Out-Of-Step Protection Oosppam; Phase Preference Logic Pplphiz; Four Step Phase Overcurrent Protection Oc4Ptoc; Instantaneous Residual Overcurrent Protection Efpioc - ABB RET670 Product Manual

Transformer protection RET670 2.0
Product version: 2.0
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
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.
Underimpedance protection for generators and transformers
ZGVPDIS
The under impedance protection is a three zone full scheme
impedance protection using offset mho characteristics for
detecting faults in the generator, generator-transformer and
transmission system. The three zones have fully independent
measuring loops and settings. The functionality also comprises
an under voltage seal-in feature to ensure issuing of a trip even
if the current transformer goes into saturation and, in addition,
the positive-sequence-based load encroachment feature for
the second and the third impedance zone. Built-in
compensation for the step-up transformer vector group
connection is available.
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.
ABB

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.
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 use
for instantaneous earth-fault protection, with the reach limited
to less than typical eighty percent of the transformer impedance
at minimum source impedance. EFPIOC can be configured to
measure the residual current from the three-phase current
inputs or 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.
IDir, UPol and IPol can be independently selected to be either
zero sequence or negative sequence.
Second harmonic blocking can be set individually for each step.
Residual current can be calculated by summing the three phase
currents or taking the input from neutral CT
Four step negative sequence overcurrent protection
NS4PTOC
Four step negative 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.
1MRK 504 141-BEN C
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