Flexible interconnection power distribution method and system based on combined energy router

Abstract

The invention provides a flexible interconnection power distribution method and system based on a combined energy router, and relates to the technical field of power distribution and power supply, and the method comprises the steps: enabling transformer areas equipped with a hybrid distribution transformer to be interconnected through a DC bus, and enabling the transformer areas to be connected with a photovoltaic unit and an energy storage unit at the same time, and forming a flexible interconnection power distribution system of the combined energy router; system operation constraints are set, and under the condition that system power dynamic balance constraints are met, transformer load rate out-of-limit and energy storage unit over-charge or over-discharge are avoided through multivariable cooperative control; according to real-time operation parameters of the system, when it is judged that the system has voltage fluctuation or load three-phase imbalance or harmonic component problems, a system electric energy quality comprehensive treatment function is started immediately; controlling the operation mode of the system to be switched between a grid-connected operation mode and an isolated island operation mode according to whether the system power grid breaks down or not; according to the optimal flow direction and the adjustment amplitude of the power in the power system, the power source is intelligently distributed to each transformer area.

Description

Technical Field

[0001] This invention relates to the field of power distribution technology, and in particular to a flexible interconnected power distribution method and system based on a combined energy router. Background Technology

[0002] In recent years, with the continuous growth of global demand for clean energy, the penetration rate of large-scale renewable energy, represented by photovoltaic power generation, in power distribution networks has been increasing. However, photovoltaic output is affected by factors such as sunlight intensity and weather conditions, causing drastic fluctuations in power injection within the power distribution network. This leads to frequent power quality problems such as voltage deviation and harmonic distortion. Furthermore, unstable power fluctuations can also cause grid frequency fluctuations, threatening the safe and stable operation of the system and significantly reducing power supply reliability.

[0003] Currently, the control strategies and equipment configurations of traditional power distribution networks are ill-suited to the dynamic characteristics of renewable energy. On the one hand, traditional power distribution networks lack the ability to flexibly regulate distributed power sources, making it impossible to effectively mitigate power fluctuations caused by the integration of renewable energy. On the other hand, the unidirectional power transmission mode and fixed voltage regulation mechanism are insufficient to meet the demands of multi-source coordinated power supply and bidirectional power flow, resulting in limited renewable energy absorption capacity and hindering efficient energy utilization. Summary of the Invention

[0004] In view of the shortcomings of the prior art, the purpose of this invention is to provide a flexible interconnected power distribution method based on a combined energy router, which can solve the technical problems of traditional power distribution networks lacking flexible control capabilities for distributed power sources, being unable to effectively mitigate power fluctuations caused by renewable energy access, having a unidirectional power transmission mode and a fixed voltage regulation mechanism that are difficult to meet the needs of multi-source coordinated power supply and bidirectional power flow, resulting in limited renewable energy absorption capacity and the inability to achieve efficient energy utilization.

[0005] A first aspect of this invention proposes a flexible interconnected power distribution method based on a combined energy router, comprising:

[0006] S1: Interconnecting the transformer substations equipped with hybrid distribution transformers via DC bus, and simultaneously connecting photovoltaic units and energy storage units to form a flexible interconnected power distribution system with combined energy routers;

[0007] S2: Set system operation constraints. Under the condition of satisfying the dynamic balance constraint of system power, avoid transformer load rate exceeding the limit, energy storage unit overcharging or over-discharging through multi-variable collaborative control.

[0008] S3: Based on the real-time operating parameters of the system, when it is determined that the system has voltage fluctuations, three-phase load imbalance, or harmonic component problems, the system power quality comprehensive management function will be activated immediately.

[0009] S4: Depending on whether a fault occurs in the power grid, the operating mode of the control system switches between grid-connected operation mode and islanded operation mode. In the grid-connected operation mode and the islanded operation mode, different control methods are used for each part of the system.

[0010] S5: Under the condition of satisfying the system operation constraints, the power source is intelligently allocated to each transformer area according to the optimal power flow direction and adjustment range in the power system.

