ABB REL670 2.2 IEC, Applications Manual

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Section 16 Scheme communication
16.1 Scheme communication logic for distance or
overcurrent protection ZCPSCH
IP15749-1 v3
16.1.1 Identification
M14854-1 v4
Function description IEC 61850
identification
IEC 60617
identification
ANSI/IEEE C37.2
device number
Scheme communication logic for
distance or overcurrent protection
ZCPSCH - 85
16.1.2 Application
IP15020-1 v1
M16866-3 v5
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
1MRK 506 369-UEN B
Section 16
Scheme communication
Line distance protection REL670 2.2 IEC 701
Application manual