The accurate modelling of large synchronous generators

A digital model has been developed which accurately simulates the behaviour of synchronous generators, by taking saturation into account. The model is based on a simple equivalent circuit the parameters of which, including those describing saturation, are readily available from standard tests. The model´s performance has been verified over a wide range of operating conditions using a microalternator. Beyond this, its validity has been checked in terms of practical generators, by successfully replicating the results of the Northfleet tests and works tests performed on a 660 MW machine. These tests and those on the micromachine revealed the need to include changes due to saturation, on a step by step basis in the modelling process in order to achieve accurate predictions of machine performance