How fast can an inverter shut off if a relay closes off the grid.

[Andy]

I've read before that the Quattro/MP can react faster if its using a CT (a standard 100A/50mA model AIUI - wired into the current sense terminals) rather than an external meter (via RS485 I guess?). Have you tried this?

Hi. The new multiplus has an option for a 100amp Ct clamp. Unfortunately the largest I can find for the Quattro is a 40 amp one. That is about half of what I need.

[Caesium]

Ah thats a shame. Was worth a thought.

[Countrypaul]

I've read before that the Quattro/MP can react faster if its using a CT (a standard 100A/50mA model AIUI - wired into the current sense terminals) rather than an external meter (via RS485 I guess?). Have you tried this?

Hi. The new multiplus has an option for a 100amp Ct clamp. Unfortunately the largest I can find for the Quattro is a 40 amp one. That is about half of what I need.

Have you tried asking Victron as there is a good chance the one for the Quattro might be the same.

[Andy]

To be fair I haven’t. I was just going by one of their tech sheets. It seems odd to stop at 40amp with such big inverters available. I’ll give them a shout.

I don’t think the multiplus ii one is compatible.

[sharpener]

I am in the latter stages of a Victron Quattro install and was going to put a SolarEdge inverter I already own on the output side of the Quattro. In the event of a power cut the idea being that when the battery is full and the inverter is at max power the Quattro would raise the frequency and then the SolarEdge would throttle its output. This is an advertised service.

Unfortunately and fortunately I tested the response to a raised frequency and it didn't work at all. So in the process of working out where to put the inverter I am looking at the dropped loads side of the Quattro. AC Out 2. In the event of a power cut, a relay is closed cutting off AC Out 2. I have my heat pump and car charger on this circuit. I was wondering what happens to the voltage etc if a circuit is cut off like that with inverter going at max power. Assume also the charger and heat pump are in idle mode. Is there a dangerous spike in voltage as there is no where for the power to go? Or is the shut off in these inverters so fast it isn't an issue? Thanks

edit-My thought logic would suggest it is a safe thing to do or it would be very easy to damage all the equipment in a house if the main breaker was shut off whilst exporting with low loads. But if anyone has anything to add that would be great. The other alternative would be on the AC IN side but I want to avoid that as there appears to be a flaw in the Victron Quattro which means that it is very slow to respond to load changes if there is anything connected on the input(grid) side.

I got this to work eventually with my Steca Inverters after a close study of their frequency response data, even though I don't think they were designed for this application.

With too much PV in island mode the Multi trips them by over-frequency, it takes about 5 mins running on battery for the freq to decay back to 50 Hz and the PV inverters to synchronise again, then after a further 5 mins the battery is full and the cycle repeats ad nauseam. A quick look at the SE application note in yr link doesn't reveal any comparable freq response vs trip time data but I am sure it is out there somewhere. As the circuitry in the Quattro is quite similar to the Multi I would have thought you had good chance of getting it to work if the SE inverter complies with any standards for freq response, maybe you can set it to a different country code to get a more favourable characteristic?

The shorter reaction time with a CT is discussed at some length on the Victron community pages and seems to be well attested. Someone there will probably know the turns ratio and burden resistor for the Victron types of CT and so you might be able to scale to 100A by using a third-party one, worth a posting there anyhow.

[Andy]

With too much PV in island mode the Multi trips them by over-frequency, it takes about 5 mins running on battery for the freq to decay back to 50 Hz and the PV inverters to synchronise again, then after a further 5 mins the battery is full and the cycle repeats ad nauseam. A quick look at the SE application note in yr link doesn't reveal any comparable freq response vs trip time data but I am sure it is out there somewhere. As the circuitry in the Quattro is quite similar to the Multi I would have thought you had good chance of getting it to work if the SE inverter complies with any standards for freq response, maybe you can set it to a different country code to get a more favourable characteristic?

The shorter reaction time with a CT is discussed at some length on the Victron community pages and seems to be well attested. Someone there will probably know the turns ratio and burden resistor for the Victron types of CT and so you might be able to scale to 100A by using a third-party one, worth a posting there anyhow.

Thanks Stinsy. The Solar Edge is supposed to be able to provide a nuanced response by setting the p(f) values to the top and bottom of a ramp. So with the Victron they are set at 50,2hz -100% and 51.3 -0% (from memory). The Victron is doing its bit from my end and slowly ramps up as the solar edge doesn't respond until it pegs at 51.3hz. The SolarEdge does nothing in response. The Victron tech note equivalent refers to the requirement to have a hidden back end menu item on the SolarEdge side changed to allow it to work. None of the tech support I have spoken to know what I am talking about. They think I have it set up correctly but obviously something still needs switching.

maybe you can set it to a different country code to get a more favourable characteristic?

This would be an option if I wasn't going to be grid connected. When the power trips the Quattro closes a relay which is connected to the SolarEdge and puts it into Diesel Generator mode. This APS function is then used to prevent back feeding the generator. I have heard that some countries don't require the back end function and some do.