Gen over frequency tripping sol-ark

[SolarJax]

Hi everyone.

Tldr: Does the generator need servicing?

The situation

We installed a 21kW system using two Sol-Ark 15k inverters. The house had an established 25kW generac generator with an ATS to power the house in an outage. He didn’t want batteries.

Per Sol-Ark’s instructions we interrupted the ATS output so it now runs through the inverters (in parallel electricity but separate for communication because there are no batteries).

The homeowners have lost power for a few minutes each day and not had power from the generator. I’m certain the generator turns on because I see AC Over Freq faults on the inverters.

I’ve already expanded the frequency range so the high frequency is 65 hz, but it keeps happening.

I’m trying to avoid adding a second ATS so the generator power bypasses the solar but it might be the only solution.

Considering the 55-65 hz range works for most generators, I suspect the generator needs a tuneup or repair. But I don’t want to send the homeowner on a wild goose chase.

I’d like to know if this is behavior that requires a Generac technician to troubleshoot. If it is truly hitting high frequency all the time, I’m inclined to say yes. But I want to feel confident in my recommendations.

Thoughts?

 

[jaggedben]

Sol Ark really supports PV and a generator in a microgrid with no batteries? Really?

 

[winnie]

Can you post a copy of the instructions for how to install these inverters with a generator?

The issue with using a generator and a PV system is that most PV systems are designed to always export excess PV production to the grid, and generators are not a grid capable of absorbing excess PV production. So _if_ this system is going to work, it has to have some mechanism of recognizing that the 'prime' AC supply is a small generator and then preventing excess PV production.

I am not a PV installer, and not familiar with your inverters, but in the instructions there should be some description of how the inverter prevents trying to export power to a generator.

-Jon

 

[SolarJax]

Sol Ark really supports PV and a generator in a microgrid with no batteries? Really?

Yes. I spoke with support twice before the install and at least once since then. The system knows there is no battery and knows that the grid input can also include a generator. This is the way they recommend installing it.

 

[SolarJax]

Can you post a copy of the instructions for how to install these inverters with a generator?

The issue with using a generator and a PV system is that most PV systems are designed to always export excess PV production to the grid, and generators are not a grid capable of absorbing excess PV production. So _if_ this system is going to work, it has to have some mechanism of recognizing that the 'prime' AC supply is a small generator and then preventing excess PV production.

I am not a PV installer, and not familiar with your inverters, but in the instructions there should be some description of how the inverter prevents trying to export power to a generator.

-Jon

Agreed. I've spoken with support multiple times. That does remind me to ask them if this requires additional CTs, because they never mentioned them.

There are settings to say that the generator is connected to the grid input and that there are no batteries.

This is the first time doing a setup like this with Sol-Ark. It would have been much simpler to have batteries but the homeowner is old and didn't want to spend the extra money, which I understand.

 

[pv_n00b]

Can you post a copy of the instructions for how to install these inverters with a generator?

In theory, it's possible for this to work but I have to wonder if Sol-Ark has many working installations. Since the homeowner does not want batteries I would just set up the system to run on the generator in backup mode and disconnect/shut down the PV system. If you have an aux contact on the ATS you can do it with that.

 

[winnie]

Sure looks like the installation requirements are different from what the op describes.

Either the generator gets connected to specific generator terminals on the inverter, or there are specific generator CTs installed and the inverter provides power only if the generator is loaded past a programmable threshold.

Jon