Determination of reduced order model for torsional interaction investigations using selective modal analysis – Part II: Application to practical power systems

► Subsynchronous resonance (SSR) is usually experienced in a limited part of the network. ► The selective modal analysis (SMA) constructs a reduced order model involving only the relevant dynamics. ► Reduction process is carried out based on a linear differential algebraic equation model of the electric network. ► The modified SMA algorithm is verified using linearized model of the IEEE second benchmark model. ► A large 353 generator practical electric power system from Central Indian grid validates the algorithm. A new strategy is proposed based on selective modal analysis (SMA) for the determination of reduced order model in torsional interaction investigations of large electric power system. SMA computes eigenvalues associated with selected modes, then constructs a reduced order model that involves only the relevant variables, incorporating the effect of the less relevant dynamics by low order model. The reduction process is carried out based on linear differential algebraic equation (LDAE) model and illustrated on IEEE benchmark model. The model does not require preprocessing of data for removal of network state redundancy. A case study is conducted on a very large electric power system for validation of the results. The reduced order model finds potential application for real-time simulation and also for testing of SSR damping controllers.