A Novel Nonlinear Programming Model for Contingency Clearing Time Calculation

Based on interpolation formula or curve fitting of all generators´ swing curves before contingency clearing, time relating function about rotor angle and speed can be formed, time variable can be introduced into transient stability calculation, too. Under special rotor relating angle limitation, all swing equations of generators in power system are involved in equality constrains set, maximum rotor angle related to COI is used to be inequality constrains, maximum contingency clearing time to be target function, the paper presents a novel nonlinear programming model that can calculate maximum contingency clearing time accurately. With the technique of equivalent transformation, all these equality constrains and inequality constrains respect to transient stability will be converted into only one inequality constrains. An interior point algorithm for solving the proposed model is derived. Proposed model and algorithm possess significant simplifying structure, excellent convergence property and can be implement or program easily. Based on time domain emulating and numerical calculation completely, proposed model and algorithm are suitable for any generator and load modules very well.