Current Protection; Out-Of-Step Protection Oosppam; Four-Step Phase Overcurrent Protection Oc4Ptoc; Instantaneous Phase Overcurrent Protection Phpioc - ABB RED670 Product Manual

Line differential protection RED670 2.1 IEC
Product version: 2.1
other. If the connection between the generators is too weak the
magnitude of the oscillations will increase until the angular
stability is lost.
The operation of a generator having pole slip will give risk of
damages to the generator, shaft and turbine.
• At each pole slip there will be significant torque impact on
the generator-turbine shaft.
• In asynchronous operation there will be induction of
currents in parts of the generator normally not carrying
current, thus resulting in increased heating. The
consequence can be damages on insulation and stator/
rotor iron.
The Pole slip protection (PSPPPAM) function shall detect pole
slip conditions and trip the generator as fast as possible if the
locus of the measured impedance is inside the generator-
transformer block. If the centre of pole slip is outside in the
power grid, the first action should be to split the network into
two parts, after line protection action. If this fails there should be
operation of the generator PSPPPAM in zone 2, to prevent
further damages to the generator, shaft and turbine.
Pole slip protection PSPPPAM
Sudden events in an electric power system such as large
changes in load, fault occurrence or fault clearance, can cause
power oscillations referred to as power swings. In a non-
recoverable situation, the power swings become so severe that
the synchronism is lost, a condition referred to as pole slipping.
The main purpose of the pole slip protection (PSPPPAM) is to
detect, evaluate, and take the required action for pole slipping
occurrences in the power system.

Out-of-step protection OOSPPAM

The out-of-step protection OOSPPAM function in the IED can
be used for both generator protection and as well for line
protection applications.
The main purpose of the OOSPPAM function is to detect,
evaluate, and take the required action during pole slipping
occurrences in the power system.
The OOSPPAM function detects pole slip conditions and trips
the generator as fast as possible, after the first pole-slip if the
center of oscillation is found to be in zone 1, which normally
includes the generator and its step-up power transformer. If the
center of oscillation is found to be further out in the power
system, in zone 2, more than one pole-slip is usually allowed
before the generator-transformer unit is disconnected. A
parameter setting is available to take into account the circuit
breaker opening time. If there are several out-of-step relays in
the power system, then the one which finds the center of
oscillation in its zone 1 should operate first.
Two current channels I3P1 and I3P2 are available in OOSPPAM
function to allow the direct connection of two groups of three-
phase currents; that may be needed for very powerful
generators, with stator windings split into two groups per
ABB
phase, when each group is equipped with current transformers.
The protection function performs a simple summation of the
currents of the two channels I3P1 and I3P2.
Phase preference logic PPLPHIZ
The optional phase preference logic main purpose is to provide
a selective tripping for cross-country faults in isolated or high
impedance-earthed networks.
Automatic switch onto fault logic, voltage and current based
ZCVPSOF
Automatic switch onto fault logic (ZCVPSOF) is a function that
gives an instantaneous trip at closing of breaker onto a fault. A
dead line detection check is provided to activate the function
when the line is dead.

5. Current protection

Instantaneous phase overcurrent protection PHPIOC

The instantaneous three phase overcurrent function has a low
transient overreach and short tripping time to allow use as a
high set short-circuit protection function.

Four-step phase overcurrent protection OC4PTOC

The four step three-phase overcurrent protection function
OC4PTOC has an inverse or definite time delay independent for
step 1 to 4 separately.
All IEC and ANSI inverse time characteristics are available
together with an optional user defined time characteristic.
The directional function needs voltage as it is voltage polarized
with memory. The function can be set to be directional or non-
directional independently for each of the steps.
A second harmonic blocking level can be set for the function
and can be used to block each step individually.
Instantaneous residual overcurrent protection EFPIOC
The Instantaneous residual overcurrent protection EFPIOC has
a low transient overreach and short tripping times to allow the
use for instantaneous earth-fault protection, with the reach
limited to less than the typical eighty percent of the line at
minimum source impedance. EFPIOC is configured to measure
the residual current from the three-phase current inputs and
can be configured to measure the current from a separate
current input.
Four step residual overcurrent protection, zero sequence and
negative sequence direction EF4PTOC
The four step residual overcurrent protection 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 directional or non-directional
independently for each of the steps.
1MRK 505 346-BEN -
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