ABB RELION 620 Series Technical Manual page 581

1MRS757644 F
620 series
Technical Manual
GUID-89207322-ADEC-4927-9402-72C112CC7C7C V2 EN
Figure 293: Functional module diagram
The module diagram illustrates all the phases of the function. Functionality for phases
A, B and C is identical.
All three phases have independent settings.
Level detector
The module compares differential currents I_A calculated by the peak-to-peak
measurement mode to the set Operate value. The Timer module is activated if the
differential current exceeds the value of the Operate value setting.
Timer
Once activated, Timer activates the START output. The time characteristic is
according to DT. When the operation timer reaches the value set by Minimum operate
time, the OPERATE output is activated. If the fault disappears before the module
operates, the reset timer is activated. If the reset timer reaches the value set by Reset
delay time, the operation timer resets and the START output is deactivated.
Section 4
Protection functions
575