110 kV power line relocation accelerated to escort construction of Hefei EMU Depot

In the early morning of Oct 23, near the elevated Baogong Avenue in Xinzhan district, Hefei, Anhui province, the relocation site of the 110 kV Paibei Line and the 110 kV Beicheng Second Line was a scene of busyness. Construction workers climbed up the iron towers over 60 meters high and cooperated with ground personnel to complete the installation of traction wires, laying the groundwork for the subsequent conductor stringing work.

[Photo provided to chinadaily.com.cn]

As the "main arterial network" of the western power grid in Feidong county, the 110 kV Paibei Line and 110 kV Beicheng Second Line serve as the connection hub for multiple 110 kV substations, undertaking the critical task of ensuring reliable power supply within the region. In recent years, with the advancement of the Hefei EMU Depot project, the construction of its main structures has been completed successively. Covering an area of over 1,100 mu (approximately 73.33 hectares), the depot features a total configuration of 10 inspection tracks and 39 stabling tracks. However, several existing transmission lines that pass through the project's construction zone have posed a constraint on the further progress of the depot construction.

To support the construction of the Hefei EMU Depot and expedite the development of the EMU operation and maintenance project, State Grid Hefei Power Supply Company promptly launched the transmission line relocation and renovation project. 

The power grid renovation scheme within Feidong county adopts a configuration where lines of two distinct voltage levels are erected on the same tower. Specifically, the double-circuit of the 220 kV Zhongdong Line is installed at the upper section of the tower, while the 110 kV Paibei Line and 110 kV Beicheng Second Line are erected at the lower section. Owing to the requirement of meeting the safety height standards from the ground for different voltage levels, the maximum height of the towers utilized in this relocation project reaches 67 meters. Furthermore, the project employs the steel pipe tower erection method, which not only reduces the land occupation area and shortens the construction duration, but also guarantees the safe and stable operation of the transmission lines.

In consideration of ensuring reliable power supply for users during the power line relocation period, State Grid Hefei Power Supply Company has fully formulated a power grid maintenance plan, adjusted the power grid operation mode in advance, further transferred power grid loads by changing the incoming power sources of substations and constructing new T-junctions of transmission lines, and improved the operation mode of substations affected during the power grid maintenance, so as to ensure the safe and reliable power supply of the power grid during the construction period.

"During the maintenance of the 110 kV Paibei Line and 110 kV Beicheng Second Line, we arranged for transmission operations and maintenance personnel to be stationed in groups, increased the frequency of UAV inspections on the involved transmission lines, checked for hidden dangers on lines and evaluated the risk of external damage to the corridor," said Wu Da, a transmission line operation and maintenance worker. 

Since the outage maintenance of these lines started, a total of more than 120 person-times of UAV inspections and patrols by transmission operation and maintenance personnel have been carried out, and two potential risk and hidden danger issues have been rectified.

"Since the end of August, we have completed the erection of 31 iron towers and the construction of 4.6 kilometers of new lines in total, and it is expected that the full commissioning of the four-circuit relocation project can be realized by the middle of November," introduced Zhang Liankai, the project manager. The project team has adopted a construction method of concentrating multiple sets of traction equipment, which has further reduced potential construction safety risks and shortened the construction period.

Since the beginning of this year, State Grid Hefei Power Supply Company has continuously advanced the upgrading and transformation of the power grid in Feidong county. It has proactively become involved with the construction of key projects and industrial parks in Feidong county, helped complete the line of the 220 kV Caomiao Traction Substation, and assisted with supporting projects of the 220 kV Circular Economy Park Substation and 220 kV Yaogang Substation. These efforts have accelerated the construction of key infrastructure, supported the power supply for important industrial parks, and contributed to the synchronized development of the regional power grid and local economic and social development.