[0011] A second aspect of the present invention provides a flexible interconnected power distribution system based on a combined energy router, comprising: a processor and a memory;

[0012] The memory stores programs or instructions that can run on the processor, which, when executed by the processor, implement the steps of the flexible interconnected power distribution method based on the combined energy router as described in the first aspect.

[0013] A third aspect of the present invention provides a readable storage medium on which a program or instructions are stored, which, when executed by a processor, implement the steps of the flexible interconnected power distribution method based on a combined energy router as described in the first aspect.

[0014] The beneficial effects of the technical solutions provided in the embodiments of the present invention include at least the following:

[0015] (1) In this embodiment of the invention, a flexible interconnected power distribution system with a combined energy router is used to carry out flexible interconnected power distribution, enhance the new energy carrying capacity of the low-voltage power distribution area, balance the power of the distribution area, reduce the pressure on the transformer, and provide a new idea for the stable operation of the power distribution area.

[0016] (2) In this embodiment of the invention, a comprehensive power quality management scheme is constructed to ensure high-quality power supply under various operating conditions, improve the efficiency of distribution substations, and meet the demand for high-quality power supply.

[0017] (3) In this embodiment of the invention, the DC microgrid switches between grid-connected operation mode and islanded operation mode to realize rapid power transfer and stable islanded operation within the system, thereby improving the ability of distribution substations with a high proportion of new energy access to operate under extreme conditions. Attached Figure Description

[0018] The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Throughout the drawings, the same reference numerals denote the same parts. Obviously, the drawings described below are merely some embodiments of the present invention, and those skilled in the art can obtain other drawings based on these drawings without any creative effort.

[0019] Figure 1 This is a schematic flowchart of a flexible interconnected power distribution method based on a combined energy router provided in an embodiment of the present invention.

[0020] Figure 2 This is a schematic diagram of the architecture of a flexible interconnected power distribution system based on a combined energy router, provided by an embodiment of the present invention.

[0021] Figure 3 This is a diagram showing the switching of a photovoltaic unit control mode according to an embodiment of the present invention.

[0022] Figure 4 This is a diagram showing the switching of control modes for an energy storage unit provided in an embodiment of the present invention.

[0023] Figure 5 This is a switching diagram of a post-stage converter control mode provided in an embodiment of the present invention.

[0024] Figure 6 This is a comparison chart of voltage fluctuation management provided by an embodiment of the present invention.

[0025] Figure 7 This is a comparison diagram of three-phase load imbalance in a system provided by an embodiment of the present invention.

[0026] Figure 8 This is a waveform diagram of a system operating in island mode provided by an embodiment of the present invention.

[0027] Figure 9 This is a schematic diagram of a flexible interconnected power distribution system based on a combined energy router, provided by an embodiment of the present invention. Detailed Implementation

[0028] To enable those skilled in the art to better understand the technical solutions in the embodiments of the present invention, the technical solutions 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, not all embodiments. It should be understood that these descriptions are merely exemplary and are not intended to limit the scope of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0029] The flexible interconnected power distribution method based on a combined energy router, provided by the present invention, will be described in detail below with reference to the accompanying drawings and through specific embodiments and application scenarios.

[0030] Reference manual attached Figure 1 The diagram shows a flowchart of a flexible interconnected power distribution method based on a combined energy router, provided by an embodiment of the present invention.

[0031] Reference manual attached Figure 2 The diagram illustrates a schematic of the architecture of a flexible interconnected power distribution system based on a combined energy router, as provided in an embodiment of the present invention.

[0032] Reference manual attached Figure 3 The diagram illustrates a photovoltaic unit control mode switching method provided by an embodiment of the present invention.

[0033] Reference manual attached Figure 4 The diagram illustrates a switching mode control method for an energy storage unit provided in an embodiment of the present invention.

[0034] Reference manual attached Figure 5 The diagram illustrates a switching mode control diagram for a downstream converter provided by an embodiment of the present invention.

