The three phase currents are monitored by the P632 to detect when they exceed the set thresholds. Alternatively, two different thresholds can be active. The “dynamic” threshold is active for the set hold time of the “dynamic parameters” (see Chapter “Activation of “Dynamic Parameters””); the “normal” threshold is active when no hold time is running. The IDMT protection function will be triggered when the 1.05-fold of the set reference current value is exceeded in one phase. The P632 will then determine the maximum current flowing in the three phases and this value is used for further processing. Depending on the characteristic selected and the current magnitude, the P632 will determine the tripping time. Furthermore, a minimum tripping time can be set; the tripping time will not fall below this minimum independently of the magnitude of the current.

The IDMT protection function can optionally be blocked by the inrush stabilization function of differential protection.