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Z. Lu and G. Zhu
which were interconnected into several regional grids across provinces. Since first
launched in the early 1980s, the 500 kV transmission lines have become the backbone
of major grids and served as the “liaison” across provinces and regions. By 1989,
seven inter-provincial grids had taken shape in China, namely: the Northeast China
Grid (NECG), North China Grid (NCG), East China Grid (ECG), Central China Grid
(CCG), Northwest China Grid (NWCG), Sichuan and Chongqing Grid (CYG), and
South China Grid (SCG) (including the Hong Kong Grid and the Macao Grid). Six
other independent provincial grids existed in Shandong, Fujian, Hainan, Xinjiang,
Tibet and Taiwan.
The third stage: the interconnection of cross-regional power grids, which began
in the late 1980s and is now under rapid development. Milestones include:
• In September 1989, the ±500 kV UHV DC transmission project (1.2 million
kW) between CCG and ECG was put into operation, marking the debute of asynchronous trans-regional interconnection in China and a major step forward from
inter-provincial to cross-regional connection.
• In July 1991, China Southern Power Associated Company (the predecessor of
China Southern Power Grid) was founded, mainly operating in Guangdong,
Guangxi, Guizhou and Yunnan provinces (regions).
• In 2002, the State Council approved the reform plan of the power system to
restructure grid and power production enterprises, which led to the establishment
of State Grid Corporation of China (State Grid) and China Southern Power Grid
(Southern Grid), with the former setting up five regional grid companies, namely,
North China Grid Company Limited (NCGC), Northeast China Grid Company
Limited (NECGC), Northwest China Grid Company Limited (NWCGC), East
China Grid Company Limited (ECGC) and Central China Grid Company Limited
(CCGC).
• Since the twenty-first century, the construction of the Three Gorges Project has
facilitated the asynchronous interconnection between CCG and ECG, CCG and
SCG, CCG and NWCG, as well as NECG and NCG. In December 2008, the UHV
AC test and demonstration project between CCG and NCG was launched. In 2010,
Xinjiang provincial grid and the main network of NWCG were connected through
750 kV lines. The year of 2011 witnessed the asynchronous networking between
Tibet provincial grid and NWCG. By then, six regional grids had emerged: NCG,
CCG, ECG, NECG, NWCG, and SCG.
Currently, the six regional grids are primarily connected through UHV AC/DC
hybrid transmission lines—a reality determined by the severe regional mismatch
between power and load distribution. UHV transmission lines enable long-distance,
large-capacity and high-efficiency transmission of electricity, optimizing the allocation of energy resources nationwide.
Z. Lu and G. Zhu
which were interconnected into several regional grids across provinces. Since first
launched in the early 1980s, the 500 kV transmission lines have become the backbone
of major grids and served as the “liaison” across provinces and regions. By 1989,
seven inter-provincial grids had taken shape in China, namely: the Northeast China
Grid (NECG), North China Grid (NCG), East China Grid (ECG), Central China Grid
(CCG), Northwest China Grid (NWCG), Sichuan and Chongqing Grid (CYG), and
South China Grid (SCG) (including the Hong Kong Grid and the Macao Grid). Six
other independent provincial grids existed in Shandong, Fujian, Hainan, Xinjiang,
Tibet and Taiwan.
The third stage: the interconnection of cross-regional power grids, which began
in the late 1980s and is now under rapid development. Milestones include:
• In September 1989, the ±500 kV UHV DC transmission project (1.2 million
kW) between CCG and ECG was put into operation, marking the debute of asynchronous trans-regional interconnection in China and a major step forward from
inter-provincial to cross-regional connection.
• In July 1991, China Southern Power Associated Company (the predecessor of
China Southern Power Grid) was founded, mainly operating in Guangdong,
Guangxi, Guizhou and Yunnan provinces (regions).
• In 2002, the State Council approved the reform plan of the power system to
restructure grid and power production enterprises, which led to the establishment
of State Grid Corporation of China (State Grid) and China Southern Power Grid
(Southern Grid), with the former setting up five regional grid companies, namely,
North China Grid Company Limited (NCGC), Northeast China Grid Company
Limited (NECGC), Northwest China Grid Company Limited (NWCGC), East
China Grid Company Limited (ECGC) and Central China Grid Company Limited
(CCGC).
• Since the twenty-first century, the construction of the Three Gorges Project has
facilitated the asynchronous interconnection between CCG and ECG, CCG and
SCG, CCG and NWCG, as well as NECG and NCG. In December 2008, the UHV
AC test and demonstration project between CCG and NCG was launched. In 2010,
Xinjiang provincial grid and the main network of NWCG were connected through
750 kV lines. The year of 2011 witnessed the asynchronous networking between
Tibet provincial grid and NWCG. By then, six regional grids had emerged: NCG,
CCG, ECG, NECG, NWCG, and SCG.
Currently, the six regional grids are primarily connected through UHV AC/DC
hybrid transmission lines—a reality determined by the severe regional mismatch
between power and load distribution. UHV transmission lines enable long-distance,
large-capacity and high-efficiency transmission of electricity, optimizing the allocation of energy resources nationwide.