Non-Uniform Aging Diagnosis of High-Voltage Machine Stator-Winding Insulation Using Multi-Indicator Fusion of Dielectric Spectra

Accurate assessment of the stator-winding insulation condition in high-voltage machines is crucial for safe operation. Conventional evaluation methods treat the insulation as spatially uniform and provide only a holistic assessment; in practice, however, degradation within the insulation wall is non-uniform, with the inner layers adjacent to the copper conductor typically deteriorating more severely. As a result, existing diagnostic approaches cannot accurately evaluate non-uniform degradation. To address this gap, this paper proposes a diagnosis method for non-uniform aging of stator-winding insulation based on multi-indicator fusion of dielectric spectroscopy. A Frequency Domain Spectroscopy (FDS) simulation model that explicitly incorporates non-uniform aging is established and experimentally validated. The validated model is then used to generate FDS responses under various non-uniform-aging scenarios, from which multiple characteristic indicators that quantify the degree of non-uniformity are extracted. Building on these indicators, a non-uniform aging evaluation method using Multi-Anchor TOPSIS is constructed for diagnosing non-uniform aging.