Voltage Protection - ABB Relion RES670 Product Manual

Phasor measurement unit RES670 2.1 IEC
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.
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
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
LCPTTR/LFPTTR
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.
ABB
GUID-485E9D36-0032-4559-9204-101539A32F47 v5
SEMOD171438-5 v5
M12020-4 v13
The three-phase current measuring protection has an I
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 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.
Directional over/underpower protection GOPPDOP/
GUPPDUP
The directional over-/under-power protection
GOPPDOP/GUPPDUP can be used wherever a high/low
active, reactive or apparent power protection or
alarming is required. The functions can alternatively be
used to check the direction of active or reactive power
flow in the power system. There are a number of
applications where such functionality is needed. Some
of them are:
• detection of reversed active power flow
• detection of high reactive power flow
Each function has two steps with definite time delay.

7. Voltage protection

Two step undervoltage protection UV2PTUV
Undervoltages can occur in the power system during
faults or abnormal conditions. Two step undervoltage
protection (UV2PTUV) function can be used to open
circuit breakers to prepare for system restoration at
power outages or as long-time delayed back-up to
primary protection.
UV2PTUV has two voltage steps, each with inverse or
definite time delay.
UV2PTUV has a high reset ratio to allow settings close to
system service voltage.
Two step overvoltage protection OV2PTOV
Overvoltages may occur in the power system during
abnormal conditions such as sudden power loss, tap
changer regulating failures, and open line ends on long
lines.
Two step overvoltage protection (OV2PTOV) function
can be used to detect open line ends, normally then
combined with a directional reactive over-power
function to supervise the system voltage. When
triggered, the function will cause an alarm, switch in
reactors, or switch out capacitor banks.
1MRK 511 367-BEN D
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SEMOD175421-4 v6
M13789-3 v11
M13798-3 v14
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