Hachtel´s Augmented Matrix Method - A Rapid Method Improving Numerical Stability in Power System Static State Estimation

In this paper we apply the so-called Hachtel´s augmented matrix method for solving linear least squares problems to static state estimation. This method does not seem to have been applied in power system state estimation by others. The test system is the 99-bus main Norwegian grid. Hachtel´s method is compared to two versions of the normal equations approach and is found to greatly improve numerical stability, which is important for ill-conditioned systems. It requires less computing time than the standard normal equations method, while needing somewhat more computer storage.