GE Grid Solutions F60, Instruction Manual

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GE Multilin F60 Feeder Protection System 5-239
5 SETTINGS 5.7 CONTROL ELEMENTS
5
5.7.6 OVERFREQUENCY (ANSI 81O)
PATH: SETTINGS

CONTROL ELEMENTS

OVERFREQUENCY

OVERFREQUENCY 1(4)
There are four overfrequency elements, numbered 1 through 4.
A frequency calculation for a given source is made on the input of a voltage or current channel, depending on which is
available. The channels are searched for the signal input in the following order: voltage channel A, auxiliary voltage chan-
nel, current channel A, ground current channel. The first available signal is used for frequency calculation.
The steady-state frequency of a power system is an indicator of the existing balance between the generated power and the
load. Whenever this balance is disrupted through the disconnection of significant load or the isolation of a part of the sys-
tem that has a surplus of generation, the effect will be an increase in frequency. If the control systems of the generators do
not respond fast enough, to quickly ramp the turbine speed back to normal, the overspeed can lead to the turbine trip. The
overfrequency element can be used to control the turbine frequency ramp down at a generating location. This element can
also be used for feeder reclosing as part of the "after load shedding restoration".
The
OVERFREQ 1 SOURCE
setting selects the source for the signal to be measured. The
OVERFREQ 1 PICKUP
setting selects
the level at which the overfrequency element is to pickup.
Figure 5–112: OVERFREQUENCY SCHEME LOGIC

OVERFREQUENCY 1

OVERFREQ 1 FUNCTION:
Disabled
Range: Disabled, Enabled
MESSAGE
OVERFREQ 1 BLOCK:
Off
Range: FlexLogic operand
MESSAGE
OVERFREQ 1 SOURCE:
SRC 1
Range: SRC 1, SRC 2, SRC 3, SRC 4
MESSAGE
OVERFREQ 1 PICKUP:
60.50 Hz
Range: 20.00 to 65.00 Hz in steps of 0.01
MESSAGE
OVERFREQ 1 PICKUP
DELAY: 0.500 s
Range: 0.000 to 65.535 s in steps of 0.001
MESSAGE
OVERFREQ 1 RESET
DELAY : 0.500 s
Range: 0.000 to 65.535 s in steps of 0.001
MESSAGE
OVERFREQ 1 TARGET:
Self-reset
Range: Self-reset, Latched, Disabled
MESSAGE
OVERFREQ 1 EVENTS:
Disabled
Range: Disabled, Enabled
827832A6.CDR
FLEXLOGIC OPERANDS
OVERFREQ 1 FUNCTION:
OVERFREQ 1 BLOCK:
OVERFREQ 1 SOURCE:
OVERFREQ 1 PICKUP :
OVERFREQ 1 DPO
OVERFREQ 1 OP
OVERFREQ 1 PKP
RUN
AND
SETTING
SETTING
OVERFREQ 1 RESET
DELAY :
OVERFREQ 1 PICKUP
DELAY :
SETTING
Enabled = 1
t
PKP
t
RST
SETTING
SETTING
Off = 0
Frequency
f ≡ PICKUP