The 220 kV Tingshan low-frequency converter station is under maintenance. [Photo provided to chinadaily.com.cn]
The Fuyang Aquatic Sports Center was the birthplace of the first gold medal of the Asian Games. Now, it will host the Hangzhou Super Cup of the International Canoe Federation in 2024. The importance of a reliable power supply is self-evident.
State Grid Hangzhou Power Supply Company innovatively applies the 220 kV flexible low-frequency transmission demonstration project, implements low-voltage uninterrupted synchronous grid connection operations and ensures the power safety of the venue and surrounding areas through accurate measurements of conductor distances.
Adopting China's original and internationally leading flexible low-frequency transmission technology to achieve power complementarity in supply areas
The 220 kV flexible low-frequency transmission demonstration project in Hangzhou is situated on both sides of the Fuchun River. It is China's first 220 kV flexible low-frequency transmission project and is currently the flexible low-frequency transmission project with the highest voltage level and largest transmission capacity in the world.
The project adopts China's original and internationally leading flexible low-frequency transmission technology. Two new high-voltage and large-capacity low-frequency converter stations, Tingshan and Zhongbu, are built and connected to the Shengguang supply area and Fuyang supply area in Xiaoshan respectively, realizing interconnection and mutual support between the two supply areas.
The flexible low-frequency transmission technology reduces the transmission frequency of 50 hertz in the traditional power grid to 20 hertz, reduces line losses and cable charging reactive power and improves the transmission capacity and range of system power. Through flexible regulation of the magnitude and direction of power flow by power electronic devices, the ability of power flow mutual support between the two supply areas is improved and the mutual support of surplus and deficiency of supply area loads is achieved.
"In simple terms, it means that whichever supply area, Shengguang or Fuyang, has a high load, the other supply area can flexibly provide power to it, effectively ensuring the power supply reliability of Fuyang area during the Hangzhou Super Cup event," said the person in charge of State Grid Fuyang District Power Supply Company, Hangzhou City.
Employees of State Grid Hangzhou Power Supply Company carry out low-voltage uninterrupted synchronous grid connection operations. [Photo provided to chinadaily.com.cn]
Adopting the "unperceived access" method to carry out customer "zero perception" maintenance.
In the traditional power supply system, when municipal power equipment is shut down for maintenance, it usually needs to cut off the power supply for maintenance, which will lead to power interruption for users. On Sept 12, the construction personnel of the company went to Minlian village, Dongzhou street to carry out low-voltage uninterrupted synchronous grid connection work, realizing a rapid and stable switch between municipal power and diesel power generation. The whole process is unperceived by users, ensuring the safety and reliability of power consumption for residents in Dongzhou block including the Aquatic Sports Center.
Uninterrupted synchronous grid connection operation is an operation mode for power grid maintenance or renovation without affecting users' normal power consumption. This operation mode adopts the "unperceived access" method to carry out customer "zero perception" maintenance. This operation mode helps improve the reliability and stability of the power supply system and reduce the risk of power interruption for users. To ensure worry-free power consumption during the Super Cup event, the company uses synchronous grid connection technology to ensure that the maintenance and renovation of distribution network equipment and customers' power consumption are not affected. At present, the company has successfully applied this technology on 0.4 kV and 10 kV line voltage level lines.
The successful practical application of uninterrupted operation and synchronous grid connection device is an important practice of adhering to innovation-driven and improving power supply service quality. It helps improve the reliability and stability of the power supply system and reduce the risk of power interruption for users, laying a foundation for the power safety and stability of the Super Cup.
Employees of State Grid Hangzhou Power Supply Company use the "laser cannon" to eliminate foreign objects on the conductor. [Photo provided to chinadaily.com.cn]
Deepening the coordinated linkage of "people-machine-strategy" to enhance the external damage prevention ability of transmission lines and optimize power hidden danger investigation.
"Here, the distance from the conductor to the ground is 25.5 meters, and the distance from the outermost conductor to the center pile of the set tower crane is 72.8 meters. The line meets the operation requirements of the safe distance of buildings." On Oct 8, operation and maintenance personnel of the transmission and distribution operation and inspection center carried out line inspection work along the lines of the Super Cup event, investigated potential safety hazards, and further provided solid power guarantee for the Super Cup event.
With the rapid development of cities, the construction and renovation of roads, houses and public facilities in Fuyang area can be seen everywhere. There are still risks of external damage to transmission lines everywhere. To better provide power guarantee for urban construction and ensure the safety of transmission lines along the line during the Super Cup competition, the company formulates a special plan for hidden danger investigation and treatment of transmission lines.
The company comprehensively carries out special actions to prevent external damage through multiple measures such as source control, government-enterprise linkage, inspection and investigation, and publicity and education, effectively curbing the occurrence of external damage events. At the same time, it uses technical means such as "intelligent sky eye" and "real-time shouting" for brutal operations, drone inspection, and online monitoring equipment to optimize power hidden danger investigation and ensure the safe and stable operation of transmission lines along and around the competition, providing solid power guarantee for the Super Cup.
