ABB RED650, Technical Manual

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IEC05000294-4-en.vsd
Calculation
of
instantaneous
differential
currents
(3x)
Calculation of
fundamental
frequency
differential
currents (3x)
& bias current
Magnitudes of
differential
currents
Bias current
[magnitude]
[samples]
Instantaneous
differential
currents
(samples)
Differential
and bias currents
applied to
operate / bias -,
and unrestrained
characteristics
Harmonic
analysis
( 2
nd
and 5
th
)
Trip by unrestrained differential protection
Calculation
of
negative-
sequence
differential
current
(1x)
Two to six
contributions
to neg. seq.
differential
current as
phasors
High sensitive
internal/external fault
discriminator
Internal fault
External fault
Output logic:
- 2nd harmonic block
- 5th harmonic block
-
Cross block logic
- Enhanced trip for
internal faults
- Decreased
sensitivity for
external faults
-
Conditional trip for
simultaneous external
and internal faults
-
Conditional extra time
delay for trip signals
Start L1
Start L2
Start L3
2nd h. block
5th h. block
CH1IL1SM
CH1IL2SM
CH1IL3SM
CH2IL1SM
Curr. samples
from all ends
CH1IL1RE
CH1IL1IM
CH1IL2RE
CH1IL2IM
Currents from
all ends as
phasors
CH1INSRE
CH1INSIM
CH1INSRE
CH1INSIM
Neg. seq.
currents from
all ends
as phasors
T
rip
c
om
m
an
ds
TRIP ³
1
STARTRES
STARTUNR
STARTENH
START
STL1
STL2
STL3
BLK2H
BLK2HL1
BLK2HL2
BLK2HL3
BLK5H
BLK5HL1
BLK5HL2
BLK5HL3
INTFAULT
EXTFAULT
In
fo
rm
at
io
n
TRL1
TRL2
TRL3
-,
-
-
-
-
Line Diffferential Function
Local end IED
Remote end IED
St L1 low sens
St L3 low sens
St L2 low sens
Local end
Remote end
LDCM
Current
samples from
remote end
Current
samples from
local end
A/D
Converter
LDCM
Pre-processing
Block
Analog Input
Module
IEC05000294 V3 EN-US
Figure 33: A simplified block diagram of the power line differential protection
The IED receives the remote currents as samples via a communication link. When
entering the IED, they are processed in the Line Differential Communication
Module (LDCM) where they are time-coordinated with the local current samples,
and interpolated in order to be comparable with the local samples.
Section 6
1MRK 505 394-UEN A
Differential protection
94 Line differential protection RED650 2.2 IEC
Technical manual