Field detection of material defect of dry transformer winding Chao Feng, Jiarui Hu, Hongchun Sun, Jun Liu, Siyuan Yang, Jun Wang, Yi Xie, Junjun Chen and Weike Liu E3S Web Conf., 165 (2020) 05023 Published online: 01 May 2020 DOI: 10.1051/e3sconf/202016505023