Switch On To Fault Feature - ABB RES670 Technical Manual

1MRK 511 408-UUS A
BLOCK
I
OP
Use_PUValue
Pickup1>
Pickup2>
Pickup3>
Pickup4>
ANSI13000015 V1 EN-US
Figure 62: Simplified logic diagram for 2nd harmonic blocking feature and Block for Parallel Transformers
feature
8.2.7.10
Phasor measurement unit RES670 2.2 ANSI
Technical manual
Extract second
harmonic current
component
Extract
fundamental
current component
2ndHarmStab
|I |
OP
a
b

Switch on to fault feature

Integrated in the four step residual overcurrent protection are the switch on to fault
logic (SOTF) and the under-time logic. The setting parameter SOTF is set to activate
SOTF, the 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.
a
a>b
0.07*IBase
b
a
a>b
b
a
a>b
b
X
OR
0-70ms
0
BlkParTransf=On
a>b
Section 8
Current protection
AND
-1
q
2ndH_BLOCK_Int
OR
AND
ANSI13000015-1-en.vsd
M13941-211 v5
209