ABB RELION 650 SERIES, Technical Manual

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on a received signal for a fast trip, so its dependability is lower than that of a
blocking scheme.
12.1.6.1 Blocking scheme
M13893-6 v7
The principle of operation for a blocking scheme is that an overreaching zone is
allowed to trip instantaneously after the settable co-ordination time
tCoord has
elapsed, when no signal is received from the remote IED.
The received signal, which shall be connected to CR, is used to block the zone to
be accelerated to clear the fault instantaneously (after time
tCoord ). The forward
overreaching zone to be accelerated is connected to the input CACC, see
figure
217 .
In case of external faults, the blocking signal (CR) must be received before the
settable timer
tCoord elapses to prevent a false trip, see figure 217 .
The function can be totally blocked by activating the input BLOCK. Tripping can
be blocked by activating the input BLKTR. Signal send can be blocked by
activating the input BLKCS.
CACC
CR
tCoord
TRIP
AND
t
en05000512.vsd
IEC05000512 V1 EN-US
Figure 217: Basic logic for trip signal in blocking scheme
Channels for communication in each direction must be available.
12.1.6.2 Delta blocking scheme
GUID-22E3BFAC-82E9-4434-B761-AD63BCFC68D5 v2
In order to avoid delays due to carrier coordination times, the initiation of sending
of blocking signal to remote end is done by a fault inception detection element
based on delta quantities of currents and voltages. The delta based fault detection is
very fast and if the channel is fast there is no need for delaying the operation of the
remote distance element. The received blocking signal arrives well before the
distance element has started. If the fault is in forward direction the sending is
immediately stopped by a forward directed distance, directional current or
directional earth fault element.
The fault inception detection element detects instantaneous changes in any phase
currents or zero sequence current in combination with a change in the
corresponding phase voltage or zero sequence voltage. The criterion for the fault
inception detection is if the change of any phase voltage and current exceeds the
settings
DeltaU and DeltaI respectively, or if the change of zero sequence voltage
and zero sequence current exceeds the settings Delta3U0 , Delta3I0 respectively.
The schemeType is selected as DeltaBlocking .
Section 12
1MRK 506 382-UEN A
Scheme communication
436 Line distance protection REL650 2.2 IEC
Technical manual