4. Current protection
Instantaneous phase overcurrent protection, 3-
phase output 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.
Instantaneous phase overcurrent protection,
phase segregated output SPTPIOC
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 and where the
requirement for tripping is one- and/or three-
phase.
Four step phase overcurrent protection, 3-phase
output 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.
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.
A 2nd harmonic blocking can be set individually
for each step.
Four step phase overcurrent protection, phase
segregated output OC4SPTOC
The four step phase overcurrent function, phase
segregated output (OC4SPTOC) has an inverse or
definite time delay independent for each step
separately.
All IEC and ANSI time delayed characteristics are
available.
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.
The tripping can be one- and/or three-phase.
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,
zero or negative sequence direction (EF4PTOC)
has a settable 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.
EF4PTOC can be set directional or non-
directional independently for each of the steps.
The directional part of the function can be set to
operate on following combinations:
• Directional current (I3PDir) versus Polarizing
voltage (U3PPol)
• Directional current (I3PDir) versus Polarizing
current (I3PPol)
• Directional current (I3PDir) versus Dual
polarizing (UPol+ZPol x IPol) where ZPol = RPol
+ jXPol
IDir, UPol and IPol can be independently selected
to be either zero sequence or negative sequence.
Second harmonic blocking restraint level can be
set for the function and can be used to block
each step individually.
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
Breaker protection REQ650
1MRK 505 283-BEN -
Product version: 1.2
ABB 17
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