This document sets out general guidelines and recommendations for the design and installation of ground-mounted photovoltaic (PV) power plants. A PV power plant is defined within this document as a grid-connected, ground-mounted system comprising multiple PV arrays and interconnected directly to a utility\u2019s medium voltage or high voltage grid. Additional criteria is that PV power plants are restricted from access by non-qualified persons and are continuously monitored for safety and protection, either by on-site personnel or by active remote monitoring. Technical areas addressed are those that largely distinguish PV power plants from smaller, more conventional installations, including ground mounted array configurations, cable routing methods, cable selection, overcurrent protection strategies, equipotential bonding over large geographical areas, and equipment considerations.<\/p>\n
Safety and design requirements are referenced to the applicable requirements of IEC 62548 to address distinct differences relative to the design requirements for residential, commercial and other non-power plant applications. In general, existing standards are referenced wherever possible for uniformity. Emphasis is placed on systems employing d.c. string based systems using large scale central inverters or 3-phase string inverters, but relevant sections are also applicable to systems employing a.c. modules or d.c.\/d.c. converters. Medium voltage transformers, switchgear, collection systems, substations, utility interconnection, auxiliary loads, energy storage systems, and communication services are addressed, but discussion is mostly limited to recommended references to other standards and requirements.<\/p>\n
Rooftop-mounted systems, building integrated PV (BIPV) and building applied PV (BAPV) are not included in the scope of this document. The principles of restricted-access power plants are not compatible with systems on buildings, which are used for purposes other than power generation.<\/p>\n
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| 2<\/td>\n | undefined <\/td>\n<\/tr>\n | ||||||
| 4<\/td>\n | CONTENTS <\/td>\n<\/tr>\n | ||||||
| 7<\/td>\n | FOREWORD <\/td>\n<\/tr>\n | ||||||
| 9<\/td>\n | INTRODUCTION <\/td>\n<\/tr>\n | ||||||
| 10<\/td>\n | 1 Scope 2 Normative references <\/td>\n<\/tr>\n | ||||||
| 13<\/td>\n | 3 Terms and definitions 4 Compliance with IEC 62548 <\/td>\n<\/tr>\n | ||||||
| 14<\/td>\n | 5 PV array system configuration 5.1 General 5.2 Earthing configurations 5.2.1 General 5.2.2 Use of un-earthed d.c. circuits 5.2.3 Use of high-ohmic earthed d.c. circuits 5.2.4 Use of functionally earthed d.c. circuits 5.3 Array electrical diagrams 5.3.1 General <\/td>\n<\/tr>\n | ||||||
| 15<\/td>\n | 5.3.2 Multiple sub-array configurations Figures Figure 1 \u2013 PV array diagram \u2013 multiple parallel string case with array divided into sub-arrays <\/td>\n<\/tr>\n | ||||||
| 16<\/td>\n | Figure 2 \u2013 PV array example using a PCE with multiple MPPT d.c. inputs <\/td>\n<\/tr>\n | ||||||
| 17<\/td>\n | 5.3.3 Single array configuration Figure 3 \u2013 PV array using a PCE with multiple d.c. inputs internallyconnected to a common d.c. bus <\/td>\n<\/tr>\n | ||||||
| 18<\/td>\n | 5.3.4 Combiner boxes and string wiring harnesses 5.3.5 Series-parallel configuration Figure 4 \u2013 PV array diagram \u2013 multiple parallel string example <\/td>\n<\/tr>\n | ||||||
| 19<\/td>\n | 5.4 Energy storage in PV power plants 5.5 Array physical configurations 5.5.1 Fixed tilt arrays 5.5.2 Adjustable tilt arrays Figure 5 \u2013 Example power plant with fixed tilt array <\/td>\n<\/tr>\n | ||||||
| 20<\/td>\n | 5.5.3 Single axis tracking arrays 5.5.4 Two-axis tracking arrays 5.5.5 Concentrating PV arrays 5.5.6 Central inverter configurations <\/td>\n<\/tr>\n | ||||||
| 21<\/td>\n | 5.5.7 String or module inverter configurations Figure 6 \u2013 Example layout of power plant central inverter based array <\/td>\n<\/tr>\n | ||||||
