Power distribution area flexible mutual aid system based on electric energy router

Abstract

The invention relates to the technical field of electric energy routers, in particular to a power distribution area flexible mutual aid system based on an electric energy router, and the system is characterized in that a DC bus in a flexible mutual aid device is connected with an external power distribution area through a plurality of bidirectional DC / AC ports, and is used for completing electrical coupling and power intercommunication; the plurality of bidirectional DC / AC ports are connected with the direct current bus in parallel, the direct current bus is connected with an energy storage port and a photovoltaic port, the energy storage port is communicated with an external energy storage device, the photovoltaic port is communicated with an external photovoltaic device, and the flexible mutual aid device is communicated with an external power grid dispatching through a controller. According to the invention, normalized flexible interconnection between feeder lines is realized through the flexible mutual aid device, potential safety hazards caused by frequent displacement of a conventional switch based on an interconnection switch are avoided, the control flexibility and rapidity of the power distribution network are improved, and the power distribution network has the advantages of open-loop operation and closed-loop operation at the same time.

Description

Technical Field

[0001] This invention relates to the field of power router technology, specifically a flexible mutual assistance system for distribution substations based on a power router. Background Technology

[0002] The power distribution network is the point in the power system where it interacts with end users. It has the largest scale in the power industry system and plays an extremely important role. Especially in the current environment of green energy, energy storage, and new load access, the power distribution network has transformed from the previous one-way, simple, and passive to two-way, complex, and proactive, and needs to cope with access environments and operating conditions that are much more complex than before.

[0003] Compared to the rapid development of secondary power distribution systems, the development of primary power distribution equipment lags behind, specifically in the following aspects: First, the current operation and control of the power distribution network is still mainly achieved through the adjustment and control of passive auxiliary devices such as on-load tap-changing transformers, capacitors, and tie switches. However, such passive auxiliary devices are generally uncontrollable, semi-controllable, or difficult to control.

[0004] Secondly, distributed power sources, energy storage, and loads are mostly in an uncontrollable, uncontrollable, or difficult-to-control state when they are owned by different people or when communication is limited.

[0005] Furthermore, conventional control methods such as adjusting transformer tap changers and switching compensation capacitors have limited adjustment capabilities, insufficient precision, and insufficient flexibility.

[0006] Furthermore, network reconfiguration based on segmentation and interconnection switches has technical and engineering limitations in terms of response speed, operating life, and inrush current, making it difficult to meet the requirements of flexibility, precision, and real-time dispatch for distribution networks when green energy and new loads fluctuate frequently.

[0007] It is evident that the lack of regulation and control capabilities of existing primary equipment has become the main bottleneck restricting the further improvement of the operation level of the power distribution system.

[0008] In recent years, the rapid development of power electronics and digital technology has made it possible to make the regulation and control capabilities of primary equipment more flexible, intelligent, and adaptable. Among these, flexible mutual assistance devices in distribution substations are one type of device that urgently needs to be improved. Distribution substations are the basic units of low-voltage power distribution in the power system. They are mainly responsible for stepping down high-voltage power into low-voltage power and then distributing it to end users. They are the core carrier connecting the power grid and end users.

[0009] However, there are a large number of distribution substations in the power distribution network. With the construction of urban power supply, new rural areas, and especially county-wide photovoltaic power generation in recent years, these distribution substations have increasingly higher requirements for power supply reliability and operational efficiency. The original single-source power supply can no longer meet the growing power capacity and reliability demands. Furthermore, if the target is to increase the power supply transformers in the distribution substations blindly, it will reduce the economic efficiency of the substation operation.

[0010] Based on the above reasons, this invention designs a flexible mutual assistance system for distribution transformer areas based on power routers. By effectively forming flexible mutual assistance between dense node distribution transformer areas, capacity can be mutually scheduled, avoiding the construction of a large number of disorderly transformer areas and improving operational efficiency. Summary of the Invention

[0011] The purpose of this invention is to overcome the shortcomings of the prior art and provide a flexible mutual assistance system for distribution substations based on power routers. This system forms a flexible mutual assistance among dense node distribution substations to achieve mutual capacity scheduling, avoids the construction of a large number of disorderly substations, and improves operational efficiency.