[0035] This invention provides a flexible interconnected power distribution method based on a combined energy router, which may include the following steps:

[0036] S1: Interconnecting power distribution areas equipped with hybrid distribution transformers via DC bus, and simultaneously connecting photovoltaic units and energy storage units to form a flexible interconnected power distribution system with combined energy routers.

[0037] In one possible implementation, S1 specifically involves: A power electronic converter, consisting of a front-end converter and a back-to-back converter, is connected in parallel to the low-voltage side of a conventional dual-winding power frequency transformer to form a hybrid distribution transformer. A low-voltage DC port is led out between the front-end and rear-end converters and connected to the DC ports of adjacent distribution areas via a DC bus to construct an interconnected distribution area. Simultaneously, photovoltaic power generation units and energy storage units are connected in parallel to the DC bus to form a flexible interconnected distribution system of a combined energy router.

[0038] For example, the flexible interconnected power distribution system includes a first distribution area 1 and a second distribution area 2. The first hybrid distribution transformer is connected to the low-voltage side of the 10kV / 0.4kV AC power grid of the first distribution area, and the second hybrid distribution transformer is connected in the same way. The first hybrid distribution transformer and the second hybrid distribution transformer are connected through an 800V DC bus; the photovoltaic unit and the energy storage unit are connected to the DC bus through a DC / DC converter.

[0039] In this embodiment of the invention, each distribution area equipped with a hybrid distribution transformer is interconnected via a DC bus, and photovoltaic and energy storage units are uniformly integrated on the DC side. This forms a multi-source, bidirectional, and flexible interconnected distribution system at the low-voltage distribution level, enabling rapid power exchange and flexible allocation between distribution areas, significantly improving the access and local consumption capacity of new energy sources. The DC bus structure reduces power flow coupling and interconnection difficulty, effectively distributing the pressure on the transformers. Furthermore, the rapid control capabilities of power electronic converters allow for precise adjustment of voltage, current, and power, thereby improving system stability, reliability, and power quality, providing greater flexibility and adaptability for distribution network operation under conditions of high proportion of distributed energy.

[0040] S2: Set system operation constraints. Under the condition of satisfying the dynamic balance constraint of system power, avoid transformer load rate exceeding the limit, and energy storage unit overcharging or over-discharging through multi-variable collaborative control.

[0041] Optionally, system operation constraints include: state of charge constraints of the energy storage system, transformer load rate constraints in the distribution substation, and system power balance constraints.

[0042] Furthermore, the specific constraints on the state of charge of the energy storage system are as follows:

[0043]

[0044] Here, SOC represents the current SOC value of the battery. max SOC min These represent the upper and lower limits of the battery's State of Charge (SOC), respectively. SOC0 represents the battery's SOC value at the previous optimization time. Q represents the battery's rated capacity. This indicates the battery charging and discharging time. P ESS This indicates the change in battery power; output power is positive, and input power is negative.

[0045] It should be noted that by setting upper and lower limits for the SOC of the energy storage unit and constraining it in conjunction with the charge and discharge model, it can be ensured that the energy storage unit is always within a safe and controllable charge range, avoiding capacity decay, shortened lifespan, or protection activation caused by overcharging or over-discharging. At the same time, it ensures that the energy storage has the necessary adjustment margin to participate in the power regulation of the distribution area and power quality management, making it an important supporting resource for the stable operation of the system.

[0046] Furthermore, when the transformer operates under light load conditions, the specific transformer load rate constraint in the distribution substation is as follows:

[0047]

[0048] Where λ0 is the rated load factor of the transformer, and S is the actual load capacity of the transformer.e This refers to the rated capacity of the transformer. Taking the boundary load rate of the distribution area as an example, the distribution area load rate λ1 is set as the maximum value for light load and λ2 as the minimum value for heavy load.

[0049] When a transformer operates under heavy load, the specific load factor constraint for the transformer in a distribution substation is as follows:

[0050]

[0051] Where λ2 is the minimum value of the overload.

