State Key Laboratory of Power System Department of Electrical Engineering Tsinghua University Haidian District Beijing 100084 P.R.China;
State Grid Hubei Electric Power Co. Research Institute(HBEPRI) Hongshan District Wuhan 430077 P.R.China;
Flexible Transmission Engineering Department Nari-Relays Electric Company 210003 Nanjing P.R.China;
State Grid Hubei Electric Power Co. Ltd Hongshan District 430077 Wuhan P.R.China;
State Key Laboratory of Power System Department of Electrical Engineering Tsinghua University Haidian District Beijing 100084 P.R.China;
State Key Laboratory of Power System Department of Electrical Engineering Tsinghua University Haidian District Beijing 100084 P.R.China;
State Grid Hubei Electric Power Co. Research Institute(HBEPRI) Hongshan District Wuhan 430077 P.R.China;
Department of Electrical and Computer Engineering Faculty of Science and Technology UNL Portugal;
Wide band frequency response; Distributed parameter model; Lumped parameter model; Distribution transformer; Lightning protection;