[0012] To achieve the above objectives, the present invention provides a flexible mutual assistance system for distribution substations based on a power router, including a flexible mutual assistance device. The DC bus in the flexible mutual assistance device is connected to an external distribution substation through multiple bidirectional DC / AC ports to complete electrical coupling and power interconnection. The multiple bidirectional DC / AC ports are connected to the DC bus in parallel. The DC bus is connected to an energy storage port and a photovoltaic port. The energy storage port is connected to an external energy storage device, and the photovoltaic port is connected to an external photovoltaic device. The flexible mutual assistance device is interconnected with the external power grid dispatch through a controller.

[0013] The bidirectional DC / AC port displays port voltage, current, and power in real time.

[0014] The bidirectional DC / AC ports feature a unified modular design.

[0015] The main DCAC in the bidirectional DC / AC port operates in PQ mode, while the slave DCAC operates in VF mode to stabilize the DC bus voltage.

[0016] The flexible mutual assistance device is installed in an integrated cabinet and is equipped with an interface for display, control, and interaction.

[0017] The controller collects actual power data from the field and selects and executes power balance strategies through algorithms.

[0018] Compared with the prior art, the present invention has the following beneficial effects: This invention achieves normalized flexible interconnection between feeders through a flexible mutual assistance device, avoiding the safety hazards caused by frequent changes in conventional switches based on tie switches. It improves the flexibility and speed of distribution network control, enabling the distribution network to possess the advantages of both open-loop and closed-loop operation. Specifically: This invention enables stepless continuous regulation within the capacity range, allowing for continuous, flexible, and precise control of both active and reactive power, resulting in stronger regulation capabilities.

[0019] The flexible mutual assistance device of this invention is based on fully controllable devices such as IGBT, MOSFET, and silicon carbide, and belongs to electronic operating mechanism, which has a rapid and faster response.

[0020] This invention primarily uses fully controllable electrical components, which are not limited by the number of operations, have a longer service life, and cause less impact on the system.

[0021] The flexible mutual assistance device of the present invention is directly composed of a DC bus or DC link structure, which can effectively isolate the two sides. The fault current is limited by the converters on both sides, thus reducing the scope of the fault impact.

[0022] The flexible mutual assistance device of this invention, as a digital control device, can achieve multi-functional composite operation by changing the control algorithm and adjusting the control strategy, including rapid reactive power compensation, precise voltage control, three-phase load balancing, and active harmonic mitigation, which is of great significance for improving the control capability and control level of primary equipment in the power distribution network.

[0023] This invention balances the load on the feeder and, through operation scheduling, ensures that each distribution area operates at high efficiency, significantly improving the economic efficiency of the power distribution system and effectively reducing operating losses.

[0024] This invention provides voltage reactive power support, improves feeder voltage levels and the ability to absorb distributed power sources, and improves feeder voltage levels and the ability to absorb green energy.

[0025] This invention provides better electrical isolation and recovery, enabling rapid recovery of non-faulty areas, improving the reliability of the power grid, and achieving fault isolation and recovery.

[0026] This invention can fully utilize the overall capacity of adjacent densely packed distribution substations through flexible power mutual assistance. It first achieves capacity expansion through mutual assistance, postpones or avoids unnecessary substation construction, reduces the number of newly built distribution substations, and greatly reduces costs. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the system principle of the present invention. Detailed Implementation

[0028] The present invention will now be further described with reference to the accompanying drawings.

[0029] See Figure 1 This embodiment provides a flexible interconnection system for distribution substations based on a power router. The system includes a flexible interconnection device. The DC bus in the flexible interconnection device is connected to external distribution substations via multiple bidirectional DC / AC ports for electrical coupling and power interconnection. These bidirectional DC / AC ports are connected to the DC bus in parallel. The DC bus connects to energy storage ports and photovoltaic ports. A common DC bus is used to couple all connections. This method easily couples green energy, energy storage, and loads via DC-DC and AC-DC converters. Only one DC voltage needs to be controlled to achieve a simple and stable interconnection. The energy storage port connects to external energy storage devices, and the photovoltaic port connects to external photovoltaic devices. As a green energy source, connecting photovoltaic devices in conjunction with energy storage devices can reduce grid investment and achieve green substitution within the distribution substation itself. The flexible interconnection device communicates with the external grid dispatch center through a controller. The external grid dispatch center requires the flexible interconnection device to execute specific requirements, and the device provides rich communication protocols, enabling access to various types of upper-level dispatch centers.

[0030] The bidirectional DC / AC port displays port voltage, current, and power in real time.

