Voltage Protection; Frequency Protection - ABB RES670 Product Manual

Phasor measurement unit RES670 ANSI
Customized
Product version: 1.2
There is also available one nondirectional 3I0 step and one 3V0
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 LPTTR
The increasing utilizing of the power system closer to the
thermal limits has generated a need of a thermal overload
protection also 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
characteristic with settable time constant and a thermal
memory..
An alarm pickup gives early warning to allow operators to take
action well before the line is tripped.

5. Voltage protection

Two step undervoltage protection UV2PTUV (27)
Undervoltages can occur in the power system during faults or
abnormal conditions. Two step undervoltage protection
(UV2PTUV, 27) 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 (27) has two voltage steps, each with inverse or
definite time delay.
Two step overvoltage protection OV2PTOV (59)
Overvoltages may occur in the power system during abnormal
conditions such as sudden power loss, tap changer regulating
failures, open line ends on long lines etc.
Two step overvoltage protection (OV2PTOV, 59) 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.
OV2PTOV (59) has two voltage steps, each of them with inverse
or definite time delayed.
OV2PTOV (59) has an extremely high reset ratio to allow
settings close to system service voltage.
10

6. Frequency protection

Underfrequency protection SAPTUF (81)
Underfrequency occurs as a result of a lack of generation in the
network.
Underfrequency protection SAPTUF (81) is used for load
shedding systems, remedial action schemes, gas turbine
startup and so on.
SAPTUF (81) is also 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
2
t
Overfrequency protection SAPTOF (81)
Overfrequency protection function SAPTOF (81) 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 (81) is used mainly for generation shedding and
remedial action schemes. It is also used as a frequency stage
initiating load restoring.
SAPTOF (81) 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 (81)
Rate-of-change frequency protection function (SAPFRC,81)
gives an early indication of a main disturbance in the system.
SAPFRC (81) can be used for generation shedding, load
shedding and remedial action schemes. SAPFRC (81) can
discriminate between positive or negative change of frequency.
SAPFRC (81) 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.
1MRK511254-BUS B
ABB