Analysis and Mitigation of Measurement Errors in High-Flux Tests of Generator Stator Cores via Optimized Trace Winding Arrangement

Abstract

High flux tests are widely employed to diagnose inter-laminar short-circuit faults in generator stator cores. The measurement accuracy and diagnostic reliability primarily depend on the precise assessment of the core flux density via trace windings; however, the physical arrangement of these windings has long been overlooked. While IEEE, IEC, and Chinese GB standards specify different requirements for trace winding placement, their impacts on measurement integrity remain insufficiently quantified. This paper calculates the air leakage flux during testing and proposes a methodology for evaluating flux density measurement errors associated with various winding positions. By establishing an equivalent circuit for core short circuits combined with finite element analysis (FEA), the influence of measurement inaccuracies on the temperature rise at fault points is analyzed. Based on the distribution principles of air leakage flux and FEA results, a more rational trace winding arrangement strategy is proposed. Experimental results on a physical core model demonstrate that by applying the proposed flux density correction, the measurement error can be reduced to less than 1%. Furthermore, the optimized trace winding arrangement effectively reduces the core flux density non-uniformity from 7.1% to 0.7%.