Annular DC main line AC-DC storage system

Abstract

The invention relates to the technical field of power distribution network protection, and discloses an annular DC main line AC-DC storage system, and the system comprises a distributed detection module which is used for collecting DC voltage and current parameters in real time; an area controller which is in communication connection with the distributed detection module and is used for collecting current direction information of adjacent nodes and constructing a direction discrimination matrix; the system protection module is in communication connection with the area controller and is used for determining a fault section according to the direction discrimination matrix; the hybrid direct current circuit breakers are arranged in each section line and are connected with the system protection module; and the energy storage module is connected with the system protection module and is used for injecting a reverse current with a specific waveform into the fault section. According to the invention, through cooperation of the distributed detection module and the area controller, rapid and accurate positioning of the fault of the annular DC system is realized, and the problem of insufficient selectivity of a traditional protection scheme in a multi-directional power supply scene is effectively solved.

Description

Technical Field

[0001] This invention relates to the field of power distribution network protection technology, specifically to a ring-shaped DC mainline AC / DC storage and refrigeration system. Background Technology

[0002] DC power distribution systems, as a new generation of power transmission technology, have shown significant advantages in scenarios such as industrial parks and data centers. Among them, the ring topology has become a research hotspot due to its high power supply reliability.

[0003] However, ring DC systems face unique challenges in fault protection: traditional overcurrent-based protection schemes are difficult to adapt to the multi-directional power supply characteristics of ring networks, and the complex fault current path makes location difficult; at the same time, DC fault currents do not have a natural zero-crossing point, which limits the circuit breaker breaking speed, and existing protection systems have an inherent contradiction between speed and selectivity. Summary of the Invention

[0004] The purpose of this invention is to provide a ring-shaped DC mainline AC / DC storage and refrigeration system to solve the above-mentioned technical problems:

[0005] The objective of this invention can be achieved through the following technical solutions:

[0006] A ring-shaped DC mainline AC / DC storage system, the system comprising:

[0007] A distributed detection module is used to acquire DC voltage and current parameters in real time.

[0008] The area controller is communicatively connected to the distributed detection module and is used to collect current direction information of adjacent nodes and construct a direction discrimination matrix;

[0009] The system protection module is communicatively connected to the area controller and is used to determine the fault section based on the direction discrimination matrix;

[0010] Hybrid DC circuit breakers are installed in each section of the line and connected to the system protection module;

[0011] An energy storage module, connected to the system protection module, is used to inject a reverse current of a specific waveform into the faulty section.

[0012] As a further technical solution, the distributed detection module includes a voltage acquisition unit and a current acquisition unit, which are used to acquire DC voltage parameters and DC current parameters, respectively; the voltage acquisition unit is electrically connected to the DC bus, and the current acquisition unit is coupled to the line conductor.

[0013] As a further technical solution, the area controller includes a data receiving port and a data processing unit. The data receiving port is connected to the distributed detection module, and the data processing unit is used to perform the construction operation of the direction discrimination matrix.

[0014] As a further technical solution, the process of constructing the direction discrimination matrix includes:

[0015] The distributed detection module includes N monitoring nodes. For any two adjacent monitoring nodes i and j:

[0016] set up ;

[0017] pass Calculate the directional eigenvalues ​​of the obtained node pair (i,j);

[0018] Constructing a matrix ;

[0019] in, , These are the times when the fault traveling wave arrives at node i and node j, respectively. For time difference; is the preset time decay constant; i and j are both node numbers.

[0020] As a further technical solution, the process of determining the fault segment based on the direction discrimination matrix includes:

[0021] pass Calculate and obtain fault characteristic parameters ;

[0022] Fault characteristic parameters With preset threshold Compare:

[0023] like The line segment between node i and node j is at risk of failure.

[0024] Otherwise, determine that there is no risk of fault in the line segment between node i and node j.

[0025] As a further technical solution, the process of determining the fault segment based on the direction discrimination matrix also includes: when the fault characteristic parameters Less than the preset value The confidence index is calculated using the following formula. :

[0026] ;in, This represents the number of adjacent nodes involved in the calculation.

[0027] Confidence index Preset confidence threshold Compare:

[0028] like If so, the line segment between node i and node j is determined to be a faulty segment;

[0029] like If so, then the line segment between node i and node j is not a faulty segment.

