Does this "pattern" have a name? (Bad current regulation on AC inverter)

[ivanjh]

Background:
I recently had a grid tie solar system installed.
Intermittently (maybe when limited by available PV power?) it's generating noise on the mains lines that I can audibly hear in some devices and it's causing other devices to "malfunction" (relays in the microwave cycle when not actually "cooking").
Luckily, I'm equipped to trace the voltage/current for the inverter (images attached)
It seems to just "lose" its current regulation ability for periods.
The underlying 20kHz switching seems to stay during these events.
Current spikes correlate with voltage spikes - so I'm pretty sure the inverter is the source.
I'm not looking to repair the unit, or diagnose the internals.
I'm looking to provide this information to the supplier/distributor/manufacturer.

The question:
Does this "pattern/failure" have a name?
I'd label it "poor current regulation" but it seems more specific - suffering constant overshoot+undershoot.
Targeting a 1.0 Power Factor, it should be a sinusoidal current wave - so is this "tracking error"?
It's not really regular so I don't think "harmonics" would suit.
Or does the irregular nature just make it "noise"?

My googling has failed me, and any help is appreciated.

Warm Fuzzies,
Ivan

[Stephen_Pejak]

I would call it "intermitently noisy output". Inverters aren't simple devices and finding out wether the problem is in current or voltage regulation is hard. The reason being that, if you are using mostly resistive loads the current will always mirror the voltage.

[Jeroen3]

This looks weird. Not like an inverter at all.
Isn't it just arcing somewhere?

[fourtytwo42]

That's certainly very unusual, the name is probably somewhere along the lines of kaput!
You say installed, was that a known qualified PV installation company ?
What is the inverter make and model ?
What country are you talking about (local regulations) ?

My initial reaction would be a grid that is to soft, high impedance connection or even worse some kind of reactive connection.
I take it you have not fitted some kind of filtering components in your house ?
Do you have any nasty reactive loads connected ?
How are you measuring current, if with a shunt, what value ?

Sorry for all the questions but your post is a little bare

[jmelson]

Wow.  I wonder if the "bad" waveform is related to specific devices in the house operating.  I might guess that some unit with a nonlinear power supply might cause this.  Possibly a refrigerator or air conditioner with an inverter driven motor, or maybe an induction stovetop.  Also, think about LED lights and SCR dimmers.
Jon