The electromagnetic force calculation of damping windings under three-phase sudden short-circuit fault of large hydro-generator

Aimed at the problems of damping winding vibration and broken caused by electromagnetic force, the electromagnetic force was quantificationally calculated under the condition of three-phase short-circuit fault of large hydro-generator. The 2-D field-circuit-motion coupled damping winding electromagnetic force calculation model was established. The time-stepping finite element method combined with Lorentz electromagnetic force calculation method were proposed as main analysis way. On the basis of fully considering scallop and saturated effect, the electromagnetic forces which acted on the damping winding and engendered in the rated and the three-phase short-circuit conditions were calculated, and the electromagnetic force peak and distribution were obtained. During the normal operation, the largest force occurred in the last one in the normal operation rotation direction, and the tangential force was nearly 8 times the radial force; In half a cycle of the fault occurring, the first and the last damping windings reached the maximum.