ABB Relion 670 Series RES670, Техническое руководство

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a
b
a>b
BLOCK
AND
I
OP
Extract second
harmonic current
component
Extract
fundamental
current component
X
2ndHarmStab
a
b
a>b
a
b
a>b
0.07*IBase
ANSI13000015-1-en.vsd
2NDHARMD
Use_PUValue
Pickup1>
Pickup2>
Pickup3>
Pickup4>
a
b
a>b
|I
OP
|
OR
AND
BlkParTransf=On
q
-1
OR 2ndH_BLOCK_Int
0-70ms
0
ANSI13000015 V1 EN
Figure 59: Simplified logic diagram for 2nd harmonic blocking feature and Block for Parallel Transformers feature
8.2.7.10 Switch on to fault feature
Integrated in the four step residual overcurrent protection are Switch on to fault logic
(SOTF) and Under-Time logic. The setting parameter
SOTF is set to activate either SOTF
or Under-Time logic or both. When the circuit breaker is closing there is a risk to close it
onto a permanent fault, for example during an autoreclosing sequence. The SOTF logic
will enable fast fault clearance during such situations. The time during which SOTF and
Under-Time logics will be active after activation is defined by the setting parameter
t4U .
The SOTF logic uses the pickup signal from step 2 or step 3 for its operation, selected by
setting parameter
StepForSOTF . The SOTF logic can be activated either from change in
circuit breaker position or from circuit breaker close command pulse. The setting
1MRK 511 365-UUS A
Section 8
Current protection
Phasor measurement unit RES670 2.1 ANSI 209
Technical manual