Frequency Rate Of Change (Ansi 81R) - GE G30 Instruction Manual

CHAPTER 5: SETTINGS
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
system that has a surplus of generation, the effect is 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 setting selects the source for the signal to be measured.
OVERFREQ 1 SOURCE
The setting selects the level at which the overfrequency element is to pickup.
OVERFREQ 1 PICKUP

5.8.7 Frequency rate of change (ANSI 81R)

SETTINGS  CONTROL ELEMENTS  FREQUENCY RATE OF CHANGE  FREQUENCY RATE OF CHANGE 1(4)
 FREQUENCY RATE
 OF CHANGE 1
G30 GENERATOR PROTECTION SYSTEM – INSTRUCTION MANUAL
Figure 5-142: Overfrequency logic
FREQ RATE 1

FUNCTION: Disabled
FREQ RATE 1 SOURCE:

SRC 1
FREQ RATE 1 TREND:

Increasing
FREQ RATE 1 PICKUP:

0.50 Hz/sec
FREQ RATE 1 OV SUPV

PICKUP: 0.700 pu
FREQ RATE 1 OC SUPV

PICKUP: 0.200 pu
FREQ RATE 1 MIN

FREQUENCY: 45.00 Hz
FREQ RATE 1 MAX

FREQUENCY: 65.00 Hz
FREQ RATE 1 PICKUP

DELAY: 0.000 s
FREQ RATE 1 RESET

DELAY: 0.000 s
FREQ RATE 1 BLOCK:

Off
Range: Disabled, Enabled
Range: SRC 1, SRC 2, SRC 3, SRC 4
Range: Increasing, Decreasing, Bi-directional
Range: 0.10 to 15.00 Hz/sec in steps of 0.01
Range: 0.100 to 3.000 pu in steps of 0.001
Range: 0.020 to 30.000 pu in steps of 0.001
Range: 20.00 to 80.00 Hz in steps of 0.01
Range: 20.00 to 80.00 Hz in steps of 0.01
Range: 0 to 65.535 s in steps of 0.001
Range: 0 to 65.535 s in steps of 0.001
Range: FlexLogic operand
CONTROL ELEMENTS
5
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