– the reasons that led the designer to make changes to the indications contained in the preliminary design (eg changes to the nominal power of the system or the degree of architectural integration, etc.);
– the characteristics of the power supply of the building or structure on which the photovoltaic system is to be installed (eg contractual and / or committed power and the supply voltage);
– list of the constraints affecting the structure (landscape, architectural, urban planning, civic use, etc.) and the relative authorizations to be requested;
– the description of the criteria used for the design choices, with express reference to the individual points of the preliminary design report, the performance characteristics of the materials chosen (e.g. panels and inverters), as well as the design criteria of the systems with regard to safety and management;
– the system solutions adopted relating to electrical safety (for example prescriptions adopted for protection against direct, indirect contacts, etc.);
– indicates the costs for ordinary and extraordinary maintenance with particular regard to the maintenance of the inverters;
– economic framework of the work complete with the costs for the construction of the plant (tailor-made, lump sum, cost-effective work), the estimate of the costs for safety, and the sums available to the administration divided into items relating to unforeseen events, technical expenses, VAT and any other taxes, connections.
The plans and any sections refer to the planimetric drawings showing the location of the photovoltaic panels (plan and section view), the route of the main electrical conduits, the technical rooms where the equipment serving the system, the characteristics of the components of the earthing system.
The wiring diagrams contain the basic information of the photovoltaic system and the functions performed by the individual components of the system. In particular, they can be single-line or multi-line system diagrams integrated in block diagrams. These diagrams show the interconnections between the available energy sources (electricity grid and self-production plant) and the development of the photovoltaic system.
The estimated metric calculation defines in more or less detail the characteristics and quantities of the system components and the relative price. Prices are mainly deducted from market prices plus overheads, business profit and installation costs.
The special tender specifications have the purpose of establishing the basic data for the execution of electrical systems and for the possible supply of materials. In public works, the special tender specifications are divided into the following two parts:
– administrative part: it contains the main contractual rules (for example time for carrying out the work, progress of the work, penalties to be applied, etc.);
– technical part: specifies the performance contents of the elements envisaged in the project, contains the description of the materials and components envisaged in the project.
The executive project integrates and completes the final project for the aspects envisaged in the following points. The executive level of the project must be drawn up in accordance with the preliminary and final design and if one of the previous design levels is missing, the executive project must develop the related topics.
The technical report is an evolution, with more detailed information, of the technical report of the final project. The report concerns the size and type of the electrical system and is the document that acts as a link between the various documents that make up the project.
The technical report, in addition to the information of the technical report of the final design, generally contains the following:
– sizing criteria with carrying over of the calculations obtained. The calculations to be reported refer to the section of the cables, the voltage drop, the fault current in the various points of the system, the levels of artificial lighting and in emergency conditions, etc .;
– description of the protection measures against overvoltages, choice and sizing criteria of the protection systems against atmospheric discharges;
– choice and sizing criteria of the systems and main electrical components in relation to the electrical parameters, the environmental conditions and use, the safety requirements required for environments subject to specific legislation by the CEI;
– economic picture of the work complete with the costs for tailor-made, lump-sum, economic work sums available to the customer for:
System diagrams show the main relationships or connections between the parts that make up a system and illustrate their function such as eg.