An integrated scheme for on-line static and transient stability constrained ATC calculations

An integrated scheme is proposed for computing on-line power system available transfer capability (ATC) while meeting static and transient stability constraints. The approach is based on the coupling of an OPF program with a method, called MAT (maximum allowable transfer), which relies on SIME (single machine equivalent) and its variants. The way in which this combined approach proceeds is outlined. Basically, the approach takes care of the stability constraints by (generally) decreasing active power on critical machines, then reallocating power generation on noncritical machines so as to ensure maximum allowable power transfer on the considered tie-lines. Stated otherwise, the combined use of the MAT method with the OPF program succeeds in reaching the multifold objective: to guarantee maximum power transfer on the defined tie-lines, and to meet transient stability constraints vis-a-vis all plausible contingencies, together with static constraints. The whole procedure is robust, in the sense that it converges consistently and readily to the solution. It is also compatible with real-time requirements.