Traction direct-current switch cabinet for intelligent operation and maintenance system

Abstract

The utility model relates to the technical field of traction direct-current power supply systems, and provides a traction direct-current switch cabinet for an intelligent operation and maintenance system, which comprises at least one wire inlet cabinet, at least one feeder cabinet, a terminal cabinet and a cathode cabinet, circuit breakers are arranged in the wire inlet cabinet and the feeder line cabinet; the wire inlet cabinet, the feeder cabinet and the terminal cabinet are connected to the positive bus, and the negative cabinet is connected to the negative bus; frames of the inlet wire cabinet, the feeder line cabinet, the terminal cabinet and the cathode cabinet are connected to a frame bus. The positive bus is externally connected with a traction converter positive pole and a networking isolation switch; the cathode sampling bus is externally connected with a traction converter cathode; each cabinet body of the traction direct-current switch cabinet is provided with a direct-current relay protection device and an intelligent operation and maintenance terminal, the direct-current relay protection device and the intelligent operation and maintenance terminal are installed in parallel, the intelligent operation and maintenance terminal comprises a Hall sensor, and the Hall sensor is connected with an opening and closing control loop of a circuit breaker; the traction direct-current switch cabinet can find a fault in time and find out a fault reason.

Description

Technical Field

[0001] This utility model relates to the technical field of traction DC power supply systems, and more specifically, to a traction DC switchgear for intelligent operation and maintenance systems. Background Technology

[0002] Rail transit has advantages such as large capacity, high speed, safety and stability, and is an important backbone of my country's urban transportation system. Since the 21st century, with the needs of construction and development of major cities, my country's urban rail transit industry has developed rapidly. As of the end of 2020, the total length of urban rail transit operating lines reached 7969.7 km.

[0003] The safe operation of numerous lines requires a significant investment of human resources for the maintenance and upkeep of various system equipment. Among these, the traction substation, as a core subsystem, is of paramount importance, directly impacting the reliable operation of the urban rail transit system. In particular, the DC switchgear, as a key piece of equipment for traction power supply, involves complex daily maintenance, a large workload, and high labor costs.

[0004] In recent years, with the mature development of technologies such as big data, cloud computing, 5G, and AI, intelligent operation and maintenance systems have been applied to subway lines in major cities across the country. Based on the mature application of emerging technologies and the need for the digitalization, greening, and intelligent development of urban rail power supply system equipment, a traction DC switchgear with intelligent operation and maintenance functions has been proposed. This meets the requirements of strong stability, high reliability, and rapid response in subway operations, reducing the operation and maintenance burden on maintenance personnel, especially addressing the need for unmanned operation of substations.

[0005] Existing DC switchgear status monitoring methods are limited, failing to obtain status characteristics and lifespan information for critical equipment such as circuit breakers beyond basic electrical signals. Replacement or repair is typically only possible after device failure. Current DC frame protection cannot cover DC cables, making it difficult to pinpoint fault locations when cable insulation is damaged and frame protection is activated. Traditional switchgear has numerous operating parameter settings, is complex to operate, and prone to errors, placing significant pressure on operators. Furthermore, fault handling relies heavily on human experience, requiring simulations based on event records and waveform parameters to reproduce the fault and identify the problem. Traditional DC power supply systems employ limited communication methods, are prone to interruptions, suffer from chaotic message management, and have slow transmission rates.

[0006] In summary, existing DC switchgear has the problem of failing to detect faults and identify their causes in a timely manner. Utility Model Content

[0007] To overcome the shortcomings of the existing technology mentioned above, which is unable to detect faults and find the causes of faults in a timely manner, this utility model provides a traction DC switch cabinet for intelligent operation and maintenance systems that can detect faults and find the causes of faults in a timely manner.

[0008] To solve the above-mentioned technical problems, the technical solution of this utility model is as follows:

[0009] A traction DC switchgear for an intelligent operation and maintenance system, the traction DC switchgear comprising at least one incoming line cabinet, at least one feeder cabinet, terminal cabinet and negative pole cabinet;

[0010] Both the incoming line cabinet and the feeder cabinet are equipped with circuit breakers; the incoming line cabinet, feeder cabinet, and terminal cabinet are connected to the positive busbar, and the negative busbar cabinet is connected to the negative busbar; the frames of the incoming line cabinet, feeder cabinet, terminal cabinet, and negative busbar cabinet are connected to the frame busbar; the positive busbar is externally connected to the positive terminal of the traction converter and the grid disconnect switch; the negative sampling busbar is externally connected to the negative terminal of the traction converter.

[0011] Each cabinet of the traction DC switchgear is equipped with a DC relay protection device and an intelligent operation and maintenance terminal. The DC relay protection device and the intelligent operation and maintenance terminal are installed in parallel. The intelligent operation and maintenance terminal is connected to the intelligent operation and maintenance system and includes a Hall sensor. The Hall sensor is connected to the circuit breaker's opening and closing control circuit.

