Estimation of external network equivalents from internal system data

The problem of estimating the admittance parameters of an external equivalent network using internal system operating data is considered. By utilizing information available from monitoring scheduled or forced internal system outages, together with static state estimator data, external network equivalents can be estimated. The algorithm for performing this type of parameter estimation is derived. Its effectiveness and Computer requirements are demonstrated by simulating a representative system. Application for this algorithm is foreseen to be in the off-line estimation and model validity assessment of network equivalent models which are used in several on-line applications.