Operation Principle - ABB RELION Series Technical Manual

Section 4
Protection functions
4.1.1.4
202
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 (F)PHxPTOC can be described by using a module diagram. All the
modules in the diagram are explained in the next sections.
A070552 V1 EN
Figure 114: Functional module diagram
Level detector
The measured phase currents are compared phasewise to the set Start value. If the
measured value exceeds the set Start value, the level detector reports the exceeding of
the value to the phase selection logic. If the ENA_MULT input is active, the Start value
setting is multiplied by the Start value Mult setting.
The protection relay does not accept the Start value or Start value Mult
setting if the product of these settings exceeds the Start value setting
range.
The start value multiplication is normally done when the inrush detection function
(INRPHAR) is connected to the ENA_MULT input.
1MRS758755 A
REC615 and RER615
Technical Manual