Frequency-dependent AC system equivalents for harmonic studies and transient convertor simulation

A technique for the the generalization of the impedance loci is described. This technique is capable of displaying the complete frequency response of any given power system including multiphase-related effects such as phase asymmetries and mutual couplings. This information is used to derive frequency-dependent equivalent circuits suitable for integration in the time-domain solutions of power-system waveforms. Direct and optimization techniques are used in the derivation of the equivalent circuits. Their effects on impedance frequency matching and computational efficiency are compared