“That’s because household inverters need to push voltages higher than the grid to be able to push solar onto the network.”
It says that here (which may be interesting for other reasons)
I have this scary vision of inverters having to push the voltage ever upwards as they export and so increase push the grid voltage.
I’m probably missing something.
Though it may be that by setting it to not export you give it a bit of a rest.
Yes, it’s a vectorial equation. In other words, phase angle difference comes into play, not just magnitude.
Hi Phil! I can’t think of a better person to enlighten us!
Has ‘retirement’ become reality?
It happens at times. In the Eastern parts of Namibia there were some farmers whose PV-inverters switched off over noon, because the voltage pushes over 265V during the day. The grid voltage was around 245V even at night, so if I have my information correct, they dropped a tap on a transformer somewhere and it all came right. But yes, now you know why the grid code has those limits in, and why a PV-inverter will disconnect if the voltage is above 253V (110%) for more than a minute or so. To stop contributing to the problem.
On top of that, it’s not as if the PV-inverter will just add more and more with no limit. They add a very small offset. You don’t need much, the grid impedance is quite low, and as always, I=V/R, or probably more correctly V/Z (impedance, which is a combination of resistive and inductive elements… I digress), so only a small V is needed.
@Phil.g00 , I actually asked an engineer about this, whether the feed-in is done purely by using a higher amplitude, or if it is also done by generating a sine wave that slightly leads the grid… dragging it along like the grid drags along a three phase motor so to speak… and apparently it is mostly done with the amplitude. Of course it can be made to lead/lag slightly if you’re doing power factor correction, but generally you want your feed-in current to be zero when the instantaneous voltage is zero (aka, when the sine wave goes through the zero point), and hence you will feed in in phase and use the amplitude to get it done.
But yes… AC is always a tad more complex 
Retirement is a reality, but my pension hasn’t come through yet.
Our area voltage, or the phase feeding my house is roughly at 246VAc, I can push back for a part of the morning, but when the sun hits all the panels, the system push my line voltage to 256 VAc, this happens at above 6kw feedback. The Zhiel does not like voltage above 253V and disconnects the grid from my system, one minute later, it closes the contactors and about 30 seconds after the Quattro reconnects to the grid, the volts is hight enough to cause the Zhiel to disconnect again. Repeating the process over and over.
See in the graph below, the longer and the harder the system feeds back, the higher the grid voltage becomes until it disconnects.
Now you can imagine what the volt drop is in an overhead bundle conductor if my little 15kva can increase the line voltage by 10 volts. the majority of the houses in my area is still being fed by overhead lines.
Edit: This is a good example of what you said in the original post. I think in my case, because of the large volt drop, the effect is more visible. The inverter needs to adjust the voltage constantly till it eliminate the line voltage drop and settle when it starts pushing against the grid itself.
