A smart T-type connection device for fault diagnosis and isolation of DC remote power supply lines

Abstract

This utility model relates to the field of DC power supply technology, and in particular to an intelligent T-type connection device for fault diagnosis and isolation of DC remote power supply lines. It includes a power distribution unit, an intelligent control unit, an insulation monitoring unit, and a communication unit. The input terminal of the power distribution unit is connected to the DC positive and negative copper busbars, and the output terminal is connected to the load line. The intelligent control unit is connected to the power distribution unit and is used to control the opening and closing of the power distribution unit and collect its status signals. The insulation monitoring unit is connected to the DC positive and negative copper busbars and is communicatively connected to the intelligent control unit. The communication unit is communicatively connected to the intelligent control unit and is used for data interaction with external devices. This solution integrates the control unit, insulation diagnosis unit, and power distribution unit into a T-type connection device through modular design, realizing dynamic control of power distribution in branch lines, thereby significantly improving the reliability, operation and maintenance efficiency, and safety of the DC power supply network.

Description

Technical Field

[0001] This utility model relates to the field of DC power supply technology, and in particular to an intelligent T-type connection device for fault diagnosis and isolation of DC remote power supply lines. Background Technology

[0002] With the development trends of high-speed transportation and long-distance power transmission and distribution, high-voltage direct current (HVDC) remote power supply technology has gradually become a research focus in the field of electrical engineering due to its advantages of low loss, large capacity, and long-distance transmission. A HVDC remote power supply system typically consists of a main power supply line and multiple branch nodes. The stable operation of the main line and the reliable power distribution at the branch nodes directly affect the power supply safety and efficiency of the entire system. However, current HVDC remote power supply systems still face many challenges in terms of power distribution at branch nodes and line safety monitoring.

[0003] Most existing DC power distribution methods employ simple splitters or direct parallel connection of cables, relying primarily on the low resistance of metallic conductors for passive power transmission. These distribution devices typically use crimping or bolting to physically connect the main DC cable and branch cables, then cover them with insulating material to meet basic electrical safety requirements. They connect to the main cable at both ends laterally, and branch cables extend longitudinally from the interface, thus achieving the power distribution function.

[0004] However, the aforementioned traditional branching scheme has significant shortcomings. First, its function is limited, only capable of physical conduction and energy distribution, unable to dynamically control the power distribution of each branch. Second, it lacks the ability to diagnose and isolate insulation degradation and faults. When insulation problems occur in the line, maintenance personnel usually have to rely on external insulation megohmmeters for offline testing, making it difficult to locate the specific faulty branch in a timely and accurate manner. This not only leads to low troubleshooting efficiency but may also cause missed opportunities for optimal maintenance. More seriously, when insulation faults occur in the main line, the lack of intelligent identification and isolation mechanisms can easily cause the fault range to expand rapidly, even leading to the paralysis of the entire DC power supply system.

[0005] With the increase in power supply distance and the number of branch nodes in DC remote power supply systems, existing traditional splitters with only mechanical splicing and passive transmission functions can no longer meet the urgent needs of high-reliability DC remote power supply systems in terms of intelligent management, real-time diagnosis and safety isolation. Utility Model Content

[0006] To address the problem that existing DC distribution devices only have passive distribution functions and lack real-time diagnosis and isolation of branch insulation faults, resulting in the inability to quickly locate fault points and effectively control fault propagation, this invention proposes an intelligent T-type connection device for fault diagnosis and isolation of DC remote power supply lines.

[0007] This utility model is achieved through the following technical solution: An intelligent T-type connection device for fault diagnosis and isolation of DC remote power supply lines includes a power distribution unit, an intelligent control unit, an insulation monitoring unit, and a communication unit. The input terminal of the power distribution unit is connected to the DC positive and negative copper busbars, and the output terminal is connected to the load line. The intelligent control unit is connected to the power distribution unit and is used to control the opening and closing of the power distribution unit and collect its status signals. The insulation monitoring unit is connected to the DC positive and negative copper busbars and is communicatively connected to the intelligent control unit. The communication unit is communicatively connected to the intelligent control unit and is used for data interaction with external devices.

[0008] Furthermore, the power distribution unit includes a main contactor, a bypass circuit breaker, and a branch circuit breaker. The input terminals of the main contactor and the bypass circuit breaker are connected in parallel to the DC positive copper busbar and the DC negative copper busbar through copper busbars. The input terminals of the branch circuit breakers are respectively connected to the DC positive copper busbar and the DC negative copper busbar.

