This alarm will display if the inverter detects harmonic distortion on the AC-side of the system. The "INTF" is short for "interference" and the "GRID" means coming from the grid-side. Harmonic distortion can come a variety of sources, such as the grid, nonlinear electrical equipment, or the inverter itself. You must search for harmonic distortion using a Power Quality Analyzer. Please follow the steps to troubleshoot harmonic distortion on the AC side of the system:
- Turn the inverter at the site off through the Advanced Settings menu (Grid ON/OFF)
- Open the AC switch (or breaker) and then open the DC switch
- Set up a Power Quality Analyzer to measure THDa (current harmonics) on the AC cables
- Turn the inverter back on - DC first and then AC
- After five minutes, the inverter should begin generating again
- Observe the harmonics and take a recording if your device allows you to
- If the harmonics are normal and the inverter is still displaying the alarm, contact Solis Support
- If the harmonics are abnormal, do the same thing to a nearby inverter for comparison
- If there is only one inverter at the site and the harmonics are abnormal, proceed with the next steps
- Note: Follow these steps if there are multiple inverters displaying the Grid-INTF alarm
- Turn the inverter(s) off: through Advanced Settings On/Off, then the AC switch, and then the DC switch
- Set up the Power Quality Analyzer in the load center (or where the breakers are)
- Observe the THDa harmonics with no inverters generating
- If the harmonics are abnormal, then the cause is the grid or nearby nonlinear electrical equipment
- If the harmonics are normal, turn on one inverter (that has been displaying the alarm)
- Observe the harmonics as one inverter produces and exports power to the utility
- If it seems as though the harmonic distortion is coming from the utility, recommend installing an EMI filter
- If the harmonic distortion appears to be caused by one inverter, contact Solis Support