Low Grid Voltage

Morning all. Looking for some advice. Couple of evenings ago I was using the air fryer and the led ceiling lights were flickering. Checked other rooms lights and they too were flickering. After about 10 minutes the flickering stopped , but it's happened sporadically ever since, not necessarily when under load.
I've checked in the portal under the inverter tab in the Grid data section, and noticed there have been quite a lot of spikes down to around 218v to 225v, then it shoots back up to 235-245v.
Would this 'grid data' be the actual grid or the A/C coming from the inverter, 5kW Gen1, to the house. What I'm really trying to do is determine if it's a grid problem or an inverter problem since the house runs mainly from the 9.5kW battery?
Thanks for your help, and I attach a pic from the portal this morning.

TimHutchings that's the grid supply voltage and frequency you are looking at above

When the voltage drops I have noticed LED lights flicker. In my case it was just before the power then went off.

Might be worth checking your DNO's website to see if there were any incidents in your area, mine has an interactive map you can search. But if it keeps happening then call the DNO and log a supply fault issue

geoffreycoan Thanks Geoff. Went onto the UK power networks website and submitted a form on the low voltage about an hour ago. Hopefully they'll get back to me soon. Just wasn't sure if I should be contacting my original installers if it was an inverter problem. I did have an EV Zappi put in by Octopus at the end of November, and also wondered if maybe one of the grid connectors was maybe a tad loose.
Thanks for your help.

TimHutchings 218V is still in spec so they won't do anything.

Spec is 230V +10%/-6% = 216V-253V

Edit - the vast majority of equipment is designed to work from 207-253V (ie 230V +/-10%).

I’ve had the same thing 3 times in the last couple of months, flickering lights, but nothing else affected. GE Portal showed fluctuating voltage and frequency, as low as 170v at one stage. I called the DNO and they actually came out, but by the time he got here it had resolved itself. He said there were no reports from any other houses in the area, and no faults visible at the Substation. He did say he’d come in and do some tests but it would involve turning the electricity off for a while. As it was 18.30 on a dark, wet January night, and dinner was cooking I turned down his offer!
I’m suspicious that the Battery may be to blame, possibly the EPS as the Kitchen, which is excluded from EPS wasn’t affected, but I have no idea how I’d investigate this further.

Well! That was efficient! Submitted a form on UK Power networks this morning telling them about the voltage spikes, and around 4pm they knocked on my door and within a few minutes had worked out the main 60 amp grid fuse was melting its holder. All now fixed with a new 100 amp unit.
Everything back to normal and a stable 240v input.

TimHutchings That'd certainly make things "flicker" 😃

Edit - might have been on its way out anyway but the EV charger probably helped it along.

Vestas I thought that was the Viagra! 🤣