This paper introduces a proposed modern philosophy/algorithm for transient stability assessment based on critical
energy function of individual machines. The algorithm depends on the creation of energy function for individual machines using
the online measurements via the Synchronized Phasor Measurement Units (SPMUs). For further speeding up the algorithm for
online assessment, a parallel algorithm for stability assessment is implemented. The proposed algorithm makes online
calculation the potential and kinetic energies for each machine in power system and then compares the total system energy to
the critical energy of the system. A decision based on the online comparison produces an output operand according to stability
situation of the power system. The proposed algorithm is tested by two machine infinite Bus test system to ensure its
effectiveness and validity.