Design And Development Of A High Voltage DC Disconnector

UHV power grid refers to the AC power grid with alternating voltage not less than 1000kV and DC power grid with DC not less than ±800kV It will greatly improve the transmission capacity of power grids with characteristics of long transmission distance,high transmission capacity,low loss of transmission power,low unit capacity cost,saving of land resources,etc.According to SGCC"The 12th Five-Year" Plan,our nation will build up the UHV backbone network of "Three Vertical and Three Horizontal" and 13 DC power transmission projects(ten of which are UHV DC)in the future.In consequence,the pattern of energy configuration of "West-to-East Power Transmission Project" and "North-to-South Power Transmission Project" can be created.Compared with UHV AC power transmission,UHV DC power transmission technology develops fast and UHV DC power transmission projects that put into use in China and at abroad are rapidly increasing.It is estimated that around 2020,the total length of UHV DC power transmission lines will be 26,000 km and transmission capacity will reach 94,400,000kW in China±816kV UHV DC disconnector is the important primary equipment in DC UHV power transmission project.Based on own advantages,our company has independently developed the±816kV UHV DC disconnector to satisfy requirements of national UHV power construction,which will occupy the national commanding height of industrial technology of disconnector.Meanwhile,our company can export the UHV DC disconnector to other countries and regions to earn foreign exchange for the country.Besides,this kind of switch can bring higher social and economic benefits.The present paper conducted the independent development of ±816kV DC disconnector on the basis of reviewing domestic and foreign research status of HV DC disconnector.The paper discussed the theory,overall structure and key technological difficulties in the development process of this HV DC disconnector,then made specific design computation of DC disconnector from the aspects of flow capacity,equilibrium structure of leading power,structure of balance spring and simulation of wireless power.The developed UHV DC disconnector has finally passed the whole-set test projects of temperature rise test,ice coating test,rated peak withstand current test,rated short-time withstand current test,mechanical operation test and insulation test required by national standard.The type tests indicate that the developed HV DC disconnector bears with following characteristics:Reasonable product design,good product appearance,scientific and reasonable structure,advanced action principle,stable and reliable operation,good mechanical and electrical performance,meeting the national development concept of energy-saving and cost-reducing and technological innovation as well as having proprietary intellectual property rights.Currently,our company has won the bidding of multiple UHV DC projects,including ±800kV UHV DC Project from Left Bank of Xiluodu to Zhejiang Jinhua,±800kV UHV DC power transmission project from Shanxi Jinbei to Jiangsu Nanjing and Brazil Belo Monte Project.Successful research and development of this product has promoted the fast entrance of our company into DC power transmission&transformation markets,bringing good effects and economic benefits.