References
2013 Nuozhadu-Guangdong, China
In January 2011, China Southern Power Grid awarded Siemens the contract for key components of the 800 kV HVDC Nuozhadu-Guangdong transmission system in southern China. Nuozhadu-Guangdong will have a transmission capacity of 5000 MW at a DC voltage of
± 800 kV and provide electricity to the megacities in the Guangdong region. For the Nuozhadu-Guangdong 800 kV HVDC bipole system Siemens together with its Chinese partners will supply the converter valves with direct light-triggered power thyristors both for the sending station in Pu’er in the province of Yunnan and for the receiving station in Jiangmen, Guangdong Province. The transmission distance of this project is 1451 kilometers. The order also includes key components for the HVDC system instrumentation and controls, the 800 kV components for the stations’ DC switchgear, supply of key materials for converter valves and the supply of eight 800 kV converter transformers, which are specially designed and proved to fit through the train profile of the west Chinese mountains, produced at the company’s manufacturing plant in Nuremberg.
| Customer | China Southern Power Grid |
| Project name | Nuozhadu – Guangdong |
| Location | Pu'er – Jiangmen |
| Power rating | 5,000 MW, bipolar |
| Type of plant | Long-distance transmission, 1451 km |
| Voltage levels | ±800 kV DC 525 kV, 50 Hz |
| Type of thyristor | Direct light-triggered (LTT), 8 kV |
| Commercial operation date | Scheduled 2013 |
2010 Xiangjiaba-Shanghai, China
In June 2010, State Grid Corporation of China commissioned the 800 kV HVDC Xiangjiaba-Shanghai transmission system. The high-voltage direct-current transmission link (HVDC) is the most powerful and longest transmission of its kind to be implemented anywhere in the world at that time, transmitting 6,400 MW of power over a distance of nearly 2,000 kilometers. Siemens Energy has equipped the sending converter station Fulong for this link with ten DC converter transformers, including five rated at 800 kV. Apart from that, Siemens provides the power electronics (6-inch thyristor valve towers and interfaces) together with its partner XD Xi’an Power Rectifier Works.
The HVDC transmission link transmits 6,400 MW of hydro power from South-Western China to Shanghai on China's East Coast over a distance of about 2,000 kilometers. The Xiangjiaba-Shanghai link also operates with a transmission DC voltage of 800 kV to further minimize transmission losses. Thanks to the use of environmentally friendly hydro power generation and low-loss HVDC transmission, the new system will save up to 44 million metric tons of CO2 p.a. versus local power supply with energy-mix.
The ten HVDC transformers which Siemens has supplied for the Fulong converter station in Sichuan close to the Xiangjiaba hydro power plant were built at the company's transformer facility in Nuremberg. This applies in particular for the newly developed 800 kV HVDC transformers that are in the highest voltage class at the present time. Last year Siemens became the world's first manufacturer to supply and commission 800 kV converter transformers.
| Customer | State Grid Corporation of China and XD Xi’an Power Rectifier Works (XPR) |
| Project name | Xiangjiaba |
| Location | Xiangjiaba to Shanghai |
| Power rating | 6400 MW, bipolar |
| Type of plant | Long-distance transmission, 2070 km |
| Voltages levels | ± 800 kV DC, 525 kV AC |
| Type of thyristor | Electric-triggered thyristor, 8 kV (6 inches) |
| COD | June 2010 |
2009 Yunnan - Guangdong, China
The long-distance transmission system of the Yunnan–Guangdong DC Transmission Project transmits 5,000 MW from the Chuxiong substation in Yunnan to the load center of the Pearl River delta in Guangdong. The contract was awarded in June 2007. Commercial operation of the first 800 kV pole started in December 2009, the complete bipole is in operation since June 2010. The system, with a transmission voltage of ±800 kV DC, sets a new dimension in the development of HVDC systems.
The bipolar system uses two series valve groups per pole: one 12 pulse valve group is rated 400 kV; the other is rated 800 kV. Apart from the converter valves, the other major components with insulation levels of 800 kV are the single-phase two-winding converter transformers and air-insulated smoothing reactors. The modular converter groups are equipped with direct light-triggered thyristors with water cooling. The 800 kV equipment in the DC Yard, e.g. bushings, support insulators, switches, and arrester are of composite type with silicone rubber external insulation to offer improved operation under severe environmental conditions. DC harmonic filtering is achieved through triple-tuned filters, whereas for AC harmonic filtering double-tuned filters together with a special low-order filter are used.
| Customer | China Southern Power Grid |
| Project name | Yunnan – Guangdong |
| Location | Chuxiong City / Yunnan – Zengcheng City / Guangdong |
| Power rating | 5,000 MW, bipolar with series valve groups |
| Type of plant | Long-distance bipole, 1418 km |
| Voltage levels | ±800 kV DC 525 kV, 50 Hz |
| Type of thyristor | Direct light-triggered (LTT), 8 kV |
| COD | 2009 |