Function Range or value Accuracy
Reset time, definite time function at f
set
- 0.02
Hz to f
set
+ 0.02 Hz
(0.000-60.000)s ±0.2% or ±120 ms whichever is
greater
Voltage dependent time delay Settings:
VNom=(50-150)% of V
base
VMin=(50-150)% of V
base
Exponent=0.0-5.0
t_MaxTripDelay=(0.010–
60.000)s
t_MinTripDelay=(0.010–
60.000)s
±1.0% or ±120 ms whichever is
greater
( )
_ _ _
Exponent
V VMin
t t MaxTripDelay t MinTripDelay t MinTripDelay
VNom VMin
-
= × - +
-
é ù
ê ú
ë û
EQUATION1559 V1 EN-US (Equation 200)
V=V
measured
10.2 Overfrequency protection SAPTOF (81)
IP15747-1 v3
10.2.1 Identification
M14866-1 v4
Function description IEC 61850
identification
IEC 60617
identification
ANSI/IEEE C37.2
device number
Overfrequency protection SAPTOF
SYMBOL-O V1 EN-US
81
10.2.2 Functionality
M14953-3 v11
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) 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 trip.
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
1MRK 502 066-UUS B Section 10
Frequency protection
671
Technical manual
To Next Page
Loading...
