Phasor Measurement Unit Calibration - GE D90 Plus Instruction Manual
Line distance protection system
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CHAPTER 11: METERING
Phasor measurement unit calibration
PLUS
D90
LINE DISTANCE PROTECTION SYSTEM – INSTRUCTION MANUAL
both voltages and currents. When configuring communication and recording features of
the phasor measurement unit, the user could 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 phasor measurement unit. It is effectively for
recording and transmission on all ports configured to use data for the phasor
measurement unit.
Select the Settings > Metering > Synchrophasors > PMU Calibration menu item to open
the phasor measurement unit calibration window.
Figure 400: Phasor measurement unit calibration settings
The following settings are available for each phasor measurement unit. 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 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
PHASOR MEASUREMENT UNIT
475
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