In the wave of coordinated development of the Guangdong-Hong Kong-Macao Greater Bay Area, Dongguan is using rail construction as a link to break urban boundaries and reshape the commuting pattern. The first phase of Dongguan Line 1 (Wanghong Station ~ Huangjiang Central Station) was born, which not only connected 10 towns and streets, allowing citizens to easily integrate into the 30-minute commuting circle in the city center, but also realized a 2-minute seamless transfer between the urban rail and the subway, building a solid traffic bridge for the five cities of Guangzhou, Shenzhen, Dongguan and Fohui to jointly build a "super big city"

As the core backbone of Dongguan's rail transit network, the first phase of Line 1 is large-scale, with a total length of about 57.496 kilometers on the right line, 25 stations (including 3 elevated stations and 22 underground stations), supporting the construction of Daojiao depot, Huangjiang parking lot (shared by Lines 1 and 4) and 4 main substations (including the main transformer of Qifeng shared with Line 2). Among them, the 110kV Songshan Lake, Huangjiang and Daojiao main stations, as the core hubs of power supply, shoulder the key mission of power guarantee on the whole line.

The AC and DC system is like the power "aorta" that runs through the whole project, deeply integrated into the overall power supply architecture, and provides core support for the stable operation of the line. As the core supplier of AC and DC power supply and UPS power supply system for this project, Huiye Da has tailor-made highly reliable, high-efficiency and highly adaptable power supply solutions for this rail transit artery with a total length of about 57.496 kilometers and 25 stations with accurate scene adaptation, leading technical strength and comprehensive service guarantee, and escorted the high-quality progress of the project with hard-core technology.

Scenario-based customization and accurate adaptation of the whole link

Adhering to the design concept of "one project, one solution", the power supply system creates differentiated configurations according to the load characteristics and operation requirements of different engineering scenarios to ensure accurate and efficient power supply.

AC and DC power supply unit: hierarchical design, stable output

According to the load requirements of different substations, the system is divided into three types of devices: A-type, B-type, and C, forming a gradient adaptation scheme. The A-type device is used in the main substation, equipped with dual sets of charging modules, dual sets of batteries and dual sets of monitoring and control units, and the configuration of 6 20A modules effectively prevents the two groups of batteries from being connected in parallel and meets the requirements of high-load and high-reliability operation. The B and C devices are respectively suitable for traction step-down hybrid substations and step-down substations, and the (N+1) thermal redundancy charging modules are used to configure 6 10A modules and 5 10A modules respectively, with the main and standby dual sets of voltage regulation devices, which ensure reliability while taking into account economy. All devices are selected with high-frequency switching power supply modules, with constant current, current limiting and constant voltage, floating charge, and balanced charging automatic conversion functions, with voltage and current regulation accuracy ≤± 0.5% and ripple coefficient ≤ 0.5%, which fully meets the strict power supply standards of the project.

Parallel DC power supply system: flexible expansion, intelligent operation and maintenance

In order to meet the flexible power supply needs of some substations, the system is equipped with parallel DC power supply devices, Type B is equipped with 22 2A modules and 22 12V/120Ah batteries, and Type C is equipped with 18 2A modules and 18 12V/120Ah batteries, using (N+2) thermal redundancy parallel power supply mode. The module supports live plugging and unplugging, which can be replaced and maintained online, greatly reducing downtime losses. The system integrates automatic nuclear capacitance function, which can only store nuclear capacitance data for more than 2 years for a single battery each time, and has intelligent functions such as internal resistance testing and melt core on/off monitoring, making operation and maintenance management more efficient.

UPS power supply: zero interruption guarantee, escort core equipment

The AC uninterruptible power supply (UPS) adopts a dual-machine dual-bus output design, with an AC input voltage covering AC323V~AC456V, a DC input voltage allowable ±15% deviation, an output voltage accuracy of ≤±3%, and a transient recovery time of ≤20ms. The system supports seamless switching between AC input and DC power supply, with a switching time of 0ms and a bypass switching time of <4ms, which can withstand long-term overload of 135% rated current and instantaneous impact of 200% rated current, providing all-weather zero-interruption power guarantee for key equipment such as substation automation systems to ensure stable operation of the core system.

