Scheme Communication; Logic; Local Acceleration Logic Zclcpsch; Tripping Logic Smpptrc - ABB REC670 Product Manual

Bay control REC670 2.2
Product version: 2.2.1

12. Scheme communication

Scheme communication logic with delta based blocking
scheme signal transmit ZCPSCH
To achieve instantaneous fault clearance for all line faults,
scheme communication logic is provided. All types of
communication schemes for permissive underreaching,
permissive overreaching, blocking, delta based blocking,
unblocking and intertrip are available.
The built-in communication module (LDCM) can be used for
scheme communication signaling when included.
Current reversal and weak-end infeed logic for distance
protection ZCRWPSCH
The ZCRWPSCH function provides the current reversal and
weak end infeed logic functions that supplement the standard
scheme communication logic. It is not suitable for standalone
use as it requires inputs from the distance protection
functions and the scheme communications function included
within the terminal.
On detection of a current reversal, the current reversal logic
provides an output to block the sending of the teleprotection
signal to the remote end, and to block the permissive tripping
at the local end. This blocking condition is maintained long
enough to ensure that no unwanted operation will occur as a
result of the current reversal.
On verification of a weak end infeed condition, the weak end
infeed logic provides an output for sending the received
teleprotection signal back to the remote sending end and
other output(s) for local tripping. For terminals equipped for
single- and two-pole tripping, outputs for the faulted phase(s)
are provided. Undervoltage detectors are used to detect the
faulted phase(s).

Local acceleration logic ZCLCPSCH

To achieve fast clearing of faults on the whole line, when no
communication channel is available, local acceleration logic
(ZCLCPSCH) can be used. This logic enables fast fault
clearing and re-closing during certain conditions, but
naturally, it can not fully replace a communication channel.
The logic can be controlled either by the autorecloser (zone
extension) or by the loss-of-load current (loss-of-load
acceleration).
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 operate time of the protection
ABB
including a channel transmission time, can be achieved. This
short operate time enables rapid autoreclosing function after
the fault clearance.
M13860-3 v10
The communication logic module for directional residual
current protection enables blocking as well as permissive
under/overreaching, and unblocking 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 (ECRWPSCH)
function.
Current reversal and weak-end infeed logic for residual
overcurrent protection ECRWPSCH
The Current reversal and weak-end infeed logic for residual
M13896-3 v15
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 tele-protection channels.
This is why the IEDs have available additions to the 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. 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 IED can detect the fault. The detection requires a
M13823-3 v7
sufficient minimum residual fault current, out from this IED.
The fault current can be too low due to an opened breaker or
high-positive and/or zero-sequence source impedance
behind this IED. To overcome these conditions, weak-end
infeed (WEI) echo logic is used. The weak-end infeed echo is
limited to 200 ms to avoid channel lockup.

13. Logic

Tripping logic SMPPTRC

A function block for protection tripping and general start
M13918-4 v11 indication is always provided as a basic function for each
circuit breaker. It provides a settable pulse prolongation time
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 a settable latch function for
the trip signal and circuit breaker lockout.
1MRK 511 404-BEN A
M13928-3 v8
M13928-6 v2
M13928-8 v5
M12275-3 v12
33