ABB RELION 670 Series Product Manual page 33

Transformer protection RET670 2.1 IEC
The estimated time to trip before operation is
presented.
Breaker failure protection CCRBRF
Breaker failure protection (CCRBRF) ensures a fast
backup tripping of the surrounding breakers in case the
own breaker fails to open. CCRBRF can be current-
based, contact-based or an adaptive combination of
these two conditions.
A current check with extremely short reset time is used
as check criterion to achieve high security against
inadvertent operation.
Contact check criteria can be used where the fault
current through the breaker is small.
CCRBRF can be single- or three-phase initiated to allow
use with single phase tripping applications. For the
three-phase version of CCRBRF the current criteria can
be set to operate only if two out of four for example,
two phases or one phase plus the residual current start.
This gives a higher security to the back-up trip
command.
CCRBRF function can be programmed to give a single- or
three-phase re-trip of its own breaker to avoid
unnecessary tripping of surrounding breakers at an
incorrect initiation due to mistakes during testing.
Pole discordance protection CCPDSC
An open phase can cause negative and zero sequence
currents which cause thermal stress on rotating
machines and can cause unwanted operation of zero
sequence or negative sequence current functions.
Normally the own breaker is tripped to correct such a
situation. If the situation persists the surrounding
breakers should be tripped to clear the unsymmetrical
load situation.
The Pole discordance protection function CCPDSC
operates based on information from auxiliary contacts
of the circuit breaker for the three phases with
additional criteria from unsymmetrical phase currents
when required.
Directional over/underpower protection GOPPDOP/
GUPPDUP
The directional over-/under-power protection
GOPPDOP/GUPPDUP can be used wherever a high/low
active, reactive or apparent power protection or
alarming is required. The functions can alternatively be
used to check the direction of active or reactive power
flow in the power system. There are a number of
applications where such functionality is needed. Some
of them are:
ABB
• detection of reversed active power flow
• detection of high reactive power flow
Each function has two steps with definite time delay.
M11550-6 v16
Broken conductor check BRCPTOC
The main purpose of the function Broken conductor
check (BRCPTOC) is the detection of broken conductors
on protected power lines and cables (series faults).
Detection can be used to give alarm only or trip the line
breaker.
Voltage-restrained time overcurrent protection
VRPVOC
Voltage-restrained time overcurrent protection
(VRPVOC) function can be used as generator backup
protection against short-circuits.
The overcurrent protection feature has a settable
current level that can be used either with definite time
or inverse time characteristic. Additionally, it can be
voltage controlled/restrained.
One undervoltage step with definite time characteristic
is also available within the function in order to provide
functionality for overcurrent protection with
undervoltage seal-in.
Capacitor bank protection (CBPGAPC)
Shunt Capacitor Banks (SCB) are used in a power system
to provide reactive power compensation and power
M13269-3 v14
factor correction. They are as well used as integral parts
of Static Var Compensators (SVC) or Harmonic Filters
installations. Capacitor bank protection (CBPGAPC)
function is specially designed to provide protection and
supervision features for SCBs.
Negative sequence time overcurrent protection for
machines NS2PTOC
Negative-sequence time overcurrent protection for
machines NS2PTOC is intended primarily for the
protection of generators against possible overheating
of the rotor caused by negative sequence current in the
stator current.
The negative sequence currents in a generator may,
among others, be caused by:
• Unbalanced loads
SEMOD175421-4 v6
• Line to line faults
• Line to earth faults
• Broken conductors
• Malfunction of one or more poles of a circuit breaker
or a disconnector
NS2PTOC can also be used as a backup protection, that
is, to protect the generator in case line protections or
circuit breakers fail to clear unbalanced system faults.
1MRK 504 155-BEN F
SEMOD171446-5 v2
GUID-935E1CE8-601F-40E2-8D22-2FF68420FADF v6
GUID-D55CEBF7-9377-4E36-BD8B-533609048A1E v2
GUID-DBF3EC07-D947-4483-ABD1-4F7D29F48D61 v6
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