The rotating field method applied to damper loss calculation in large hydrogenerators

Abstract

In this paper, we discuss key aspects of analytical rotating field models that can be used to estimate the damper losses in large hydrogenerators during steady load conditions. Model features of particular importance, like the saturation permeance and the structure of the damper circuit are described in greater detail. Damper currents extracted from the analytic model are found to be in good agreement with currents obtained from coupled field-circuit 2-D finite element calculations. The applicability of the model for damper current prediction during steady unbalanced load conditions is also demonstrated.

Comprehensive Broken Damper Bar Fault Detection of Synchronous Generators

“…This leads to the induction of voltages inside the damper cage and a consequent circulation of current in the damper bars. Four factors cause these induced currents during steady-state operation of the machine: the air-gap magnetic field pulsation due to stator and rotor slotting effect [3], [7]; internal faults, like eccentricity and short circuits [8]; the stator load variation; and the space harmonics in the air-gap magnetic field due to the fractional slot winding layout [9].…”

Finite‐element analysis combined with an ensemble Gaussian process regression to predict the damper eddy current losses in a large turbo‐generator

“…According to this research, the damping winding eddy current extracted from the analytical model is highly consistent with the finite-element calculation results of the two-dimensional field path coupling. Therefore, the applicability of the prediction model for the damping winding eddy current loss under steadystate unbalanced conditions was demonstrated [12].…”

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

“…The magnetic field in the airgap is predicted using permeance model that is used as input for an equivalent circuit model. [11] uses permeance data from stationary finite element simulations together with a rotating field model to predict damperbar losses. Both methods are compared to finite element simulations.…”

“…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].…”