OV-G-V Alarm

Fault Description

The fault OV-G-V is caused by the inverter detecting grid voltage outside of its normal operating range. Specifically the grid voltage being TOO high. That's why it says OVER voltage. Alternatively you also have the error UN-G-V which is the opposite, the grid voltage is too low. 01/02 indicates that the 1st or 2nd set point have been breached. 

Possible Solutions

Grid code/standard not set properly

The primary cause of the error is the grid code being set improperly. Typically this happens at the factory during the units "burn" in period. They are programmed with a specific grid code for the burn in process, right before they are shipped out the grid code is changed to their country of origin's grid standard. To learn how to change the grid standard go here: https://usservice.ginlong.com/solution/articles/36000113455-selecting-the-grid-standard-video

On the LCD proceed to the ADVANCED SETTING section. Enter the password 0010. Select “Turn Grid off or on”. Select off. Choose SELECT STANDARD select UL-240V-A, UL-208V-A, UL-240V, UL-240V. hit ENTER to confirm setting. Go back to Select “Turn Grid off or on”. Select on. Wait 5 minutes and the alarm should clear. 

US Grid Code Meaning

UL-240V-A - AFCI ENABLED - Split Phase

UL-208V-A - AFCI ENABLED - Single Phase

UL-240V -  AFCI DISABLED - Split Phase

UL-208V -  AFCI DISABLED - Single Phase

  • It can be caused by undersized wires which increase the voltage drop, the inverter raises its voltage to compensate for the drop until it hits its grid standard limit and shuts down.
  • Any loose AC connections can also cause problems with the grid voltage. When resistance is introduced into the line heat and excess voltage issues can happen. Check all AC connections

Inverter measurement device out of tolerance

The inverter's internal voltage measurement system is not accurately reading the AC votlages from the grid. This unit will need to have an RMA. You can test this out by using a meter to read the AC voltages, and comparing them to the voltages on the inverter's LCD. If there is a difference, particularly on one phase, then the inverter will need to be replaced. 

Bad transformer down stream

Due to an issue with the transformer providing power to a home or facility, the voltage may appear TOO high or TOO low, the transformers taps will need to be adjusted to provide the proper output to the inverter. The inverter is performing it's job of notifying the customer that there is a problem with the grid voltage being too low or too high. This is not an internal fault on the inverters part, it will need to be diagnosed with the equipment on site. 

Under sized wire

Line loss can cause voltages to spike leading to an OV-G error. This happens when the line loss causes excess resistance to build up in the AC circuit, the inverter attempt to compensate for this by increasing the voltage to drive the current. When the AC voltage exceeds the inverter's limit it causes a shut down. Once production stops the inverter will see the grid voltage decrease, so it will attempt to restart. This will continue to happen in a cycle throughout the day. It can be seen on monitoring platforms as multiple faults every day. Lowing the transformer taps, or increasing the conductor size is the solution. Alternatively the inverter's internal set points can be adjusted with the permission of the utility or facility owner. 

Loose AC Connections

Any loose AC connections can also cause grid voltage spikes. When resistance is introduced into the line heat and excess voltage issues can happen. Check all AC connections.


Test – DC switch OFF
• Check AC at the inverter
• If AC measures high, adjust upper limit with
permission from utility
Test – DC Switch ON, full power
• Check AC at inverter test points
• Compare with LCD
• If AC measures high, cables between inverter
and interconnect are too small
• Check ampacity and voltage drop calculations

Victor is the author of this solution article.

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