Analysis of large synchronous machines with axial skew, part 2: inter-bar resistance, skew and losses

On Permeance Modeling of Large Hydrogenerators With Application to Voltage Harmonics Prediction

“…The appearance of the MMF function that describes the excitation of a single damper loop is not clear cut. In earlier works, the definition of the shape function of the kth damper loop MMF provided in next seems to be the most widely employed [10], [12]:…”

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

“…3a. Next, for each frequency component, the damper loop equations U = Z l I l + j ω 2 M I l (8) are formulated and solved for the unknown loop currents. In (8), U is the loop voltage vector, I l refer to the loop current vector and ω 2 refer to any of the angular frequencies mentioned above.…”

“…Next, for each frequency component, the damper loop equations U = Z l I l + j ω 2 M I l (8) are formulated and solved for the unknown loop currents. In (8), U is the loop voltage vector, I l refer to the loop current vector and ω 2 refer to any of the angular frequencies mentioned above. The elements of the matrix Z l correspond to the impedances of the bars and end-ring connections, with deep-bar effects accounted for [11], and the matrix M contains self and mutual inductances of the damper loops.…”

“…Recently, rotating field models have been extended to include the effects of skewing and inter-bar current paths via rotor iron on the damper circuit formulation [6]- [8].…”

Space Harmonics of Synchronous Machines Calculated by Finite Element Method

“…Harmonics influence on design, operation and control of synchronous machines have been an on-going research topic for decades [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19]. There are two types of harmonics related to synchronous machines: time harmonics [1][2][3][4][5][6][7][8] and space harmonics [6][7][8][9][10][11][12][13][14][15][16][17][18][19][20].…”