| Function description | IEC 61850 identification | IEC 60617 identification | ANSI/IEEE C37.2 device number |
|---|---|---|---|
| Non-directional earth-fault protection, low stage | EFLPTOC | Io> | 51G/51N-1 |
| Non-directional earth-fault protection, high stage | EFHPTOC | Io>> | 51G/51N-2 |
| Non-directional earth-fault protection, instantaneous stage | EFIPTOC | Io>>> | 50G/50N |