Yuzuru Imamura

State Estimation for a Power System with Dense and Short Transmission Lines

Abstract This paper presents experimental results of applying several state estimation methods to a power system. This power system is located in a small island and has high load density. The fast decoupled weighted least squares method turned out to be not suitable to this system, because the assumption of the decoupling between P and Q is not appropriate, and the magnitude of impedances vary widely. As for the variety of the impedance magnitude, the ratio of the maximum to minimum values is larger than 1000. The usual bad data detection method using the statistical approach also turned out to be not applicable to this system, because of the trouble in maintaining accuracy in numerical calculation. To cope with these troubles, we adopted the weighted least squares method without decoupling between P and Q, and developed a new bad data detection method without matrix computation. The method was validated by numerical experiments.