  This letter studies the synchrophasor measurement error of electric power
distribution systems with on-line and off-line measurements using graphical and
numerical tests. It demonstrates that the synchrophasor measurement error
follows a non-Gaussian distribution instead of the traditionally-assumed
Gaussian distribution. It suggests the need to use non-Gaussian or Gaussian
mixture models to represent the synchrophasor measurement error. These models
are more realistic to accurately represent the error than the traditional
Gaussian model. The measurements and underlying analysis will be helpful for
the understanding of distribution system measurement characteristics, and also
for the modeling and simulation of distribution system applications.
