CCRBRF provides three different options to select how
t1
and
t2
timers are run:
1. By external start signals which is internally latched
2. Follow external start signal only
3. Follow external start signal and the selected
FunctionMode
CCRBRF can be single- or three- phase initiated to allow
its use with single phase tripping applications. For the
three-phase application of the CCRBRF the current
criteria can be set to operate only if
“2 elements
operates out of three phases and neutral”
for example;
two phases or one phase plus the residual current start.
This gives a higher security to the backup trip command.
The CCRBRF function can be programmed to give a
single- or three- phase retrip to its own breaker to avoid
unnecessary tripping of surrounding breakers at an
incorrect initiation due to mistakes during testing.
Stub protection STBPTOC
M12902-3 v10
When a power line is taken out of service for
maintenance and the line disconnector is opened in
multi-breaker arrangements the voltage transformers
will mostly be outside on the disconnected part. The
primary line distance protection will thus not be able to
operate and must be blocked.
The stub protection (STBPTOC) covers the zone between
the current transformers and the open disconnector.
The three-phase instantaneous overcurrent function is
released from a normally open, NO (b) auxiliary contact
on the line disconnector.
Pole discordance protection CCPDSC
M13269-3 v15
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
SEMOD175421-4 v7
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:
• detection of reversed active power flow
• detection of high reactive power flow
Each function has two steps with definite time delay.
Broken conductor check BRCPTOC
SEMOD171446-5 v2
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
GUID-935E1CE8-601F-40E2-8D22-2FF68420FADF v6
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.
Average Power Transient Earth Fault Protection
APPTEF
GUID-A16ED4BC-855F-4561-8512-B4F30775784F v1
The APPTEF (Average Power Transient Earth Fault
Protection) function is a transient measuring directional
earth-fault protection. Determination of the earth fault
direction is based on the short-term built-up transient
at the beginning of the earth fault. This transient is to a
large extent independent of the neutral point treatment.
This means that the function can be used without any
modification in all types of high-impedance grounded,
resonant grounded or isolated power systems.
For a resonant grounded system, the correct directional
measurement is ensured regardless of how many
Petersen coils are used throughout the interconnected
power network. The function is not sensitive to the
actual compensation degree of the coils. It will operate
equally well in an under- or over-compensated system.
Parallel neutral resistor to the Petersen coil are not
needed to correctly determine earth fault direction.
However, these neutral resistors can still be used if
already installed in the network.
The function is suitable to be used in distribution and in
meshed HV sub-transmission networks using high-
impedance grounding. In meshed systems a directional
permissive scheme is required in order to ensure
Line differential protection RED670
1MRK 505 379-BEN N
40 Hitachi Power Grids
© Copyright 2017 Hitachi Power Grids. All rights reserved
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