Phasor Measurement Unit Calibration - GE D90 Plus Instruction Manual

CHAPTER 11: METERING

Phasor Measurement Unit calibration

PLUS
D90 LINE DISTANCE PROTECTION SYSTEM – INSTRUCTION MANUAL
symmetrical components (0, 1, and 2) of both voltages and currents. When configuring
communication and recording features of the PMU, the user can select—from the above
superset—the content to be sent out or recorded.
Post-Filter
Range: None, Symm-3-point, Symm-5-point, Symm-7-point
Default: Symm-3-point
This setting specifies amount of post-filtering applied to raw synchrophasor
measurements. The raw measurements are produced at the rate of nominal system
frequency using one-cycle data windows. This setting is provided to deal with interfering
frequencies and to balance speed and accuracy of synchrophasor measurements for
different applications. The following filtering choices are available:
– None — No post-filtering
– Symm-3-point — Symmetrical three-point filter (one historical point, one present
point, one future point)
– Symm-5-point — Symmetrical five-point filter (two historical points, one present
point, two future points)
– Symm-7-point — Symmetrical seven-point filter (three historical points, one
present point, three future points)
This setting applies to all channels of the PMU. It is effectively for recording and
transmission on all ports configured to use data for the PMU.
Select the Settings > Metering > Synchrophasors > PMU Calibration menu to open the
Phasor Measurement Unit calibration window.
Figure 466: Phasor Measurement Unit calibration settings
The following settings are available for each PMU. These settings specify user angle
calibration data. This data is combined with the factory adjustments to shift the phasors
for better accuracy.
Va Angle, Vb Angle, Vc Angle, Vx Angle
Range: –5.00 to 5.00° in steps of 0.05
Default: 0.00°
These settings recognize applications with protection class voltage and current sources,
and they allow the user to calibrate each channel (phase A, B, and C voltage, as well as
auxiliary voltage) individually to offset errors introduced by VTs, CTs, and cabling. The
setting values are effectively added to the measured angles. Enter a positive correction if
the secondary signal lags the true signal. Enter a negative value if the secondary signal
leads the true signal.
PHASOR MEASUREMENT UNIT
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