ABB REC670 Product Manual page 13

ABB
Bay control REC670
Pre-configured
Product version: 1.1
Scheme communication logic for residual
overcurrent protection ECPSCH
To achieve fast fault clearance of earth faults
on the part of the line not covered by the
instantaneous step of the residual overcurrent
protection, the directional residual
overcurrent protection can be supported with
a logic that uses communication channels.
In the directional scheme, information of the
fault current direction must be transmitted to
the other line end. With directional
comparison, a short operates time of the
protection including a channel transmission
time, can be achieved. This short operate
time enables rapid autoreclosing function
after the fault clearance.
The communication logic module for
directional residual current protection
enables blocking as well as permissive under/
overreaching schemes. The logic can also be
supported by additional logic for weak-end
infeed and current reversal, included in
Current reversal and weak-end infeed logic
for residual overcurrent protection Current
reversal and weak-end infeed logic for
residual overcurrent protection (ECRWPSCH)
function.
Current reversal and weak-end infeed logic
for residual overcurrent protection
ECRWPSCH
The Current reversal and weak-end infeed
logic for residual overcurrent protection
ECRWPSCH is a supplement to Scheme
communication logic for residual overcurrent
protection ECPSCH.
To achieve fast fault clearing for all earth
faults on the line, the directional earth-fault
protection function can be supported with
logic that uses communication channels.
The 670 series IEDs have for this reason
available additions to scheme communication
logic.
If parallel lines are connected to common
busbars at both terminals, overreaching
permissive communication schemes can trip
unselectively due to fault current reversal.
1MRK 511 192-BEN B
This unwanted tripping affects the healthy
line when a fault is cleared on the other line.
This lack of security can result in a total loss
of interconnection between the two buses. To
avoid this type of disturbance, a fault current
reversal logic (transient blocking logic) can
be used.
Permissive communication schemes for
residual overcurrent protection, can basically
operate only when the protection in the
remote terminal can detect the fault. The
detection requires a sufficient minimum
residual fault current, out from this terminal.
The fault current can be too low due to an
opened breaker or high positive and/or zero
sequence source impedance behind this
terminal. To overcome these conditions,
weak end infeed (WEI) echo logic is used.
Logic
Tripping logic SMPPTRC
A function block for protection tripping is
provided for each circuit breaker involved in
the tripping of the fault. It provides the pulse
prolongation to ensure a trip pulse of
sufficient length, as well as all functionality
necessary for correct co-operation with
autoreclosing functions.
The trip function block includes functionality
for evolving faults and breaker lock-out.
Trip matrix logic TMAGGIO
Trip matrix logic (TMAGGIO) function is
used to route trip signals and/or other logical
output signals to different output contacts on
the IED.
TMAGGIO output signals and the physical
outputs are available in PCM600 and this
allows the user to adapt the signals to the
physical tripping outputs according to the
specific application needs.
Configurable logic blocks
A number of logic blocks and timers are
available for user to adapt the configuration
to the specific application needs.
Issued: June 2010
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