A method and system for real-time monitoring of a power system having a plurality of locations forming a transmission and distribution grid, wherein each location includes a plurality of connected components. A plurality of pseudorandom signals are injected at selected locations in the power system. A plurality of power system data are collected at other locations in the power system in response to the injected signals. A dynamic behavior of the power system is determined through a synchronized cross-correlation of the injected signals with the collected power system data. The dynamic behavior of the power system is analyzed to assess a dynamic stability and security state of the power system. The real-time, dynamic stability and security state of the power system is displayed to an operator at a monitoring station. The operational stability and security state can be depicted on an overlay of the nationwide power system grid.