Multiport Frequency-Dependent Network Equivalent Using a Modified Matrix Pencil Method

The paper presents a frequency-domain matrix pencil method (FDMPM) for identification of multiport network equivalents to be properly incorporated in electromagnetic transient calculations. In this method, a rational approximation for the network admittance matrix is inferred by the solution of a generalized eigenvalue problem. The obtained rational approximation is then employed to construct an Electromagnetic Transients Program-compatible multiport frequency-dependent network equivalent (FDNE). The proposed method is a direct process and requires no starting poles unlike the vector fitting method. It is also well suited to the matrix fitting applications with a common set of poles without any limitation on the number of poles. The FDMPM is first validated for calculating the time-domain response of a small three-port electrical circuit. It is then applied for the calculation of the FDNE of two networks; a 20-kV distribution system and a 230-kV regional transmission system. In each example, the accuracy of the proposed technique is verified by comparing the results with those obtained by detailed representation of the system.