Does your PV system output instantly recover after an outage?

[CaptSpiff]

Question for you with PV installs (regular or micro inverter):

I noticed a youtube video where the homeowner closed the "disconnect/cutoff" for his home system, and it took almost 60 seconds for any effect to be noticeable on the meter. Once the inverters woke-up, the change in meter rotation from consuming to producing was only 2 seconds.

I'm wondering if all PV systems need time to "boot up" following any outage, and if this applies to even short blinks during wind storms?

 

[Where2]

My Enphase micro-inverters need 5 minutes of stable 60hz and voltage within tolerances before they will begin synchronized grid-tied output.

It's all about UL compliance. If the grid is unstable, you don't want grid tied systems back feeding into it. You also don't want to potentially injure any utility workers doing their job.

 

[peakbagger]

Agreed, the UL1741 requirements require a 5 minute wait time before reconnecting with the grid. Generally the protective relaying on the grid will try to clear a fault by resetting the fault once and then if the fault it still on the line it will take the line down for good. The 5 minute wait keep the inverters off line when this is occurring.

 

[CaptSpiff]

Thanks for those pointers. The UL1741 and IEEE1547 standards docs were exactly what I was looking for.
Once again the contributors here have been a great resource.

I've learned that inverters will need to see between 3 to 5 minutes of continuous high quality AC power from the Utility before they sync on and begin outputing power.
Any significant disturbance of Voltage or Frequency can cause an inverter to come offline or stay offline.

Since voltage spikes, dips and sags are what I see often, these are the parameters which interested me most:
The inverter will switch offline when the Utility voltage deviates below 88% or above 110% of nominal for greater than 2 seconds and 1 sec respectively.
The inverter will switch offline when the Utility voltage deviates below 50% or above 120% of nominal for greater than 0.16 seconds.

Now I need to find out what is considered "nominal" voltage.
Is it 110v that my grandfather remembers?
Is it 115v that my dad always called it?
Is it 120v we see on most of the equipment rating labels today?
Or is it the 122v I usually measure on my duplex outlets at home?

 

[Where2]

You're looking at line to neutral voltages. The inverters put out 240v as measured from L1 to L2.

When I look at the voltages my micro-inverters see throughout a day, they never see 110v, 115v, 122v. They see 238v, 240v, 244v.

If you're truly experiencing frequent sags, you may wish to have your panel connections, your meter can contacts and internal connections, and your drop to your residence checked by a licensed electrician and representatives from the power company. The power company has logging equipment to analyze power quality over time to help them determine if they have a problem supplying your house and your neighborhood with reliable service up to your meter. If the issue is on your side of the electric meter, it's your responsibility and expense to maintain it.