Solar and 3 phase power

There are a few ways to check whether you have three phase or not.

Open your switchboard and look for three black fuses.(see picture above).
Check your 'Main Switch' and see if it has three breakers.
Single phase would be just one switch.
You could ring Synergy and ask them.

You are allowed to connect up to 10kW of solar inverter per phase, so 30kW in total.
Then you can connect up to 40kW of solar panels (108 x 370W)

In WA, until the recent drop of the feed in tariff to 3 cents, most people kept to the 5kW inverter limit. That limit, imposed by Synergy, says that if you exceed 5kW of inverter, then you get zero feed in tariff.

Now it's only 3 cents FiT, we are seeing many people consider larger systems.
They understand it is now a 'use it or lose it' situation, and that is why 'solar + battery' inverters are popular.

They aren't buying too many batteries yet, just preparing for the fast approaching day when we get forced onto 'Time of Use' (TOU) charging, and 3pm to 9pm power costs 60 cents or more.

Can I connect a single phase inverter to 3 phase supply?
In WA you must have the phases evenly balanced if you connect single phase inverters.

You could have a 3kW inverter on each phase, or even a 5kW. That's balanced.
You could have a 3kW and a 2kW, or 2 x 2.5kW. Close enough.
But, nothing larger than a 3kW inverter if that is ALL you are connecting.

The rules on the East Coast of Australia are different to ours.
10kW single phase inverters on 3 phase is fine for many electricity distributors.
Somtimes they insist on 'export limiting' the surplus to 5kW maximum.
In WA, we aren't allowed to export limit.

If I have a single phase inverter won't I lose money?
It's a perfectly logical question.
The inverter is on phase 1 for example, but many loads are on phases 2 and 3.
That's rather the point of three phase after all. Balanced loads, greater supply.

The electricity meter is the answer to most people's question of 'How?'
It varies a little across Australia but the principle is the same as it is in WA, as follows.

Firstly, the solar power would supply what it can to household loads on phase 1.
Any surplus would then flow to the electricity meter that would record that surplus as 'export'.
The power supplied to the loads on the other two phases would be recorded as 'import'.

But here is the 'light-bulb moment'.

Every ten minutes the meter adds up all the exports and imports, takes one from the other to reach a negative or postive 'net' amount across all the phases, therefore determining for that 10 minutes whether you owe them money or the other way around.

That's how a single phase inverter can work, without losing you money when it is only connected to one out of three phases, or for that mattter, if you had two single phase inverters on two phases. It simply doesn't matter.

The electricty meter, called a 'Net Meter' because it works out the 'net result every ten minutes' is why.

The Western Power description of this is explained in the highlighted red text at the bottom of the page.

What three phase solar inverters are there in Australia?
The really good quality three phase inverters are from Fronius, Huawei, SolarEdge and SMA. with the first three also offering 'hybrid' inverters in their range.

Hybrid inverters run the solar panels AND a battery.

Goodwe have a three phase hybrid, their ET range as do Sungrow with thr SH.ORT model.

If you are looking for a cheaper three phase solution then Growatt, Solis, SolaX, Solplanet, and Sofar have inverters that fit a tighter budget.
It's been my experience over the past ten years that cheaper inverters have a much higher failure rate than quality ones, which should surprise no-one. Whilst they are all covered by decent warranties, I'm not convinced the hassle of inverter changeouts is worth it to either you as the consumer or us as the retailer and installer.

The Western Power (WA) Rules

This is how Western Power officially describes how their meter works...

"The 3 phase meter measures the combined consumption and

generation across all three phases continuously - it does not distinguish

between phases and then takes the net after a set period (of 10 minutes).

If there is excess generation on one phase, and a load on another phase,

then the excess generation will supply that load. If there is still more power

required, then the customer will receive electricity from the network and it

will be recorded in the meter as purchased/imported electricity. But if

there is still excess generation after supplying all of the household load,

it will be sent out onto the network and recorded as sent out (or exported

onto the network), which is where the customer receives REBS and/or FiT

(or neither if they aren't eligible)."