PV*SOL for retrofit string redesign of existing rooftop PV system

[MONA]

Hello everyone,

I am currently working on a university project involving an existing large rooftop PV system.

The system consists of more than 13,000 PV modules in total, distributed across many strings, existing generator junction boxes (GAK) and inverter units.

Due to a requirement from a regulatory authority, several modules in the upper roof rows have to be removed because they extend beyond the roof ridge. As a result, parts of the existing PV generator field must be redesigned to remain compliant while minimizing energy losses.

My task is not to design a completely new PV system from scratch. Instead, I have to evaluate and optimize an existing installation after the removal of several hundred modules.

The project includes:

• analysis of the existing PV generator field,

• development and comparison of different retrofit solutions,

• redesign of the string layout,

• reassignment of strings to existing generator junction boxes (GAK),

• verification of electrical constraints such as string voltage, current, inverter limits and MPPT operating range,

• evaluation of whether existing cabling can continue to be used,

• consideration of possible shading effects,

• adaptation of the existing string monitoring system,

• and comparison of the technical and economic impacts of different solutions.

My question is:

Would PV*SOL Premium be a suitable tool for checking and validating such retrofit variants?

Or is this type of task usually better done manually, for example by using the existing string plans, module and inverter datasheets, Excel calculations, and separate electrical checks?

I am especially interested in how such retrofit projects are normally handled in practice:

Do engineers usually model the modified system in software, or do they mainly redesign the strings manually and then verify voltage, current and inverter limits separately?

I would be very grateful for any practical experience or recommendations.

Thank you very much.

[hotline_oh]

Hello,

Thank you for your inquiry.

PV*SOL is generally suitable for retrofit string redesign of existing rooftop PV systems, subject to the following limitations:

• The 3D visualization allows a maximum of up to 7,500 elevated modules or up to 10,000 roof-mounted modules. You can only simulate the entire system, comprising 13,000 modules, in the 2D planning tool. For 3D planning (including shading analysis), we recommend that you split your overall project into two or three sub-projects.
• There is also an area limitation. When planning with the Google Solar API or with a map section from another provider, you are limited to a size of 200 m x 200 m. If your overall system is larger, you will need to simulate sub-systems.
• When carrying out 3D planning, please follow our guidelines on dividing large systems into subsystems so that you can make changes at a later stage or create different retrofitting options.
• Save different retrofitting versions in separate project files. By selecting ‘File’ --> ‘Project Comparison’, you can compare the simulation results of up to 6 project versions.