of the required symbols on the PV square matrix combiner box (712.514.102) 43 Figure C.712.2 Example of marking the PV switchboard symbol on a building 43 Figure D.712.1 The role of the isolation diode in the case of a short circuit in the PV string 44 Figure D.712.2 The role of the isolation diode when an insulation fault occurs in a PV installation with a grounded DC negative side 45 Figure D.712.3 The role of the isolation diode in the event of a fault in a PV installation with a grounded DC positive side 45 Figure E.712.1 Examples of arc types in PV square array 47 Table 712.1 Calculation of critical length Lcrit 20 Table 712.2 Minimum current rating of the circuit 28 Table 712.3 Requirements for different system types based on PCE isolation and PV square array functional grounding 30 Table 712.4 Minimum insulation resistance threshold for ground insulation fault detection 31 Table 712.5 Response time limit for sudden change of residual current 32 Table 712.6 The rated current of the automatic disconnector in the functional grounding conductor 33 Table 712.7 Impulse withstand voltage Uw 34 without relevant information Table 712.8 Breaking appliances required in PV square array device 36 Table A.712.1 PV DC configuration 40 Part 7-712 of low-voltage electrical installations. Requirements for special installations or places Solar photovoltaic (PV) power system 712 Solar Photovoltaic (PV) Power Supply Unit Note. "PV" is the abbreviation of the English word "Photovoltaic", which means "photovoltaic". In this section, "photovoltaic device" is abbreviated as "PV device". 712.1 Scope This part of GB/T 16895 is applicable to PV system electrical installations that supply power to electrical installations in whole or in part. Like any other equipment, for the equipment in the PV installation, only its choice and application in the installation are involved. The PV installation starts from a single PV module provided by the manufacturer or a group of PV modules connected in series with cables, until the user installation or municipal The part of the power supply point (common connection point). The requirements of this section apply to. ---PV installations not connected to the public power distribution system; ---PV devices connected to the public power distribution system grid-connected; ---PV installation as an alternative to the public power distribution system; --- Appropriate combination of the above. This section does not include specific installation requirements for battery packs or other energy storage equipment. Note 1.Additional requirements for PV devices equipped with battery energy storage on the DC side are under consideration. Note 2.This section includes the protection requirements for PV arrays due to the use of battery packs in PV installations. Additional requirements for the relevant voltage and current ratings, switches and protective appliances applicable to the use of DC-DC converter systems are under consideration. In addition to the hazards caused by traditional AC power devices, DC systems, especially PV arrays, will also bring some hazards. Included in small A situation in which an arc is generated and maintained under normal operating current conditions. The purpose of this part is to solve the design and safety requirements due to the characteristics of PV installations. All requirements. However, the safety requirements for grid-connected PV installations in this part mainly depend on the PV array and comply with IEC 62109-1 and Power Conversion Equipment (PCE) required by IEC 62109-2. 712.2 Normative references The following documents are indispensable for the application of this document. For dated reference documents, only the dated version applies to this article Pieces. For undated reference documents, the latest version (including all amendments) is applicable to this document. GB/T 16895.21-2011 Low-voltage electrical installations Part 4-41.Safety protection and electric shock protection (IEC 60364-4-41. 2005, IDT) IEC 60228 Conductors of insulated cables IEC 60269-6 Low-voltage fuses Part 6.Supplementary requirements for fuse-links for the protection of solar photovoltaic systems (Low-voltage fuses-Part 6.Supplementaryrequirementsforfuse-linksfortheprotectionofsolarphotovoltaicener- gysystems) IEC 60332-1-2 Tests for electric and optical cables under burning conditions Part 1-2.Vertical burning test for single insulated wires and cables 1kW premixed flame method test process (Testsonelectricandopticalfibrecablesunderfireconditions-Part 1-2.Testforverticalflamepropagationforasingleinsulatedwireorcable-Procedurefor1kWpre- 712.31.101.1.3.2 Each input has its own PCE with Maximum Power Point Tracking (MPPT) If each input circuit of the PCE provides independent MPPT control, the anti-overcurrent of each part of the square array connected to these input circuits Protection should consider feedback current. Each PV section connected to the input circuit (see Figure 712.5) can be treated as a separate PV square array. Should be set in each PV phalanx Isolation switch to provide isolation from PCE. The isolation switch of the PV square array can be integrated into an electrical appliance for normal mechanical operation. 