Abstract— Phasor Measurement Units (PMUs) are getting
increasingly popular. Major incidents in the near past, such as
the big blackouts in 2003 in the northeast of the USA and in Italy,
have raised the interest in all means that support the observation
of the condition of the electrical power network, assessing system
stability, and predicting problems. PMUs are perceived to be
valuable tools for this. The paper gives a brief introduction to the
principle of operation of PMUs and the metrics for assessing
their performance. Some exemplary test cases are explained and
possible test configurations to perform the test cases are
discussed. The shown methods are not only suited for laboratory
applications. The usage of a classical protection test set with
versatile time synchronization interfaces (GPS, IRIG-B, PPS)
brings PMU testing into the reach of protection engineers for
applications in the field.