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Four step phase overcurrent protection OC4PTOC
The four step phase overcurrent protection function
OC4PTOC has an inverse or definite time delay independent
for step 1 and 4 separately. Step 2 and 3 are always definite
time delayed.
All IEC and ANSI inverse time characteristics are available
together with an optional user defined time characteristic.
The directional function 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 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 can be configured to
measure the residual current from the three-phase current
inputs or the current from a separate current input. EFPIOC
can be blocked by activating the input BLOCK.
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
separately.
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.
EF4PTOC can be used as main protection for phase-to-earth
faults.
EF4PTOC 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.
Directional operation can be combined together with
corresponding communication logic in permissive or blocking
teleprotection scheme. Current reversal and weak-end infeed
functionality are available as well.
EF4PTOC can be configured to measure the residual current
from the three-phase current inputs or the current from a
separate current input.
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 or dual 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 back-up 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.
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.SDEPSDE can
be set as low 0.25% of IBase.
Thermal overload protection, one time constant LPTTR
The increasing utilizing of the power system closer to the
thermal limits has generated a need of a thermal overload
protection also for power lines.
A thermal overload will often not be detected by other
protection functions and the introduction of the thermal
overload protection can allow the protected circuit to operate
closer to the thermal limits.
Bay control REC670
1MRK511232-BEN E
Pre-configured
Product version: 1.2
10
ABB
Содержание Relion 670 series REC670
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