[0030] As a further technical solution, the hybrid DC circuit breaker includes a main current-carrying branch and an auxiliary disconnecting branch;

[0031] The main current-carrying branch is connected in series in the DC line to carry the continuous operating current during normal system operation; the auxiliary disconnecting branch includes a solid-state switch unit and an energy absorption unit, which are connected in parallel at both ends of the main current-carrying branch.

[0032] The solid-state switching unit is used for current transfer and disconnection in case of a fault; the energy absorption unit is used to absorb overvoltage energy generated during the disconnection process.

[0033] When a faulty section is detected, a corresponding auxiliary disconnecting branch quickly cuts off the current in the faulty section, and then the main current-carrying branch safely disconnects under zero current conditions.

[0034] As a further technical solution, the energy storage module includes an energy storage medium and a power conversion device. The energy storage medium is connected to the DC bus through the power conversion device. The power conversion device is used to control the energy conversion and power regulation between the energy storage module and the DC bus.

[0035] The beneficial effects of this invention are as follows: This invention achieves rapid and accurate fault location in a ring DC system through the coordinated operation of a distributed detection module and a regional controller, effectively solving the problem of insufficient selectivity in traditional protection schemes under multi-directional power supply scenarios. The hybrid DC circuit breaker combined with the reverse current injection of the energy storage module significantly improves the fault current interruption speed and arc extinguishing effect, overcoming the technical problem of the lack of a natural zero-crossing point in DC systems. The multi-level decision-making mechanism of the system protection module ensures the reliability and coordination of protection actions under complex operating conditions, providing a complete fault protection solution for AC / DC energy storage and discharging integrated systems. Attached Figure Description

[0036] The invention will now be further described with reference to the accompanying drawings.

[0037] Figure 1 This is a system framework diagram of the annular DC mainline AC / DC storage and refrigeration system in this invention. Detailed Implementation

[0038] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0039] Please see Figure 1 As shown, a ring-shaped DC mainline AC / DC storage system includes:

[0040] A distributed detection module is used to acquire DC voltage and current parameters in real time.

[0041] A region controller, communicatively connected to the distributed detection module, is used to collect current direction information from adjacent nodes and construct a direction discrimination matrix. A system protection module, also communicatively connected to the region controller, is used to determine the fault section based on the direction discrimination matrix. Holographic perception is achieved through a distributed detection network, and a direction discrimination algorithm based on spatiotemporal correlation overcomes the challenge of ring topology localization.

[0042] Hybrid DC circuit breakers are installed in each section of the line and connected to the system protection module. The coordinated control of the hybrid circuit breaker and intelligent energy storage solves the bottleneck of DC interruption technology.

[0043] An energy storage module, connected to the system protection module, is used to inject a reverse current of a specific waveform into the faulty section.

[0044] The system's collaborative working mechanism includes the following steps: When a fault occurs, the distributed detection module captures the abnormal signal within 100μs, the area controller completes preliminary location within 300μs, the system protection module makes a decision within 500μs by integrating multi-source information, the hybrid circuit breaker completes disconnection within 1ms, and simultaneously the energy storage system injects optimized reverse current (amplitude ≥ 30% of the fault current) to accelerate arc extinction. After the fault is cleared, the system automatically restores power supply within 15ms.

[0045] Through the above technical solution, this embodiment achieves rapid and accurate fault location in a ring DC system by coordinating the distributed detection module and the area controller, effectively solving the problem of insufficient selectivity in traditional protection schemes under multi-directional power supply scenarios. The hybrid DC circuit breaker combined with the reverse current injection of the energy storage module significantly improves the fault current interruption speed and arc extinguishing effect, overcoming the technical problem of the lack of a natural zero-crossing point in the DC system. The multi-level decision-making mechanism of the system protection module ensures the reliability and coordination of protection actions under complex operating conditions, providing a complete fault protection solution for the AC-DC-energy storage integrated system.

[0046] The distributed detection module includes a voltage acquisition unit and a current acquisition unit, which are used to acquire DC voltage parameters and DC current parameters, respectively. The voltage acquisition unit is electrically connected to the DC bus, and the current acquisition unit is coupled to the line conductor. Through the above technical solution, the distributed detection module in this embodiment achieves accurate measurement and high-speed transmission of DC system electrical parameters through the optimized design and coordinated operation of the voltage and current acquisition units.

