The ABC did a piece on high voltages across the network and we are getting a lot of enquiries about it.
A device called a SolarIQ from a company called Edge Electrons was proposed as a potential solution. These cost about $1500 installed.
Are they worth it?
At the moment I cannot comment either way. Here's why:
I have a SolarIQ (also called EdgeIQ) on my house, so I can evaluate it as a potential solution to overvoltage issues. But because I have a complicated installation (battery, backup circuits, micro inverters + 3 phase supply) it is not fully commissioned.
When it is fully commissioned I will post a full review - but I don't expect this until mid 2019.
If you do have high voltage issues - my advice is that voltage regulation devices on your home should be a last resort.
The first thing you should always do is check that the voltage rise is not caused by your solar system (specifically the cable to the grid being too thin).
Then your sparky should check the voltage of the local grid.
Those steps are described here:
My Inverter Keeps Tripping or Reducing Power On Over-voltage. What can I do?
If the above checks determine that the voltage issue is your local grid - you should do everything you can to get your local network to fix the grid - they have a legal obligation to. Get your local Energy Ombudsman involved if you have to.