Schwarz-Christoffel-Based Open-Circuit Clamping Plate Field Calculation in Hydro Generators

This paper introduces an approach to calculating the field normal to the surface of a highly permeable clamping plate in open-circuit operation using a numerically solved Schwarz-Christoffel mapping without accounting for eddy currents or saturation. The intrinsically three-dimensional nature of the fringing air-gap flux density is reduced to a 2D problem by introducing a flux sink to account for 3D flux paths. A comparison with 3D FE simulations for six different hydro generators shows that the proposed method retains a high degree of accuracy at greatly reduced computational cost. The proposed flux sink concept can conceivably be implemented in 2D FEA achieving a similar reduction in computational cost.