PT/CT correction

The primary application for PT/CT correction is to apply correction factors for ratio errors and phase angle errors to instrument transformers. Instrument transformer correction reduces or eliminates the need to replace transformers in installations where high accuracy is required.

PT/CT correction is done using the Instrument Transformer Correction (Instr Xformer) module. There is an ITC module for each current input (I1, I2, I3) and for each voltage input (V1, V2, V3) to the meter. Note that the correction affects only the 1-second values in the Power Meter module. No high-speed, harmonics, or waveform values are affected by the correction. For more information, see the ITC (Instr Xformer) module description in the ION Reference.

Configuring PT/CT correction

  1. Open the Setup Assistant for your meter. See the ION Setup Help for instructions.
  2. Select Revenue > PT/CT Correction.
  3. Select Active Correction on the ITC Correction tab then click Edit. The Transformer Correction Setup wizard appears.
  4. Select the checkbox beside the Voltage Inputs or Current Inputs and click Next. The first correction screen appears.
  5. Select a test point and click Edit to edit the test points. Click OK to return to the correction wizard then click Next to move to the next correction screen. Go through all the correction screens then click Finish.

    6. NOTE: You can select a maximum of eight (8) test points.

  6. Select Active Correction on the ITC Correction tab and click Analyze to access screens where you can input your wiring configuration and power system information.