Remaining Useful Life Prediction of Low‐Voltage DC Circuit Breaker Contacts Based on a Shared Degradation Subspace

To reduce the influence of contact‐to‐contact differences in life prediction for arc‐eroded contacts of low‐voltage DC circuit breakers, this paper proposes a shared degradation subspace method. First, a resistance‐constrained region growing algorithm is designed to achieve stable extraction of the contact region, and three degradation features, namely contour rectangularity, edge activity, and gray structural entropy, are constructed according to the morphological evolution mechanism. Then, a low‐dimensional shared degradation subspace is established through global standardization, individual baseline debiasing, degradation direction normalization, and dominant degradation direction extraction, and a one‐dimensional shared degradation coordinate, inv1, is obtained. Finally, remaining useful life (RUL) prediction experiments are carried out using leave‐one‐subject‐out (LOSO) cross‐validation. The LOSO validation results for the tested contacts show that the proposed method can improve the prediction performance of life prediction models, especially for models that can effectively utilize the structural information of the feature space. © 2026 Institute of Electrical Engineers of Japan and Wiley Periodicals LLC.