ABB RELION Series Technical Manual page 266

Section 4
Protection functions
260
GUID-7B0FC64E-8C0B-4742-8252-522B91EFC4BC V1 EN
Figure 138: 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.
The protection relay does not accept the Start value to be smaller than
Current block value
Level detector 2
This is a low-current detection module that monitors the de-energized condition of the
protected object. The module compares the phase currents (RMS value) to the Start
value low setting. If all the phase current values are less than the Start value low
setting, a signal is sent to block the operation of the timer.
Timer
Once activated, the timer activates the START output and the phase-specific ST_X
output. The time characteristic is according to DT. When the operation timer has
reached the value set by Operate delay time, the OPERATE output and the phase-
specific OPR_X output are activated. If the fault disappears before the module
operates, the reset timer is activated. If the reset timer reaches the value set by Reset
delay time, the operate timer resets and the START output is deactivated.
1MRS758755 A
REC615 and RER615
Technical Manual