• The numerical value of the difference |ΣIphase| – |Iref| is higher than 80% of the
numerical value of the sum |ΣIphase| + |Iref|.
• The numerical value of the current |ΣIphase| – |Iref| is equal to or higher than the
set operate value IMinOp.
• No phase current has exceeded Ip>Block during the last 10 ms.
• CCSRDIF is enabled by setting Operation = On.
The FAIL output remains activated 100 ms after the AND-gate resets when being
activated for more than 20 ms. If the FAIL lasts for more than 150 ms an ALARM will
be issued. In this case the FAIL and ALARM will remain activated 1 s after the AND-
gate resets. This prevents unwanted resetting of the blocking function when phase
current supervision element(s) operate, for example, during a fault.
å
I
L1
I
L2
I
L3
I
ref
å
+
-
å
+
+
I>IMinOp
å
+
-
x
0,8
AND
BLOCK
1,5 x I
r
10 ms
OPERATION
100 ms
1 s150 ms
20 ms
I>Ip>Block
en05000463.tif
FAIL
ALARM
I
L1
I
L2
I
L3
I
ref
BLOCK
OR
IEC05000463 V2 EN
Figure 87: Simplified logic diagram for Current circuit supervision CCSRDIF
The operate characteristic is percentage restrained, see figure 88.
1MRK 511 287-UEN A Section 9
Secondary system supervision
193
Technical manual
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