ABB RELION 650 SERIES, Technical Manual

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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
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 95: Simplified logic diagram for 2nd harmonic blocking feature and Block for Parallel Transformers
feature
7.4.7.10 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 506 382-UEN A
Section 7
Current protection
Line distance protection REL650 2.2 IEC 201
Technical manual