[0047] The area controller includes a data receiving port and a data processing unit. The data receiving port is connected to the distributed detection module, and the data processing unit is used to perform the construction operation of the direction discrimination matrix. The data receiving port adopts a multi-channel parallel interface design, establishes a low-latency communication connection with the distributed detection module, and supports real-time reception of current direction signals and precise timestamp information from each monitoring node. The data processing unit integrates a dedicated matrix operation coprocessor and a fault feature recognition algorithm. By analyzing the correlation of current direction between adjacent nodes and the traveling wave propagation timing characteristics, it dynamically constructs a direction discrimination matrix reflecting the fault current distribution of the entire network, and uses an adaptive threshold mechanism to intelligently analyze the matrix feature values, ultimately outputting the confidence assessment results of suspected fault sections. Through the coordinated optimization of hardware acceleration and software algorithms, this area controller achieves rapid extraction and preliminary location of fault features, providing highly reliable intermediate-layer data processing support for the decision-making of the system protection module, effectively improving the accuracy and real-time performance of fault diagnosis in the ring DC system.

[0048] The process of constructing the direction discrimination matrix includes:

[0049] The distributed detection module includes N monitoring nodes. For any two adjacent monitoring nodes i and j:

[0050] set up ; pass Calculate the directional eigenvalues ​​of the obtained node pair (i,j);

[0051] Constructing a matrix ;

[0052] in, , These are the times when the fault traveling wave arrives at node i and node j, respectively. For time difference; is the preset time decay constant; i and j are both node numbers.

[0053] Through the above technical solution, this embodiment provides a process for constructing a direction discrimination matrix. Specifically, firstly, the number of monitoring nodes included in the distributed detection module is counted and denoted as N. Then, for any adjacent monitoring nodes i and j:

[0054] set up ,pass Calculate the time difference between the arrival of the fault traveling wave at node i and node j, by... Calculate the directional eigenvalues ​​of the obtained node pairs, denoted as (i,j). Finally, construct a matrix based on the eigenvalues. .

[0055] The process of determining the fault section based on the direction discrimination matrix includes:

[0056] pass Calculate and obtain fault characteristic parameters ;

[0057] Fault characteristic parameters With preset threshold Compare:

[0058] like The line segment between node i and node j is at risk of failure.

[0059] Otherwise, determine that there is no risk of fault in the line segment between node i and node j.

[0060] Through the above technical solution, this embodiment provides a process for initially identifying line sections that may be prone to faults. Specifically, through... Calculate and obtain fault characteristic parameters , among which, according to As can be seen from the definition for The opposite of the normal value, when a fault occurs in a certain section, the traveling wave generated at the fault point will propagate along the line to both sides at near the speed of light (approximately 300 m / μs). Because the fault point is located within this section, the traveling wave only needs to traverse a portion of the section length to reach the two end nodes, rather than the entire ring network, forming the shortest propagation path, resulting in a very small time difference. Normal section Smaller, due to the time difference of traveling wave propagation The amplitude is relatively large, and the exponential decay is significant. However, in the fault section, the traveling wave propagation time difference near the fault point is relatively large. Very small, in case of failure and The opposite signs and similar amplitudes highlight the contradictory current directions at the fault location. Based on the above, the fault characteristic parameters are... With preset threshold Compare: If If the line segment between node i and node j is at risk of failure, then the line segment between node i and node j is at risk of failure; otherwise, the line segment between node i and node j is at risk of failure.

[0061] The process of determining the fault section based on the direction discrimination matrix also includes: when the fault characteristic parameters Less than the preset value The confidence index is calculated using the following formula. :

[0062] ;in, This represents the number of adjacent nodes involved in the calculation.

[0063] Confidence index Preset confidence threshold Compare:

[0064] like If so, the line segment between node i and node j is determined to be a faulty segment;

[0065] like If so, then the line segment between node i and node j is not a faulty segment.

