Figure 378: CVGAPC function main logic diagram for built-in protection elements
Logic in figure 378 can be summarized as follows:
1. The selected currents and voltage are given to built-in protection elements. Each protection
element and step makes independent decision about status of its PICKUP and TRIP output
signals.
2. More detailed internal logic for every protection element is given in the following four figures
3. Common PICKUP and TRIP signals from all built-in protection elements & steps (internal OR
logic) are available from multipurpose function as well.
Second
harmonic check
Selected voltage
X
PickupCurr_OC1
a
b
a>b
Voltage
control or
restraint
feature
OC1=On
BLKOC1
Directionality
check
Current
Restraint
Feature
I
measured
> k I
restraint
DIR_OK
Inverse
0-DEF
DEF time
selected
Inverse
time
selected
OR
Enable
second
harmonic
en05000831_ansi.vsd
Selected current
PU_OC1
TROC1
AND
BLKTROC1
Selected restrain current
AND
NOT
0
ANSI05000831 V1 EN-US
Figure 379: Simplified internal logic diagram for built-in first overcurrent step that is, OC1 (step OC2 has the
same internal logic)
Section 11 1MRK 502 066-UUS B
Multipurpose protection
710
Technical manual
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