[0012] Compared with the prior art, the beneficial effects of this utility model's technical solution are:

[0013] The traction DC switchgear for intelligent operation and maintenance system described in this application changes the traditional switchgear's limitation of only monitoring basic switching quantities and storing a small amount of data waveforms by installing an intelligent operation and maintenance terminal on the traction DC switchgear and connecting the intelligent operation and maintenance terminal to the intelligent operation and maintenance system. This upgrades the operation and maintenance of DC switches from passive acceptance and repair / replacement to proactive prediction and early warning. The operating status of key components is displayed as basic data on the intelligent terminal, and the intelligent system performs advance analysis and prediction. Based on accurate prediction using big data, it accurately determines the specific time and specific parts of each device in the cabinet that need maintenance, effectively avoiding the problem of replacement only after an accident, and enabling timely detection of faults and identification of their causes. Attached Figure Description

[0014] Figure 1 This is a topology diagram of the urban rail DC traction power supply system based on traction DC switchgear proposed in Example 1;

[0015] Figure 2 This is a schematic diagram of the DC bus positive terminal cabinet proposed in Example 3;

[0016] Figure 3 This is a schematic diagram of the DC bus negative terminal cabinet proposed in Example 3;

[0017] Figure 4 This is a schematic diagram of the intelligent operation and maintenance terminal proposed in Example 3;

[0018] Figure 5 This is a schematic diagram of the traction DC switchgear proposed in Example 3;

[0019] Figure 6 This is the network diagram of the intelligent operation and maintenance DC switchgear proposed in Example 3. Detailed Implementation

[0020] The accompanying drawings are for illustrative purposes only and should not be construed as limiting the scope of this patent.

[0021] To better illustrate this embodiment, some parts in the accompanying drawings may be omitted, enlarged, or reduced, and do not represent the actual product dimensions;

[0022] It will be understood by those skilled in the art that certain well-known structures and their descriptions may be omitted in the accompanying drawings.

[0023] The technical solution of this utility model will be further described below with reference to the accompanying drawings and embodiments.

[0024] Example 1

[0025] This embodiment proposes a traction DC switchgear for an intelligent operation and maintenance system. Figure 1 This is a topology diagram of the urban rail DC traction power supply system based on traction DC switchgear proposed in Example 1.

[0026] This embodiment proposes a traction DC switchgear for an intelligent operation and maintenance system. The traction DC switchgear includes at least one incoming line cabinet, at least one feeder cabinet, terminal cabinet, and negative pole cabinet.

[0027] Both the incoming line cabinet and the feeder cabinet are equipped with circuit breakers; the incoming line cabinet, feeder cabinet, and terminal cabinet are connected to the positive busbar, and the negative busbar cabinet is connected to the negative busbar; the frames of the incoming line cabinet, feeder cabinet, terminal cabinet, and negative busbar cabinet are connected to the frame busbar; the positive busbar is externally connected to the positive terminal of the traction converter and the grid disconnect switch; the negative sampling busbar is externally connected to the negative terminal of the traction converter.

[0028] Each cabinet of the traction DC switchgear is equipped with a DC relay protection device and an intelligent operation and maintenance terminal. The DC relay protection device and the intelligent operation and maintenance terminal are installed in parallel. The intelligent operation and maintenance terminal is connected to the intelligent operation and maintenance system and includes a Hall sensor. The Hall sensor is connected to the circuit breaker's opening and closing control circuit.

[0029] In this embodiment, the traction DC switchgear for intelligent operation and maintenance system of this application, by setting up an intelligent operation and maintenance terminal on the traction DC switchgear and connecting the intelligent operation and maintenance terminal to the intelligent operation and maintenance system, changes the status quo of traditional switchgear that can only monitor basic switching quantities and store a small amount of data waveforms. It improves the operation and maintenance of DC switches from passive acceptance and repair and replacement to proactive prediction and early warning. The operating status of key components is displayed as basic data on the intelligent terminal, and advance analysis and prediction are performed on the intelligent system. Based on accurate prediction of big data, it accurately determines the specific time and specific parts of each device in the cabinet that need maintenance, effectively avoiding the problem of replacement only after an accident, and enabling timely detection of faults and identification of fault causes.

[0030] In one optional embodiment, the intelligent operation and maintenance terminal includes an equipment status prediction module, an insulation status monitoring module, an equipment fault analysis module, and a communication module, and the modules of the intelligent operation and maintenance terminal are communicatively connected to each other.

[0031] In one optional embodiment, the device status prediction module includes a voltage and current monitoring unit, a wireless temperature measurement unit, several mechanical characteristic monitoring units, and a lifespan prediction unit;

[0032] The life prediction unit is connected to the voltage and current monitoring unit, the wireless temperature measurement unit, and several mechanical characteristic monitoring units, respectively.

[0033] The mechanical characteristic monitoring unit is connected to the main circuit of the circuit breaker.

[0034] In one optional embodiment, the voltage and current monitoring unit includes a plurality of current sampling devices and voltage sampling devices; the current sampling devices include a shunt and a current transmitter; the voltage sampling devices include a high-voltage conductor and a voltage transmitter.

