On the morning of June 10, accompanied by the humming of distribution transformers, the substation at Yinzhou District Government Station was successfully energized in a single operation, marking the full-line "power connection" of Ningbo Rail Transit Line 5 Phase I. Digital construction is accelerating the "Ningbo metro speed": from "track connection" on May 31 to "power connection" today (June 10), it took only 10 days for Line 5 Phase I to achieve another new milestone!

Shortened from 2 months to 10 days

Digital construction accelerates metro development

In addition to stations and shield tunnels, metro construction also involves the construction of power supply systems. These provide reliable power for trains, station mechanical and electrical equipment, communications, signaling and auxiliary system equipment. Under the normal construction schedule, it takes about 2 months after "track connection" to achieve "power connection."

"But to ensure that Line 5 Phase I achieves the goal of high-quality opening within the year, we broke with conventional practices and used digital construction to empower faster metro construction."

So-called "digital construction" means that, before tracks are laid in the tunnel, a digital model is established to create a "digital track," and then the positioning of cable brackets is analyzed theoretically to provide parameters for on-site power supply construction. This technology is also called trackless measurement construction. Huang Qingfeng introduced that this method breaks through the construction sequence of first achieving "track connection" and then carrying out "measurement and installation" for power supply construction. Construction of the catenary system begins right after the tunnel structure is completed, allowing track-laying construction and power supply construction to proceed in parallel. The construction period is shortened by at least 50 days, achieving the Ningbo metro speed of "power connection" only 10 days after "track connection" for Line 5 Phase I.

Efficient coordinated progress

Digital management builds smart construction sites

Through technological innovation and digital management, not only is construction efficiency greatly improved and the construction period shortened, but it also promotes optimized processes and efficient coordinated progress in rail transit projects under construction, thereby reducing costs and increasing efficiency and empowering high-quality development of rail transit.

On February 9, 2021, power supply system construction was launched for Line 5 Phase I. Facing the difficulty of cross-operation by multiple trades in the track area, Ningbo Rail Transit used the track area dispatch monitoring system, which is "like installing a pair of 'clairvoyant eyes' for on-site management personnel, enabling real-time monitoring, real-time communication, alarms and other functions for operating vehicles, and rationally and orderly arranging cross-construction of track engineering vehicles for various specialties, ensuring both safety and improved work efficiency," Huang Qingfeng said. With the support of digital management, Ningbo Rail Transit safely and efficiently secured multiple project milestones: completing 108 kilometers of cable laying and related work in 45 days, and completing the hoisting of 583 pieces of equipment in 75 days...

Digital management also makes later operation and maintenance more effective with less effort. In the equipment interlayer of the substation at Yinzhou District Government Station, the editor saw that both ends of each cable were hung with QR code "identity information." A scan reveals important information about the cable's "past and present," such as relevant parameters, construction drawings and acceptance standards, laying a digital foundation for inspection, repair and maintenance during subsequent metro operation.

Behind efficient construction, overall coordination and investment in manpower and equipment are also indispensable. "During the peak construction period of the Line 5 power supply system, there were about more than 1,000 construction workers and management personnel, more than 10 large track vehicles, and more than 20 sets of large hoisting equipment. Among them, to ensure the progress of ring-network cable laying on the existing line section from Yongxing Main Substation to South Higher Education Park Station, nearly 100 workers and management personnel stayed at their posts and fought on the front line during the Spring Festival."

The Line 5 Phase I project runs from Buzheng Station to Xingzhuang Road Station, with a total length of 27.9 kilometers and 22 stations. The power supply system of Line 5 Phase I adopts a 110 kV/35 kV two-level voltage centralized power supply mode, and the medium-voltage power supply network adopts a mixed power supply network for traction and power lighting. The entire line has two main substations, respectively sharing the Shuangqiao Main Substation with Line 2 and the Yongxing Main Substation with Line 4.