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Z. Lu and G. Zhu
• CCG-ECG: ±500 kV Ge Nan DC transmission project (1989), Long Zheng DC
transmission project (2003), Yi Hua DC transmission project (2006), Lin Feng DC
transmission project (2011), ±800 kV Upward DC transmission project (2010),
Jinping-South Jiangsu DC transmission project (2012), Left Bank of XiluoduJinhua, Zhejiang DC transmission project (2014);
• NWCG-ECG: ±800 kV Ningdong-Zhejiang DC transmission project (2016);
• NECG-ECG: ±800 kV Ximeng-Taizhou DC transmission project (2017);
• NCG-ECG: ±800 kV North Shanxi-Jiangsu UHV DC transmission project
(2017).
The UHV AC transmission projects set to be completed in 2020 include “west
vertical” and “mid vertical” lines, the former being the UHV AC line from west
Mongolia to south Hunan, and the latter being the UHV AC line from Ximeng to
Zhangbei to Ganzhou, with a total capacity of 17 million kW, serving central and north
China respectively. UHV DC transmission projects include Huaidong-South Anhui,
Qinghai-Henan, Yazhong-Jiangxi and North Shaanxi-Wuhan lines. The voltage of
Huaidong-South Anhui line is ±1100 kV with a capacity of 12 million kW, while
the other lines are ±800 kV and 10 million kW, also serving central and north China.
4.3.1.2 UHV DC Transmission Network
High voltage direct current transmission (HVDC) technology is very important in
long-distance and large-capacity power transmission, asynchronous networking of
power systems, improvement of reliability, and new energy development and its grid
connection. It is one of the major grid technologies and produces tremendous impact
on grid structure.
A late mover in DC transmission technology, China independently built the first
DC transmission line running from Zhoushan to Ningbo in 1987. Thanks to three
decades of development, enormous strides have been made in conventional HVDC
transmission, with notable improvement in voltage classes, transmission capacity
and distance, localization of equipment and engineering, etc. For China’s HVDC
projects, their voltage classes range from ±400 kV (Golmud-Lhasa HVDC project)
to ±1100 kV (Changji-Guquan UHV DC project); the capacity varies from 600 MW
(Golmud-Lhasa HVDC project) to 12,000 MW (Changji-Guquan UHVDC Project);
transmission length is between 890 km (Three Gorges-Changzhou HVDC project)
and 3324 km (Changji-Guquan UHVDC project). On the whole, China’s UHV DC
transmission is featured by high and multiple voltage classes, wide span in capacity
and transmission length.
Equipment for HVDC transmission mainly includes converters, converter transformers, smoothing reactors, AC filters, DC arresters and control and protection
equipment, as shown in Fig. 4.19 (Wang and Cao 2018). Converters are used for
rectification and inversion, during which higher harmonics will be produced. In this
case, filters should be configured on the AC bus of converter station to reduce the
Z. Lu and G. Zhu
• CCG-ECG: ±500 kV Ge Nan DC transmission project (1989), Long Zheng DC
transmission project (2003), Yi Hua DC transmission project (2006), Lin Feng DC
transmission project (2011), ±800 kV Upward DC transmission project (2010),
Jinping-South Jiangsu DC transmission project (2012), Left Bank of XiluoduJinhua, Zhejiang DC transmission project (2014);
• NWCG-ECG: ±800 kV Ningdong-Zhejiang DC transmission project (2016);
• NECG-ECG: ±800 kV Ximeng-Taizhou DC transmission project (2017);
• NCG-ECG: ±800 kV North Shanxi-Jiangsu UHV DC transmission project
(2017).
The UHV AC transmission projects set to be completed in 2020 include “west
vertical” and “mid vertical” lines, the former being the UHV AC line from west
Mongolia to south Hunan, and the latter being the UHV AC line from Ximeng to
Zhangbei to Ganzhou, with a total capacity of 17 million kW, serving central and north
China respectively. UHV DC transmission projects include Huaidong-South Anhui,
Qinghai-Henan, Yazhong-Jiangxi and North Shaanxi-Wuhan lines. The voltage of
Huaidong-South Anhui line is ±1100 kV with a capacity of 12 million kW, while
the other lines are ±800 kV and 10 million kW, also serving central and north China.
4.3.1.2 UHV DC Transmission Network
High voltage direct current transmission (HVDC) technology is very important in
long-distance and large-capacity power transmission, asynchronous networking of
power systems, improvement of reliability, and new energy development and its grid
connection. It is one of the major grid technologies and produces tremendous impact
on grid structure.
A late mover in DC transmission technology, China independently built the first
DC transmission line running from Zhoushan to Ningbo in 1987. Thanks to three
decades of development, enormous strides have been made in conventional HVDC
transmission, with notable improvement in voltage classes, transmission capacity
and distance, localization of equipment and engineering, etc. For China’s HVDC
projects, their voltage classes range from ±400 kV (Golmud-Lhasa HVDC project)
to ±1100 kV (Changji-Guquan UHV DC project); the capacity varies from 600 MW
(Golmud-Lhasa HVDC project) to 12,000 MW (Changji-Guquan UHVDC Project);
transmission length is between 890 km (Three Gorges-Changzhou HVDC project)
and 3324 km (Changji-Guquan UHVDC project). On the whole, China’s UHV DC
transmission is featured by high and multiple voltage classes, wide span in capacity
and transmission length.
Equipment for HVDC transmission mainly includes converters, converter transformers, smoothing reactors, AC filters, DC arresters and control and protection
equipment, as shown in Fig. 4.19 (Wang and Cao 2018). Converters are used for
rectification and inversion, during which higher harmonics will be produced. In this
case, filters should be configured on the AC bus of converter station to reduce the