| 22<\/td>\n | 5.6 Mechanical design 5.6.1 Mechanical loads on PV structures 5.6.2 Wind 5.6.3 Snow 5.6.4 Thermal expansion 5.6.5 Flooding Figure 7 \u2013 Example layout of power plant with string inverters <\/td>\n<\/tr>\n | ||||||
| 23<\/td>\n | 5.6.6 Seismic activity 5.6.7 Corrosion 5.6.8 Access 6 Safety issues 6.1 General <\/td>\n<\/tr>\n | ||||||
| 24<\/td>\n | 6.2 Restricted access 6.2.1 General 6.2.2 Access to components 6.3 Protection against overcurrent 6.3.1 DC overcurrent protection devices 6.3.2 Requirement for string overcurrent protection 6.3.3 String overcurrent protection sizing <\/td>\n<\/tr>\n | ||||||
| 25<\/td>\n | 6.3.4 PV sub-array and array overcurrent protection <\/td>\n<\/tr>\n | ||||||
| 26<\/td>\n | 6.4 Protection against the effects of insulation faults 6.5 Protection against effects of lightning and overvoltage 6.5.1 Lightning protection <\/td>\n<\/tr>\n | ||||||
| 27<\/td>\n | Figure 8 \u2013 Example ground plan for equipotential bondingof a PV array field <\/td>\n<\/tr>\n | ||||||
| 28<\/td>\n | 6.5.2 Protection against overvoltage 6.6 Protection against fire 6.6.1 Earth-fault protection 6.6.2 Protection against arcing currents 7 Selection and erection of electrical equipment 7.1 General <\/td>\n<\/tr>\n | ||||||
| 29<\/td>\n | 7.2 PV array design voltage 7.2.1 PV array maximum voltage 7.2.2 Considerations due to inverter MPPT voltage window 7.2.3 Considerations due to inverter efficiency 7.3 Component requirements 7.3.1 General <\/td>\n<\/tr>\n | ||||||
| 30<\/td>\n | 7.3.2 PV combiner boxes <\/td>\n<\/tr>\n | ||||||
| 31<\/td>\n | 7.3.3 Disconnectors and switch-disconnectors <\/td>\n<\/tr>\n | ||||||
| 32<\/td>\n | 7.3.4 Cables <\/td>\n<\/tr>\n | ||||||
| 34<\/td>\n | Figure 9 \u2013 Example of above-ground cable tray configurations for PV plants <\/td>\n<\/tr>\n | ||||||
| 36<\/td>\n | Figure 10 \u2013 Example trench diagram with cables in ducts <\/td>\n<\/tr>\n | ||||||
| 37<\/td>\n | Figure 11 \u2013 Example trench diagram with direct buried d.c.and communication cables <\/td>\n<\/tr>\n | ||||||
| 38<\/td>\n | Figure 12 \u2013 Example trench diagram with direct buried medium voltage a.c.and communication cables <\/td>\n<\/tr>\n | ||||||
| 39<\/td>\n | 7.3.5 Trackers 8 Acceptance 8.1 General 8.2 Monitoring 8.3 Commissioning tests 8.4 Preliminary performance acceptance test 8.5 Final performance acceptance test <\/td>\n<\/tr>\n | ||||||
| 40<\/td>\n | 9 Maintenance 10 Marking and documentation 10.1 General 10.2 Labelling and identification 10.2.1 General 10.2.2 Labelling of disconnection devices and combiner boxes 10.3 Documentation <\/td>\n<\/tr>\n | ||||||
| 41<\/td>\n | 11 Medium and high voltage a.c. systems 11.1 General 11.2 Selection of a.c. collection system voltage 11.3 Collection system configurations 11.3.1 General 11.3.2 Radial systems <\/td>\n<\/tr>\n | ||||||
| 42<\/td>\n | 11.3.3 Loop systems 11.4 Medium or high voltage transformers 11.4.1 Transformer types 11.4.2 Installation <\/td>\n<\/tr>\n | ||||||
| 43<\/td>\n | 11.4.3 Protection 11.5 Medium or high voltage switchgear and stations 11.5.1 General 11.5.2 Switchgear specifications 11.6 Medium voltage cable <\/td>\n<\/tr>\n | ||||||
| 44<\/td>\n | 11.7 Utility interface 12 Auxiliary power systems 13 Communications systems 13.1 General 13.2 Data sampling speed requirements <\/td>\n<\/tr>\n | ||||||
| 45<\/td>\n | Annex A (informative)Inverter application considerations in PV power plants A.1 General A.2 Advantages and disadvantages of central inverters A.3 Advantages and disadvantages of string inverters <\/td>\n<\/tr>\n | ||||||
| 46<\/td>\n | A.4 Issues affecting inverter size A.4.1 PV array output A.4.2 Inverter ratings A.4.3 Inverter output control requirements A.4.4 PV power to inverter power ratio (PVIR) <\/td>\n<\/tr>\n | ||||||
| 48<\/td>\n | Bibliography <\/td>\n<\/tr>\n<\/table>\n","protected":false},"excerpt":{"rendered":" Ground-mounted photovoltaic power plants. Design guidelines and recommendations<\/b><\/p>\n |