Modified on Mon, 30 Oct 2023 at 12:34 PM

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UN-G-V means the Grid voltages are lower than the protective value set in the inverter according to the local Grid standard. 



1.  Get the basic information:

Model,  serial number, error code,  how often the error happens,  software version,  installation & commissioning date,  Grid standard that is using inside of the inverter currently.

2.   Other steps to be taken:


1. If installation is new then please check connectivity is proper or not of AC gland make sure AC cable connect properly in connector terminal only. (The polarity is clearly mentioned on AC gland).


2. Check how often the error happens. If only one or two times a day, then it’s caused by the unstable Grid. If error is continuous then refer below mentioned steps.


3. First make grid off from advance setting in inverter. Then check display voltage i.e. VA, VB and VC either VGrid and then check grid side voltage.


4. Measure the Grid voltages at the AC connectors to make sure there is voltage properly coming on connector (wire side; (as showing in the picture below).


5: Please check all the Grid voltages that are showing on the LCD of the inverter( as showing in the picture below).


A close up of a device

Description automatically generated


6. Please check all the wire connections in the AC side. Specially in the AC connectors.

7. Please check the wire sequence inside of the AC connectors


8. If suspecting loose contact please properly connect the cable after disconnect from connector or ACDB.


9. If system is three phase (Check AC side voltage Phase to Phase, phase to neutral and neutral to earthing.) Always check reading from inverter AC gland end.


10. If system is single phase (Check AC side voltage Phase to neutral, phase to earthing and neutral to earthing.) Always check reading from inverter AC gland end.


11. Check the Grid standard and select right one like user-def or EN50438L or the required standard so that the fault doesn't occur again. You should change the standard after make grid OFF only after standard change done then only make Grid ON.


12. Take complete reading of information menu like DC1 , DC2 , DC3 , DC4 then VA , VB, VC or VGrid

then Status (Error) and Total energy.


13. Take reading from advance info Alarm messages, version, running messages, warning messages.


14. Take ACDB, DCDB close and clear photo, inverter serial no. which is stick on inverter body and inverter complete installation photo.


15. Please check the VOC of all of the PV strings (Voltage should check from connector end after disconnect string from inverter).


16. Use a multi-meter to check the voltages between PV+ and earth, PV- and earth of all the PV strings. It should be decreasing from values between 5% and 95% of single PV module Voc. If voltage stuck on above single module VOC or in decreasing condition if voltage getting increase that means there is some fault with that strings.



If you are experiencing any further issue after troubleshooting, please do not hesitate to contact the Solis Support. 

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