Analytical calculation of damper winding losses in large hydrogenerators

Abstract

The damper winding is one of the key components of hydro generators. At steady load conditions, currents are induced in the damper winding due to the harmonic field in the air-gap, which lead to parasitic losses in generators. This paper describes an analytical method for calculation of currents and power losses in the damper winding. The described method is based on harmonic analysis of the air-gap magnetic field and the equivalent circuit of the damper winding. The obtained analytical results are compared with values by 2-D transient finite element (FE) studies.

Analysis of Additional Eddy-Current Copper Losses in Large Converter-Fed Hydropower Generators

“…In [10] an analytical method for calulcating damperbar currents and losses are presented. The magnetic field in the airgap is predicted using permeance model that is used as input for an equivalent circuit model.…”

“…z t is the number of strands in the conductor, f is the harmonic frequency, σ c is the conductivity of the conductor, z a the number of parallel strands, b c0 is the strand width and b u the slot width. ϕ and ψ given by (10) and (11) are factors that are dependent on the reduced conductor height ξ [20].…”