ABB Relion REC615, Техническое руководство

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Figure 137: 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.
The timer calculates the start duration value
START_DUR
, which indicates the
percentage ratio of the start situation and the set operating time. The value is
available through the monitored data view.
The
BLOCK
signal blocks the operation of the function and resets the timer.
Protection functions 1MRS758755 C
274 REC615 & RER615
Technical Manual