Grid voltage out of range

The inverter reports that the grid voltage at its AC terminals is outside the allowed protection range, and it disconnects from the grid. In monitoring data, AC output stops while the measured grid voltage is above or below the set limits. Some inverters also trip on the ten-minute average voltage. Usually the inverter reconnects by itself once the grid is normal again, so first watch it for about ten minutes to see whether the alarm clears. If the alarm keeps coming back, measure the actual grid voltage at the inverter. If it really is out of range, or the phases differ a lot, contact the utility. If the grid voltage measures normal, check the AC connections and cable between the inverter and the grid. Make sure the cable is firmly in place and its cross-section is large enough, because high impedance at the connection point can push the voltage up. Also check that the voltage protection settings are right for the grid standard that applies. Change them only with the grid operator's consent. On CPS inverters, restart the inverter after the cause is fixed. If the fault persists, contact the manufacturer's service.

<!-- review notes

• sentence 5: support check: partial - Passages say to check AC connections, cable firmness and cross-section, and that grid impedance is too high, but they do not tie these to the case where voltage measures normal.
• sentence 6: support check: partial - Passages say to check protection parameters and modify overvoltage values only with operator consent, but the grid-standard match and consent for all settings (including undervoltage) are not fully stated.
• sentence 7: support check: partial - u1 says restart the inverter, but 'restart after the cause is fixed' and 'contact the manufacturer's service' for CPS are not stated for CPS; the contact-service text is from Sungrow. -->