ABB REG670 Product Manual page 25

Generator protection REG670 2.2 and Injection equipment REX060,
REX061, REX062
Product version: 2.2.1
Directional residual overcurrent protection, four steps
EF4PTOC
Directional residual overcurrent protection, four steps
(EF4PTOC) can be used as main protection for phase-to-
earth faults. It can also be used to provide a system back-up,
for example, in the case of the primary protection being out of
service due to communication or voltage transformer circuit
failure.
EF4PTOC has an inverse or definite time delay independent
for each step.
All IEC and ANSI time-delayed characteristics are available
together with an optional user-defined characteristic.
EF4PTOC can be set to be directional or non-directional
independently for each step.
IDir, UPol and IPol can be independently selected to be either
zero sequence or negative sequence.
A second harmonic blocking can be set individually for each
step.
Directional operation can be combined together with the
corresponding communication logic in permissive or blocking
teleprotection scheme. The current reversal and weak-end
infeed functionality are available as well.
The residual current can be calculated by summing the three-
phase currents or taking the input from the neutral CT.
Four step directional negative phase sequence overcurrent
protection NS4PTOC
Four step directional negative phase sequence overcurrent
protection (NS4PTOC) has an inverse or definite time delay
independent for each step separately.
All IEC and ANSI time delayed characteristics are available
together with an optional user defined characteristic.
The directional function is voltage polarized.
NS4PTOC can be set directional or non-directional
independently for each of the steps.
NS4PTOC can be used as main protection for unsymmetrical
fault; phase-phase short circuits, phase-phase-earth short
circuits and single phase earth faults.
NS4PTOC can also be used to provide a system backup for
example, in the case of the primary protection being out of
service due to communication or voltage transformer circuit
failure.
Directional operation can be combined together with
corresponding communication logic in permissive or blocking
teleprotection scheme. The same logic as for directional zero
sequence current can be used. Current reversal and weak-
end infeed functionality are available.
ABB
M13667-3 v19
GUID-485E9D36-0032-4559-9204-101539A32F47 v6
Sensitive directional residual overcurrent and power
protection SDEPSDE
In isolated networks or in networks with high impedance
earthing, the earth fault current is significantly smaller than
the short circuit currents. In addition to this, the magnitude of
the fault current is almost independent on the fault location in
the network. The protection can be selected to use either the
residual current or residual power component 3U0·3I0·cos j,
for operating quantity with maintained short circuit capacity.
There is also available one nondirectional 3I0 step and one
3U0 overvoltage tripping step.
No specific sensitive current input is needed. Sensitive
directional residual overcurrent and power protection
(SDEPSDE) can be set as low 0.25% of IBase.
Thermal overload protection, two time constants TRPTTR
If a power transformer reaches very high temperatures the
equipment might be damaged. The insulation within the
transformer will experience forced ageing. As a consequence
of this the risk of internal phase-to-phase or phase-to-earth
faults will increase.
The thermal overload protection estimates the internal heat
content of the transformer (temperature) continuously. This
estimation is made by using a thermal model of the
transformer with two time constants, which is based on
current measurement.
Two warning levels are available. This enables actions in the
power system to be done before dangerous temperatures are
reached. If the temperature continues to increase to the trip
value, the protection initiates a trip of the protected
transformer.
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 unwanted
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
1MRK 502 074-BEN A
SEMOD171438-5 v6
M13243-3 v11
M11550-6 v17
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