Thread: Solar systems and mains failure

Being involved in the Rural Fire Service it has been found on a number of occasions that the lines from a house are live whilst the mains cable is laying on the ground and dead. These solar systems are backfeeding with no mains connected.

Originally Posted by Chucaro

Just a question with the purpose of learning something.
Are there available a kind of hybrid system that in the events of power black out (like in the cyclone affected areas) the solar system can start charging batteries so the house can have the own power via an inverter?

Yes indeed.
Something like this for example... Hybrid system

Grid connected battery backup systems are now becoming more common, though of course they're more expensive than a simple grid connected system.
They use a combined smart inverter/charger that keeps you battery bank topped up from solar or mains, and then feeds power from the battery to the house when the mains fails. It's like a big UPS, supplemented by solar.
See this forum on the subject... Grid tie solar systems with battery - Solar - Green tech

So when you buy your first electric Land Rover, (in the next 5 to 10 years), it will have a nice big battery that could be used to backup your house power if the mains goes down!

Alan

Yes all the linesmen at the distribution company in my area had to be retrained a couple of years ago to expect and check for 240 volts on the dead side of a mains failure.

Not so simple for them any more.
I wonder if the people with solar panels were billed for the retraining. I think not.
Regards Philip A

Impossible jimbo, unless it has been installed incorrectly or illegally.

Originally Posted by Vern

illegally.

i think you have hit the nail on the head

Originally Posted by Vern

Impossible jumbo, unless it has been installed incorrectly or illegally.

But if that it is the case, how they will get the power credits by the energy supplier?
I guess that have to be a lot of incompetence, negligence and perhaps brown paper bags to make it possible.

They won't be, will be using a non compliant inverter, or have installed the system themselves

Getting back to the OP.
While the regulator output and mains are working to supply power to the same circuit, and any excess from the regulator can be fed back into the mains, they are not actually connected directly together. There is some sensing gear between, or should be.

The situations of the "dead" lines being alive is either due to a fault/failure, or they were installed yonks ago and not updated, or they are dodgy/DIY installations.

The ability to have a stand-alone system that is topped up by the mains and can also be sold back to the mains is attractive, but I fear costly.

You can have an automatic/ or manual isolator/contactor system to allow safe generator use while the mains are down.

Or you can have a couple of leads handy to connect your fridge and freezer directly to your portable generator. Probably the easiest.

A generator or PV system big enough to run a full house with a heavy load is going to be big and costly.