GE G60 Instruction Manual page 397

CHAPTER 5: SETTINGS
This element responds to frequency rate of change. Separate thresholds are provided for rising and dropping frequency.
The trigger responds to the rate of change of frequency (df/dt) of the Phasor Measurement Unit (PMU) source.
— Specifies the pickup threshold for the rate of change of frequency in the raising direction
PMU 1 df/dt TRIGGER RAISE
(positive df/dt). The comparator applies a 4% hysteresis.
— Specifies the pickup threshold for the rate of change of frequency in the falling direction
PMU 1 df/dt TRIGGER FALL
(negative df/dt). The comparator applies a 4% hysteresis.
PMU 1 df/dt TRIGGER PKP TIME
PMU 1 df/dt TRIGGER DPO TIME
when using the recorder in the forced mode (recording as long as the triggering condition is asserted).
5.5.7.18 PMU recording
SETTINGS  SYSTEM SETUP  PHASOR MEASUREMENT UNIT  PHASOR MEASUREMENT UNIT 1  RECORDING
PMU 1
 PMU 1
 RECORDING
— This setting enables or disables the recorder for PMU 1. The rate is fixed at the reporting rate set within
PMU 1 FUNCTION
the aggregator (that is, Aggregator 1).
— Specifies the number of timed records that are available for a given logical PMU 1. The
PMU 1 NO OF TIMED RECORDS
length of each record is equal to the available memory divided by the content size and number of records. As the number
of records is increased, the available storage for each record is reduced. The relay supports a maximum of 128 records in
either timed or forced mode.
— Specifies what happens when the recorder uses its entire available memory storage. With
PMU 1 TRIGGER MODE
"Automatic Overwrite," the last record is erased to facilitate new recording, when triggered. Under the "Protected"
selection, the recorder stops creating new records when the entire memory is used up by the old uncleared records.
G60 GENERATOR PROTECTION SYSTEM – INSTRUCTION MANUAL
PMU 1 df/dt TRIGGER

EVENTS: Disabled
— Use to filter out spurious conditions and avoid unnecessary triggering of the recorder.
— Use to extend the trigger after the situation returns to normal. This setting is of importance
Figure 5-97: Rate of change of frequency trigger logic
PMU 1 FUNCTION:

Disabled
PMU 1 NO OF TIMED

RECORDS: 10
PMU 1 TRIGGER MODE:

Automatic Overwrite
PMU 1 TIMED TRIGGER

POSITION: 10%
Range: Enabled, Disabled
Range: Enabled, Disabled
Range: 2 to 128 in steps of 1
Range: Automatic Overwrite, Protected
Range: 1 to 50% in steps of 1
SYSTEM SETUP
5
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