[0009] Furthermore, an interlocking structure is provided between the main contactor and the bypass circuit breaker, which blocks the closing channel of the main contactor when the bypass circuit breaker is in the closed state.

[0010] Furthermore, the output terminals of the main contactor and the bypass circuit breaker are connected to the main outgoing busbar via anti-reverse diodes.

[0011] Furthermore, the intelligent control unit includes a microcontroller, a high-resistance voltage divider circuit, a relay drive circuit, and a switching interface. The input terminal of the high-resistance voltage divider circuit is connected to the DC positive and negative copper busbars, the relay drive circuit is connected to the main contactor coil, and the switching interface is connected to the auxiliary contacts of the bypass circuit breaker.

[0012] Furthermore, the intelligent control unit also includes a dual-color LED indicator, which is connected to the switch port of the intelligent control unit.

[0013] Furthermore, the insulation monitoring unit includes a precision resistor network, a differential amplifier, and a lock-in amplifier circuit. The precision resistor network is connected in parallel between the DC positive and negative copper busbars to form a reference bridge arm. The differential amplifier is connected to the bridge arm of the precision resistor network, and the lock-in amplifier circuit is connected to the output terminal of the differential amplifier. The insulation monitoring unit communicates with the intelligent control unit through an RS485 port.

[0014] Furthermore, the communication unit includes an RS485 port and a smart gateway module. The RS485 port is connected to the RS485 port of the smart control unit, and the smart gateway module is connected to external devices via an Ethernet interface.

[0015] Beneficial effects of the utility model: (1) The present invention provides an intelligent T-type connection device for fault diagnosis and isolation of DC remote power supply line. Through the power distribution unit, the load is accurately distributed, which effectively reduces the energy loss under the traditional mechanical wiring method, significantly improves the power distribution efficiency and power supply reliability at the branch node, and ensures the stable operation of remote equipment.

[0016] (2) The present invention provides an intelligent T-type connection device for fault diagnosis and isolation of DC remote power supply line. Through the insulation monitoring unit combined with the intelligent control unit, the insulation status of the line can be detected and diagnosed in real time. It can identify the trend of insulation deterioration in advance and issue an early warning. Compared with the traditional manual inspection, it can significantly shorten the fault response time and reduce the risk of safety accidents caused by insulation breakdown or leakage.

[0017] (3) The present invention provides an intelligent T-type connection device for fault diagnosis and isolation of DC remote power supply line, which has automatic segment diagnosis and step-by-step isolation functions, can quickly locate and isolate fault sections, avoid fault spread and affect the operation of the whole system, and supports intelligent control and mechanical bypass dual mode switching, so as to ensure that basic power supply and isolation functions can still be maintained in the case of intelligent unit failure.

[0018] (4) The present invention provides an intelligent T-type connection device for fault diagnosis and isolation of DC remote power supply line, which integrates a communication unit and can upload power distribution and insulation status information to the monitoring center in real time, realize remote configuration and centralized scheduling, reduce on-site operation and maintenance workload, and improve the level of intelligent system management.

[0019] (5) The present invention provides an intelligent T-type connection device for fault diagnosis and isolation of DC remote power supply line. It adopts a pole-mounted installation design, is small in size and light in weight, and is easy to deploy and relocate quickly. The device has good waterproof, dustproof and weather-resistant performance, which can effectively reduce the impact of rain, moisture, ultraviolet rays and temperature difference on line joints and improve the long-term stability and reliability of power supply line.

[0020] In summary, the intelligent T-type connection device for fault diagnosis and isolation of DC remote power supply lines provided in this application solves the problem of collaborative management of power distribution and real-time diagnosis of line insulation status at branch nodes in DC remote power supply systems. Specifically, through modular design, the control unit, insulation diagnosis unit, and power distribution unit are integrated into the T-type connection device to achieve dynamic control of power distribution of branch lines; online insulation monitoring of main and branch lines; and rapid location and intelligent isolation of faulty branches through the communication mechanism between the central office and remote offices, thereby significantly improving the reliability, operation and maintenance efficiency, and safety of the DC power supply network. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of this utility model, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 This is a system topology diagram of an intelligent T-type connection device for fault diagnosis and isolation of DC remote power supply lines proposed in this utility model; Figure 2 This is a schematic diagram of the power distribution unit of an intelligent T-type connection device for fault diagnosis and isolation of DC remote power supply lines proposed in this utility model. Figure 3 This invention presents a schematic diagram of the intelligent control unit of an intelligent T-type connection device for fault diagnosis and isolation of DC remote power supply lines. Figure 4 This invention presents an insulation monitoring schematic diagram of an intelligent T-type connection device for fault diagnosis and isolation of DC remote power supply lines. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of this utility model clearer, the present utility model will be further described in detail below with reference to the embodiments and accompanying drawings. The illustrative embodiments and descriptions of this utility model are only used to explain this utility model and are not intended to limit this utility model.

