The first part of the book discusses the online controller coordination requirements in WAN (wide-area network) which gives motivation to the new innovative schemes to predict future system status by a look-ahead approach to maintain system transient stability by introducing proper thyristor controlled series compensation (TCSC) in the post-disturbance scenario. The important feature of this scheme is in giving a general feasible approach by considering various time delays such as the communication channel delays and computation delays which are significant in geographically wide-spread power system network, WAN. The second part of the book develops the strategy for an estimation of the internal state variables, of a synchronous generator, based on available measurements. With the reducing cost of phasor measurement units (PMUs) and wide-area communication network, the research develops a new estimation strategy to investigate the actual values of internal state variables for accurate comment on power system transient stability in any operating conditions (steady state or transient) using available limited sets of measurements.