Functionality; Operation Principle - ABB RELION 620 Series Technical Manual

Section 4
Protection functions
4.1.10.3
4.1.10.4
342

Functionality

The loss of phase, undercurrent, protection function PHPTUC is used to detect an
undercurrent that is considered as a fault condition.
PHPTUC starts when the current is less than the set limit. Operation time
characteristics are according to definite time (DT).
The function contains a blocking functionality. It is possible to block function outputs
and reset the definite timer 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 PHPTUC can be described with a module diagram. All the modules
in the diagram are explained in the next sections.
GUID-7B0FC64E-8C0B-4742-8252-522B91EFC4BC V1 EN
Figure 168: Functional module diagram
Level detector 1
This module compares the phase currents (RMS value) to the Start value setting. The
Operation mode setting can be used to select the "Three Phase" or "Single Phase"
mode.
If in the "Three Phase" mode all the phase current values are less than the value of the
Start value setting, the condition is detected and an enable signal is sent to the timer.
This signal is disabled after one or several phase currents have exceeded the set Start
value value of the element.
If in the "Single Phase" mode any of the phase current values are less than the value
of the Start value setting, the condition is detected and an enable signal is sent to the
timer. This signal is disabled after all the phase currents have exceeded the set Start
value value of the element.
1MRS757644 F
620 series
Technical Manual