[0024] Example 1 refer to Figure 1 This utility model proposes an intelligent T-type connection device for fault diagnosis and isolation of DC remote power supply lines, including a power distribution unit, an intelligent control unit, an insulation monitoring unit, and a communication unit.

[0025] The power distribution unit adopts a circuit breaker and contactor architecture to achieve integrated power distribution and protection design. The main line access end is equipped with a main line contactor with rated current according to the power level, and its input end is connected to the DC positive / negative trunk line through a copper busbar. The branch output side is equipped with an independent miniature circuit breaker, and the branch circuit breaker output is connected to the load line. The main line contactor has dual characteristics of overload long delay and short circuit instantaneous protection. The intelligent control unit is linked with the contactor through the coil drive interface. After receiving the insulation diagnosis signal, it can trigger the designated main line and branch line to disconnect in a short time. At the same time, the main line contactor has built-in auxiliary contacts to feed back the on / off status to the monitoring system.

[0026] The power distribution unit adopts a dual-disconnection redundancy architecture with a main-bypass circuit breaker. The bypass circuit breaker is equipped with a mechanical circuit breaker of the same level, and both are connected in parallel to the DC trunk line via a copper busbar. An interlocking design is added; when the bypass circuit breaker is in the closed position, the interlocking function will forcibly block the closing channel of the main circuit contactor, ensuring physical isolation safety. This embodiment includes intelligent and manual modes. In intelligent mode, the main circuit breaker is controlled by the intelligent control unit to achieve protection and remote opening and closing. In manual mode, the bypass circuit breaker is switched to directly connect or disconnect the circuit, at which point the main circuit is completely removed from the control system.

[0027] The intelligent control unit is built around an STM32F407ZET6 microcontroller. This control unit controls the shunt trip coil of the main contactor via a relay drive circuit, achieving electric disconnection (response time ≤100ms); simultaneously, it collects the main voltage via a high-resistance voltage divider circuit. A status feedback module drives a dual-color LED indicator; a solid green light indicates normal insulation, while a solid red light indicates a serious insulation fault. Furthermore, the circuit breaker's opening and closing status is uploaded via a digital interface, and real-time voltage values ​​and fault information are transmitted to the monitoring platform via an RS-485 interface.

[0028] The insulation monitoring unit employs an unbalanced bridge circuit design. A precision resistor network is connected in parallel between the positive and negative main lines to form a reference bridge arm, and the branch lines are connected to the detection bridge arm to ground. By injecting a characteristic signal, the voltage imbalance of the bridge arm is obtained through a differential amplifier, and the impedance phase characteristics are extracted through a lock-in amplifier circuit. Based on the ratio of the positive / negative insulation resistance to ground and the trend of the capacitive component, the diagnostic processor realizes the monitoring of insulation faults to ground in the positive / negative main lines and the location of faulty branches.

[0029] The communication unit supports multiple communication protocols, such as Modbus, TCP / IP, RS485, and Ethernet, facilitating communication with external devices and making it suitable for remote monitoring and data acquisition. The integrated intelligent gateway module supports multiple communication protocols for communication with the networked cloud and for uploading information. It is suitable for remote monitoring data.

[0030] Example 2 This embodiment proposes a specific structure for an intelligent T-type connection device for fault diagnosis and isolation of DC remote power supply lines, based on embodiment 1.

[0031] A smart T-type connection device for fault diagnosis and isolation of DC remote power supply lines, the device comprising a power distribution unit, an intelligent control unit, an insulation monitoring unit, and a communication unit.

[0032] refer to Figure 2The power distribution unit is based on a main contactor and a bypass mechanical circuit breaker with the same current rating. The input terminals of the main contactor and bypass circuit breaker are connected in parallel to the DC positive / negative trunk lines via copper busbars. The output terminals of the main contactor and bypass circuit breaker are connected to the main outgoing busbar via anti-reverse diodes. An interlocking design is implemented between the main and bypass circuits. When the bypass circuit breaker is closed, the linkage control blocks the control coil of the main contactor; conversely, when the main circuit is closed, the bypass circuit breaker is in the open position. Each branch circuit is equipped with an independent miniature circuit breaker. Regarding control signals, the shunt coil of the main contactor is connected to the intelligent control unit via an isolation circuit. Its auxiliary contacts (normally open / normally closed dual contacts) feedback the on / off status to the monitoring system, and the auxiliary contacts of the bypass circuit breaker upload the switching position in real time.

