Devices called Phasor Measurement Units (PMUs) report the values of (for example) amplitude, frequency and phase of the power system. These parameters describe a mathematical entity called a phasor. But the power system quantities are not phasors—they are 'phasor-like.' Their frequency and amplitude are not constant, and constant parameters are a requirement of a phasor. Further, the word phase is not even defined as a parameter relating two signals of different frequencies, and yet that is a required output of a PMU.
Kirkham, Harold
Related Projects
Description:
The new technology of Voltage Source Converters allows dc lines to be made into networks, much as ac lines are. However, some aspects of networking are different between ac (with which power engineers are familiar) and dc (which has not been networked). The first year of the study outlined the differences and began to explore some of the possibilities offered by networking dc. The follow-on work will continue to explore the benefits, and address some of the obstacles.
Description:
This study addresses the potential use of phasor measurement units (PMUs) within electricity distribution systems, and was written to assess whether or not PMUs could provide significant benefit, at the national level. We analyze examples of present and emerging distribution-system issues related to reliability, integration of distributed energy resources, and the changing electrical characteristics of load. We find that PMUs offer important and irreplaceable advantages over present approaches.