Applications and regulations
Synchrophasor
Also: PMU
A synchrophasor is a measurement of the phase angle and amplitude of voltage or current, carrying an extremely accurate time stamp. Phasor measurement units (PMUs) provide these measurements dozens of times per second from across the grid.
Because all PMUs are stamped to the same time (via GNSS or PTP), the grid operator can compare the state of the whole grid in real time and detect stability problems.