CHAPTER 11: METERING
PHASOR MEASUREMENT UNIT
D90
PLUS
LINE DISTANCE PROTECTION SYSTEM – INSTRUCTION MANUAL
547
Figure 475: Frequency rate of change triggering configuration settings
The following settings are available for each phasor measurement unit.
Function
Range: Enabled, Disabled
Default: Disabled
This setting enables and disables the phasor measurement unit frequency rate of
change triggering function.
Raise
Range: 0.10 to 15.00 Hz/s in steps of 0.01
Default: 0.25 Hz/s
This setting specifies the pickup threshold for the rate of change of frequency in the
raising direction (positive df/dt). The comparator applies a 3% hysteresis.
Fall
Range: 0.10 to 15.00 Hz/s in steps of 0.01
Default: 0.25 Hz/s
This setting specifies the pickup threshold for the rate of change of frequency in the
falling direction (negative df/dt). The comparator applies a 3% hysteresis.
Pickup Time
Range: 0.00 to 600.00 seconds in steps of 0.01
Default: 0.10 seconds
This setting can be used to filter out spurious conditions and avoid unnecessary
triggering of the recorder.
Dropout Time
Range: 0.00 to 600.00 seconds in steps of 0.01
Default: 1.00 seconds
This setting could be used to extend the trigger after the situation returned to normal.
This setting is of particular importance when using the recorder in the forced mode
(recording as long as the triggering condition is asserted).
Block
Range: any metering logic operand or shared operand
Default: OFF
Assertion of the operand assigned to this setting blocks operation of the phasor
measurement unit frequency rate of change triggering function.
Events
Range: Enabled, Disabled
Default: Disabled
This setting enables and disables the logging of phasor measurement unit frequency
rate of change triggering events in the sequence of events recorder.
