Open Source Time Synchronised Sampled Value Logger for Power System Studies

Time synchronized measurements in the form of synchrophasors have been successful in the last decades in improving understanding of AC electrical power systems. Most adoption has been at transmission voltages, and there is now interest in deploying such technology at lower voltages including distribution supply voltage. A complicating factor is that the wave shape of voltages and currents at these low voltage levels is incompatible with the measurement model of the Phasor Measurement Unit (PMU), and thus measurements produced using this model will be of questionable value. An alternative approach is to record the time synchronized sampled values (SV), sometimes called Continuous Point on Wave (CPOW). Access to empirical data at this level is necessary to improve understanding of measurement requirements at low voltages. This paper presents an open source software approach for long term recording and storage of time synchronized SVs, or CPOW, using either the OpenPMU GPS disciplined ADC, or professional substation merging unit technology.