[0033] refer to Figure 3 The intelligent control unit uses an STM32F407ZET6 microcontroller as its core, runs a power distribution algorithm, and controls the main contactor control coil through an optocoupler-isolated drive circuit to achieve electric closing / opening within 100ms. Signal acquisition and processing involves obtaining the main circuit's positive and negative voltages via a high-impedance voltage divider network, converting them into digital quantities by a built-in ADC, with a measurement range covering up to 2000VDC (accuracy ±0.5%). The status feedback module uses dual-color driven LED indicators. The green light, controlled by an active switch, remains constantly lit to indicate normal insulation and normal line operation. The red light, also controlled by an active switch, remains lit after the insulation monitoring unit outputs a fault signal. Bypass mode detection is achieved through switch signals from the circuit breaker's opening and closing auxiliary contacts, automatically switching the control logic to manual mode. Upon completion of monitoring, a binary status code is uploaded via the communication interface.

[0034] refer to Figure 4 The insulation monitoring unit is built based on the unbalanced bridge principle and consists of a high-precision insulation resistance sensor, a signal conditioning module, and a microprocessor module. The insulation resistance sensor is installed at the DC line node using a four-wire measurement method and calculates the insulation resistance value by collecting the leakage current between the line and the grounding terminal. The signal conditioning module uses a combination of a high-precision operational amplifier and a low-pass filter to amplify and suppress noise in the weak electrical signal output by the sensor, converting it into a digital signal before transmitting it to the microprocessor. The microprocessor has a built-in insulation status assessment algorithm that judges the insulation status by comparing the real-time measured value with a preset threshold. When the insulation resistance is detected to be lower than the warning threshold, fault information is immediately generated and sent to the intelligent control unit through an interface.

[0035] The communication module unit supports multiple communication protocols, such as Modbus, TCP / IP, RS485 and Ethernet, which facilitates information exchange with external monitoring and control systems and is suitable for remote monitoring and data acquisition.

[0036] The integrated smart gateway module supports multiple communication protocols for communicating with the cloud and uploading information. It is suitable for remote monitoring data.

[0037] It should be clarified that the core technical solution of the intelligent T-type connection device involved in this utility model lies in the improvement of the device structure and electrical connection relationship. Although the intelligent control unit uses a microcontroller to run an algorithm to drive the contactor and process signals, this function essentially relies on the physical implementation of the internal circuit structure of the device (including relay drive circuit, shunt trip coil, voltage sampling circuit, insulation monitoring bridge circuit, signal conditioning module, etc.). The essential technical feature of this utility model lies in the combination and structural arrangement of the above-mentioned hardware units, as well as their synergistic role in power distribution, insulation monitoring, and fault isolation.

[0038] Example 3 This embodiment proposes a specific connection relationship for an intelligent T-type connection device for fault diagnosis and isolation of DC remote power supply lines, based on embodiment 1.

[0039] The positive terminal of the DC remote high-voltage DC power supply is connected to the high-voltage DC positive copper busbar IN+ via a transmission wire; the negative terminal of the DC remote high-voltage DC power supply is connected to the high-voltage DC positive copper busbar IN- via a transmission wire. The main contactor input port KMin+ of the power distribution unit is connected to the high-voltage DC positive copper busbar IN+ and the positive input port of the bypass circuit breaker QS1; the branch circuit breaker QS2 input port DC+ is connected to the high-voltage DC positive copper busbar IN+; the branch circuit breaker QS2 input port DC- is connected to the high-voltage DC negative copper busbar IN-. The high-voltage acquisition port V1+ of the intelligent control unit is connected to the high-voltage DC positive copper busbar IN+; the high-voltage acquisition port V1- is connected to the high-voltage DC negative copper busbar IN-; the closing / opening output port is connected to the control coil power supply port of the main contactor unit; the bypass circuit breaker QS1 auxiliary contact port is connected to the intelligent control unit's digital output port DI1+ / -; the status feedback LED indicator is connected to the intelligent control unit's digital output ports DO1+ / - and DO2+ / - respectively. The DC+ acquisition port V2+ of the insulation monitoring unit is connected to the high-voltage DC positive copper busbar IN+; the DC- acquisition port V2- is connected to the high-voltage DC negative copper busbar IN-; the communication port RS485A / RS485B of the insulation monitoring unit is connected to the RS485A1 / RS485B1 communication port of the intelligent control unit. The RS485-A / RS485-B ports of the communication unit are connected to the RS485A2 / RS485B2 communication ports of the intelligent control unit; and information is exchanged with the external monitoring and control system platform through the 4G / 5G communication network.

