Frequency Protection; Multipurpose Protection - ABB Relion RES670 Product Manual

Phasor measurement unit RES670 2.1 IEC
OV2PTOV has two voltage steps, each of them with
inverse or definite time delayed.
OV2PTOV has a high reset ratio to allow settings close
to system service voltage.

8. Frequency protection

Underfrequency protection SAPTUF
Underfrequency occurs as a result of a lack of
generation in the network.
Underfrequency protection SAPTUF measures frequency
with high accuracy, and is used for load shedding
systems, remedial action schemes, gas turbine startup
and so on. Separate definite time delays are provided
for operate and restore.
SAPTUF is provided with undervoltage blocking.
The operation is based on positive sequence voltage
measurement and requires two phase-phase or three
phase-neutral voltages to be connected. For information
about how to connect analog inputs, refer to
Application manual/IED application/Analog inputs/
Setting guidelines
Overfrequency protection SAPTOF
Overfrequency protection function SAPTOF is applicable
in all situations, where reliable detection of high
fundamental power system frequency is needed.
Overfrequency occurs because of sudden load drops or
shunt faults in the power network. Close to the
generating plant, generator governor problems can also
cause over frequency.
SAPTOF measures frequency with high accuracy, and is
used mainly for generation shedding and remedial
action schemes. It is also used as a frequency stage
initiating load restoring. A definite time delay is
provided for operate.
SAPTOF is provided with an undervoltage blocking.
The operation is based on positive sequence voltage
measurement and requires two phase-phase or three
phase-neutral voltages to be connected. For information
about how to connect analog inputs, refer to
Application manual/IED application/Analog inputs/
Setting guidelines
Rate-of-change frequency protection SAPFRC
The rate-of-change frequency protection function
SAPFRC gives an early indication of a main disturbance
in the system. SAPFRC measures frequency with high
accuracy, and can be used for generation shedding, load
shedding and remedial action schemes. SAPFRC can
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discriminate between a positive or negative change of
frequency. A definite time delay is provided for operate.
SAPFRC is provided with an undervoltage blocking. The
operation is based on positive sequence voltage
measurement and requires two phase-phase or three
phase-neutral voltages to be connected. For information
about how to connect analog inputs, refer to
Application manual/IED application/Analog inputs/
Setting guidelines.
M13349-3 v12
Frequency time accumulation protection FTAQFVR
Frequency time accumulation protection FTAQFVR is
based on measured system frequency and time
counters. FTAQFVR for generator protection provides
the START output for a particular settable frequency
limit, when the system frequency falls in that settable
frequency band limit and positive sequence voltage
within settable voltage band limit. The START signal
triggers the individual event timer, which is the
continuous time spent within the given frequency band,
and the accumulation timer, which is the cumulative
time spent within the given frequency band. Once the
timers reach their limit, an alarm or trip signal is
activated to protect the turbine against the abnormal
frequency operation. This function is blocked during
generator start-up or shut down conditions by
monitoring the circuit breaker position and current
threshold value. The function is also blocked when the
M14953-3 v11
system positive sequence voltage magnitude deviates
from the given voltage band limit which can be enabled
EnaVoltCheck setting.
by
It is possible to create functionality with more than one
frequency band limit by using multiple instances of the
function. This can be achieved by a proper configuration
based on the turbine manufacturer specification.

9. Multipurpose protection

General current and voltage protection CVGAPC
The General current and voltage protection (CVGAPC)
can be utilized as a negative sequence current
protection detecting unsymmetrical conditions such as
open phase or unsymmetrical faults.
CVGAPC can also be used to improve phase selection for
high resistive earth faults, outside the distance
protection reach, for the transmission line. Three
functions are used, which measures the neutral current
and each of the three phase voltages. This will give an
independence from load currents and this phase
M14965-3 v12
selection will be used in conjunction with the detection
of the earth fault from the directional earth fault
protection function.
1MRK 511 367-BEN D
GUID-020CE8CF-9BEA-455D-ACBD-13023B93B4D1 v4
M13083-11 v9
ABB