Pole Discordance Protection Ccpdsc - ABB REG670 Applications Manual

Section 9
Current protection
9.9
9.9.1
9.9.2
374
t2MPh: Time delay of the back-up trip at multi-phase start. The critical fault clearance
time is often shorter in case of multi-phase faults, compared to single phase-to-earth
faults. Therefore there is a possibility to reduce the back-up trip delay for multi-phase
faults. Typical setting is 90 – 150 ms.
t3: Additional time delay to t2 for a second back-up trip TRBU2. In some applications
there might be a requirement to have separated back-up trip functions, tripping
different back-up circuit breakers.
tCBAlarm: Time delay for alarm in case of indication of faulty circuit breaker. There
is a binary input CBFLT from the circuit breaker. This signal is activated when
internal supervision in the circuit breaker detect that the circuit breaker is unable to
clear fault. This could be the case when gas pressure is low in a SF6 circuit breaker.
After the set time an alarm is given, so that actions can be done to repair the circuit
breaker. The time delay for back-up trip is bypassed when the CBFLT is active.
Typical setting is 2.0 seconds.
tPulse: Trip pulse duration. This setting must be larger than the critical impulse time
of circuit breakers to be tripped from the breaker failure protection. Typical setting is
200 ms.

Pole discordance protection CCPDSC

Identification
Function description
Pole discordance protection
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.
Generator protection REG670 2.2 IEC and Injection equipment REX060, REX061, REX062
IEC 61850 IEC 60617
identification identification
CCPDSC
PD
SYMBOL-S V1 EN
1MRK 502 071-UEN -
ANSI/IEEE C37.2
device number
52PD
Application manual