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 {TAIL ~ a wide area monitoring system} to a central server clock at {HEAD ~ a Network Control Center} of 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 { TAIL ~ a wide area monitoring system } to a central server clock at { HEAD ~ a Network Control Center } of 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 TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH