The world's largest multi-end AC-DC hybrid flexible distribution network interconnection project successfully put into operation in Guangdong

At 16:00 on the 25th, the world's largest multi-terminal AC-DC hybrid flexible distribution network interconnection project was successfully put into operation in Tangjiawan, Zhuhai, Guangdong.

This project is an important milestone for China Southern Power Grid to promote the construction of the first batch of “Internet +” smart energy demonstration projects of the National Energy Administration. It has applied a series of important equipment and technologies with domestic independent intellectual property rights to form a technical standard specification for flexible DC distribution network systems. The realization of China's flexible DC distribution network equipment and technology is at the forefront of the world, filling the gap at home and abroad.

01 Exploring the new direction of energy Internet construction

In order to actively explore the new direction of energy Internet construction, Guangdong Power Grid Corporation of China Southern Power Grid began preparations in early 2017 to build a “city-park dual-level ‘Internet+’ smart energy demonstration project” supporting the energy consumption revolution in Tangjiawan, Zhuhai. The project will provide support for the exploration of energy Internet construction from the three levels of “physical layer”, “information layer” and “application layer” around Zhuhai City and “Tangjia” and “Hengqin” parks. The successful multi-terminal AC-DC hybrid flexible distribution network interconnection project is the most critical part of the project's physical level.

The Tangjiawan multi-end AC/DC hybrid flexible distribution network interconnection project consists of three flexible DC converter stations and one DC microgrid. The converter stations are connected by underground cables. The project is the world's first ±10kV, ±375V, ±110V multi-voltage grade AC-DC hybrid distribution network demonstration project, and is also the world's largest capacity ±10kV distribution network flexible converter station.

If the multi-end AC-DC hybrid flexible network interconnection project is likened to a large pool, each end is like a water pipe, which can inject water into the pool or pump water out of the pool. Multi-end AC-DC hybrid flexible distribution network interconnection project must first keep the voltage constant, and ensure that the incoming and outgoing currents are normally controlled. Just as the pool water has to control the water level and control the water flow direction, the technical difficulty is very high. The multi-terminal AC-DC hybrid flexible network interconnection project started this time can adjust the current flow by adopting the world's largest capacity ±10kV medium-voltage soft-reducing valve, the first application of three-port DC circuit breaker, and the world's largest capacity ±10kV DC transformer. Moreover, the voltage can be adjusted to realize real-time regulation of the voltage levels of various nodes in the power grid.

02 overcome the key technology of energy Internet

According to Huang Wei, deputy director of the Infrastructure Department of Guangdong Power Grid Corporation of China Southern Power Grid, the multi-terminal AC/DC hybrid flexible distribution network interconnection project in Tangjiawan, Zhuhai has realized the interconnection and mutual benefit of the power supply area, improved the flexibility and controllability of the distribution network, and promoted distributed Friendly access to renewable energy to improve grid resource use efficiency and power quality.

Guangdong Zhuhai Power Supply Bureau of China Southern Power Grid revealed that the solution to support the energy consumption revolution in the city-park dual-level 'Internet + 'Smart Energy Demonstration Project” is to upgrade the network intelligence through the physical layer and realize the integration of various energy information through the information layer. Finally, the smart energy service will be implemented at the application layer to enhance the energy consumption experience and improve the overall energy efficiency of the society.

Li Ying, the head of the distribution planning department of the company's planning and development department, said that during the whole project, the Zhuhai Power Supply Bureau has overcome the key technologies of the energy Internet – in addition to the successful operation of the Zhuhai multi-end AC-DC hybrid flexible network interconnection. The project also includes flexible distribution network dispatch management of AC/DC hybrid, big data fusion information mining, and open Internet platform construction. These key technologies have formed corresponding core standards and promoted the high-quality development of energy Internet.

  By: JUCRO Electric (Focus on Vacuum Interrupter, Vacuum circuit breaker, Vacuum contactor and Switchgear)

 January 5, 2019