The P632 calculates the negative-sequence current from the three phase current values according to this equation. This is based on the setting at MAIN: Phase sequence.

Phase sequence A-B-C:

Phase sequence A-C-B:

The negative-sequence current is monitored by the P632 with three-stage functions to detect when it exceeds the set thresholds. One of two different threshold types can be active. The “dynamic” thresholds are active for the set hold time for the “dynamic parameters” (see Chapter “Activation of “Dynamic Parameters””) and the “normal” thresholds are active when no hold time is running. If the current exceeds the set thresholds in one phase, timer stages are started. Once the time delays have elapsed, a trip signal is issued. The timer stages can be blocked by appropriately configured binary signal inputs.

The first stage of the negative-sequence current protection function can optionally be blocked by the inrush stabilization function of differential protection.