OpenPMU GPS Disciplined DAQ


Accurate waveform sampling is essential for phase, frequency and harmonic estimation of power system measurements. For this information to be of use over a wide geographical area, it is important that the sampling process is disciplined by, and in phase with, a common timebase. This is normally UTC, frequently derived from the GPS satellite system (NAVSTAR).

The OpenPMU contributers are presently developing a GPS Disciplined Data Acquisition Card (DAQ) to enable developers of phase estimation techniques to test their algorithms on live data. Here follows a brief specification for the OpenPMU GPS Disciplined DAQ:

Sampling:
  • Input channels: - 8
  • Resolution: - at least 14-bits
  • Sampling rate: - 12 kHz
    • Disciplined by GPS / UTC
    • In phase with GPS / UTC
    • Each sample timed to better than ± 1 us
  • Windowed at 50 Hz and 60 Hz (i.e. 240 samples and 200 samples) (default)
  • Windowed at customisable sizes (extended, unsupported, functionality)

Communications:
  • UDP / IP
  • XML data payload (more here)
    • Time of acquisition
    • Date of acquisition
    • Location of acquisition
    • Waveform data payload
  • XML configuration settings

The intention of this data card is to acquire accurate waveform data for processing on an embedded PC. Data import tools will be written for popular analysis packages inc. Matlab, Labview and Python.

Last edited Jun 15, 2011 at 5:31 PM by clockdoctor, version 3

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