The typical characteristics of ferroresonance accident happening in a network grounded with arc extinguishing coil are manifested in multiple times by 3U0 off-limit alarm
with two of the three-phase voltage and its historical curve
protection alarm
arc extinguishing alarm information appearing in pairs in the dispatching automation interface. They can be used as the ferroresonance comprehensive criterion
while ferroresonance recognition time is no longer than 10 minutes by the standard identifying process.