Influence of Magnetic Shield Thickness on Stator End Leakage Reactance of Synchronous Condenser

In order to decrease the stator end loss of the synchronous condenser (SC), a magnetic shield is often installed in the end region of the SC. However, the high magnetic conductivity of the magnetic shield would result in the increase of the stator end leakage reactance, which will affect the dynamic process of the SC. The selection of the magnetic shield is, therefore, a key factor that should be carefully considered in the design of SC. This paper presents a mathematical model of the three-dimensional (3-D) transient electromagnetic field in the end region of a 300-MVar SC. The flux densities in the end region of the SC are calculated and compared under different magnetic shield thickness, and the effect of the magnetic shield thickness on the end flux densities are revealed. The stator end leakage reactance is calculated by the flux linkage method and the energy method, and the variation of the stator end leakage reactance along with the magnetic shield thickness is revealed. The results provide the theoretical basis for the improvement of the design in the end region of the SC.