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N60 NETWORK STABILITY AND SYNCHROPHASOR MEASUREMENT SYSTEM – INSTRUCTION MANUAL
SYSTEM SETUP
CHAPTER 5: SETTINGS
5
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.
PMU 1 df/dt TRIGGER RAISE
— Specifies the pickup threshold for the rate of change of frequency in the raising direction
(positive df/dt). The comparator applies a 4% hysteresis.
PMU 1 df/dt TRIGGER FALL
— Specifies the pickup threshold for the rate of change of frequency in the falling direction
(negative df/dt). The comparator applies a 4% hysteresis.
PMU 1 df/dt TRIGGER PKP TIME
— Use to filter out spurious conditions and avoid unnecessary triggering of the recorder.
PMU 1 df/dt TRIGGER DPO TIME
— Use to extend the trigger after the situation returns to normal. This setting is of importance
when using the recorder in the forced mode (recording as long as the triggering condition is asserted).
Figure 5-97: Rate of change of frequency trigger logic
5.5.7.18 PMU recording
SETTINGS
SYSTEM SETUP
PHASOR MEASUREMENT UNIT
PHASOR MEASUREMENT UNIT 1(6)
RECORDING PMU 1(6)
PMU 1 FUNCTION
— This setting enables or disables the recorder for PMU 1. The rate is fixed at the reporting rate set within
the aggregator (that is, Aggregator 1).
PMU 1 NO OF TIMED RECORDS
— Specifies the number of timed records that are available for a given logical PMU 1. The
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.
PMU 1 TRIGGER MODE
— Specifies what happens when the recorder uses its entire available memory storage. With
“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.
PMU 1 df/dt TRIGGER
EVENTS: Disabled
Range: Enabled, Disabled
PMU 1
RECORDING
PMU 1 FUNCTION:
Disabled
Range: Enabled, Disabled
PMU 1 NO OF TIMED
RECORDS: 10
Range: 2 to 128 in steps of 1
PMU 1 TRIGGER MODE:
Automatic Overwrite
Range: Automatic Overwrite, Protected
PMU 1 TIMED TRIGGER
POSITION: 10%
Range: 1 to 50% in steps of 1