ABB Relion 670 Series Technical Reference Manual page 604

Section 11
Secondary system supervision
598
• 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 Pickup_Block during the last 10 ms.
• CCSRDIF (87) is enabled by setting Operation = Enabled.
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.
I I
I
A A
I
I
B
B
I
I
C
C
I I
ref
ref
OPERATION
BLOCK
ANSI05000463 V1 EN
Figure 300: Simplified logic diagram for Current circuit supervision CCSRDIF (87)
The operate characteristic is percentage restrained, see figure 301.
I>Pickup_Block
BLOCK
I>IMinOp
+
å
å
-
+
+
å
å
x
+ -
0,8
1,5 x I r
10 ms
OR
1MRK505222-UUS C
FAIL
OR
AND
20 ms 100 ms
ALARM
150 ms 1 s
en05000463_ansi.vsd
Technical reference manual