By Stephane Do, Global Product Manager
The other week PSL had the honor and pleasure of presenting at IEEE PES T&D Conference & Exposition in Denver, CO.
PSL’s founder, Alex McEachern presentation focused on “Synchrophasor Technology in Distribution Systems.” Alex talked about the technical challenges performing useful phasor measurements in distribution grids compared with the more common use in transmission grids. Amongst the many applications reviewed, his favorite was the detection of grid cyber-attack rehearsals with ultra-precise instruments, such as the microPMU.
Alex discussed the reasons why millidegree accuracy and resolution is key to measuring in distribution grids and micro-grids, as well as the technical challenges of measuring phase angles with very high accuracy. He also discussed the role of signal immunity from various noise sources, for example, with long cables connecting to GPS antennas (microPMU has a GPS receiver built into the antenna to prevent this very issue). Another challenge is the impact on phase angle accuracy when measuring downstream from a distribution transformer. Distribution transformers present a phase angle offset which is several orders of magnitude worse than the required accuracy. The good news is that this angle offset is usually stable over the course of at least a few minutes, so measurements of the variation of phase angles are relevant. Another challenge for distribution grid operators is the possible loss of real time communication during and after disturbances, and therefore lack of critical measurement data (microPMU continuously records and keeps phasor measurements in memory for extended outage periods of up to 15 days).
To learn more about cyber security and the role of synchrophasors, take a look at this March 27th IEEE Spectrum article: “Cyber Defense Tool Is an Early Warning System for Grid Attacks.”
Power Standards Lab
980 Atlantic Ave.
Alameda, California 94501
US: 1.888.SEMI.F47 or 1.888.736.4347