GRID-INTF Alarm

GRID-INTF Alarm

This alarm appears if the inverter detects harmonic distortion on the AC side of the system. "INTF" stands for "interference," and "GRID" refers to grid-side interference. Harmonic distortion can arise from various sources, including the grid, nonlinear electrical equipment, or the inverter itself. Since cycling loads causing distortion can be momentary—lasting only a half or quarter cycle—accurate diagnosis requires a Power Quality Analyzer (PQA) to chart the readings. A standard Fluke meter is insufficient due to the speed and fleeting nature of these issues. Follow these steps to troubleshoot:

1. Turn Off the Inverter

   • Go to the Advanced Settings menu and select Grid ON/OFF.
   • Open the AC switch (or breaker) and then the DC switch.

2. Set Up Power Quality Analyzer

   • Use the analyzer to measure THDa (current harmonics) on the AC cables.

3. Turn the Inverter Back On

   • Power on the DC switch first, then the AC switch.
   • Allow five minutes for the inverter to begin generating.

4. Observe and Record Harmonics

   • Monitor harmonic levels and record them if possible.
   • If harmonics are normal but the alarm persists, contact Solis Support.
   • If harmonics are abnormal, compare with a nearby inverter (if available).
   • If only one inverter is at the site and harmonics are abnormal, continue with the next steps.

5. Troubleshooting Multiple Inverters with GRID-INTF Alarm

   • Turn off each inverter via Advanced Settings ON/OFF, then the AC switch, and then the DC switch.
   • Set up the Power Quality Analyzer in the load center (breaker panel).
   • Observe THDa harmonics with no inverters generating:
     • If harmonics are abnormal, the grid or nearby equipment is likely the source.
     • If harmonics are normal, turn on one inverter showing the alarm.
     • Observe harmonics as this inverter exports power to the utility.

6. Determine Source of Harmonics

   • If the utility appears to cause distortion, consider installing an EMI filter.
   • If one inverter appears to be the source, contact Solis Support for further assistance.