GTosPMU End of Life Notice - Sep 10, 2019
The GridTrak PMU concepts are still functional and repeatable. It appears to be still possible to find suppliers for all of the components and build the GTosPMU sensor and program its firmware for anyone wanting to test the concepts. However, the advances and lower cost for single board computers with their extra features and accessories make them a practical alternative for experimenting with synchrophasor measurement.

Project Description
The Open Source SynchroPhasor PMU Project provides resources that enable you to build your own SynchroPhasor measuring sensors for use with the openPDC project, research, development, or electric grid observation.

• Open source resources enable you to construct your own PMU for research, experimentation, development, or fun. The information provided here is intended to be reproducible, repeatable, and reusable in your own projects.
• The open source resources hosted here can be used with the openPDC - Open Source Phasor Data Concentrator project software.

The GridTrak PMU is a hardware sensor designed to measure and transmit AC SynchroPhasor Frequency, Phase Angle, and Magnitude digitally by:

• Converts the AC signal to complimentary square waves using a operatonal amplifier and precision voltage reference
• Uses a precision timer to measure square wave cycle (Frequency) and offset from a PPS time reference (Phase angle)
• Calculates Magnitude for the ideal sine wave of the signal
• Optionally uses GPS for precision PPS triggering and SynchroPhasor measurement values
• Transmits Data per IEEE C37.118-2005 specifications or in plain text
• Compatible with openPDC for extended application and systems development

The GridTrak concept filters out the original wave form, harmonics, and distortion by the square wave conversion of the analog input signal to a digital signal. If you need to measure or observe wave form distortion or harmonics, this is not the PMU for the job.

Photo - GridTrak Model A, Rev 9.5 kit Operational Open Source SynchroPhasor PMU with GPS Integration.
Photo - Testing a GridTrak Model A PMU with Garmin GPS 15xL-W.  A bypass capacitor (upper right) is added to the PPS to reduce transient false signals. Two serial port connections are shown.  A completed Model A PMU will only require 1 serial port connection for operation, however, the second serial port remains available for direct PC to GPS connection for development and diagnostics.