ABB RELION 670 Series Technical Manual page 677

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