Protecting ground mounted PV equipment from lightning strikes

[SolarCity]

We were called to a job today where all three SolarMax 15mt inverters have failed. No display on the inverter and it was around the time of a severe electric storm. We are to replace the three inverters but I wanted to offer him some protection.

Does anyone have any idea what kind of measures I should be taking. It's not something we've come across before.

 

[BruceB]

Nothing much will protect against a direct strike, but some surge protection would give you a fighting chance against local strikes. Also keep the area enclosed by cables as small as posssible. If Sibert is on he might be able to offer some advice as he stocks the kit.

 

[SolarCity]

Thanks Bruce. I don't think this was a direct strike as there are no signs of damage whatsoever. Just dead LCD screens and data logging showing that they failed during the storm.

 

[Gavin A]

Type 2 DC surge protection devices on the DC side, Type 2 on the AC (or type 1/2 combo units to protect against direct strikes on the grid side if it's pole mounted incoming supply).

Check how it's been wired. Need to have pos and neg cables run together, and ideally run below the panels to minimise the surface area between the 2 cables, as that's what governs the level of surge current that will be collected by the cables.

ABB have this integrated into their 20 and 27.7kW units as standard, SMA offer it as kits, but note that currently only Rexel hold stocks for the 20 and 25kW SMA units which are different to the tripower units...... and they only hold stocks because I pointed that out and asked them to supply them.

Or Sibert do add on kits for any set up

 

[SibertSolar]

Give me a buzz tomorrow if you want to chat Chris. All advice above is sound, although Type1 DC devices do exist which will protect the inverters from a direct strike on the DC side....sounds like you just need Type2 surge protection though....I've yet to come across many ground mount arrays where the design (or end client stipulatations) includes full Type1 protection....it adds quite a considerable cost to the system, but those costs have almost halved on the DC side recently tbh

 

[SolarCity]

Thanks Andy, I'll give you a call shortly.

 

[SolarCity]

Check how it's been wired. Need to have pos and neg cables run together, and ideally run below the panels to minimise the surface area between the 2 cables, as that's what governs the level of surge current that will be collected by the cables.

Good idea. The cabling is all over the place at the moment so I'll have a look at sorting that