Patent ID: 11881349
Assignee: HITACHI ENERGY LTD
Field: Electrical machinery, apparatus, energy (Electrical engineering)
Classification: CPC H | IPC H

Claim 0:
1. A winding for a phase winding of a transformer, said winding having coil turns around a coil axis, said winding being adapted to transform voltage in a transformer at a predetermined frequency, when said transformer is operating, said winding is excited by a mechanical load having a main frequency corresponding to said predetermined frequency multiplied by two and having vibration modes, wherein the combination of load and vibration modes results in a vibration of said winding, said winding having a set of vibration modes, each vibration mode having a vibration mode frequency, wherein at least one main contributing vibration mode of the set of vibration modes is the vibration mode resulting in the largest acoustic power, of said vibration modes, when the winding is excited by said load,
wherein the winding comprises a plurality of winding portions, said plurality of winding portions comprising at least a first winding portion and a second winding portion, wherein said first winding portion has a first winding portion stiffness and said second winding portion has a second winding portion stiffness,
wherein a stiffness difference between said first winding portion stiffness and said second winding portion stiffness is such that the acoustic power is minimized at said main frequency, and
wherein the first winding portion is located in a different sector of the winding than the second winding portion, and wherein the first winding portion is located in a sector of the winding delimited by a first center angle and wherein the second winding portion is delimited by a second center angle, wherein a respective sector is delimited by a circumferential arc length around the coil axis, which arc length is determined by the respective first and second center angles between two radii extending between the coil axis and the coil turns of the respective first and second winding portions.