Assessment of time synchronization requirements for Phasor Measurement Units

This paper assesses time synchronization sources suitable for Phasor Measurement Unit (PMU) applications in power systems. The paper investigates PMU phase error due to PMU timing inaccuracy and the presence of current and voltage transformers. This paper also shows that in practical on-field applications of commercial PMUs, the required accuracy of the time source should be better than the 31.8µs limit mentioned in the IEEE Standard for Synchrophasor Measurements for Power Systems C37.118.1-2011 and could be well in the sub-microsecond range. The laboratory test set-up is discussed in brief.