[0040] Further explanation is provided regarding the specific implementation method of the intelligent T-type connection device for fault diagnosis and isolation of DC remote power supply lines.

[0041] (1) Incorporate the T-type connection device into the DC remote power supply system of the expressway section; (2) The T-type connection device is installed at the intersection of the power supply trunk line and the branch line along the highway, usually at the smart integrated pole point every 1-2 kilometers, to realize the connection between the main power supply line and the branch load. The input port of the power distribution unit is connected to the high voltage DC power of the trunk line, and continuously distributes power to the branch load under normal operation. (3) If there is an insulation fault in the main power supply line at this time, the T-type connection device will automatically enter the fault self-check state. When the intelligent control unit detection module detects the fault, it will disconnect the main circuit contactor and the fault indicator light will illuminate. The T-type connection device cooperates with the diagnostic device to complete the detection. The diagnostic device enters the line insulation diagnosis mode and starts the diagnosis of the 1# T-type connection device. The 1# T-type connection device disconnects the power transmission contactor and disconnects the downstream line. The diagnostic device judges the insulation status of the first section of the line. If the insulation value is abnormal, it indicates that the section of the line is faulty and reports maintenance information. If the insulation value is normal, the diagnosis of the 2# T-type connection device is started. The 1# T-type connection device closes the power transmission contactor. The 2# T-type connection device disconnects the power transmission contactor and disconnects the downstream line. The diagnostic device judges the insulation status of the second section of the line. If the insulation value is abnormal, it indicates that the section of the line is faulty and reports maintenance information. If the insulation value is normal, the diagnosis of the next level T-type connection device is started. This cycle continues to determine the faulty line. (4) During the above process, the intelligent control unit controls the shunt trip coil of the main contactor through the relay drive circuit to realize the electric disconnection function; at the same time, the main voltage is collected through the high-resistance voltage divider circuit. The status feedback module drives the dual-color LED indicator: a green light indicates that the insulation status is normal, and a red light indicates that the insulation status is seriously faulty. In addition, the circuit breaker opening and closing status is uploaded through the switch interface, and the real-time voltage value and fault information are sent to the communication unit through the RS-485 interface; (5) The T-type connection device can upload all internal data to the management platform through the communication unit to meet the networking requirements and realize remote monitoring, remote management and remote maintenance.

[0042] The T-shaped intelligent connection device described in this embodiment has the following functional characteristics: The intelligent T-connector features intelligent diagnostic capabilities, automatically identifying abnormal line sections, marking faults, and performing step-by-step isolation testing. In conjunction with diagnostic devices, it provides real-time feedback on insulation anomalies, directly locating faulty sections and marking fault segments. This reduces manual, blind troubleshooting, lowers the difficulty of manual inspection, and reduces maintenance costs. The device has a built-in RS485 communication interface and an isolated communication module, supporting host computer control and adjustment of device software parameters. It integrates an input isolated voltage acquisition module with a sampling range of 100Vdc~1600Vdc and an isolation level of 4000V. Power cut-off indicator lights and operating mode indicator lights provide a clear view of the current device status. The intelligent T-connector, in conjunction with the diagnostic device, enables both manual and automatic line insulation diagnostic modes.

[0043] Disconnect the main power supply to the power router on this line, and begin operation at the T-connector at the very end of the line. Disconnect the end power circuit breaker and use a megohmmeter to test the insulation of the downstream line. An abnormal insulation value indicates a fault in this section of the line. The T-connector works in conjunction with the diagnostic device to complete the test. The diagnostic device enters the line insulation diagnostic mode and activates the #1 T-connector for diagnosis. The #1 T-connector disconnects the transmission contactor, disconnecting the downstream line. The diagnostic device assesses the insulation status of the first section of the line; an abnormal insulation value indicates a fault in this section, and a maintenance report is sent. If the insulation value is normal, activate the #2 T-connector for diagnosis. The #1 T-connector closes the transmission contactor, and the #2 T-connector disconnects the transmission contactor, disconnecting the downstream line. The diagnostic device assesses the insulation status of the second section of the line; an abnormal insulation value indicates a fault in this section, and a maintenance report is sent. If the insulation value is normal, the next-level T-connection device is activated for diagnosis, and this process is repeated to identify the faulty line. For faults such as short circuits or leakage caused by single-point branch lines or equipment, fault isolation can be implemented without affecting the operation of downstream power supply lines and downstream equipment.

