Real-Time Decoupled Equivalent Models for Static Security Analysis

This paper presents some new decoupled external system equivalent models for use in system security evaluation. Three different models i.e., decoupled Tie-line power flow model, decoupled Boundary bus Impedance model and decoupled Impedance-Admittance model are developed based on P-¿ and Q-V relations of fast decoupled load-flow formulation. The structure component of the models are then identified by processing real time data using Kalman filtering technique. Then the operating components of the decoupled equivalents are obtained from two new approaches. The performance of the various models with regard to contingency analysis has been presented using simulated data on a 25 bus test system. Persistency analysis of different input-output data is given to determine apriori choice of models. Also the bias conditions are derived to ascertain the accuracy of the models.