712.31.101.1.3.3 PCE with multiple inputs (each input circuit is connected in parallel inside the PCE) If the input circuit of the PCE is connected in parallel to the common DC bus in the PCE, the PV part connected to each input circuit (see Figure 712.6) is regarded as a sub-square, and all these PV parts belong to a complete PV square. Should be set for each PV sub-array Isolation switch to provide isolation from PCE. This isolation function can also be provided by a shared PV square array isolation switch. 712.31.101.1.3.4 Series and parallel configuration All PV strings connected in parallel in the square array should have the same technical characteristics, and each string should be connected in series with the same number of PV modules (see Figure 712.2~ Figure 712.4), unless these components are individually set for MPPT tracking. In addition, all PV modules connected in parallel in the PV array should have similar Rated electrical performance, including short-circuit current, open circuit voltage, maximum power current, maximum power voltage and rated power (under standard test conditions), Unless these components are individually set up for MPPT tracking. This is a design issue considered by the project implementer, especially when replacing components or retrofitting already built PV installations. 712.31.101.1.3.5 Consideration of the expected failure situation in the PV array The source of the fault current of any device needs to be confirmed. Due to the characteristics of batteries, PV devices containing battery packs may have higher expected fault currents. In a PV installation without a battery pack, the photovoltaic cells (and the PV array formed therefrom) behave like electricity when a low-resistance fault occurs. Stream source. Therefore, even in the case of a short circuit, the fault current cannot be much larger than the normal full load current. The fault current depends on the number of strings, the location of the fault, and the irradiance level. Therefore, it is very important to perform short-circuit current detection in the PV square matrix. difficult. In PV installations, the fault current lower than the operating current of the protective device may still form an arc. 712.31.101.1.3.6 performance issues The performance of the PV array may be affected by many factors, including but not limited to. ---Overall or partial occlusion; ---The temperature rises; ---Cable voltage drop; ---Dust, soil, bird droppings, snow, industrial pollution, etc. cause dirt on the surface of the square array; ---PV module direction; ---PV module attenuation. The location of the PV array should be carefully selected.The shadows formed by nearby trees and buildings may be on the PV side at some time of the day. In battle. It is important to minimize any shadows as much as possible. Keep in mind that even a small shadow on the square will significantly limit its performance. In 712.515.101, the performance degradation due to temperature rise and the need for good ventilation are stated. It should be paid attention to as much as possible. The components remain cool. In the design process, the selection of the cables in the square array and the cables connected from the square array to the application circuit all affect the current carrying conditions of these cables. Voltage drop. This is particularly important in PV installations with low output voltage and high output current. Under the maximum load condition, the most The voltage drop from the remote component to the input terminal of the application circuit should not exceed 3% of the maximum power point voltage of the PV matrix. Dust, soil, bird droppings, snow and other pollution on the surface of PV modules can significantly reduce the output of the square array. Arrangements should be made to Clean these components regularly in case of heavy contamination. 712.4 Safety protection 712.4.101 Overview See Appendix B for the calculation methods of UOCMAX and ISCMAX. 