ABB Relion 670 Series RES670, Technical Manual

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13.1.6 Operation principle
Current circuit supervision CCSSPVC (87) compares the absolute value of the vectorial
sum of the three phase currents |ΣIphase| and the numerical value of the residual current
|Iref| from another current transformer set, see figure
124 .
The FAIL output will be set to a logical one 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
trip value
IMinOp .
• No phase current has exceeded Pickup_Block during the last 10 ms.
• CCSSPVC (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) trip, 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 124: Simplified logic diagram for Current circuit supervision CCSSPVC (87)
The trip characteristic is percentage restrained, see figure 125 .
1MRK 511 365-UUS A
Section 13
Secondary system supervision
Phasor measurement unit RES670 2.1 ANSI 361
Technical manual