Overfrequency - GE T60 Instruction Manual

5.7 CONTROL ELEMENTS
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PATH: SETTINGS CONTROL ELEMENTS
 OVERFREQUENCY 1
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5
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
the level at which the overfrequency element is to pickup.
5-266
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OVERFREQUENCY

OVERFREQ 1 FUNCTION:
Disabled
OVERFREQ 1 BLOCK:
MESSAGE
Off
OVERFREQ 1 SOURCE:
MESSAGE
SRC 1
OVERFREQ 1 PICKUP:
MESSAGE
60.50 Hz
OVERFREQ 1 PICKUP
MESSAGE
DELAY: 0.500 s
OVERFREQ 1 RESET
MESSAGE
DELAY : 0.500 s
OVERFREQ 1 TARGET:
MESSAGE
Self-reset
OVERFREQ 1 EVENTS:
MESSAGE
Disabled
setting selects the source for the signal to be measured. The
Figure 5–141: OVERFREQUENCY SCHEME LOGIC
T60 Transformer Protection System

OVERFREQUENCY 1(4)
Range: Disabled, Enabled
Range: FlexLogic operand
Range: SRC 1, SRC 2, SRC 3, SRC 4, SRC 5, SRC 6
Range: 20.00 to 65.00 Hz in steps of 0.01
Range: 0.000 to 65.535 s in steps of 0.001
Range: 0.000 to 65.535 s in steps of 0.001
Range: Self-reset, Latched, Disabled
Range: Disabled, Enabled
OVERFREQ 1 PICKUP
5 SETTINGS
5.7.6 OVERFREQUENCY
setting selects
GE Multilin