[0052] It should be noted that setting load factor constraints for transformers under both light and heavy load conditions can effectively prevent overheating, life loss, and protection tripping caused by overload, and can also prevent efficiency reduction or voltage deviation caused by long-term light load operation. By flexibly setting the upper and lower limits of the load factor, the system can automatically adjust the power distribution according to the load differences between transformers, thereby reducing the pressure on individual transformers and improving the overall utilization efficiency and operational safety of the transformer group.

[0053] Furthermore, the system power balance constraints are specifically as follows:

[0054]

[0055] Where C represents the set of all power sources. i This represents the active power transmitted by the i-th power conversion unit. N represents the set of distribution substations in the system. P LOADj This represents the total load borne by the j-th transformer substation.

[0056] It should be noted that setting system-level power balance constraints can ensure that all power sources and loads in each distribution area always meet real-time supply and demand balance, avoiding voltage fluctuations and frequency deviations caused by power shortages or excesses. By uniformly constraining the active power of each conversion unit, the energy flow between multiple distribution areas becomes more coordinated, providing a reliable basis for subsequent power optimization allocation and improving the stability and dynamic adjustability of the entire flexible interconnected power distribution system.

[0057] S3: Based on the real-time operating parameters of the system, when it is determined that the system has voltage fluctuations, three-phase load imbalance, or harmonic component problems, the system power quality comprehensive management function will be activated immediately.

[0058] In one possible implementation, the system power quality comprehensive management function in S3 specifically involves: compensating for voltage fluctuations through the front-end converter and suppressing harmonics and balancing the three-phase current through the back-end converter.

[0059] In this embodiment of the invention, by immediately activating the comprehensive power quality management function upon detecting voltage fluctuations, three-phase imbalance, or harmonic exceedances, the voltage can be rapidly compensated using the front-end converter, and harmonic suppression and three-phase current balancing can be achieved through the rear-end converter. This restores the voltage and current quality of the distribution system within a millisecond timescale. This real-time management mechanism effectively reduces voltage deviations, suppresses harmonic interference, reduces the additional losses to equipment caused by zero-sequence current and unbalanced current, improves the power supply stability of the distribution network, equipment lifespan, and user-side power quality, and provides strong support for safe and reliable operation under conditions of high-proportion distributed energy access.

[0060] S4: Depending on whether a fault occurs in the power grid, the control system switches between grid-connected operation mode and islanded operation mode. In grid-connected operation mode and islanded operation mode, different control methods are used for different parts of the system.

[0061] In one possible implementation, S4 specifically refers to: when a fault occurs in the power grid of a distribution substation that is in grid-connected operation mode, the system quickly switches from grid-connected operation mode to islanded operation mode.

[0062] In this embodiment of the invention, when a fault occurs in a distribution area under grid-connected operation mode, the system can quickly switch to islanded operation mode. The advantages are: it can prevent the fault impact from spreading outward along the distribution network, so that the non-faulty distribution areas can maintain continuous power supply; at the same time, through energy storage units and grid-type converters, stable voltage and frequency support is provided in the island, so that the faulty distribution area can still operate independently for a short time when the external network is disconnected, ensuring that critical loads are not interrupted, improving the resilience and power supply reliability of the distribution network under faults and extreme conditions, and creating a safety window for fault isolation and subsequent recovery.

[0063] Furthermore, when the system is in grid-connected operation mode, a master-slave control system is adopted. The downstream converter of the transformer area with a lower load factor is selected as the master controller, employing constant voltage and constant frequency control to provide voltage support to the DC microgrid, maintain DC voltage stability, and achieve bidirectional energy flow. The downstream converter and energy storage unit of another transformer area act as slave controllers. The energy storage unit transmits power according to system demand under constant power control. The downstream converter, acting as a grid-connected converter, uses constant power control to control the power transmission from that transformer area to the DC microgrid. In the operation and control strategy of the photovoltaic power generation system, the photovoltaic units typically always follow the maximum power point tracking control mode to optimize the output power of the photovoltaic array. Only when the system experiences a power supply-demand imbalance will the photovoltaic units dynamically switch to a power-limited operation mode to ensure the overall power balance and stable operation of the system.

