Operation Principle - ABB RELION 620 Series Technical Manual

Section 4
Protection functions
4.1.3.4
260
In the DT mode, the function operates after a predefined operate time and resets when
the fault current disappears. The IDMT mode provides current-dependent timer
characteristics.
The function contains a blocking functionality. It is possible to block function outputs,
timers or the function itself, if desired.

Operation principle

The function can be enabled and disabled with the Operation setting. The
corresponding parameter values are "On" and "Off".
The operation of DPHxPDOC can be described using a module diagram. All the
modules in the diagram are explained in the next sections.
GUID-C5892F3E-09D9-462E-A963-023EFC18DDE7 V3 EN
Figure 124: Functional module diagram
Directional calculation
The directional calculation compares the current phasors to the polarizing phasor. A
suitable polarization quantity can be selected from the different polarization
quantities, which are the positive sequence voltage, negative sequence voltage, self-
polarizing (faulted) voltage and cross-polarizing voltages (healthy voltages). The
polarizing method is defined with the Pol quantity setting.
1MRS757644 F
620 series
Technical Manual