Low RISO problem

[BruceB]

Power One low RISO problems have been discussed here before. I have one on an installation from Dec 11 where the issue now manifests itself after lots of rain on one string of a 2 string/mppt 4 kW array. I am fairly sure it is one MC4 connector, probably one connecting one core of an SWA cable to a panel.

I know there is only one proper answer and that is to get up on the roof, remove a panel or 2, clean up or replace a connector and secure it properly.

However the array is on an old vicarage, 3 storeys high, with a steep roof slope and small plain tiles above a glass conservatory. The scaffolding would have to bridge the conservatory and would cost >£1,000. I am not even sure it is our fault, because I was able to go up on top of the roof from the rear (which gave a safe access route, but not possible to work from there without proper ropework) and there was mortar splattered on the SWA cable where a roofer had been up after us doing chimney repairs.

I have said I will go up when he next has scaffolding up to redecorate and remove panels etc. But I wondered whether there were any interim solutions available:

- has anyone managed to adjust the standard 4kW Power One inverter so that it does not cry foul at 1 megaohm, but perhaps at a few hundred kilohms?

- has anyone used any firms here in the SW that might have appropriate rope access experience?

 

[SibertSolar]

Hi Bruce,

It may well be possible to adjust the RISO threshold from within the Service Level config screens. You will need to register on the ABB website (https://registration.abbsolarinverters.com/index.php) and you will need to know the serial number of the inverter to generate/receive a Service Password. That password will allow you to drill down through the config parameters.

In the meantime, I am trying to find out the specific parameter ID/codes for you, and whether it is indeed possible to do.

 

[BruceB]

Thanks Andy. The ABB site was so slow on Friday pm that I kept thinking that either my browser had crashed or their site had. I repeated myself a few times and now have two registrations active! It seems I need the inverter type and serial number which I have. But I also need the WW/YY it was manufactured and the 'update version' which I do not have. I have a firmware version C.0.2.2 but the site is telling me the update version should be 5 digits. So I will go along and look at the screens on Monday morning to see what I can find.

 

[SibertSolar]

Ok, the WW/YY is the first 4 digits of the serial number (although I think it might be YY/WW), not sure about which update version it needs (GUI/DSP etc), will see if I can shed some light on it Monday

 

[BruceB]

Using the model type, serial no, and wwyy digits, the site generated a 6 digit password valid for 2 weeks. I'll hang on for any guidance on which parameter might do it rather than rushing to delve into the service menu!

 

[BruceB]

A rolling, derivable, time sensitive password to get into the service menu seems a bit over the top but I went to the site this morning and the password got me into the menu. However, I was expecting a host of variables to be available like the SMA inverters, but there were only 3:

- Nominal Vgrid could go as high as 8,500 ish which is scary!
- Max Av.Vgrid
- Amorph.Enable not a clue

So no further forward really. Good resistances on the dc circuits today but might give problems in the expected rain later.

I know there is a program that allows access to the inverter to update the firmware. I believe it needs a proprietary RS485/usb interface box. I believe that the program only allows firmware to be updated rather than allowing access to parameters but would like to be corrected if I have that wrong.

Andy, did you get anywhere looking for parameters?

 

[SibertSolar]

Sorry Bruce, I let this slip - I'll chase it today and come back to you asap.

 

[SibertSolar]

Bruce - what particular inverter is it? You can adjust the Trio's RISO settings using the Aurora Manager Lite software. The RISO level for the Trios is 1MOhm, they don't recommend lower than 400kOhm without further analysis. Not sure if it's possible on the PVI-3.6 units though, I am investigating.

 

[BruceB]

The inverter is a PVI-3.6-OUTD-UK
what I think of as the bog standard power one offering at the time.
It was made Wk43/11
with firmware C.0.2.2

 

[SibertSolar]

Can you call me please Bruce? (0777 5427243)