ABB RED650 - Switch on to Fault Feature

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
IEC13000015-4-en.vsdx
UseStartValue
IN1>
IN2>
IN3>
IN4>
a
b
a>b
t
t=70ms
OR
AND
BlkParTransf=On
q
-1
OR
2ndH_BLOCK_Int
q
-1
= unit delay
IEC13000015 V4 EN-US
Figure 88: Simplified logic diagram for 2nd harmonic blocking feature and Block for Parallel Transformers
feature
8.4.7.10 Switch on to fault feature
M13941-211 v5
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.
The SOTF logic uses the start signal from step 2 or step 3 for its operation, selected
by setting parameter StepForSOTF. The setting parameter ActivationSOTF can be
set for activation of CB position open change, CB position closed change or CB
close command. In case of a residual current start from step 2 or 3 (dependent on
1MRK 505 394-UEN A Section 8
Current protection
Line differential protection RED650 2.2 IEC 201
Technical manual