Home > News Center > Feature Story

Last “Isolated Grid” in Zhejiang Connected

Release time: 2020-01-02        bigmeansmall

A newly built 35 kV substation on Nanji Island in Wenzhou City of Zhejiang Province commenced operation on November 30. It marked the formal electrification of the interconnection project between the Nanji Island and the continent. Thus the isolated grid operation of this island comes to an end, realizing full access to the grid in all towns of the province.


Upon hearing the news, Yu Desheng, who lived in the island for over three decades and owned a local agritainment business, was overwhelmed with happiness. “My family had to resort to a standby diesel generator from time to time. Finally, I can put it away!”

Nanji Island is about 30 nautical miles away from the continent. It is the largest of the Nanji Archipelago’s 52 islands, and home to a permanent population of over 2,000 people whose main income comes from fishery, tourism and the service industry. Confined by geographical and technical challenges, for many years the island had powered itself by microgrids. Rapid development over recent years dramatically increased energy consumption which exceeded the load capacity of the island.

The end of March this year witnessed the launch of the construction of a 35 kV substation on the island. Over the past eight months, State Grid Zhejiang Electric Power Company has assigned over 400 staffs of design, construction and support services to the project. These efforts paid off as electrification was achieved one month ahead of schedule despite difficulties posed by the climate, geological conditions and typhoons.

From diesel generation, microgrid, to today’s connection to large grid, the island has come a long way over the past 60 years for power access. The first generator landed on the island by boat in 1955 while today the power cable reaches the island across the sea. Challenges tough to tackle in the past, such as long distances and the complex environment, have now been solved thanks to the significant development of power technology. It is worth mentioning that the submarine photoelectric composite cable not only expedites power transmission, but also upgrades the Telecommunication between the continent and the island, providing more opportunities for the island to develop the Internet of Things in Electricity.


The access to clean electricity is expected to bring huge ecological benefits to the Nanji Island. Seeking to create a pollution-free “fully electrified island”, State Grid Zhejiang Electric Power is to work with the local government to increase the proportion of electricity in the final energy consumption of the island. An integrated intelligent service platform will also be built to monitor the island’s power load, power demand and relevant characteristics to help create a cleaner and smarter environment for marine aquaculture and tourism.

According to the forecast of Nanji township government, underpinned by robust and clean electric power, the Nanji Island will be able to fully tap its potential for the marine economy. With energy constraints removed, pillar industries such as fisheries and tourism will have broader prospects for development. It is expected that the island’s annual income would increase by more than 40 million yuan, bringing concrete benefits to local people.

“As a key project supervised by State Grid Corporation of China, the Nanji Island interconnection is another success in our efforts to fulfill the mission of ‘Power Utility for the People’ while contributing to ‘Three Functions and Two Networks’”, explained the head of Captial Construction Department of State Grid. “This project broke new ground as it utilized China’s own state-of-the-art workboat able to load cables weighing 5,000 tons, and completed the layout of China’s longest 35 kV submarine cable without joints. It made important breakthroughs in submarine cable design, manufacturing and construction.”

Sources: Xinhua News Agency, State Grid Zhejiang Electric Power Company

closed print