[0035] The current sampling device is connected to the circuit breaker via a current sampling line;

[0036] The voltage sampling device is installed between the positive bus and the negative bus via a bus voltage sampling line;

[0037] The voltage sampling device is installed between the outgoing side of the circuit breaker and the negative busbar via a feeder voltage sampling line.

[0038] In one optional embodiment, the wireless temperature measurement unit includes a plurality of temperature sensors, which are respectively connected to the busbar of the positive busbar, the busbar of the negative busbar, the busbar of the frame busbar, the wiring connection of the upper and lower ports of the circuit breaker, the connection of the incoming and outgoing cables of each cabinet of the traction DC switch cabinet, the connection of the busbar voltage sampling line, the connection of the feeder voltage sampling line, and the connection of the current sampling line.

[0039] In one optional embodiment, the equipment status prediction module includes a surge arrester monitoring unit;

[0040] The incoming line cabinet and the feeder cabinet are equipped with surge arresters, and the surge arresters are connected to the surge arrester monitoring unit.

[0041] In one optional embodiment, the device status prediction module includes a switch status monitoring unit; the switch status monitoring unit includes a Hall sensor.

[0042] In this optional embodiment, by setting Hall sensors and other sensors in the intelligent operation and maintenance terminal, the characteristics of the circuit breaker (disconnecting switch) control circuit, main circuit, key connection points, copper busbars, etc. are monitored. Based on the difference between the action curve and the standard curve, the health of the object being tested is determined, and its lifespan is predicted. This can change the traditional "fault-only maintenance" to a proactive approach, predicting alarms and thus performing "condition-based maintenance".

[0043] Example 2

[0044] This embodiment is an improvement on the traction DC switchgear for intelligent operation and maintenance system proposed in Embodiment 1.

[0045] This embodiment proposes a traction DC switchgear for an intelligent operation and maintenance system. The traction DC switchgear includes at least one incoming line cabinet, at least one feeder cabinet, terminal cabinet, and negative pole cabinet.

[0046] Both the incoming line cabinet and the feeder cabinet are equipped with circuit breakers; the incoming line cabinet, feeder cabinet, and terminal cabinet are connected to the positive busbar, and the negative busbar cabinet is connected to the negative busbar; the frames of the incoming line cabinet, feeder cabinet, terminal cabinet, and negative busbar cabinet are connected to the frame busbar; the positive busbar is externally connected to the positive terminal of the traction converter and the grid disconnect switch; the negative sampling busbar is externally connected to the negative terminal of the traction converter.

[0047] Each cabinet of the traction DC switchgear is equipped with a DC relay protection device and an intelligent operation and maintenance terminal. The DC relay protection device and the intelligent operation and maintenance terminal are installed in parallel. The intelligent operation and maintenance terminal is connected to the intelligent operation and maintenance system and includes a Hall sensor. The Hall sensor is connected to the circuit breaker's opening and closing control circuit.

[0048] In an optional embodiment, the insulation monitoring module is disposed on the connecting cable between the positive busbar and the positive terminal of the traction converter, on the connecting cable between the positive busbar and the grid disconnect switch, and between the negative busbar and the frame busbar.

[0049] In this optional embodiment, by adding a cable monitoring module to the intelligent operation and maintenance terminal device, a new solution is proposed that can simultaneously take into account the traditional frame voltage and frame current protection, and can also monitor the insulation status of power transmission cables; by expanding the frame protection range of the DC traction power supply section, the frame protection fault point can be accurately identified through system analysis, thereby improving the entire frame protection mechanism.

[0050] In an optional embodiment, the equipment fault analysis module is communicatively connected to the equipment status prediction module, the insulation status monitoring module, and the communication module;

[0051] The communication module is connected to the traction DC switchgear via Ethernet and optical fiber;

[0052] The communication module communicates with the equipment status prediction module, insulation status monitoring module, and equipment fault analysis module via the IEC61850 protocol.

[0053] In this optional embodiment, immediately after a fault occurs, the intelligent operation and maintenance system analyzes the cause of the fault and provides solutions based on the real-time status of each part of the DC switchgear using empirical algorithms; this greatly reduces the time for fault handling and improves the accuracy and real-time performance of post-fault maintenance.

[0054] In this optional embodiment, the IEC61850 protocol is introduced to change single-end communication into multiple communication methods that are mutually redundant, and different processing methods are established for different types of messages; this makes message processing simple, efficient and fast; the communication method is redundant and highly reliable.

[0055] In an optional embodiment, the intelligent operation and maintenance terminal further includes a display module, and the equipment status prediction module, insulation status monitoring module, equipment fault analysis module and communication module are all connected to the display module.

[0056] Example 3

[0057] This embodiment proposes a specific implementation example based on the traction DC switchgear for intelligent operation and maintenance systems proposed in Embodiments 1 and 2.

[0058] In urban rail transit, subway vehicles generally use a DC power supply system (750V DC / 1500V DC), powered by a DC traction power supply system located in a ground substation. DC switchgear is the core equipment in the DC traction power supply system, its function being to provide stable and reliable power to subway vehicles operating on the tracks and to provide safe fault protection.

