Instantaneous residual overcurrent protection EFPIOC
M12701-3 v16
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.
Directional residual overcurrent protection, four steps
EF4PTOC
M13667-3 v19
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
GUID-485E9D36-0032-4559-9204-101539A32F47 v6
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.
Sensitive directional residual overcurrent and power
protection SDEPSDE
SEMOD171438-5 v6
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, one time constant LCPTTR/
LFPTTR
M12020-4 v14
The increasing utilization of the power system closer to the
thermal limits has generated a need of a thermal overload
protection 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.
The three-phase current measuring protection has an I
2
t
characteristic with settable time constant and a thermal
memory. The temperature is displayed in either Celsius or
Fahrenheit, depending on whether the function used is
Thermal overload protection (LCPTTR) (Celsius) or (LFPTTR)
(Fahrenheit).
An alarm level gives early warning to allow operators to take
action well before the line is tripped.
Estimated time to trip before operation, and estimated time to
reclose after operation are presented.
Thermal overload protection, two time constants TRPTTR
M13243-3 v11
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.
1MRK 511 404-BEN A
Bay control REC670 2.2
Product version: 2.2.1
ABB
29
