Cost Comparison Based on Transformer Operating State Under Two Kinds of Inspection StrategiesBoyang Cao, Yi Ren, Yaping Wang, Weining Wen, Huijun Sun, Yan Zhang, Lisha You and Wenhao WangE3S Web Conf., 118 (2019) 02053DOI: https://doi.org/10.1051/e3sconf/201911802053