ABB REL670 2.2 IEC, Applications Manual

Page: 519 / 908

I> : Current level for the Stub protection, set in % of IBase . This parameter should
be set so that all faults on the stub can be detected. The setting should thus be based
on fault calculations.
t : Time delay of the operation. Normally the function shall be instantaneous.
9.10 Pole discordance protection CCPDSC
IP14516-1 v5
9.10.1 Identification
M14888-1 v4
Function description IEC 61850
identification
IEC 60617
identification
ANSI/IEEE C37.2
device number
Pole discordance protection CCPDSC
PD
SYMBOL-S V1 EN-US
52PD
9.10.2 Application
M13270-3 v6
There is a risk that a circuit breaker will get discordance between the poles at
circuit breaker operation: closing or opening. One pole can be open and the other
two closed, or two poles can be open and one closed. Pole discordance of a circuit
breaker will cause unsymmetrical currents in the power system. The consequence
of this can be:
• Negative sequence currents that will give stress on rotating machines
• Zero sequence currents that might give unwanted operation of sensitive earth-
fault protections in the power system.
It is therefore important to detect situations with pole discordance of circuit
breakers. When this is detected the breaker should be tripped directly.
Pole discordance protection CCPDSC will detect situation with deviating positions
of the poles of the protected circuit breaker. The protection has two different
options to make this detection:
• By connecting the auxiliary contacts in the circuit breaker so that logic is
created, a signal can be sent to the protection, indicating pole discordance.
This logic can also be realized within the protection itself, by using opened
and close signals for each circuit breaker pole, connected to the protection.
• Each phase current through the circuit breaker is measured. If the difference
between the phase currents is larger than a
CurrUnsymLevel this is an
indication of pole discordance, and the protection will operate.
1MRK 506 369-UEN B
Section 9
Current protection
Line distance protection REL670 2.2 IEC 513
Application manual