[0064] For example, in grid-connected operation mode (assuming a lower load rate for transformer 1): Transformer 1 acts as the master station (constant voltage and frequency control), transformer 2 acts as the slave station (PQ control), and the photovoltaic unit uses MPPT control. When the output of renewable energy exceeds the load, it switches to power limiting mode; the energy storage unit uses constant power control to charge and discharge according to the state of charge. Under this control mode, various system control constraints are met, and power distribution is achieved.

[0065] Furthermore, when the system is in islanded operation mode, the energy storage unit adopts constant voltage control to maintain a constant DC bus voltage. The downstream converter in the faulty distribution area, acting as a grid-type converter, employs constant voltage and frequency control to provide reliable voltage and frequency support for the operation of the AC microgrid in the faulty distribution area. The downstream converter in the non-faulty distribution area adopts constant power control to transfer power to the DC microgrid according to system requirements.

[0066] For example, in islanded operation mode (with transformer area 1 as the default faulty area): the converter after transformer area 1, as a grid-type converter, adopts constant voltage and frequency control to provide reliable voltage and frequency support for the operation of the AC microgrid in transformer area 1; the converter after transformer area 2 adopts constant power control to transfer power to the DC microgrid according to system demand, thereby realizing power interaction within the system. The energy storage unit adopts constant voltage control to maintain a constant DC bus voltage; the photovoltaic unit adopts MPPT control, switching to power limiting mode when the output of new energy exceeds the load.

[0067] S5: Under the condition of meeting the system operation constraints, the power source is intelligently distributed to each distribution area according to the optimal power flow direction and adjustment range in the power system.

[0068] In this embodiment of the invention, under the premise of meeting system operation constraints, the outputs of photovoltaic, energy storage and transformers in each distribution area are intelligently allocated according to the optimal power flow direction and adjustment range. The advantages are: the system as a whole can complete the power supply and demand matching in the most economical and stable way, and realize the power coordination and load balance between distribution areas; while improving the utilization rate of new energy sources, it avoids local overload or resource idleness; and by optimizing the power flow path, it reduces losses and transformer pressure, thereby improving the overall operating efficiency, reliability and adaptive capability of the flexible interconnected power distribution system to dynamic load changes.

[0069] Example 1: Voltage fluctuation management.

[0070] Refer to the instruction manual appendix Figure 6The diagram illustrates a comparison of voltage fluctuation management provided by an embodiment of the present invention. During the 0.1~0.2s interval, the grid-side voltage operates normally at the power frequency. During the 0.2~0.3s interval, the 10kV grid-side voltage suddenly increases; at this time, the upstream converter activates its voltage compensation function to ensure that the DC side and 0.4kV side voltages remain stable. During the 0.3~0.4s interval, the grid-side voltage returns to normal.

[0071] Example 2: Three-phase imbalance treatment.

[0072] Refer to the instruction manual appendix Figure 7 The diagram shows a comparison of three-phase load imbalance mitigation provided by an embodiment of the present invention. The time interval from 0.1 to 0.2 seconds indicates the impact of three-phase load imbalance on the grid-side current. At 0.2 seconds, the downstream converter activates its three-phase imbalance mitigation function, resulting in a significant improvement in the 0.4kV grid-side current and zero-sequence current waveforms from 0.2 to 0.4 seconds.

[0073] Example 3: Island mode operation.

[0074] Refer to the instruction manual appendix Figure 8 The diagram illustrates a system waveform diagram for islanded operation mode provided by an embodiment of the present invention. At 0.1s, the system operates in normal operation mode; at 0.2s, the system enters islanded operation mode, with transformer area 1 experiencing a fault, while transformer area 2 operates normally in grid-connected mode.