[0066] In real-world systems, interference factors such as measurement noise and traveling wave distortion exist, making it difficult to rely solely on a single index of the direction discrimination matrix. This could lead to misjudgments. The confidence index, through cross-validation of multi-node data, can effectively filter out occasional interference. The closed nature of a ring network may cause temporary current direction discrepancies in non-faulty sections (e.g., when adjacent sections fail simultaneously). Confidence calculation avoids being misled by local features by evaluating the consistency of all network nodes. This embodiment provides the calculation process of the confidence index, specifically, through the formula... Calculate and obtain the confidence index. Then the confidence index Preset confidence threshold Compare: If If the line segment between node i and node j is determined to be a faulty segment; if If so, then the line segment between node i and node j is not a faulty segment.

[0067] The hybrid DC circuit breaker includes a main current-carrying branch and an auxiliary disconnecting branch;

[0068] The main current-carrying branch is connected in series in the DC line to carry the continuous operating current during normal system operation; the auxiliary disconnecting branch includes a solid-state switch unit and an energy absorption unit, which are connected in parallel at both ends of the main current-carrying branch.

[0069] The solid-state switching unit is used for current transfer and disconnection in case of a fault; the energy absorption unit is used to absorb overvoltage energy generated during the disconnection process.

[0070] When a faulty section is detected, a corresponding auxiliary disconnecting branch quickly cuts off the current in the faulty section, and then the main current-carrying branch safely disconnects under zero current conditions.

[0071] Through the above technical solution, the hybrid DC circuit breaker in this embodiment achieves efficient interruption and energy dissipation of fault current in DC systems through the coordinated operation of the main current-carrying branch and the auxiliary breaking branch. The main current-carrying branch handles normal current carrying, ensuring low-loss operation; the solid-state switching unit in the auxiliary breaking branch achieves microsecond-level rapid breaking, and the energy absorption unit effectively suppresses operational overvoltage. In case of a fault, the auxiliary branch first completes the current transfer and disconnection, and then the main current-carrying branch safely breaks under zero-current conditions. This design has the following significant advantages: First, it concentrates arc energy in the auxiliary branch for processing, protecting the main current-carrying contacts; second, the two-stage breaking strategy balances breaking speed and equipment safety; third, the multi-stage design of the energy absorption unit can adapt to different levels of fault energy; and fourth, the clear division of labor between the main and auxiliary branches extends the overall lifespan of the equipment. This hybrid structure effectively solves the contradiction between speed, reliability, and economy in DC circuit breakers, providing a reliable fault isolation method for ring DC systems.

[0072] The energy storage module includes an energy storage medium and a power conversion device. The energy storage medium is connected to the DC bus through the power conversion device. The power conversion device is used to control the energy conversion and power regulation between the energy storage module and the DC bus.

[0073] Through the above technical solution, the energy storage module in this embodiment achieves efficient energy storage and flexible scheduling of the system through the coordinated operation of the energy storage medium and the power conversion device. The energy storage medium adopts a composite energy storage structure, possessing both energy storage and power support capabilities. The power conversion device, as the core hub for energy interaction, can realize voltage level conversion, bidirectional power flow control, multi-mode intelligent switching, and dynamic harmonic suppression. Through the intelligent regulation of the power conversion device, the energy storage module can provide millisecond-level fault current support and participate in the system's steady-state energy management, significantly improving the power supply reliability and operational economy of the ring DC system. Simultaneously, its modular architecture facilitates capacity expansion and maintenance.

[0074] This invention can be a system, method, and / or computer program product. A computer program product may include a computer-readable storage medium having computer-readable program instructions loaded thereon for causing a processor to implement various aspects of the invention.

[0075] Computer-readable storage media can be tangible devices capable of holding and storing instructions for use by an instruction execution device. Computer-readable storage media can be, for example, electrical storage devices, magnetic storage devices, optical storage devices, electromagnetic storage devices, semiconductor storage devices, or any suitable combination thereof. More specific examples (a non-exhaustive list) of computer-readable storage media include: portable computer disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), static random access memory (SRAM), portable compact disc read-only memory (CD-ROM), digital multifunction disc (DVD), memory sticks, floppy disks, mechanical encoding devices, such as punch cards or recessed protrusions storing instructions thereon, and any suitable combination thereof. The computer-readable storage media used herein are not to be construed as transient signals themselves, such as radio waves or other freely propagating electromagnetic waves, electromagnetic waves propagating through waveguides or other transmission media (e.g., light pulses through fiber optic cables), or electrical signals transmitted through wires.

