BS IEC 62548:2016
$215.11
Photovoltaic (PV) arrays. Design requirements
| Published By | Publication Date | Number of Pages |
| BSI | 2016 | 72 |
This International Standard sets out design requirements for photovoltaic (PV) arrays including DC array wiring, electrical protection devices, switching and earthing provisions. The scope includes all parts of the PV array up to but not including energy storage devices, power conversion equipment or loads. An exception is that provisions relating to power conversion equipment are covered only where DC safety issues are involved. The interconnection of small DC conditioning units intended for connection to PV modules are also included.
The object of this document is to address the design safety requirements arising from the particular characteristics of photovoltaic systems. Direct current systems, and PV arrays in particular, pose some hazards in addition to those derived from conventional AC power systems, including the ability to produce and sustain electrical arcs with currents that are not greater than normal operating currents.
In grid connected systems, the safety requirements of this document are however critically dependent on the inverters associated with PV arrays complying with the requirements of IEC 62109‑1 and IEC 62109‑2 .
Installation requirements are also critically dependent on compliance with the IEC 60364 series (see Clause 4).
PV arrays of less than 100 W and less than 35 V DC open circuit voltage at STC are not covered by this document.
PV arrays in grid connected systems connected to medium or high voltage systems are not covered in this document. Variations and additional requirements for large-scale ground mounted PV power plants with restricted access to personnel will also be addressed in IEC TS 62738 1 .
Additional requirements may be needed for more specialized installations, for example concentrating systems, tracking systems or building integrated PV.
The present international standard also includes extra protection requirements of PV arrays when they are directly connected with batteries at the DC level.
PDF Catalog
| PDF Pages | PDF Title |
|---|---|
| 4 | English CONTENTS |
| 7 | FOREWORD |
| 9 | 1 Scope and object 2 Normative references |
| 11 | 3 Terms, definitions, symbols and abbreviated terms 3.1 Terms, definitions and symbols |
| 18 | 3.2 Abbreviations 4 Compliance with IEC 60364 (all parts) 5 PV array system configuration 5.1 General |
| 19 | Figures Figure 1 – General functional configuration of a PV powered system |
| 20 | Figure 2 – PV array diagram – single string example |
| 21 | Figure 3 – PV array diagram – multiple parallel string example |
| 22 | Figure 4 – PV array diagram – multiple parallel string example with array divided into sub-arrays |
| 23 | Figure 5 – PV array example using a PCE with multiple MPPT DC inputs |
| 24 | Figure 6 – PV array example using a PCE with multiple DC inputs internally connected to a common DC bus |
| 26 | Figure 7 – PV string constructed using DC conditioning units |
| 28 | 5.2 Mechanical design |
| 30 | 6 Safety issues 6.1 General |
| 31 | 6.2 Protection against electric shock 6.3 Protection against thermal effects 6.4 Protection against the effects of insulation faults |
| 33 | Tables Table 1 – Requirements for different system types based on PCE isolation and PV array functional earthing |
| 34 | Table 2 – Minimum insulation resistance thresholds for detection of failure of insulation to earth |
| 35 | Table 3 – Rated current of automatic earth fault interrupting means |
| 36 | 6.5 Protection against overcurrent |
| 38 | Figure 8 – Example of a PV array diagram where strings are grouped under one overcurrent protection device per group |
| 40 | 6.6 Protection against effects of lightning and overvoltage |
| 41 | 7 Selection and erection of electrical equipment 7.1 General |
| 42 | 7.2 PV array maximum voltage 7.3 Component requirements Table 4 – Voltage correction factors for crystalline and multi-crystalline silicon PV modules |
| 46 | Table 5 – Minimum current rating of circuits |
| 47 | Figure 9 – Examples of reinforced protection of wiring |
| 50 | 7.4 Location and installation requirements |
| 51 | Table 6 – Disconnection device requirements in PV array installations |
| 53 | Figure 10 – PV array exposed conductive parts functional earthing/bonding decision tree |
| 54 | Figure 11 – Exposed conductive parts earthing in a PV array |
| 57 | Figure 12 – Examples of PV string wiring with minimum loop area |
| 58 | 8 Acceptance 9 Operation/maintenance 10 Marking and documentation 10.1 Equipment marking 10.2 Requirements for signs |
| 59 | 10.3 Identification of a PV installation 10.4 Labelling of PV array and PV string combiner boxes 10.5 Labelling of disconnection devices 10.6 Documentation |
| 60 | Annexes Annex A (informative) Examples of signs Figure A.1 – Example of sign required on PV array combiner boxes (10.4) Figure A.2 – Example of switchboard sign for identification of PV on a building |
| 61 | Annex B (informative) Examples of system functional earthing configurations in PV arrays Figure B.1 – System functional earthing/grounding |
| 62 | Figure B.2 – Examples different PV configurations in common use |
| 63 | Annex C (informative) Blocking diode C.1 Introduction C.2 Use of blocking diodes to prevent overcurrent/fault current in arrays C.3 Examples of blocking diode use in fault situations C.3.1 General C.3.2 Short circuit in PV string |
| 64 | Figure C.1 – Effect of blocking diode where there is a short circuit in PV string Figure C.2 – Effect of blocking diode where there is an earth fault on a system with earthing on the minus side |
| 65 | C.4 Specification of blocking diode C.5 Heat dissipation design for blocking diode Figure C.3 – Effect of blocking diode where there is an earth fault on a system with positive side earthing |
| 67 | Annex D (informative) Arc fault detection and interruption in PV arrays Figure D.1 – Examples of types of arcs in PV arrays |
| 68 | Annex E (normative) DVC limits Table E.1 – Summary of the limits of the decisive voltage classes |
| 69 | Bibliography |
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BS IEC 62548:2016 – TC:2020 Edition
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