[0059] Figure 2 This is a schematic diagram of the DC bus positive terminal cabinet proposed in this embodiment. Figure 3 This is a schematic diagram of the DC bus negative terminal cabinet proposed in this embodiment. Figure 4 This is a schematic diagram of the intelligent operation and maintenance terminal in this embodiment. Figure 5 This is a schematic diagram of the traction DC switchgear proposed in this embodiment. Figure 6 This is a network diagram of the intelligent operation and maintenance DC switchgear proposed in this embodiment.

[0060] As an example, the basic structure of the traction DC switchgear in this application includes: an incoming line cabinet, a feeder cabinet, a terminal cabinet, and a negative pole cabinet. Two incoming line cabinets and four feeder cabinets constitute the positive pole of the DC bus, used to transmit electrical energy to the DC traction contact network line. Figure 2 As shown; the negative terminal cabinet connects the rail return branch to the negative terminal of the traction converter, forming a DC negative busbar, as shown. Figure 3 As shown; the terminal cabinet undertakes the communication transmission and logic interface functions of the DC switchgear and is installed in parallel with the DC positive terminal section. The connection topology between different types of DC switchgear and with related equipment within the substation is as follows: Figure 1 As shown, this DC switchgear consists of two incoming line cabinets, four feeder cabinets, and one negative terminal cabinet. Each incoming line cabinet is equipped with one DC circuit breaker, designated as 201 and 202, which are connected to the positive terminals of traction converter 1 and traction converter 2, respectively. Each feeder cabinet is equipped with one DC circuit breaker, designated as 211, 212, 213, and 214, which are connected to the DC contact network via a disconnecting switch. The negative terminal cabinet is equipped with two electrically operated disconnecting switches, designated as 2012 and 2022, which are connected to the negative terminal of the traction converter and the rail.

[0061] Existing DC switchgear still falls short in terms of application and functionality, lacking intelligence and ease of operation. With a large number of lines in operation, maintenance and upkeep of equipment are required to ensure the safe operation of the lines, which necessitates a significant investment of human resources. In particular, traction substations, as core subsystems, have exceptionally important equipment that directly affects the reliable operation of urban rail transit. Among these, DC switchgear, as a key piece of equipment for traction power supply, suffers from cumbersome daily maintenance, a large workload, and high labor costs.

[0062] In this embodiment, in addition to existing protection devices, an intelligent operation and maintenance terminal device and related sensor units are added to the DC switchgear body. A database is established in the background based on the intelligent operation and maintenance platform, thereby combining software and hardware to form a platform-based intelligent DC switchgear. The operating status of the DC switchgear is monitored, effectively predicting circuit breaker life and mechanical characteristics; the operation of surge arresters is monitored; temperature monitoring and early warning are performed at key connections within the entire cabinet; and real-time insulation monitoring is conducted at all points within the cabinet, effectively reducing the scope of faults and improving safety. Based on the intelligent operation early warning and fault analysis capabilities of the big data platform, as well as multiple reliable communication processing methods, the DC power supply system of the substation is transformed from traditional "fault repair" to "condition-based repair," greatly reducing the pressure on operation personnel.

[0063] Intelligent operation and maintenance functions are achieved by installing intelligent operation and maintenance terminal devices on each specific cabinet type of the DC switchgear. For example... Figure 4 As shown, the intelligent operation and maintenance terminal device is designed in a modular fashion according to functional requirements. The modules are roughly divided according to functional requirements, and the detailed division of the modules according to functional requirements is shown below. Figure 5 As shown, the intelligent operation and maintenance terminal device consists of a wireless temperature measurement module, a switch status monitoring module, a mechanical characteristic monitoring module, a life prediction module, an insulation status monitoring module, an intelligent fault analysis module, a voltage and current monitoring module, a surge arrester monitoring module, and a communication module. Each module's function is supported by corresponding software systems and sensor acquisition units. These units work together to implement specific functions within the intelligent operation and maintenance system. The intelligent operation and maintenance system terminal device includes an LCD display screen for showing specific operating information of the switchgear.

[0064] For incoming line cabinets and feeder cabinets equipped with circuit breakers, each cabinet is equipped with one set of intelligent operation and maintenance system terminal device, installed in parallel with traditional DC relay protection devices, enabling information interconnection between the two. The layout of each functional module and its corresponding sensor unit of the intelligent operation and maintenance system terminal device is shown below. Figure 5 As shown.

[0065] In the wireless temperature measurement module, a total of 10 temperature measurement points are arranged in each cabinet: positive busbar copper busbar, negative busbar copper busbar, frame busbar copper busbar, connection points of upper and lower copper busbars of circuit breakers, connection points of incoming and outgoing cables of the cabinet, connection points of busbar voltage sampling lines, connection points of feeder voltage sampling lines, and connection points of current sampling lines. During switchgear operation, the temperature sensors transmit real-time copper busbar temperatures to the wireless temperature measurement module. The module then uploads the collected data to the intelligent operation and maintenance system, enabling temperature monitoring of all critical components of the switchgear. The temperature data is processed within the intelligent operation and maintenance system and used for circuit breaker status monitoring and lifespan prediction.

