Identification; Application; Setting Guidelines - ABB Relion REC670 Applications Manual

Section 7
Current protection
7.11.1

Identification

Function description
Pole discordance protection
7.11.2

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 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
and the protection will operate.
7.11.3

Setting guidelines

The parameters for the Pole discordance protection CCPDSC are set via the local HMI or
PCM600.
The following settings can be done for the pole discordance protection.
GlobalBaseSel : Selects the global base value group used by the function to define ( IBase ),
UBase ) and ( SBase ).
(
Operation : Off or On
tTrip : Time delay of the operation.
ContSel : Operation of the contact based pole discordance protection. Can be set: Off / PD
signal from CB . If PD signal from CB is chosen the logic to detect pole discordance is made in
the vicinity to the breaker auxiliary contacts and only one signal is connected to the pole
discordance function. If the
connected to the IED and the logic to detect pole discordance is realized within the function
itself.
152
IEC 61850 IEC 60617
identification identification
CCPDSC
SYMBOL-S V1 EN-US
CurrUnsymLevel this is an indication of pole discordance,
Pole pos aux cont. alternative is chosen each open close signal is
ANSI/IEEE C37.2
device number
52PD
PD
Application manual
1MRK 511 358-UEN A
M14888-1 v4
M13270-3 v6
M13274-3 v8