Selecting g59 parameters on tri power inverters

[wozzit99]

Hi

In the process of in stalling a system with Sunny tripower inverter. DNO said no need for the g59 relay as long as the inverter has g59 settings selected.

The Sunny tri power was chosen because SMA have issued a certificate saying the inverter is g59 compliant.

After reading through the inverter manual I could not find the g59 parameter selection, only g83 (rotary selection 5 and 8).

Am i missing something here or do i have to put the g59 parameters in manually via comms?

Wozzit

 

[BruceB]

Good question. Hopefully someone here has done this recently. The implication of the G59 type test certificate is that there are some factory settings which become password locked. It may be that SMA just have not yet updated the installation manual. A call to SMA would be worthwhile.
Regards
Bruce

 

[SolarCity]

Aren't the G83 settings more strict than the G59 settings anyway? If the inverter was set up as G83 then wouldn't this satisfy G59 also?

I don't see the point of the G59 relay and I'm sure I must be missing something.

 

[BruceB]

That is the point, G59 settings are broader in order that the inverter does NOT disconnect from the grid during grid excursions. Large power sources disconnecting causes instability.

 

[SolarCity]

That's a fair point but on a scenario where inverters with G83 settings are used and they are then connected to G59 rates relays, surely the G59 relays would be redundant. The G83 settings of the inverter would mean that the inverter cut out before the G59 relays.

The DNO is saying that the G59 relay is not needed as long as the inverter is set to G59 settings, but surely this is nonsensical as a standard set up would be limited at G83 anyway?

 

[JD6400]

That's a fair point but on a scenario where inverters with G83 settings are used and they are then connected to G59 rates relays, surely the G59 relays would be redundant. The G83 settings of the inverter would mean that the inverter cut out before the G59 relays.

The DNO is saying that the G59 relay is not needed as long as the inverter is set to G59 settings, but surely this is nonsensical as a standard set up would be limited at G83 anyway?

Hi Biggs

This would be the case , but both Western Power and UK Power Networks have in the past asked us to open up the parameter settings on the the inverters to allow the G59 relay to take precedence on our 50kw plus systems , and this was checked by them at commissioning .
We have laid off the solar side for the last month or so as it has been grain store season for us and we have been stacking the solar installs but we have a couple of 50kw ones to do in the next month , so will let you know if it is still the case for under 50kw jobs ?

 

[SolarCity]

Thanks fella, that'd be interesting to hear about.

We've not installed above 50kWp (and are never likely to now) and our G59 installs have always been standard G83 settings on inverters and G59 rated relays. Opening the parameters on the inverters for certain ratings would make sense but we could only do this on written request of the DNO.

 

[Worcester]

The G59 settings can only be accessed (seen / set up or modified) via a Grid Guard code and Sunny Explorer.

You'll need to apply to SMA in Germany for a Grid Guard code.

The DNO will want G59 because of the different tolerances of switching large (generator) loads in and out of the grid.

If you email the Serial #'s to SMA support in the UK they will tell you wether it was factory configured for G59 or G83.

All the G59 cert from SMA says is, "if it's set up using those parameters, it responds like this, so it complies". Your DNO will usually want to 'witness test' the settings, i.e come down to site and you'll need to show them all the configuration settings of the Inverter.

If it isn't set as G59, you'll need a little while to go through and set up all the G59 parameters (the Certificate from SMA will give you the information you need)

All a G59 relay does is control the connection of the inverter to the grid in accordacne with the G59 parameters, (the relay cuts the grid connection to / from the inverters) hence as the SMA inverters can be programmed to do that you don't NEED a seperate relay. - There are occasions when one might be useful (see one of my other posts). Also a seperate G59 relay means that you can use almost any make of inverter - it doesn't need to be G83 or G59 approved for the UK as the G59 relay is the controlling component.

Most G59 Relays if supplied as seperate components from the inverter are more than that, they usually include MCB's, Isolators / contactors etc so act a s a one box connection for the inverter to the DNO supply.

@BiggsSolar - whose relays have you been using?

 

[SolarCity]

All a G59 relay does is control the connection of the inverter to the grid in accordacne with the G59 parameters, (the relay cuts the grid connection to / from the inverters) hence as the SMA inverters can be programmed to do that you don't NEED a seperate relay. - There are occasions when one might be useful (see one of my other posts). Also a seperate G59 relay means that you can use almost any make of inverter - it doesn't need to be G83 or G59 approved for the UK as the G59 relay is the controlling component.

It's a fair point and I suppose different DNOs will see it different ways. On previous installs we have used G83 rated inverters (SMA ones which we didn't reconfigure) and then G59 relays. I argued that the G83 settings will cut in before the G59 relays - releasing the G83 parameters for the inverter would sort that out but we didn't do so.

We have used Macklins for our first couple of G59 relays but a friend of mine has made my others up himself.