[0044] Featuring a pole-mounted installation design, it is compact, lightweight, and has a short construction period, facilitating installation and subsequent relocation, making it ideal for rapid deployment and flexible adjustments. It boasts excellent waterproof and dustproof performance, allowing it to withstand complex outdoor environments for extended periods. The sealed structure effectively prevents rainwater penetration, avoiding insulation degradation caused by moisture at cable joints; the protective outer shell resists UV exposure and temperature fluctuations, reducing the risk of insulation failure due to joint aging; it significantly reduces line faults caused by environmental factors, ensuring stable operation of the power supply system and improving the safety and reliability of power lines.

[0045] The foregoing has shown and described the basic principles, main features, and advantages of this utility model. Those skilled in the art should understand that this utility model is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of this utility model. Various changes and modifications can be made to this utility model without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed utility model. The scope of protection of this utility model is defined by the appended claims and their equivalents.

Claims

1. An intelligent T-connection device for DC remote supply line fault diagnosis and isolation, characterized in that, It includes a power distribution unit, an intelligent control unit, an insulation monitoring unit, and a communication unit; the input terminal of the power distribution unit is connected to the DC positive and negative copper busbars, and the output terminal is connected to the load line; the intelligent control unit is connected to the power distribution unit and is used to control the opening and closing of the power distribution unit and collect its status signals; the insulation monitoring unit is connected to the DC positive and negative copper busbars and is communicatively connected to the intelligent control unit; the communication unit is communicatively connected to the intelligent control unit and is used to exchange data with external devices. 2.The intelligent T-type connection device for DC remote supply line fault diagnosis and isolation of claim 1, wherein, The power distribution unit includes a main contactor, a bypass circuit breaker, and a branch circuit breaker. The input terminals of the main contactor and the bypass circuit breaker are connected in parallel to the DC positive copper busbar and the DC negative copper busbar through copper busbars. The input terminals of the branch circuit breakers are respectively connected to the DC positive copper busbar and the DC negative copper busbar. 3.The intelligent T-type connection device for DC remote supply line fault diagnosis and isolation according to claim 2, characterized in that, An interlocking structure is provided between the main contactor and the bypass circuit breaker. When the bypass circuit breaker is in the closed state, it blocks the closing channel of the main contactor.

4. The intelligent T-type connection device for DC remote supply line fault diagnosis and isolation according to claim 2, characterized in that, The output terminals of the main contactor and the bypass circuit breaker are connected to the main outgoing busbar via anti-reverse diodes.

5. The intelligent T-connection device for DC remote feeding line fault diagnosis and isolation according to claim 1, characterized in that, The intelligent control unit includes a microcontroller, a high-resistance voltage divider circuit, a relay drive circuit, and a digital input interface. The input terminal of the high-resistance voltage divider circuit is connected to the DC positive and negative copper busbars, the relay drive circuit is connected to the main contactor coil, and the digital input interface is connected to the auxiliary contacts of the bypass circuit breaker.

6. The intelligent T-connection device for DC remote feeding line fault diagnosis and isolation according to claim 5, characterized in that, The intelligent control unit also includes a dual-color LED indicator, which is connected to the switch port of the intelligent control unit.

7. The intelligent T-connection device for DC remote-fed line fault diagnosis and isolation according to claim 1, characterized in that, The insulation monitoring unit includes a precision resistor network, a differential amplifier, and a lock-in amplifier circuit. The precision resistor network is connected in parallel between the positive and negative DC copper busbars to form a reference bridge arm. The differential amplifier is connected to the bridge arm of the precision resistor network, and the lock-in amplifier circuit is connected to the output of the differential amplifier. The insulation monitoring unit communicates with the intelligent control unit through an RS485 port. 8.The intelligent T-type connection device for DC remote supply line fault diagnosis and isolation of claim 1, wherein, The communication unit includes an RS485 port and a smart gateway module. The RS485 port is connected to the RS485 port of the smart control unit, and the smart gateway module is connected to external devices via an Ethernet interface.

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