From what you have said and your string voltages, it sounds like you have 2 strings with 8 panels on each string.
Just to go slightly into technical territory to explain it, you have 8 Longi 430W panels which can output 430W at 33.16V (that is their maximum power point voltage), they are in series so the voltage will be multiplied by 8.
So to do the maths 8 * 430W = 3,440W and the voltage they will be providing that at is (33.16V * 8) = 265.28V, the current flowing will be ( A = W/V ) which is 12.97A and the maximum current the FoxESS inverter will allow is 13.5A peak (so in theory you are in limits).
The voltage of 310V you are seeing is the panels open circuit voltage (39.43V) which is what happens when the inverter powers off the string (it goes open circuit)
Whilst their maximum current is just below the inverters maximum limit, the problem occurs because the panels are rated at 430W at 25C with 1000M3 of solar irradiance - they actually reduce in power as the temperature increases, but equally they are slightly more powerful as the temperature falls and so on a summers day they won't get much past their maximum power, but on a cold day at this time of year their power is just a little bit too high.
What that means is that panels produce more than the 13.5A limit the inverter has, and so the inverter will raise an alarm and shut the string down, as soon as the inverter works out that the power has fallen below it's maximum limit it will turn the string back on again, which is what you are seeing.
Whilst it sounds the same as clipping, it is a different thing - with clipping your panels are generating more power than the inverter is allowed to output (as you have an H1 5.0, your max power is 5 kW) so if you exceed 5kW the inverter will reduce the power point so that it maintains it's maximum power. What you are seeing is it exceed the maximum string current which results in an alarm and it turning off the string temporarily until it can safely turn it back on.
Ironically had the lower powered panels been installed you probably wouldn't have seen this problem.
So a couple of things to run through -
- It's not dangerous, the inverter is protecting itself from the over power limit and it will recover as soon as the power drops again.
- I would normally say speak to your installer about this to re-configure your strings, but as they are both maxed out there are no simple options, ideally the smaller panels would have been the better solution.
- But if it doesn't happen very often, and recovers quickly you should find that the problem reduces as the weather warms up and it likely won't happen at all in summer - in winter it won't happen either, it is just the 'goldilocks' point you are in at the moment with brand new panels, high solar elevation, strong sun but cold air temp and panels - so only likely to occur in April or October.
- As your panels age their power will (slowly) reduce, they will also get debris and dust on them, all of which will gradually reduce the maximum power they can ever achieve.
A few things to think about there, but if it doesn't happen too much and it gets better as we head towards summer - I would say leave it as it is, given a bit of time the panels won't be as good as they were when they were new so it shouldn't happen at all.
I would definitely mention it to your installer, they need to know and there maybe something they can do to limit it - but for the reasons I mentioned i'm hoping that the problem will remove itself naturally over time.