Justification for creating a mobile complex to assess electric energy loss in power transformers during the operation processA. V. Vinogradov, A. V. Vinogradova, V. E. Bolshev, M. O. Ward, N. V. Makhiyanova and L. V. DolomaniukE3S Web Conf., 124 (2019) 02009DOI: https://doi.org/10.1051/e3sconf/201912402009