Back-to-Back DC Project for Interconnection of Northwest China and Central China（hereinafter called Lingbao project）is a pilot project of localization, which has borrowed and adapted wholesale the introduced technologies of DC transmission projects of Three Gorges-Changzhou, Three Gorges-Guangdong DC transmission project and Gui-Guang I Line of DC transmission project in the process of engineering consultant and research, preparing functional specifications, system design and design of complete system, engineering design, complete set of AC Back-to-Back equipment, control and protective devices.
In the project, the rated DC voltage is 120kv, rated DC current is 3000a, and transmission capacity is 360mw. Xi'an Xizheng Power Electronic Equipment Co., Ltd., owned by our company, undertook research of high voltage thyristor valve, the core equipment of the project, and its relative equipment. According to requirement of state grids (the employer), three direct light trigger thyristor valves (hereinafter called ltt valve), which use the introduced Siemens technology, are used at the side of Central China 220kv; three electric trigger thyristor valves (hereinafter called ett valve), which use the introduced abb technology, are used at the side of Northwest China 330kv. Xi'an Xibian Power Electronic Equipment Co., Ltd., owned by our company, undertook research of smoothing reactor, the major equipment of the project, and converter transformer at the side of Northwest China 330kv. Back-to-Back project still belongs to the first time in our country.
In the acceptance conference of Lingbao Back-to-Back project, organized by Three Gorges Project Construction Commission of the State Council, the opinions of final acceptance of the expert group are as below:
The project is operating smoothly after it is put into operation. It started test run on June 18, 2005, and total transmission energy was 1.17 billion kwh by Nov. 20, 2005; energy availability was 89.81% while energy utilization was 85.78%.
The final acceptance inspection shows that Lingbao Back-to-Back project has realized the requirements of using domestic made products in the following processes: organization and construction of project, system design, complete set of equipment, project design, manufacture and purchase of equipment, construction and debug of project. The construction of project is successful; quality of equipments and project is excellent and has reached the objective of DC pilot project of localization.
It autonomously designed and manufactured converter valve, converter transformer, smoothing reactor and thyristor on the basis of adapting the introduced technology for the first time.
XPR of China XD Group has independently developed converter valve, which uses electric trigger technology and light trigger technology, for Lingbao Project through adapting self-existent DC technology on the basis of assimilating and absorbing the imported technologies of ABB’s electric trigger and Siemens’ light trigger converter valve；thyristor（which is made by Xi'an Power And Electronic Technology Research Institute, valve lightning arrester（which is made by Xi'an Electro-ceramic Research Institute, and the supporting equipment（which is independently developed by itself）, are used in the valve; Xizheng Company has the ability as an independent vendor. Type tests have been made in accordance with iec international standard and the objectives of localization for independent production and test have been achieved. The debugging and operation experience of Lingbao inverter station project proves that the quality of converter valve designed and manufactured by XPR of China XD Group is good, and the company has the ability of designing and manufacturing high-power thyristor valve.
XD Transformer Co., Ltd. of China XD Group independently designed and manufactured four 330kv converter transformers and one DC 120kv smoothing reactor for Lingbao Converter Station. XD Transformer Co., Ltd. has mastered the core technology of converter transformer design on the basis of assimilating and absorbing the imported ABB’s technology, and its own technology is created by combining the imported technology with the company’s original DC technology. The quality of the converter transformer and smoothing reactor, which are independently designed, own purchased, manufactured, tested and supplied by XD Transformer Co., Ltd., are good, with qualified performance index and technical target; have passed test of operation. This shows that XD Transformer Co., Ltd. has mastered the technology of design and test of converter transformer and smoothing reactor; the company has the ability of independently manufacturing and supplying converter transformer and smoothing reactor.