Operation

Direction Protection is continuously monitoring the line voltage and current in order to determine the direction of power flow through the switchgear.

It is also monitoring the pickup thresholds for each configured element for each of the active protection groups.

When any pickup threshold in either of the active groups is exceeded, the power flow direction is checked to determine if the fault has occurred on the Source or Load side of the switchgear.

If the fault is discovered to be on the Load side and a forward protection group trip setting has been exceeded, a Pickup Forward event is logged and the protection calculates the time to trip according to the forward protection group settings for the faulted element.

If the active protection groups are A and B, then Group A is used.

If the fault is discovered to be on the Source side and a reverse protection group trip setting has been exceeded, a Pickup Reverse event is logged and the protection calculates the time to trip according to the reverse protection group settings. In this case, Group B.