A Modest Attempt on the Electromagnetic Design and Performance Prediction of Turbo Wound-Field Flux Switching Synchronous Condensers

Since there appears to be a revival of the old synchronous condenser (SC) technology, an attempt is made in this paper to modestly design a turbo SC based on the wound-field flux switching machine (WF-FSM). Unlike classical rotating SCs, the brushless and robust design of WFFSMs is the main motivation for this study. The preliminary design process is based on well-known theoretical formulas and conceptual empirical derivations, following which the electromagnetic characterisation is initiated in a fast and robust 2D finite element analyses (FEA) environment in conjunction with a proposed analytical approach to accurately predict the WFFSM SC performance. To attain the specific design requirements (at least 300 MVAR at 16 kV), a conceptual model (CM) is first developed from which a lightly optimised model (POM) is evolved. Based on POM, the SC analytical design procedure is tested with expected V-curves obtained. Although the design targets were accomplished with the analytical modelling, but due to oversimplification of the design approach that resulted in armature reaction effects, some discrepancies were observed when directly tested in FEA. To address the issue, future works would incorporate the complex cross-coupling inductances prevailing in the WF-FSM by using the frozen permeability (FP) method, among others. The concept is experimentally verified on an existing small-scale WF-FSM prototype, which when directly connected to the grid, is clearly proven.