The term "smart grid" covers a range of devices and systems that leverage recent advances in digital technology and communications to improve the efficiency, performance and reliability of the existing electric power system infrastructure.
Phasor measurement units, or PMUs, are a new "smart" technology being deployed throughout North America, monitoring what happens on the electric power system.
The North American SynchroPhasor Initiative (NASPI) reports there are about 500 networked PMUs installed. NASPI expects that approximately 1,000 PMUs will be in place and networked by the end of 2014, a timeline associated with the Department of Energy's Smart Grid Investment Grant (SGIG) program.