[0066] In the voltage and current monitoring module, a current sampling device, consisting of a shunt and a current transmitter, is installed on the main circuit of the circuit breaker to monitor the current flowing through the circuit breaker during switchgear operation. A voltage sampling device, consisting of a high-voltage conductor and a voltage transmitter, is installed between the positive and negative busbars to monitor the voltage of the DC busbar during switchgear operation. A voltage sampling device, consisting of a high-voltage conductor and a voltage transmitter, is installed between the circuit breaker outgoing side and the negative busbar to monitor the voltage of the feeder during switchgear operation. A total of two voltage channels (busbar voltage and feeder voltage) and one current channel (current flowing through the circuit breaker) are sampled. These voltage and current data are used for basic voltage and current display and are also sent to various module units of the intelligent operation and maintenance system terminal for circuit breaker condition monitoring analysis, mechanical characteristic analysis, and life prediction.

[0067] In the surge arrester monitoring module, a surge arrester monitoring unit is installed on the surge arrester of each feeder cabinet and each incoming cabinet, and connected to the intelligent operation and maintenance terminal to monitor the operation of the surge arrester.

[0068] In the switch status monitoring module, each intelligent operation and maintenance terminal has a unit with a Hall sensor connected to the circuit breaker's opening and closing control circuit. The sensor monitors the coil current for each opening and closing (including fault tripping conditions), and the data is uploaded to the intelligent operation and maintenance system for analysis of the circuit breaker's status, mechanical characteristics, and life prediction.

[0069] In the mechanical characteristic monitoring module, a mechanical sensor unit is preset on the main circuit of each circuit breaker to collect the number of times the mechanical circuit breaker operates, the degree of mechanical wear during each operation (opening and closing once), and the open / closed position status of the circuit breaker. The data is used for analysis of the mechanical characteristics and life prediction of the circuit breaker.

[0070] The life prediction module mainly calculates the life of the circuit breaker by comprehensively analyzing the voltage and current curves, mechanical characteristic curves, coil current conditions, and operating time at different temperatures when the circuit breaker operates.

[0071] In the insulation condition monitoring module, insulation monitoring modules are installed on the cables connecting the traction converter and the incoming line cabinet, on the cables connecting the feeder cabinet and the grid disconnect switch, and between the negative busbar and the frame busbar in each incoming line cabinet and feeder cabinet. The insulation monitoring modules are connected to the intelligent operation and maintenance system.

[0072] The equipment fault analysis module (intelligent fault analysis module) is an independent module on the intelligent operation and maintenance system terminal. It predicts and analyzes faults based on the information collected by the above modules.

[0073] The communication module is an independent module on the intelligent operation and maintenance system terminal, mainly used for communication functions.

[0074] For negative terminal cabinets equipped with electrically operated disconnect switches, each cabinet is configured with one set of intelligent operation and maintenance system terminal devices, installed in parallel with traditional DC relay protection devices, enabling information interconnection between the two. The functions of each unit module of the intelligent operation and maintenance system terminal device are the same, and their applications are similar, except that the application target is electrically operated disconnect switches.

[0075] Currently, the DC switchgear in operation on urban rail lines across the country only meets basic breaking and making functions. Monitoring of the circuit breakers and the entire switchgear involves collecting only basic electrical signals to meet basic operational needs. For critical equipment within the cabinets (such as circuit breakers and disconnectors), aside from factory testing and lifespan prediction, there are no other monitoring methods. This means that when critical components fail, operators cannot determine how long they can remain operational until the problem is exposed during the next failure or when the component is completely damaged and unable to function, creating potential operational risks. Urban rail lines require high reliability and stability, necessitating the prediction of overall equipment performance and the mitigation of all foreseeable risks.

[0076] This application installs a Hall effect sensor within an intelligent operation and maintenance device, connected to the circuit breaker's opening and closing control circuit (or the disconnector's motor control circuit). It monitors the coil current for each opening and closing operation (including fault tripping conditions), and stores the resulting current waveform curve within the intelligent operation and maintenance terminal device. It also calculates the operating time, average operating current, maximum operating current, actual power, and energy consumption. Simultaneously, it compares each operating current waveform with a standard waveform within the intelligent operation and maintenance system to determine the similarity. Based on the difference between the operating curve and the standard curve, it judges the health status of the monitored object. The stored waveforms and calculated data can be transmitted to the intelligent operation and maintenance system for further analysis.

[0077] By monitoring the current in the main circuit of the circuit breaker in real time, especially the breaking current and short-circuit current during each fault, and combining the arcing time, number of operations, and temperature of the main circuit copper busbar, the wear and burn-out degree of the main contacts of the circuit breaker can be calculated using a mature intelligent operation and maintenance system electrical life prediction and analysis algorithm. This allows for the prediction of the remaining life of the circuit breaker and the prediction of its electrical life.

