ABB Relion 670 Series Applications Manual page 413

1MRK 511 401-UUS F
Section 15
15.1 Scheme communication logic for distance or overcurrent
protection ZCPSCH(85)
15.1.1 Identification
Function description
Scheme communication logic for
distance or overcurrent protection
15.1.2 Application
To achieve fast fault clearing for a fault on the part of the line not covered by the instantaneous
zone 1, the stepped distance protection function can be supported with logic that uses a
communication channel.
One communication channel in each direction, which can transmit an on/off signal is required. The
performance and security of this function is directly related to the transmission channel speed
and security against false or lost signals. Communication speed, or minimum time delay, is always
of utmost importance because the purpose for using communication is to improve the tripping
speed of the scheme.
To avoid false signals that could cause false tripping, it is necessary to pay attention to the
security of the communication channel. At the same time it is important to pay attention to the
communication channel dependability to ensure that proper signals are communicated during
power system faults, the time during which the protection schemes must perform their tasks
flawlessly.
The logic supports the following communications schemes:
• blocking schemes (blocking and delta blocking)
• permissive schemes (overreaching and underreaching)
• unblocking scheme and direct intertrip
A permissive scheme is inherently faster and has better security against false tripping than a
blocking scheme. On the other hand, a permissive scheme depend on a received CR signal for a
fast trip, so its dependability is lower than that of a blocking scheme.
15.1.2.1 Blocking schemes
In a blocking scheme a reverse looking zone is used to send a block signal to the remote end to
block an overreaching zone.
Bay control REC670
Application manual
Scheme communication
IEC 61850
identification
ZCPSCH
© Copyright 2017 ABB. All rights reserved
IEC 60617 ANSI/IEEE C37.2
identification device number
- 85
Section 15
Scheme communication
IP15749-1 v3
M14854-1 v4
IP15020-1 v1
M16866-3 v5
M16866-24 v5
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