Influence of the Electromagnetic Field Model on the Calculated No‐Load Magnetic Field of Tubular Hydro Generators

ABSTRACT The selected electromagnetic field model of a hydro generator directly affects the calculation of the no‐load magnetic field, which in turn affects the grid‐connected power quality of the hydrogenerator and the power transmission safety. Tubular hydro generators have a horizontal structure with less internal space than the conventional vertical hydro generator, which results in a particularly complex and strong internal magnetic field distribution. This study investigated the influence of the selected electromagnetic field model on the calculation of the no‐load magnetic field of a tubular hydro generator. Straight and skewed stator slots were considered for the structure of the hydro generator. Three models were considered: the transient motion electromagnetic field‐circuit coupling model, the transient motion electromagnetic field model, and the static electromagnetic field model. The calculation accuracy and computational efficiency of the three models were evaluated by comparison to measured data. The results were used to make reasonable suggestions for the selection of a suitable electromagnetic field model in different scenarios. The findings are expected to support the electromagnetic field analysis and design of hydro generators.