[0078] Based on the database of the intelligent operation and maintenance system and the rich interfaces of the intelligent terminal, wireless temperature sensors capable of withstanding high voltage and high temperature are deployed on key components of the DC switchgear (such as main circuit copper busbars, busbar copper busbars, and cable connections). These sensors can monitor the real-time temperature of the main circuit copper busbars, busbar copper busbars, and critical cable connections. By setting over-temperature thresholds, alarm signals are issued. The LCD display of the intelligent terminal can simultaneously display the temperature and the actual operating current of the switchgear. The sensors obtain energy by sensing primary current, and the temperature data transmission frequency automatically adjusts according to the real-time temperature, achieving wireless temperature measurement.

[0079] An online surge arrester monitoring unit is installed inside the switchgear and connected to the intelligent operation and maintenance terminal via RS485. This unit monitors the surge arrester's operating frequency and leakage current, enabling real-time online monitoring. Monitoring data is displayed on an LCD screen and transmitted to the power supply intelligent operation and maintenance system, thus achieving online surge arrester monitoring.

[0080] In urban rail DC traction power supply systems, electrical leakage between the casing and the positive terminal of the line is prone to occur along the power transmission path. Long-term neglect of maintenance can lead to major accidents such as short circuits. The current mainstream approach uses current and voltage detection to form frame voltage and frame current protection, thus achieving frame protection for the DC power supply section. However, this approach has a drawback: the protection range is limited, only protecting specific equipment such as DC traction switchgear and traction converters, and not covering the entire DC traction power supply. For example, if a short circuit to ground occurs between the cables of various DC devices due to damage to the insulation, triggering frame protection, the traditional frame protection mechanism can detect the fault and trip the circuit breaker. However, even after multiple inspections of the DC power supply equipment by operators, it is difficult to find the problem. This monitoring blind spot makes it difficult to locate the fault point for repair.

[0081] This application utilizes an intelligent operation and maintenance terminal device equipped with a cable monitoring module to monitor the insulation status of key transmission lines, such as between the positive terminal of the traction converter and the DC switchgear, between the DC switchgear and the grid disconnect switchgear, between the rail return current and the negative terminal cabinet, and between the negative terminal cabinet and the negative terminal of the traction converter. It monitors the leakage current of each part and generates waveform data reports, which are then processed and analyzed by the intelligent operation and maintenance system to determine the insulation status and displayed on an LCD screen. Simultaneously, the waveform curves of each part are transmitted to the intelligent operation and maintenance database. Through analysis and judgment, when a leakage current trend appears, the system issues an early warning through the intelligent operation and maintenance terminal, accurately locating the fault points in each part.

[0082] In DC traction power supply systems, switchgear is responsible for the control and protection of power transmission along the entire line. Its protection logic is complex and requires setting many protection settings. On operating lines, due to the varying number and formation of trains during peak hours, the same equipment often needs to be set with multiple sets of protection settings under different operating conditions. Each set of settings has a different meaning depending on the logic, which puts pressure on operators and can easily lead to incorrect or mismatched settings.

[0083] Based on the analytical capabilities of the intelligent operation and maintenance system and the screen processing function of the intelligent terminal, this application pre-records all the various operating conditions faced by the DC switchgear into the operation and maintenance system, and organizes them into protection setting groups for different operating conditions according to their needs. When operators need to operate, the intelligent terminal will provide prompts and animation demonstrations based on the current operating status, thereby making the operation simple and efficient when revising the settings for various operating conditions. At the same time, it forms a standardized operating procedure for the interlocking and locking relationships within the DC switchgear and with other equipment, providing guidance and prompts to prevent equipment failure or major accidents caused by violent operation.

[0084] Currently, the equipment with the highest failure rate on the operating urban rail power supply lines is still the DC switchgear. The fault handling method still relies on manually simulating and reconstructing the fault after it occurs by retrieving the equipment's event records and voltage and current waveform curves at the time of the fault, combined with the equipment's internal logic and the interlocking, tripping, and blocking relationships between equipment, to deduce whether the key data and logic can match, thereby inferring the fault problem, checking related equipment and lines, and locating the fault point for repair. This fault handling method relies too much on human experience, increases the handling pressure on operation personnel, and is not timely enough.

[0085] This application establishes a fault occurrence database based on the long-term operating conditions of DC switchgear and the occurrence of faults under different operating conditions. It records and uploads current and voltage waveform data from three key periods—before, during, and after a fault—to the system, forming data blocks that correspond one-to-one with event records. This allows for the synchronization of voltage, current, and switching status data at every moment. Based on different fault analysis and handling methods and response strategies, and combined with operational experience, the application initially incorporates different fault handling logic for different operating conditions into the operation and maintenance system. Leveraging the logical computing capabilities of big data processing, a fault analysis expert system is formed. When a fault occurs, the system uses real-time operating data, waveform comparison within the system, and ultra-fast logical calculations within the fault analysis expert system to generate a fault assessment opinion and analysis report immediately upon fault occurrence.

[0086] Traditional substation equipment typically connects to the backend system via RS485 communication or Modbus TCP / IP communication protocol network cables, thereby enabling data upload.

[0087] This communication method requires a switch for relaying during network setup, which is complex and not conducive to real-time control and information exchange of the entire system. Moreover, data information is generally not classified and organized, but is directly uploaded to the backend after being packaged as a whole. This results in chaotic message information management and makes it impossible to identify the importance of various messages.