712.4.102 Functional grounding (FE) of the live part on the DC side Due to functional reasons, some PV module technologies need to ground the live parts. If a transformer with electrical isolation between the primary and secondary windings is used to form the most basic simple separation between the AC side and the DC side, it is allowed Allow the functional grounding of the live part of the DC side of the PCE. The transformer can be located inside or outside the PCE. But should not connect the PCE The transformer winding is grounded, and the PCE should meet this requirement. The functional grounding of the live part should be implemented at a single point on the DC side, near the DC input end of the PCE or at the PCE itself. The ground is preferably located between the disconnecting device and the DC terminal of the photovoltaic PCE. At the same time, it should meet the requirements of 712.421.101.2.3. Cables used for functional grounding shall not be marked with a combination of green and yellow colors. Pink should be used. 712.41 Protection against electric shock 712.410 Introduction 712.410.101 Even if the grid is disconnected on the AC side or the PCE is disconnected on the DC side, the PV equipment on the DC side should be considered live. 712.410.3.5 The barriers described in Appendix B of GB/T 16895.21-2011 and the protective measures placed outside the reach of the arm should not be used. 712.410.3.6 The following protective measures described in Appendix C of GB/T 16895.21-2011 should not be used. --- Non-conductive places; ---Ungrounded local equipotential bonding; ---Electrical separation for supplying power to more than one electrical equipment. 712.410.102 One of the following protective measures should be used on the DC side. ---Double or reinforced insulation; ---Safety Extra Low Voltage (SELV) or Protective Extra Low Voltage (PELV). 712.412 Protective measures. double or reinforced insulation 712.412.101 The equipment used on the DC side such as PV modules, distribution boxes or distribution cabinets shall be Class II insulation specified in IEC 61140 Or equivalently insulated. 712.414 Protective measures. use SELV and PELV extra low voltage 712.414.101 If SELV and PELV protection measures are used on the DC side, UOCMAX should not exceed DC 60V. 712.414.102 The maximum voltage UOCMAX of the PV square matrix should be considered as a smooth DC voltage. 712.42 Protection against thermal effects 712.42.101 Fire safety of PV installations The national or local fire protection requirements shall be complied with. 712.421 Protection against fire caused by electrical equipment Note. Refer to Appendix E for arc fault detection and interruption in the PV array. 712.421.101 Protection against the effects of insulation faults 712.421.101.1 Protection against the effects of insulation failures in the PCE or when there is no simple separation on the AC side 712.421.101.1.1 Functional grounding of live parts on the DC side is not allowed. 712.421.101.1.2 Insulation failure occurs on the DC side, should. ---The AC side of the PCE is automatically disconnected, or; ---The faulty part of the PV array is automatically disconnected in the PCE. Note 1.Automatic disconnection can be implemented by PCE, see IEC 62109 (all parts). Note 2.Automatic disconnection can also be implemented by RCD. 712.421.101.1.3 When an insulation fault occurs on the DC side, an alarm shall be automatically issued (see 712.531.3.101.3). Note. If the PCE detects an insulation failure, according to the provisions of IEC 62109 (all parts), the alarm is issued by the PCE. 712.421.101.2 Protection against the effects of insulation failure when there is a simple separation in the PCE or on the AC side 712.421.101.2.1 allows the functional grounding of the live part of the DC side. 712.421.101.2.2 If the live part of the DC side is not functionally grounded, an insulation monitoring device (IMD) should be installed or the same Other electrical appliances that monitor the performance. Note. An inverter that meets the requirements of IEC 62109 (all parts) can be used to provide this function. 712.421.101.2.3 In addition to the application in the next paragraph, it shall provide a 712.532.102 requires an electrical appliance or electrical appliance combination that interrupts the current in the functional grounding conductor when an insulation fault occurs on the DC side. In addition, the root According to the requirements of 712.421.101.2.4, the appliance (or appliance combination) should also report to the police. When the functional ground is implemented by the resistor R that meets the formula (1), the provisions of the previous paragraph do not apply. R ≥ UOCMAX In (1) Where. In---the current value given in Table 712.6. Note 1.Due to functional reasons, it may be necessary to turn off the PCE immediately in the event of an insulation failure. If the live part of the DC side is functionally grounded through a resistor, an insulation monitoring device (IMD) or another type that can provide Electrical appliances that are also effectively monitored (see 712.531.3). Note 2.PCE conforming to IEC 62109 (all parts) can be used to provide this function. 712.421.101.2.4 An insulation failure on the DC side should automatically send an ala...... |