[0031] The bidirectional DC / AC ports feature a unified modular design, similar to industrial rack product modules. This enhances the flexibility and stability of port combinations, reduces procurement and design costs, adapts to different application scenarios, and avoids waste caused by redesign.

[0032] Since multiple bidirectional DC / AC ports are connected in parallel, the master-slave relationship needs to be clearly defined to avoid conflicts. The master DCAC in the bidirectional DC / AC port operates in demand output power mode (PQ mode), while the slave DCAC operates in system voltage frequency stability mode (VF mode) to stabilize the DC bus voltage.

[0033] The flexible mutual assistance device is installed in an integrated cabinet and is equipped with an interface for display, control, and interaction.

[0034] The controller collects actual power data from the field and selects and executes power mutual assistance strategies through algorithms. The algorithm is the "brain" of the flexible mutual assistance device and needs to take into account multiple aspects such as safety, stability, and economy. By introducing big data and AI, automation and intelligence can be further realized.

[0035] In designing this invention, priority was given to ensuring the modularity of the key component, the bidirectional DC / AC port, requiring its controllable size and compact integration. This ensured the bidirectional DC / AC ports could be paralleled to adapt to a wide range of power applications. High integration of the bidirectional DC / AC ports was achieved through a DC bus coupling method, fully considering control and protection at each level and integrating them within the integrated cabinet to ensure electrical safety. This invention integrates an intelligent upper-level operation controller within the cabinet, enhancing the intelligence level of the power router. Simultaneously, the compact cabinet design improves adaptability to application scenarios and facilitates large-scale production, while a user-friendly human-machine interface enhances ease of use.

[0036] The above are merely preferred embodiments of the present invention, intended only to aid in understanding the method and core ideas of this application. The scope of protection of the present invention is not limited to the above embodiments; all technical solutions falling within the scope of the present invention's concept are within its protection. It should be noted that for those skilled in the art, any improvements and modifications made without departing from the principles of the present invention should also be considered within the scope of protection of the present invention.

[0037] This invention comprehensively addresses the shortcomings of existing technologies where power distribution network operation control primarily relies on the adjustment and control of passive auxiliary devices such as on-load tap-changing transformers, capacitors, and tie switches. Through power mutual assistance between distribution substations and modular port design, integration of green energy and energy storage modules, and intelligent controller monitoring and control, it achieves on-demand support and full utilization of existing capacity, dynamically optimizes and adjusts load operation modes, and provides stepless, continuous, and stable regulation. This enables power distribution network reconfiguration. Achieving ideal optimization results with a small number of flexible mutual assistance devices deployed in key locations reduces the impact of faults, quickly blocks or disconnects external connections, and rapidly restores operation. Simultaneously, the DC bus side features built-in voltage stabilization control, and the algorithm ensures that when the instantaneous total power of the equipment exceeds the maximum charge / discharge power of the energy storage battery, the battery possesses bidirectional voltage stabilization capability, guaranteeing reliable operation of the device.

Claims

1. A flexible mutual assistance system for distribution substations based on a power router, characterized in that, The system includes a flexible mutual assistance device. The DC bus in the flexible mutual assistance device is connected to an external distribution substation through multiple bidirectional DC / AC ports to complete electrical coupling and power interconnection. The multiple bidirectional DC / AC ports are connected to the DC bus in parallel. The DC bus is connected to an energy storage port and a photovoltaic port. The energy storage port is connected to an external energy storage device, and the photovoltaic port is connected to an external photovoltaic device. The flexible mutual assistance device is interconnected with the external power grid dispatch through a controller.

2. The flexible mutual assistance system for distribution substations based on power routers according to claim 1, characterized in that, The bidirectional DC / AC port displays port voltage, current, and power in real time.

3. The flexible mutual assistance system for distribution substations based on power routers according to claim 2, characterized in that, The bidirectional DC / AC port features a unified modular design.

4. The flexible mutual assistance system for distribution substations based on power routers according to claim 3, characterized in that, The main DCAC in the bidirectional DC / AC port operates in PQ mode, while the slave DCAC operates in VF mode, to stabilize the DC bus voltage.

5. The flexible mutual assistance system for distribution substations based on power routers according to claim 1, characterized in that, The flexible mutual aid device is installed in an integrated cabinet and is equipped with an interface for display, control, and interaction.

6. The flexible mutual assistance system for distribution substations based on power routers according to claim 1, characterized in that, The controller collects actual power data from the site and selects and executes power balancing strategies through algorithms.

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