AbstractThis paper presents an on‐line stabilization control method developed with the aim of maintaining transient stability in a local power system which includes large‐capacity generation plants. The characteristics of this method are that the power/angle curve is estimated from the on line active and reactive power measured at the generator terminal, and the optimum generation shedding for stabilization is determined by applying the equal area method to this curve.Simulation tests using detailed models of the power system confirmed that the optimum generation shedding for stabilization could be computed for various fault conditions, both symmetrical or asymmetrical.It was also determined that the on‐line data could be sampled for several tens of milliseconds after clearing the fault. Thus, this method provides effective control logic for practical stabilizing sy