[0075] Between 0.2 and 0.4 seconds, system area 1 is under heavy load with a load of 8kW, while area 2 is under light load with a load of 2kW. The initial capacity of the energy storage unit is 3kWh, and the initial state of charge (SOC) of the battery is 60%. At this time, the grid in area 2 transmits 3kW of power to area 1 through the downstream converter, and all 5kW of photovoltaic power is transmitted to area 1.

[0076] Between 0.4s and 0.6s, system transformer substation 1 carries a load of 5kW, and transformer substation 2 carries a load of 3kW. The load in transformer substation 2 is powered by the local power grid, while the load in transformer substation 1 is powered by the photovoltaic unit. At the same time, the photovoltaic unit supplies power to the energy storage unit, and the battery is charged, reaching a state of charge (SOC) of 80%.

[0077] Between 0.6s and 0.8s, system area 2 carries a load of 9kW, and area 1 carries a load of 2kW. The energy storage unit and the photovoltaic unit together output 7kW of power. In the faulty area, the photovoltaic and energy storage units supply 2kW of power, and the energy storage unit's SOC reaches 20%.

[0078] The beneficial effects of the technical solutions provided in the embodiments of the present invention include at least the following:

[0079] (1) In this embodiment of the invention, a flexible interconnected power distribution system with a combined energy router is used to carry out flexible interconnected power distribution, enhance the new energy carrying capacity of the low-voltage power distribution area, balance the power of the distribution area, reduce the pressure on the transformer, and provide a new idea for the stable operation of the power distribution area.

[0080] (2) In this embodiment of the invention, a comprehensive power quality management scheme is constructed to ensure high-quality power supply under various operating conditions, improve the efficiency of distribution substations, and meet the demand for high-quality power supply.

[0081] (3) In this embodiment of the invention, the DC microgrid switches between grid-connected operation mode and islanded operation mode to realize rapid power transfer and stable islanded operation within the system, thereby improving the ability of distribution substations with a high proportion of new energy access to operate under extreme conditions.

[0082] Reference manual attached Figure 9 The diagram shows a structural schematic of a flexible interconnected power distribution system based on a combined energy router, provided by an embodiment of the present invention.

[0083] This invention provides a flexible interconnected power distribution system 20 based on a combined energy router, including: a processor 201 and a memory 202;

[0084] The memory 202 stores programs or instructions that can run on the processor 201. When the program or instructions are executed by the processor 201, they implement the steps of the flexible interconnected power distribution method based on the combined energy router described above and achieve the same technical effect. To avoid repetition, the present invention will not repeat the above.

[0085] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the embodiments of the present invention, and are not intended to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the protection scope of the present invention.

Claims

1. A flexible interconnected power distribution method based on a combined energy router, characterized in that, include: S1: Interconnecting the transformer substations equipped with hybrid distribution transformers via DC bus, and simultaneously connecting photovoltaic units and energy storage units to form a flexible interconnected power distribution system with combined energy routers; S2: Set system operation constraints. Under the condition of satisfying the dynamic balance constraint of system power, avoid transformer load rate exceeding the limit, energy storage unit overcharging or over-discharging through multi-variable collaborative control. S3: Based on the real-time operating parameters of the system, when it is determined that the system has voltage fluctuations, three-phase load imbalance, or harmonic component problems, the system power quality comprehensive management function will be activated immediately. S4: Depending on whether a fault occurs in the power grid, the operating mode of the control system switches between grid-connected operation mode and islanded operation mode. In the grid-connected operation mode and the islanded operation mode, different control methods are used for each part of the system. S5: Under the condition of satisfying the system operation constraints, the power source is intelligently allocated to each transformer area according to the optimal power flow direction and adjustment range in the power system.

2. The flexible interconnected power distribution method based on a combined energy router according to claim 1, characterized in that, Specifically, S1 is: A hybrid distribution transformer is formed by connecting a power electronic converter with a front-end converter and a back-to-back converter on the low-voltage side of a traditional dual-winding power frequency transformer. A low-voltage DC port is led out between the front-end converter and the back-end converter, and connected to the DC port of the adjacent transformer area through a DC bus to build an interconnected transformer area. At the same time, photovoltaic power generation units and energy storage units are connected in parallel on the DC bus to form a flexible interconnected power distribution system of combined energy router.

