ground fault condition

[So solar]

Hey guys
I recently installed a multiple inverter system. 2-2000 kw fronius inverter. 70 amp MLO sub with 2 double 15. 30 amp main pv breaker. 200 amp main, buss. One of these inverters is ground faulting and blowing fuse. I have 2 strings per inverer. When testing VOC on strings of blown inverter with GFDI fuse removed I get half the VOC on pos and negative when tested to ground. I see no damaged or frayed wires and VOC normal. Any ideas?

[So solar]

Oops..(2) 2 kw...where V1(Pos) equals V2(Neg ) to ground. On both strings. With GFDI removed. Not equipment ground. But electrode terminal.

[Sunking]

If the fault is in the panels, it should not damage the inverter as the fault current is not flowing in the inverter.

As for the voltages you see on the panels tells me immediately either one of the panels in one string has shorted to ground,one of the interconnect cables in between one of the panels has shorted, or it is wired incorrectly. You should only see voltage on one polarity.

Tell me this what is the voltage between - to + from the panels, voltage + to G, and voltage - to G

[So solar]

I'll double check on site. I have a ms presentation that shows their way of detecting ground fault location. ( Fronius) it explains if an installer was to remove all strings from inverter and connect each string individually. Remove the GFDI fuse and test positive (V1) to ground then test Neg(V2) to ground. That V1 equals V2 equals VOC/2. If they don't the ration will show you where ground fault is. For example: 6 modules in series at 10 VOC. If the V1 test is 20 volts and V2 is 40 volts. Then the fault is in mod 3. Otherwise, no fault exists. Is this wrong? The polarity of modules is correct and aren't wired wrong. I checked.

[So solar]

Ok...I checked system.
String #1:
VOC. 298 Vdc
+ to ground: 257 vdc
- to ground: -43 vdc
But I do get - to ground voltage. Can you explain?

String#2:
296 VOC
+ to ground 0 Dc
- to ground 0 Dc

This tells me string #2 is short circuited. But I don't see anything. Im gonna have to remove each module seperately and test? Does anyone have any other tricks.

[Sunking]

Ok...I checked system.
String #1:
VOC. 298 Vdc
+ to ground: 257 vdc
- to ground: -43 vdc
But I do get - to ground voltage. Can you explain?

String#2:
296 VOC
+ to ground 0 Dc
- to ground 0 Dc

This tells me string #2 is short circuited. But I don't see anything. Im gonna have to remove each module seperately and test? Does anyone have any other tricks.

Do you have any kind of wiring diagram the installer left with you. Neither of the string voltages are correct. I do not want to guess what is going on.