Fault Reset Operation

If after a Phase Over current pickup, the current falls to between 90% and 100% of the Pickup Current, a Protection Paused event is logged. At this point the trip timer freezes and will recommence if the current rises back above the pickup. The current going back above the pickup in this case will cause a Protection Timing event. This is not a Pickup as the controller is already in a pickup state and cannot record another pickup unless the fault that caused the pickup has reset.

If the current falls below 90% of the pickup current, a Protection Resetting event is logged and the Fault Reset Timer starts.

If the Fault Reset Timer expires before the current rises back above 90%, the protection pickup will reset and an event (Max Current) will be logged to record the highest fault current sampled while the pickup was active. In this case protection timing will start again at the next pickup event.

If a fault is sustained long enough for a protection trip to occur, a Current at Trip event will be logged to indicate the measured fault current at the time of the trip. Max Current events will also occur as well as a Protection Resetting event followed by a Protection Reset event.

If after a pickup, the current falls into the band between the pickup current and the reset threshold (90-100% of the Setting Current by default), protection is said to be in a Paused state. In the Paused state, the pickup is still active but the trip timer is frozen.

The Pickup Multiplier effect on the Pause band

With the default Phase Over current settings shown below, the pickup current is 200 A and the reset threshold is 180 A (90% of 200 A). The pause band is 20 A wide, 180 A...200 A.

When the Pickup Multiplier is changed to x 1.5 as shown below, the pickup current becomes 300 A and the reset threshold changes to 270 A. This makes the pause band 30 A wide, 270 A...300 A.

The Maximum Time setting is a Global Setting which helps to ensure that a fault will never take longer than a predetermined time to cause a trip. This setting is Off by default but can be configured for between 2 s and 180 s.