GE Grid Solutions
D25
User's Manual
GE Information
994-0081-3.00-21
137
CT/PT Modules,
Continued
42x Nominal
CT Module
To compensate for the current transformer’s possible magnitude inaccuracy, it
must be calibrated using a precision current source.
Use the following procedures to measure the magnitude error at both
metering and over-current levels. Use your measurements to calculate the
calibration factors to compensate for the gain error.
Note
: The label inside the D25 box stating the compensation factors should
be removed or corrected by the technician. A new label will not be supplied
with the CT/PT modules.
Procedure:
Metering
Range
Calibration
(0% - 195%)
Steps to calibrate the transformer for inputs in the metering range:
Step
Action
1.
Using SGConfig:
•
Set the calibration and correction factors for the phase and magnitude
to the following default values:
1.00000 for magnitude, and 0.00000 for phase.
−
To set the calibration factors, go to
D25 AC Configuration>Calibration tab>Internal Calibration tab
−
To set the correction factors, go to
D25 AC Configuration >Calibration tab>External Correction tab.
•
Set the configured frequency to match the test signal’s frequency
(either 50 or 60 Hz).
−
To set the configured frequency, go to:
D25 DCA Configuration>Advanced tab>Line Frequency
•
Set each input’s magnitude point Report Deadband to zero and
Averaging ON.
−
To set the Report Deadband, go to:
D25 AC Configuration>I/O Configuration tab>Physical AC
Analog Inputs>Report Deadband
−
To set the Averaging, go to:
D25 AC Configuration>I/O Configuration tab>Physical AC
Analog Inputs>Averaging
2.
Generate and download the configuration to the unit you are
calibrating.
3.
For each input use a precision AC current source to inject the test
currents indicated in the table in Step 4
Summary of Contents for D25
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