Calculation and Analysis of Electromagnetic Force on Stator End Winding of Synchronous Condenser for UHVDC Transmission System under Three Phase Short Circuit Condition

Large synchronous capacity condenser is an important dynamic reactive power compensation device in UHVDC power grid. Its safe and stable operation is very important for power system and power energy. Furthermore, it is very important to predict the end electromagnetic force under three-phase short circuit condition. The end winding of large capacity condenser presents involute shape and complex structure, which leads to inaccurate estimation of radial, tangential and axial electromagnetic force density at the end. To solve this problem, a method is proposed to obtain the radial, tangential and axial electromagnetic force density of the linear segment and involute segment at the end of the stator winding through coordinate transformation. Based on the three-dimensional finite element model, taking a 300Mvar synchronous condenser as an example, the electric density, magnetic density and electromagnetic force density of the straight section and involute section at the end of the stator winding under three-phase short circuit conditions are calculated, and the distribution laws of electric density, magnetic density and electromagnetic force density in different directions are given. The results can provide a theoretical basis for fault assessment of power systems.