On the accuracy specifications of Phasor Measurement Units

A critical overview of the accuracy specifications of Phasor Measurement Units in the measurement of synchrophasors is presented in this work. The focus is both on the possible ambiguity arising from the definition of Total Vector Error (TVE), provided by the IEEE Standard C37.118-2005, and on the lack of homogeneity in the information provided by PMU manufacturers, that makes a very difficult task the comparison of the performance ensured by the different commercial devices. The discussion is based on both theoretical considerations and experimental results on PMU prototypes.

I. Introduction

The dynamic operation of modern power systems has become a crucial activity, combined with the ability to realize real-time system control. The correct behavior of control and protection schemes is based on the estimated state of the power system which, in turn, depends on data collected by a Wide Area Monitoring System (WAMS) in strategic points of the network.