Influence of Metal Shield on Electromagnetic Field and Loss in the End Region of Synchronous Condenser

The synchronous condenser is used to in the convertor station of Extra High Voltage Direct Current (EHVDC) for its superior regulating characteristic of reactive power. However, the characteristic can also increase the end leakage magnetic flux and eddy current in the stator end region. In order to investigate the shielding effect of different metal shield materials on the magnetic field and loss in the end region, the mathematical models of the three dimensional (3-D) transient electromagnetic field in the end region of a 300 Mvar full air-cooled synchronous condenser is established. The flux density distributions of end structural components, such as finger plate, clamping plate, magnetic shield and metal shield, are calculated with different materials of metal shield under the rated excitation and 3.5 times rated excitation. The flux density of the key zones on the end structural components are compared and analyzed. In addition, the loss distributions of the end structural components are calculated and compared in three cases. The influence of different metal shield materials on losses of the end region is studied, and the end structural component that has the maximum loss is obtained. The research results provide the technical support for the end structural design of the large capacity synchronous condenser.