ABB Relion 670 series, Technical Reference Manual

Page: 604 / 1232

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