3. The flexible interconnected power distribution method based on a combined energy router according to claim 1, characterized in that, The comprehensive power quality management function of the system in S3 is specifically as follows: the voltage fluctuation is compensated by the front-end converter, and the harmonics are suppressed and the three-phase current is balanced by the back-end converter.

4. The flexible interconnected power distribution method based on a combined energy router according to claim 1, characterized in that, The system operation constraints include: the state of charge constraints of the energy storage system, the transformer load rate constraints in the distribution substation, and the power balance constraints of the system.

5. The flexible interconnected power distribution method based on a combined energy router according to claim 4, characterized in that, The specific state-of-charge constraints of the energy storage system are as follows: ； Where SOC represents the current SOC value of the battery; max SOC min These represent the upper and lower limits of the battery's State of Charge (SOC); SOC0 represents the battery's SOC value at the previous optimization time; Q represents the battery's rated capacity. Indicates the battery charging and discharging time; P ESS This indicates the change in battery power; the output power is positive, and the incoming power is negative.

6. The flexible interconnected power distribution method based on a combined energy router according to claim 4, characterized in that, When the transformer operates under light load, the transformer load rate constraint in the distribution substation is specifically as follows: ； Where λ0 is the rated load factor of the transformer; S is the actual load capacity of the transformer; S e The rated capacity of the transformer; taking the boundary load rate of the distribution area as an example, the distribution area load rate λ1 is set as the maximum value of light load and λ2 is the minimum value of heavy load; When the transformer operates under heavy load, the transformer load rate constraint in the distribution substation is specifically as follows: ； Where λ2 is the minimum value of the overload.

7. The flexible interconnected power distribution method based on a combined energy router according to claim 4, characterized in that, The specific system power balance constraint is as follows: ； Where C represents the set of all power sources; P i Represents the active power transmitted by the i-th power conversion unit; N represents the set of distribution substations in the system; P LOADj This represents the total load borne by the j-th transformer substation.

8. The flexible interconnected power distribution method based on a combined energy router according to claim 1, characterized in that, Specifically, S4 is: When a fault occurs in a distribution area of ​​the grid that is in the grid-connected operation mode, the system quickly switches from the grid-connected operation mode to the islanded operation mode.

9. The flexible interconnected power distribution method based on a combined energy router according to claim 1, characterized in that, When the system is in the grid-connected operation mode, master-slave control is adopted. The downstream converter of the transformer area with a low transformer load rate is selected as the master controller. Constant voltage and constant frequency control is used to support the DC microgrid, maintain DC voltage stability, and realize bidirectional energy flow. The downstream converter and energy storage unit of another transformer area act as slave controllers. The energy storage unit transmits power according to the system demand under constant power control. The downstream converter of the grid-connected converter adopts constant power control to control the power transmission from the transformer area to the DC microgrid. In the operation control strategy of the photovoltaic power generation system, the photovoltaic unit usually always follows the maximum power point tracking control mode to optimize the output power of the photovoltaic array. Only when the system experiences a power supply and demand imbalance will the photovoltaic unit dynamically switch to the power-limited operation mode to ensure the overall power balance and stable operation of the system. When the system is in the islanded operation mode, the energy storage unit adopts constant voltage control to maintain the constant DC bus voltage; the faulty transformer downstream converter, as a grid-type converter, adopts constant voltage and constant frequency control, aiming to provide reliable voltage and frequency support for the operation of the AC microgrid in the faulty transformer area; the non-faulty transformer downstream converter adopts constant power control to transmit power to the DC microgrid according to system requirements.

10. A flexible interconnected power distribution system based on a combined energy router, characterized in that, include: Processor and memory; The memory stores programs or instructions that can run on the processor, which, when executed by the processor, implement the steps of the flexible interconnected power distribution method based on a combined energy router as described in any one of claims 1 to 9.

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