The FAIL output will be set to high when the following criteria are fulfilled:
• 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.
• CCSSPVC 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-US
Figure 90: Simplified logic diagram for Current circuit supervision CCSSPVC
The operate characteristic is percentage restrained, which is shown in Figure 91.
1MRK 505 384-UEN A Section 8
Secondary system supervision
Breaker protection REQ650 2.2 IEC 205
Technical manual
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