ABB Relion REG670, Руководство по эксплуатации продукта

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8. Frequency protection
Underfrequency protection SAPTUF
M13349-3 v13
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.
Overfrequency protection SAPTOF
M14953-3 v12
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.
Rate-of-change of frequency protection SAPFRC
M14965-3 v13
The rate-of-change of 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 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.
Frequency time accumulation protection FTAQFVR
GUID-020CE8CF-9BEA-455D-ACBD-13023B93B4D1 v5
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 system positive
sequence voltage magnitude deviates from the given voltage
band limit which can be enabled by
EnaVoltCheck
setting.
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
M13083-3 v6
The protection module is recommended as a general backup
protection with many possible application areas due to its
flexible measuring and setting facilities.
The built-in overcurrent protection feature has two settable
current levels. Both of them can be used either with definite
time or inverse time characteristic. The overcurrent protection
steps can be made directional with selectable voltage
polarizing quantity. Additionally they can be voltage and/or
current controlled/restrained. 2nd harmonic restraining facility
is available as well. At too low polarizing voltage the
overcurrent feature can be either blocked, made non
directional or ordered to use voltage memory in accordance
with a parameter setting.
Additionally two overvoltage and two undervoltage steps,
either with definite time or inverse time characteristic, are
available within each function.
The general function suits applications with underimpedance
and voltage controlled overcurrent solutions. The general
function can also be utilized for generator transformer
protection applications where positive, negative or zero
sequence components of current and voltage quantities are
typically required.
Additionally, generator applications such as loss of field,
inadvertent energizing, stator or rotor overload, circuit
breaker head flash-over and open phase detection are just a
few of possible protection arrangements with these functions.
1MRK 502 074-BEN A
Generator protection REG670 2.2 and Injection equipment REX060,
REX061, REX062
Product version: 2.2.1
ABB 29