Risk Assessment and Solar PV Systems
The recent floods here in Thailand got me thinking about Solar PV installations in low lying areas and whether a risk assessment should be included with all solar surveys. We are quite fortunate here in Thailand that we don’t get much bad weather like typhoons, strong winds, hale storms etc. Not like our close neighbour’s from the Philippines or Hong Kong! But we do get plenty of flooding! Seeing news pictures showing houses underwater or half-submerged got me thinking. What would be the consequence of this in regards to electrical safety?
Obviously, any submerged equipment would be written off in terms of damage, but what about electrical safety?
If a grid-tied system was installed and the utility switched off the power, the inverter and AC side would be shut down, but what about the DC side? Even if the Solar Inverter and DC isolators have been turned off, the Solar Array will still be live (during daylight hours). This is a major concern as you could face serious injury from electric shock. What about Solar Hybrid systems? Well, these could be more problematic as they would stay online, as they are supposed to do, during a power outage. This means that the connected loads and the Solar PV array would still be live and a potential source of electric shock.
“solar panels continue producing electricity even if your utility has cut off power to your property.”
What to do, what solutions are available?
Knowing what we know now, we can assess the property and area to see if it’s prone to flooding, then design the Solar PV Systems equipment location accordingly. Options could include installing the Solar PV System higher up, like on the second floor of a house or mounting the systems high up, which would mean servicing access would need a ladder. Consider installing a second DC isolation switch on the roof (or as close to the array as possible); that way, you can isolate the PV array entirely from the system. If you have a Solar Hybrid system and it looks like you may get flooded, shut down the system completely, even the backup power supply.
What to do after a flood?
If your Solar PV System gets wet or submerged after a flood, do not turn it back on. Call your local Solar PV System installer to come out and assess your system to see if it’s safe, can be repaired or will need to be replaced.