Phasor Measurement Units (PMU) are distributed round a power network and send information to a central Phasor Data Concentrator (PDC) which records and analyses the data to detect stability issues. Although mostly used for Wide Area Measurement Systems (WAMS) on transmission grids PMUs are also used at distribution levels for special applications like angle constraint measurements.

With the embedded GPS receiver option can be used as a PMU which meets the IEEE standard C37.118-2011. Voltage, current and sequence component phasors can be included in the data frame along with the analogue and contact inputs. This function is supported on the Ethernet and serial ports. Data frame rates up to the supply frequency (50/60Hz) are supported.