... Structure, 200Kv Polygonal, Flange Connected Transmission Line Steel Pole, Lighting Pole, Signal Steel Pole, Telecommunication Steel Tower, 500Kv and ... China Electric Power Research Institute of SGCC, Beijing, P.R. China 220kV Double Circuit Transmission Line Steel Poles 2009/ ... China Electric Power Research Institute of SGCC, Beijing, P.R. China 220kV Double Circuit Transmission Line Steel Poles 2009/ ...