The time synchronization schemes based on a Global Positioning System and a wide area communication network can be combined to synchronize the stationary clocks of phasor measurement units of a wide area monitoring system to a central server clock at {HEAD ~ a Network Control Center} of {TAIL ~ the system} 
The time synchronization schemes based on a Global Positioning System and a wide area communication network can be combined to synchronize the stationary clocks of phasor measurement units of a wide area monitoring system to a central server clock at { HEAD ~ a Network Control Center } of { TAIL ~ the system }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL