GE D90 Plus Instruction Manual page 550

PHASOR MEASUREMENT UNIT
Frequency triggering
540
The trigger responds to the frequency signal of the Phasor Measurement Unit source. The
frequency is calculated from phase voltages, auxiliary voltage, phase currents, or ground
current, in this hierarchy, depending on the source configuration as per D90
This element requires that the frequency be above the minimum measurable value. If the
frequency is below this value, such as when the circuit is de-energized, the trigger drops
out.
Select the Settings > Metering > Phasor Measurement Unit > Triggering > Frequency
Trigger menu to open the PMU frequency triggering window.
Figure 470: Frequency triggering configuration settings
The following settings are available for each PMU.
Function
Range: Enabled, Disabled
Default: Disabled
This setting enables and disables the PMU frequency triggering function.
Low Frequency
Range: 20.00 to 70.00 Hz in steps of 0.01
Default: 49.00 Hz
This setting specifies the low threshold for the abnormal frequency trigger. The
comparator applies a 0.03 Hz hysteresis.
High Frequency
Range: 20.00 to 70.00 Hz in steps of 0.01
Default: 61.00 Hz
This setting specifies the high threshold for the abnormal frequency trigger. The
comparator applies a 0.03 Hz hysteresis.
Pickup Time
Range: 0.00 to 600.00 seconds in steps of 0.01
Default: 0.10 seconds
This setting is 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 is used 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).
PLUS
D90 LINE DISTANCE PROTECTION SYSTEM – INSTRUCTION MANUAL
CHAPTER 11: METERING
Plus
standards.