Technology empowerment creates a highly reliable power supply system

This power supply system solves the multiple challenges of rail transit power supply scenarios with four core technical advantages, demonstrating strong technical strength and innovation capabilities.

Extremely reliable and uninterrupted operation

The system fully meets the requirements of 24×7 uninterrupted operation, and ensures that the failure of a single device does not affect the overall system operation through redundancy design and high-reliability component selection. The battery adopts 12V valve-regulated sealed lead-acid colloidal battery (station substation) and 2V valve-regulated sealed lead-acid battery (main substation), with a floating charging service life of not less than 10 years, and the third cycle of 10h rate capacity can reach the rated value, which can ensure the 2-hour accident load discharge and shock load power supply demand. All equipment has passed the electromagnetic compatibility type test, has perfect anti-electromagnetic interference measures, can calmly cope with the complex electromagnetic environment of the subway, and operate stably under the harsh conditions of thunderstorm days ≥90 days / year and seismic intensity VIII degrees.

Intelligent monitoring and more efficient operation and maintenance management

The whole series of products integrate advanced microcomputer monitoring systems, with remote control, remote signal, and telemetry "three remote" functions, and the communication protocols are compatible with international standards such as IEC61850 and Modbus, and can be seamlessly connected with the integrated automation system of the substation. The monitoring unit can monitor key parameters such as AC input, DC bus voltage, and battery status in real time, with a measurement accuracy of up to 4 bits and a half-meter level, and can automatically identify abnormal conditions such as insulation faults, overvoltage and undervoltage, and module failures, and issue sound and light alarms in time and upload them to the SCADA system. At the same time, it supports functions such as battery cell voltage inspection and event record traceability, providing accurate data support for operation and maintenance personnel, greatly improving operation and maintenance efficiency, and reducing management costs.

Safety protection, multiple barriers without dead ends

The system strictly follows a series of national standards such as GB and DL, and the electrical clearance and creepage distance meet the requirements of the specification, the power frequency withstand voltage reaches 2.5kV/1min, and the impact withstand voltage meets the corresponding grade standards. It is equipped with surge protector, insulation monitoring device (insulation monitoring level ≥50kΩ) and perfect over-current, over-voltage, short-circuit, and phase loss protection measures, and the outlet of the battery pack is equipped with short-circuit protection, and the feeder loop adopts a well-known brand DC special bipolar circuit breaker, and the current capacity of breaking the short-circuit is not less than 10kA. The equipment has a protection level of not less than IP2X (parallel system) and IP3X (AC and DC power supply unit, UPS), and has good moisture, corrosion, and dust resistance, and can withstand ambient temperature of -5~+40°C and daily average relative humidity of 95%.

Green energy saving, full life cycle optimization

The system adopts a modular design, with digital and analog I/O, switch ports, etc. reserved for no less than 20% expansion capacity, and the power supply devices of Songshan Lake and Huangjiang main substations are reserved for the subsequent power supply conditions of Lines 3 and 4, so as to realize resource sharing and long-term expansion to avoid duplicate construction. The efficiency of the high-frequency switching power supply module ≥ 90%, and the output efficiency of the UPS inverter ≥ 85%, combined with intelligent voltage regulation, load matching and other technologies, effectively reducing energy consumption. The equipment supports module-level maintenance and live plugging, reducing downtime and maintenance time, reducing the operating cost of the whole life cycle, and is in line with the concept of green and low-carbon construction.

The construction of Dongguan Line 1 is not only a transportation project, but also a strategic measure for Dongguan to integrate into the Greater Bay Area and build a "super big city". In the future, with the full operation, this efficient and reliable AC and DC power supply solution will continue to empower the safe and efficient operation of the line, further activate the regional development momentum, make the "Greater Bay Area on the track" more closely connected and more efficient, bring a more convenient, safer and more comfortable travel experience to citizens, and write a new chapter in the synergy of urban development and transportation construction!