4.1.2.3 Functionality
The three-phase overcurrent protection function (F)DPHxPDOC is used as one-
phase, two-phase or three-phase directional overcurrent and short-circuit protection
for feeders.
(F)DPHxPDOC starts up when the value of the current exceeds the set limit and
directional criterion is fulfilled. The operate time characteristics for low stage
FDPHLPDOC and high stage DPHHPDOC 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 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.
4.1.2.4 Operation principle
The function can be enabled and disabled with the Operation setting. The
corresponding parameter values are "On" and "Off".
The operation of (F)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 121: Functional module diagram
Section 4 1MRS758755 A
Protection functions
224 REC615 and RER615
Technical Manual
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