ABB Relion REQ650, Руководство по применению

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GlobalBaseSel : Selects the global base value group used by the function to define
( IBase ), ( UBase ) and ( SBase ).
Operation : Off / On
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.
6.12 Pole discordance protection CCRPLD
6.12.1 Identification
Function description IEC 61850
identification
IEC 60617
identification
ANSI/IEEE C37.2
device number
Pole discordance protection CCRPLD
PD
SYMBOL-S V1 EN
52PD
6.12.2 Application
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 CCRPLD 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
and a signal can be sent to the pole discordance protection, indicating pole
discordance.
• 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 505 291-UEN A
Section 6
Current protection
141
Application manual