Function Block; Functionality; Operation Principle - ABB RELION 620 Series Technical Manual

1MRS757644 F
4.1.4.2
4.1.4.3
4.1.4.4
620 series
Technical Manual

Function block

GUID-22B2621B-5B78-4C71-97F8-4BD477A50D51 V1 EN
Figure 138: Function block

Functionality

Directional three-independent-phase directional overcurrent protection function
DPH3xPDOC is used as one-phase, two-phase or three-phase directional overcurrent
and short circuit protection for feeders.
DPH3xPDOC starts when the value of the current exceeds the set limit and directional
criterion is fulfilled. Each phase has its own timer. The operation time characteristics
for the low stage, DPH3LPDOC, and the high stage, DPH3HPDOC, can be selected
to be either definite time (DT) or inverse definite minimum time (IDMT).
In the DT mode, the function operates after a predefined operation 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 DPH3xPDOC can be described using a module diagram. All the
modules in the diagram are explained in the next sections.
Section 4
Protection functions
283