A new technical material prepared by Canal Solar, GRUPO INTELLI and Professor Paulo Edmundo Freire propose updating the grounding design standard for photovoltaic plants, one of the most sensitive phases of large-scale projects.
The guide provides guidance based on standards, engineering techniques, and design decisions that directly impact the safety and performance of solar plants. Topics covered include soil resistivity mapping, geoelectrical modeling, and the correct specification of conductors and connectors, all of which are essential for a well-functioning grounding system.
The document also highlights a critical challenge: in large power plants, measurements of grounding resistance and step and touch voltages become impractical after construction is completed. Therefore, practical verification methods, such as continuity testing, become increasingly important in validating the installation.
The purpose of the material is to bring theory closer to field practice, offering support to designers, installers and operators seeking to reduce risks, avoid rework and ensure reliability in large-scale photovoltaic projects.
Manual outlines ideal grounding measures for large-scale photovoltaic plants
The team that prepared this manual proposes technical guidelines that modernize the way grounding is designed in photovoltaic power plants, with a special focus on ground-based plants above 1 MW.
The process begins with a detailed mapping of the soil resistivity parameter. As presented in the material, everything begins with the survey of soil resistivity and the construction of its geoelectrical model. For areas up to 20.000 m², the Brazilian standard NBR 7117 recommends between 2 and 16 measurement lines, but does not define parameters for larger areas, a gap that is addressed in this manual.
The limitation of direct measurements after the work
According to the content presented, for UFVs that occupy areas greater than 20.000 m², directly measuring grounding resistance and touch voltages throughout the installation becomes impractical after the UFV has been built.
This is because the necessary equipment must be extremely robust to cover such large scales, which is currently not commercially viable. Physical space constraints for measurements also often make this type of measurement unfeasible.
Recommended materials and their applications
Regarding practical electrical sizing, the guide indicates:
- For general areas of the GD plant: 50 mm² copper-plated steel conductors;
- In the measuring cabin: 50 mm² copper or copper-plated steel conductors.
Focus on pre-design and feasible testing
In this scenario, the project's focus falls on the stages prior to construction, namely the design and sizing phase. Once this stage is completed and the UFV is built, the commissioning phase begins, where it is crucial to verify the recommended tests.
In this case, for the UFV grounding system, conductor continuity tests and connection integrity verification are recommended. These two tests are considered strategic items during commissioning, since ground loop, touch voltage, and step tests are impractical, as previously mentioned.
Therefore, modeling and simulation work becomes critical: errors in calculation or parameter selection can lead to irreversible problems later. The message is that "measurement later" is not worth it; all resources and attention must be focused on the project.
Partnership and technical support
The document also cites GRUPO INTELLI as a supplier of a complete line of grounding materials, which, according to the authors, meets all regulatory requirements.
It is worth noting that this e-book was produced by GRUPO INTELLI in partnership with Canal Solar and with Professor Paulo Freire.
Click here and download the complete eBook.
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