[0076] The computer-readable program instructions described herein can be downloaded from computer-readable storage media to various computing / processing devices, or downloaded via a network, such as the Internet, local area network, wide area network, and / or wireless network, to an external computer or external storage device. The network may include copper transmission cables, fiber optic transmission, wireless transmission, routers, firewalls, switches, gateway computers, and / or edge servers. A network adapter card or network interface in each computing / processing device receives the computer-readable program instructions from the network and forwards them to the computer-readable storage media in the respective computing / processing device.

[0077] While the present invention has been disclosed above, its scope of protection is not limited thereto. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention, and all such changes and modifications will fall within the scope of protection of the present invention.

Claims

1. A ring-shaped DC mainline AC / DC storage system, characterized in that, The system includes: A distributed detection module is used to acquire DC voltage and current parameters in real time. The area controller is communicatively connected to the distributed detection module and is used to collect current direction information of adjacent nodes and construct a direction discrimination matrix; The system protection module is communicatively connected to the area controller and is used to determine the fault section based on the direction discrimination matrix; Hybrid DC circuit breakers are installed in each section of the line and connected to the system protection module; An energy storage module, connected to the system protection module, is used to inject a reverse current of a specific waveform into the faulty section.

2. The annular DC mainline AC / DC storage system according to claim 1, characterized in that, The distributed detection module includes a voltage acquisition unit and a current acquisition unit, which are used to acquire DC voltage parameters and DC current parameters, respectively. The voltage acquisition unit is electrically connected to the DC bus, and the current acquisition unit is coupled to the line conductor.

3. The annular DC mainline AC / DC storage system according to claim 2, characterized in that, The area controller includes a data receiving port and a data processing unit. The data receiving port is connected to the distributed detection module, and the data processing unit is used to perform the construction operation of the direction discrimination matrix.

4. The annular DC mainline AC / DC storage system according to claim 1, characterized in that, The process of constructing the direction discrimination matrix includes: The distributed detection module includes N monitoring nodes. For any two adjacent monitoring nodes i and j: set up pass Calculate the directional eigenvalues ​​of the obtained node pair (i,j); Constructing a matrix ; in, , These are the times when the fault traveling wave arrives at node i and node j, respectively. For time difference; is the preset time decay constant; i and j are both node numbers.

5. A ring-shaped DC mainline AC / DC storage system according to claim 1, characterized in that, The process of determining the fault section based on the direction discrimination matrix includes: pass Calculate and obtain fault characteristic parameters ; Fault characteristic parameters With preset threshold Compare: like The line segment between node i and node j is at risk of failure. Otherwise, determine that there is no risk of fault in the line segment between node i and node j.

6. A ring-shaped DC mainline AC / DC storage system according to claim 5, characterized in that, The process of determining the fault section based on the direction discrimination matrix also includes: when the fault characteristic parameters Less than the preset value The confidence index is calculated using the following formula. : ;in, This represents the number of adjacent nodes involved in the calculation. Confidence index Preset confidence threshold Compare: like If so, the line segment between node i and node j is determined to be a faulty segment; like If so, then the line segment between node i and node j is not a faulty segment.

7. A ring-shaped DC mainline AC / DC storage system according to claim 1, characterized in that, The hybrid DC circuit breaker includes a main current-carrying branch and an auxiliary disconnecting branch; The main current-carrying branch is connected in series in the DC line to carry the continuous operating current during normal system operation; the auxiliary disconnecting branch includes a solid-state switch unit and an energy absorption unit, which are connected in parallel at both ends of the main current-carrying branch. The solid-state switching unit is used for current transfer and disconnection in case of a fault; the energy absorption unit is used to absorb overvoltage energy generated during the disconnection process. When a faulty section is detected, a corresponding auxiliary disconnecting branch quickly cuts off the current in the faulty section, and then the main current-carrying branch safely disconnects under zero current conditions.

8. A ring-shaped DC mainline AC / DC storage system according to claim 1, characterized in that, The energy storage module includes an energy storage medium and a power conversion device. The energy storage medium is connected to the DC bus through the power conversion device. The power conversion device is used to control the energy conversion and power regulation between the energy storage module and the DC bus.

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