Axial and Radial Force Distributions Computation in Disc-Type Winding Under Switching Surge

This paper presents the calculations and simulation of surge distributions and estimation of axial and radial forces experienced by a disc-type winding due to Switching Impulse (SI). Firstly, the resistance, inductance and capacitance (RLC) of the high voltage (HV) disc winding were computed to construct the winding equivalent circuit. A standard switching impulse wave generated from a switching impulse generator circuit was subjected to the HV winding to obtain the transient resonance affecting the disc windings. The force in axial and radial components was then calculated through the voltage surge distributions in the windings. It is found that the highest switching surge is experienced by the topmost disc winding. An uneven voltage distribution is detected among the topmost disc, disc 96 and disc 93, which results in voltage stress. A conclusion is drawn that the highest force would be exerted on the topmost disc, disc 96.