Abstract: The SSZT2 tower,on which 1 000 kV AC double-circuit and 500 kV AC double-circuit are arranged,is the highest steel tubular tower with the biggest load and largest transmission capacity within conventional lines all over the world. The tube is made from Q420 high-strength steel and connected by plug-in boards and forging flanges. The strength classification technical is applied in forging flanges for the first time. The design of multi-circuit steel tubular tower for UHV and EHV is improved through different aspects of studies including tower structure, wind vibration coefficient, Eiffel effect and bending moment. The success of full-scale test verified the reliability in design and manufacture of multi-circuit steel tubular tower for UHV and EHV which can be used in future projects.

Key words: multi-circuit, UHV and EHV, steel tubular tower, full-scale test, wind vibration coefficient, bending moment at member end