  With the increasing renewable energy sources, concerns about how renewable
energy sources impact frequency have risen. There are few reports regarding
power frequency status in worldwide main power grids and what are differences
of frequency status between power grids in mainland and island. FNET/GridEye, a
wide-area measurement system collecting frequency and phase angle data at the
distribution level, provides an opportunity to observe and study the power
frequency in different power grids over the world. In this paper, 13 different
power grids, spreading at different mainland and islands over the world, are
observed and compared. A more detail statistical analysis was conducted for
typical power grids in three different places, e.g., U.S Eastern
Interconnection (EI), Egypt, and Japan. The probability functions of frequency
based on the measured data are calculated. The distributions of frequency in
different power grids fall into two categories, e.g., single-peak distribution
and multi-peak distribution. Furthermore, a meaningful insight that the
single-peak distributions of the frequency almost follow the normal
distribution is found. The frequency observations and statistic analysis of
worldwide main power grids using FNET/GridEye could help the power system
operators understand the frequency statistical characteristic more deeply.
