Yunnan – Guangdong China HVDC is the 4th largest HVDC project in the world. Here's a picture of a transmission tower (Pylon).
The Yunnan–Guangdong HVDC is a high-voltage direct current transmission system connecting Chuxiong in the Yunnan to Suidong, Zengcheng in Guangdong, China. It is the first HVDC link in the world operating at a transmission voltage of 800 kV. The transmission line is operated by China Southern Power Grid.
Ningxia - Shandong China HVDC Static Inverter Plant is the 5th largest HVDC project in the world.
Three Gorges - Changzhou China Converter transformers are 9th world's largest HVDC.
With support from The Three Gorges Office of the State Council, National Development and Reform Commission and State Grid Corporation, a combination formed by our company and ABB Corporation designed and submitted a bid jointly for Three Gorges — Shanghai DC Transmission Project （?500kv，3000a，3000mw）; the XD Transformer Co., Ltd. of the XD Group has obtained manufacture task of 14 converter transformers and 3 smoothing reactors, and the quantities of machines it made are much more than the quantities it made in Three Gorges — Guangdong DC Transmission Project. Significant breakthrough has been made in localization of manufacture of thyristor valve, system research and design of complete set of equipment of converter station: a combination formed by our company and ABB Corporation designed and submitted a bid jointly, 50% thyristor valve used in the project, i.e. twelve lockshield valves, were made by XPR of our company, and thyristor components（348 components totally）of another 50% thyristor valves were also assembled by XPR XIHARI（Xi'an High Voltage Apparatus Research Institute Co., Ltd.）of the company has undertaken system research and design of complete set of equipment of the converter station of the project together with Beijing Wanglian DC Engineering Technology Co., Ltd. Total amount of the contract is USD 114.877 million, which is equivalent to RMB 949.34352 million Yuan according to list price of exchange rate 1: 8.264 of Bank of China on June 16, 2004.
China XD Group’s ability on technology and manufacture of DC transmission has taken three steps through the engineering practice of four 500kv DC Transmission Projects of Three Gorges-Changzhou, Three Gorges-Guangdong, Guizhou-Guangdong and Three Gorges-Shanghai:
Therefore, China XD Group has the ability of designing and manufacturing and supplying converter transformer, smoothing reactor and thyristor valve used in ?500kv HVDC Transmission Project; has two programs for transporting converter transformer and smoothing reactor by rail and by road; can take part in or undertake system research and design of complete system of converter station of ?500kv HVDC Transmission Project.
Source: China XD Group
Guizhou – Guangdong, China converter station is top 10 largest HVDC line in the world.
The DC Transmission Project (the long-distance transmission system of the Guizhou-Guangdong II line ± 500 kV) transmits 3,000 MW power from the Xingren substation in the Guizhou Province of Southwest China to the load center of Shenzhen in the Guangdong Province.
The system has a long-term overload capability of up to 115 %. Power transmission in the reverse direction is also possible. The project is carried out in cooperation with Chinese partners supported by Siemens. The bipolar system is designed for a ceiling suspended 12-pulse converter bridge arrangement with single-phase two-winding converter transformers and oil-insulated smoothing reactors.
The 500 kV DC converter groups of modular design are equipped with direct light-triggered thyristors with water cooling. Most of the DC equipment is provided with composite housings improving the performance of operation under severe environmental conditions.
For harmonic filtering triple tuned AC and DC filters are used. The design considers the installation at 1450 m above sea level (Xingren converter station). The interconnection of the neutrals of both stations is implemented by means of ground electrodes. The contract was awarded in May 2005.
After successful completion of the test phase, Siemens Energy commissioned the “Guizhou-Guangdong II” high voltage DC transmission link (HVDC) on schedule at the beginning of January 2008.