In the field of rail transit, equipment renewal and transformation is Huiyeda's "daily homework". This time, we are renovating the overall renovation project of the UPS power supply system of Beijing Line S1. Line S1 is the first medium and low-speed maglev subway train in Beijing and the second medium and low-speed maglev line in China. Opened in 2017, with a total length of about 10.2 kilometers, 8 elevated stations and 1 depart, it is an important traffic artery connecting Mentougou District and the central urban area of Beijing.

Since its opening in 2017, the UPS power supply system of Line S1 has been operating at high load for 8 years, facing serious aging of components, frequent system failures, rising operation and maintenance costs, power supply safety and other problems, and the upgrading and transformation is imminent

Facing challenges: retrofitting challenges under extreme conditions

When receiving this project, the project team was under great pressure, the maglev line of Line S1 was really too special, and the site conditions were also very complicated, but the more difficult the project, the more courageous the Huiye experts were to move forward. In the end, the technical team sorted out the seven core difficulties throughout the whole construction process through multiple rounds of on-site survey and scheme deduction:

1) Time window limit: The subway night maintenance window is only 3 hours (00:00-03:30), and the equipment switching needs to be completed in a very short time

2) Complex handling environment: The equipment room of some stations (such as Shichang Station) is located on the mezzanine, without freight elevators, and can only be carried by climbing equipment + manpower

3) Difficult to dismantle old equipment: Old equipment with output isolation transformer, heavy weight, complex installation, and "clamping" by other cabinets, narrow displacement space

4) Complex transformation of battery packs: The primary battery pack is 50 cells× 2 groups are connected in parallel, and need to be regrouped into 32 cells× 3 groups are connected in parallel, and there are 4 different wiring schemes on site

5) Interface compatibility risk: New equipment needs to be seamlessly connected with existing power distribution systems and monitoring systems (PSCADA/BAS), and there is uncertainty about protocol compatibility

6) Unforeseeable site conditions: rust on the electrostatic floor at some sites, insufficient load-bearing, insufficient power cord length, water baffle design defects, etc

7) Multi-site synchronous promotion: involving 10 installation sites on the whole line, widely distributed, difficult to coordinate, and need to be finely managed

Customized solutions: precise policies, a game of chess across the board

In the face of complex challenges, Huiye Da customized a UPS power system renewal and transformation plan of "unified planning of the whole line and precise implementation of sub-stations" for Line S1, with the self-developed HYD-UT33 series industrial-grade power frequency UPS power supply system as the core, to achieve unified standards, unified monitoring, unified operation and maintenance of the power supply system in 10 installation parts of the whole line

Precise customization, one place, one strategy

According to the different characteristics of each site, the Huiyeda team has developed differentiated solutions:

Shichang Station:
There are problems: the equipment room is located on the mezzanine, there is no freight elevator; the battery switch cabinet is installed against the wall

Solution: equipment disassembly and transportation (main cabinet, isolation transformer separation), stair-climbing equipment handling; battery switch assembly front installation, front panel opening; water baffle redesign.

Xiaoyuan Station:
There is a problem: the length of the existing power cord is insufficient

Solution: Input copper bar to lengthen by 60MM, and produce 3 more sets of spare parts

Apple Orchard Station:
There are problems: the original system is a second-generation product, and the protocol is inconsistent; electrostatic floor rust

Solution: Secondary development of touch screen protocol program; Emergency replacement of rusted electrostatic flooring

Depot Usage Library:

Problem: The link of the background monitoring B network is unstable

Solution: R&D follow-up to troubleshoot communication protocol problems, and upgrade after solution verification

Full line of battery systems:

There is a problem: the battery pack needs to be changed from 50 cells × 2 groups to 3 groups × 32 cells

Solution: Formulate transformation strategies for 4 different battery wiring schemes

Application of key technologies

The key equipment used in this renovation project is Huiyeda's HYD-UT33 series industrial-grade power frequency UPS power supply, which adopts a double isolation design and has the following characteristics:

● Online dual-conversion DSP technology, supporting 4 parallel machines

● LCD Chinese and English interface, easy to operate

● Wide input range and high input power factor (12 pulse inputs optional), easily coping with various complex power grid environments

● Pure sine wave output, high voltage accuracy, low total harmonic distortion

● 110V, 220V, 384V DC voltage levels are selectable, and the battery configuration is more flexible

● Powerful protection function, with overload, short circuit, over-undervoltage protection function, etc

● Rich communication interfaces, equipped with RS485, RS232, RJ45 interfaces

Intelligent technology application

Power frequency isolation technology:

Adapt to the characteristics of humidity, dust and electromagnetic interference in the subway environment to ensure stable operation under harsh working conditions

Parallel redundancy architecture:

Parallel redundancy is used at key sites, and a single module failure does not affect the load power supply

Intelligent battery life cycle management:

Real-time monitoring of battery voltage, internal resistance, and temperature, and evaluation of health (SOH) for preventive maintenance

Black box fault traceability:

Record the operation data 30 seconds before the fault, greatly shortening the troubleshooting time

Remote monitoring and unified management:

Seamless access to the existing PSCADA/BAS system to realize the "four remote" function

Remarkable results: from quantitative change to qualitative change

After the transformation is completed, the system performance achieves a qualitative leap:

                        Before and after the transformation

This transformation not only greatly improves the reliability of power supply, but also fundamentally solves the pain points of operation and maintenance, and provides a solid power guarantee for the safe and stable operation of Line S1.

This time, the UPS power system transformation project of Beijing Metro Line S1 is another concentrated embodiment of Huiyeda's technical strength and service capabilities in the field of rail transit. Faced with the challenges of tight time, complex environment, and high requirements, the Huiyeda team successfully built a "highly reliable heart" for Beijing's first maglev line with rich industry experience, customized solutions, and efficient project execution.

In the future, Huiye Da will continue to deepen the field of rail transit, driven by technological innovation and centered on customer value, to provide smarter and more reliable power solutions for global urban rail transit, so that every trip can be guaranteed by safe and reliable power.