Three phase and solar


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?
All the inverter manufacturers have both single and three phase inverters.
Some are better quality than others.
Some can connect a battery, others can't.

The Fronius Symo range has been the most popular 'solar only' three phase inverter since 2014. Remarkably, as we move through early 2021 when I write this, it still is. Totally unchanged in seven years.
The reason for its success is simple.
Solar installers love it, so they 'push' nothing else.
It's VERY reliable, great to install, has many programming options, pretty decent WIFI reporting.
It's NOT 'Made in China', and now more than ever, that is a BIG selling point.
Made in Austria.

The Symo cannot connect to a battery, but the new Fronius Symo GEN24Plus can !!
The irony that it connects to Chinese BYD batteries is not lost on us.
I think everyone would prefer that Fronius had their own batteries.
Better integration, lots of extra sales revenue, but they don't.

Enter stage left, Huawei.
As Chinese as a Chinese company could be. Huge.
Smartphones, data, telecoms, and more, but No.1 in solar by a large margin.
48th on the fortune 500, and until recently the pawn in the China V USA Trump trade war.

Huawei have a 5kW and 6kW 'M1' model that connects to the Huawei Luna 5kWh to 30kWh battery.
We have had zero Huawei faults, and are into our 4th year selling and installing them.

It's a beauty. If Fronius re-badged it, no-one would ever buy anything else.

Huawei have 8kW, 10kW all the way to 50kW inverters, but none of the larger ones in Australia, at the moment, are 'hybrids, 'solar + battery'. Some of our customers have installed 2 x 5kW three phase Huawei to get a 10kW 'solar + battery'. That works fine.

Goodwe have their 'ET' range that goes from 5kW to 10kW, 'solar + battery' inverters. Good products in our opinion but lightweight 5 year warranty. Like Fronius, they connect to BYD batteries.

German SMA have their ever-faithful Tripower range, but like the similar vintage Fronius Symo, there is no battery connection.
There are fans of SMA...lots of them, but to me, if it was an SMA Tripower v Fronius Symo choice, and no other were considered, I would go Fronius.
Fronius are simply a more reliable inverter in our experience.

There are others.
Growatt, SolaX, Solis, Sungrow, Goodwe, Zeversolar (I think they are still around)
Typical price for the 'solar only' 5kW models of these brands is $1400 to $1500.

Huawei M1 'solar + battery' 5kW is $1,900, Fronius Symo or SMA Tripower $2,300, Fronius GEN24Plus, over $4,000 which can justify some of that extra price, but to me at least, it's a bit too exxy this time.

We often sell the cheaper basic models to people who aren't going to stay in that home much more than 5 years.


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)."