[0088] After long-term operation, aging and damage to communication lines or loosening of interfaces are inevitable. For manned substations, these problems can be detected and repaired during routine maintenance. However, for unmanned substations, after each communication interruption, repairs can only be made during long-term scheduled maintenance. During communication interruptions, it is impossible to view equipment status information in real time. If a fault occurs, it cannot be reported and resolved quickly, resulting in significant economic losses. For DC switchgear, a critical piece of equipment used to supply power to train traction systems, it is essential to ensure that the equipment's operating status can be viewed in real time and that communication speed is uninterrupted.

[0089] like Figure 6 As shown, this application addresses the problems of complex networking and chaotic message management by introducing the IEC61850 protocol communication method to replace the traditional serial communication method, so as to realize real-time information interaction and intelligent control. As an Ethernet-based communication protocol, IEC 61850 adopts an object-oriented data model and standardized communication services. Based on the system's operating mode, it classifies switchgear messages into six categories: Type 1 (fast messages), Type 1A (trip messages), Type 2 (medium-speed messages), Type 3 (low-speed messages), Type 4 (raw data messages), Type 5 (file transfer function), and Type 6 (time synchronization messages). Different types of messages use different transmission modes due to their different attributes (e.g., data volume, importance, real-time requirements). Type 1 and Type 1A messages, due to their high real-time requirements, are mapped to dedicated Ethernet types. Type 2, 3, and 5 messages use the general TCP / IP protocol. Type 6 messages, due to their large data volume and low real-time requirements, can be distinguished from Type 2, 3, and 5 messages. This classification and organization of messages before uploading greatly improves message recognition, especially enabling basic judgment by applying different processing methods to various types of messages (highly important, moderately important, and minor).

[0090] To address the communication interruption issue, leveraging the robust compatibility of the intelligent operation and maintenance system, a combined "fiber optic + Ethernet" communication method is adopted. The two communication methods serve as backups for each other and are connected to each other's monitoring range. If either communication method experiences a communication interruption due to a physical disconnection, the other communication method can promptly detect and alert backend personnel, and upload the data to the intelligent operation and maintenance system for analysis, thus identifying and locating the fault point in advance. Simultaneously, because the two communication methods serve as backups for each other, uninterrupted real-time communication can be achieved throughout the entire process.

[0091] By installing intelligent operation and maintenance terminals and sensor units on DC switchgear and connecting them to an intelligent operation and maintenance system, and effectively applying current cloud computing technology, an intelligent traction DC switchgear platform integrating data acquisition and analysis has been established. This changes the traditional switchgear's limitation of only monitoring basic switching quantities and storing a small amount of data waveforms. It elevates the operation and maintenance of DC switches from passive acceptance and repair / replacement to proactive prediction and early warning. The operating status of key components is displayed as basic data on the intelligent terminal, and advance analysis and prediction are performed on the intelligent system. Based on accurate predictions using big data, the system precisely determines the specific time and specific parts of each device in the cabinet that require maintenance, effectively avoiding the situation where replacements are only performed after an accident.

[0092] By adding a cable monitoring module to the existing frame voltage and frame current protection mechanism, the scope of frame protection for DC traction power supply is expanded. Through system analysis, it can accurately distinguish whether voltage or current leakage occurs in DC equipment or transmission lines. Through data comparison and analysis, it can provide early warning of weak insulation points, thereby further improving the DC power supply frame leakage detection mechanism and nipping threats in the bud.

[0093] Intelligent operation prompts via smart terminals make switchgear operation simpler and more efficient, improving upon traditional operation ticket systems; demonstrations to prevent misoperation improve upon traditional signage warnings, making switchgear operation safer; and the establishment of systematic and standardized operating procedures makes the interlocking and locking relationships between various devices clearer and more explicit, enhancing the safety and standardization of operational procedures.

[0094] By fully exploring the operating conditions of DC switches and considering the probability of various faults occurring under different operating conditions, the experience of traditional manual handling of event faults is standardized, systematized, proceduralized, and digitized, and incorporated into the intelligent operation and maintenance system. With the powerful computing and analytical capabilities of the operation and maintenance system, an expert system that can quickly analyze and handle faults is formed; thereby greatly improving the efficiency of fault analysis and handling, and significantly saving the time for emergency repairs after a fault occurs.

[0095] By introducing dual communication lines for mutual backup and a new communication mode based on intelligent analysis, uninterrupted communication under extreme conditions is achieved. Messages are intelligently classified, organized, and uploaded, reducing the workload of operators and enabling more rational hierarchical handling of various operational events, making the urban rail traction system more flexible, reliable, and efficient. Simultaneously, a large amount of data, after being classified and organized, is automatically entered into the intelligent operation and maintenance database via dual-link communication, achieving information sharing with substation monitoring systems, integrated automation systems, intelligent power distribution systems, and maintenance and repair systems. This enriches the database and facilitates data retrieval and operation and maintenance.

