gbradford
New User
- Location
- Durham, NC
- Occupation
- Solar Grid Designer
Hello all,
I work with a startup company building solar microgrids in Nigeria. We've built a few grids in the 100 - 300kW range, and our grounding and lightning protection systems were set up by a local contractor. In the last year we've had lightning strikes at 2 of our sites, and I want to make sure our protection systems are really up to a good standard. I've looked through a lot of posts on this forum and elsewhere, and I'm seeing conflicting advice for how to best ground the entire solar+inverter system and how to best protect from lightning (without breaking the bank).
Our systems are all ground mount on relatively level ground with trees and buildings usually nearby. Some are within populated areas, and others are more removed. Each site has a small "grid house" that has rooms for the inverters and batteries.
An important note: While code compliance is generally useful, since code is not very regulated where we are installing, my goal is actual functionality vs code compliance. I want our grounding/lightning systems to work to protect people and equipment, not to comply with code regulations.
Here are my open questions:
1. Do we need to use ground lugs and bare copper wire to ground panel racks if the earth resistance measured on the racks themselves is already low?
2. If we do use bare copper and ground lugs to ground the panels, should we connect the copper wire to ground rods located near the panel arrays? Or should we connect the wire to the ground rods used to ground the inverters at the grid house? (The distance between the arrays and grid house varies, but can be from 5 to 100 meters)
3. Our default is to install 1x surge protective device (SPD) on each set of wires running between the panel arrays and inverters. Do we need additional lightning protection such as lightning rods or air terminals?
I know it's difficult to give exact answers without knowing the full setup of the systems, but any general principles and advice are appreciated! Again, the goal is functionality, not code compliance! Thanks in advance!
I work with a startup company building solar microgrids in Nigeria. We've built a few grids in the 100 - 300kW range, and our grounding and lightning protection systems were set up by a local contractor. In the last year we've had lightning strikes at 2 of our sites, and I want to make sure our protection systems are really up to a good standard. I've looked through a lot of posts on this forum and elsewhere, and I'm seeing conflicting advice for how to best ground the entire solar+inverter system and how to best protect from lightning (without breaking the bank).
Our systems are all ground mount on relatively level ground with trees and buildings usually nearby. Some are within populated areas, and others are more removed. Each site has a small "grid house" that has rooms for the inverters and batteries.
An important note: While code compliance is generally useful, since code is not very regulated where we are installing, my goal is actual functionality vs code compliance. I want our grounding/lightning systems to work to protect people and equipment, not to comply with code regulations.
Here are my open questions:
1. Do we need to use ground lugs and bare copper wire to ground panel racks if the earth resistance measured on the racks themselves is already low?
2. If we do use bare copper and ground lugs to ground the panels, should we connect the copper wire to ground rods located near the panel arrays? Or should we connect the wire to the ground rods used to ground the inverters at the grid house? (The distance between the arrays and grid house varies, but can be from 5 to 100 meters)
3. Our default is to install 1x surge protective device (SPD) on each set of wires running between the panel arrays and inverters. Do we need additional lightning protection such as lightning rods or air terminals?
I know it's difficult to give exact answers without knowing the full setup of the systems, but any general principles and advice are appreciated! Again, the goal is functionality, not code compliance! Thanks in advance!