China XD Group has imported five special 500kv HVDC transmission technologies from former Switzerland BBC Corporation by using the means of combination of technology and trade during “the Seventh Five-Year Plan period”while the former Department of Energy imported equipments for Gezhouba — Shanghai Nanqiao ?500kv，1200a，1200mw DC Transmission Project：
Control and protection
System research and design
At the same time, three equipments, such as simulation device for DC transmission, have been imported, thus China XD Group has the preliminary ability to develop equipment of converter station of 500kv DC transmission project.
The relative units of China XD Group have assimilated and absorbed some technologies through intensive research and development:
1. A thyristor component has been developed. Except that the technical parameter of thyristor couldn’t reach the level of Gezhouba – Shanghai Project, other components and parts have reached localization, such as water cooling radiator, water cooling non inductive damping equalizing resistance, damping voltage sharing capacitor, impact voltage sharing capacitor, water cooling anode reactor, electronic unit at high potential, framework of special aluminum extruded section, etc.
Filter capacitor, damping voltage sharing capacitor and impact voltage sharing capacitor.
2. Dry-type air reactor to filter circuit
3. Put forward the control and protective equipments used for power reversal of Zhoushan DC Transmission Project and technical specification for equipments of Shengsi DC Transmission Project through system research on power reversal of Zhoushan DC Transmission Project and Shengsi DC Transmission Project; and made dynamic simulation tests for control and protective equipments used for power reversal of Zhoushan DC Transmission Project and for control and protective equipments used in Shengsi DC Transmission Project.
Xi'an Electro-ceramic Research Institute of China XD Group has supplied 92kv e type DC zinc oxide arrester and 192kv f type lightning arrester for Gezhouba — Shanghai Nanqiao DC Transmission Project; Xi'an XD Power Capacitor Co., Ltd.（the former Xi'an Power Capacitor Factory, short for XD Power Capacitor）has provided spare parts of filter capacitor for the project.