[0096] In summary, the design and operation of the new intelligent operation and maintenance traction DC switchgear meet the requirements of strong stability, high reliability and rapid response in subway operation, reduce the operation and maintenance pressure of maintenance personnel, and especially meet the needs of unmanned operation of substations.

[0097] The same or similar labels correspond to the same or similar parts;

[0098] The terms used to describe positional relationships in the accompanying drawings are for illustrative purposes only and should not be construed as limiting this patent.

[0099] Obviously, the above embodiments of this utility model are merely examples for clearly illustrating this utility model, and are not intended to limit the implementation of this utility model. Those skilled in the art can make other variations or modifications based on the above description. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this utility model should be included within the protection scope of the claims of this utility model.

Claims

1. A traction DC switchgear for an intelligent operation and maintenance system, characterized in that, The traction DC switchgear includes at least one incoming line cabinet, at least one feeder cabinet, terminal cabinet, and negative pole cabinet; Both the incoming line cabinet and the feeder cabinet are equipped with circuit breakers; the incoming line cabinet, feeder cabinet, and terminal cabinet are connected to the positive busbar, and the negative busbar cabinet is connected to the negative busbar; the frames of the incoming line cabinet, feeder cabinet, terminal cabinet, and negative busbar cabinet are connected to the frame busbar; the positive busbar is externally connected to the positive terminal of the traction converter and the grid disconnect switch; the negative sampling busbar is externally connected to the negative terminal of the traction converter. Each cabinet of the traction DC switchgear is equipped with a DC relay protection device and an intelligent operation and maintenance terminal. The DC relay protection device and the intelligent operation and maintenance terminal are installed in parallel. The intelligent operation and maintenance terminal is connected to the intelligent operation and maintenance system and includes a Hall sensor. The Hall sensor is connected to the circuit breaker's opening and closing control circuit.

2. The traction DC switchgear for an intelligent operation and maintenance system according to claim 1, characterized in that, The intelligent operation and maintenance terminal includes an equipment status prediction module, an insulation status monitoring module, an equipment fault analysis module, and a communication module, and the modules of the intelligent operation and maintenance terminal are connected to each other.

3. The traction DC switchgear for an intelligent operation and maintenance system according to claim 2, characterized in that, The equipment status prediction module includes a voltage and current monitoring unit, a wireless temperature measurement unit, several mechanical characteristic monitoring units, and a life prediction unit. The life prediction unit is connected to the voltage and current monitoring unit, the wireless temperature measurement unit, and several mechanical characteristic monitoring units, respectively. The mechanical characteristic monitoring unit is connected to the main circuit of the circuit breaker.

4. The traction DC switchgear for an intelligent operation and maintenance system according to claim 3, characterized in that, The voltage and current monitoring unit includes several current sampling devices and voltage sampling devices; the current sampling device includes a shunt and a current transmitter; the voltage sampling device includes a high-voltage conductor and a voltage transmitter. The current sampling device is connected to the circuit breaker via a current sampling line; The voltage sampling device is installed between the positive bus and the negative bus via a bus voltage sampling line; The voltage sampling device is installed between the outgoing side of the circuit breaker and the negative busbar via a feeder voltage sampling line.

5. The traction DC switchgear for an intelligent operation and maintenance system according to claim 4, characterized in that, The wireless temperature measurement unit includes several temperature sensors, which are respectively connected to the busbar of the positive busbar, the busbar of the negative busbar, the busbar of the frame busbar, the wiring connection of the upper and lower ports of the circuit breaker, the connection of the incoming and outgoing cables of each cabinet of the traction DC switch cabinet, the connection of the busbar voltage sampling line, the connection of the feeder voltage sampling line, and the connection of the current sampling line.

6. The traction DC switchgear for an intelligent operation and maintenance system according to claim 2, characterized in that, The equipment status prediction module includes a surge arrester monitoring unit; The incoming line cabinet and the feeder cabinet are equipped with surge arresters, and the surge arresters are connected to the surge arrester monitoring unit.

7. The traction DC switchgear for an intelligent operation and maintenance system according to claim 2, characterized in that, The device status prediction module includes a switch status monitoring unit; the switch status monitoring unit includes a Hall sensor.

8. The traction DC switchgear for an intelligent operation and maintenance system according to any one of claims 2 to 7, characterized in that, The insulation status monitoring module is installed on the connecting cable between the positive busbar and the positive terminal of the traction converter, on the connecting cable between the positive busbar and the grid disconnect switch, and between the negative busbar and the frame busbar.

9. The traction DC switchgear for an intelligent operation and maintenance system according to any one of claims 2 to 7, characterized in that, The equipment fault analysis module is communicatively connected to the equipment status prediction module, the insulation status monitoring module, and the communication module. The communication module is connected to the traction DC switchgear via Ethernet and optical fiber; The communication module communicates with the equipment status prediction module, insulation status monitoring module, and equipment fault analysis module via the IEC61850 protocol.

10. The traction DC switchgear for an intelligent operation and maintenance system according to any one of claims 2 to 7, characterized in that, The intelligent operation and maintenance terminal also includes a display module, and the equipment status prediction module, insulation status monitoring module, equipment fault analysis module and communication module are all connected to the display module.

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