Loop closing device topological structure deduction optimization method and related device

Abstract

The invention discloses a loop closing device topological structure deduction optimization method and a related device, and belongs to the technical field of power distribution network flexible loop closing, and the method comprises the steps: obtaining a power electronic and electromagnetic hybrid loop closing device through deduction based on a power electronic loop closing device and an electromagnetic loop closing device; and based on the obtained power electronic and electromagnetic hybrid loop closing device, reducing the capacity of power electronic equipment is taken as a core, and a topology scheme of the power electronic and electromagnetic hybrid loop closing device is obtained through optimization. According to the novel hybrid loop closing device topology scheme deduced by the method disclosed by the invention, the cost is reduced while the power flow regulation and control precision is ensured.

Description

Technical Field

[0001] The present invention belongs to the technical field of flexible ring closing of distribution networks, and in particular relates to a method for topological structure deduction and optimization of a ring closing device and related devices. Background Art

[0002] As the foundational carrier of urban electric energy, the distribution network's efficient energy acceptance and carrying capacity directly impacts the city's power supply quality and economic operation. With the continued expansion of distribution networks, the increasing diversification of load types, and the unordered integration of new sources and loads, online power transfer and adjustment of line operation modes are becoming increasingly difficult, significantly impacting power supply reliability. Implementing closed-loop operation of distribution networks is considered an effective means of addressing these issues. Flexible closed-loop technology, which can flexibly implement power flow control and closed-loop power transfer, is a key area of ​​technological development in this field and has garnered widespread attention from researchers.

[0003] Closed-loop operation is an effective solution. By connecting multiple power sources to form a closed-loop network, if a power source fails, it can quickly switch to other power sources to ensure uninterrupted power supply. Furthermore, closed-loop operation allows for flexible power flow control and improves the efficiency of the distribution network.

[0004] However, traditional loop-closing technologies have several drawbacks. For example, power electronics topologies based on back-to-back converters, while capable of continuous power flow regulation, are expensive, have weak overload capacity, and exhibit low reliability. Electromagnetic topologies based on phase-shifting transformers, while cost-effective, offer only discrete power flow regulation and suffer from low accuracy. These drawbacks limit their widespread application in urban distribution networks.

[0005] To overcome these problems, various flexible interconnection equipment topology solutions have been proposed, including soft-tie switches, flexible ring network control devices, power electronic transformers, and flexible AC transmission equipment for distribution networks. However, power electronic topologies centered around back-to-back converters suffer from high costs, weak overload capacity, and low reliability. Electromagnetic topologies centered around phase-shifting transformers, while reducing device costs, only enable discrete power flow regulation and suffer from low accuracy. The single selection of these topologies makes it difficult to apply to medium- and high-voltage scenarios in urban distribution networks, which have strict application constraints. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to address the deficiencies in the above-mentioned prior art and provide a method and related device for deducing and optimizing the topology structure of a loop closing device, which reduces the cost of the topology scheme of the loop closing device while ensuring the accuracy of power flow control, and is used to solve the technical problems that the existing topology scheme of the loop closing device with the converter as the core is high in cost, weak in overload capacity, and difficult to promote and use in urban distribution networks.

[0007] The present invention adopts the following technical solutions: A method for deducing and optimizing the topological structure of a ring closing device comprises the following steps: Based on the power electronic loop closing device and the electromagnetic loop closing device, a power electronic electromagnetic hybrid loop closing device is derived; Based on the obtained power electronic and electromagnetic hybrid loop closing device, a topology scheme of the power electronic and electromagnetic hybrid loop closing device is obtained by reducing the capacity optimization of power electronic equipment.

[0008] Preferably, the power electronic and electromagnetic hybrid loop closing device derived based on the power electronic loop closing device and the electromagnetic loop closing device is specifically: The cost of the power electronic closing device is analyzed according to the access method; the cost of the electromagnetic closing device is analyzed according to the number of windings and the connection method; the power electronic closing device and the electromagnetic closing device are combined to form a power electronic electromagnetic hybrid closing device based on the comprehensive cost, adjustment accuracy and overload capacity. The hybrid power flow controller of the power electronic electromagnetic hybrid closing device includes a unified power flow controller and an improved Sen transformer. The output voltage of the hybrid power flow controller is the output voltage vector of the improved Sen transformer. The output voltage vector of the unified power flow controller The vector sum of .

[0009] Preferably, the unified power flow controller and the improved Sen transformer share the excitation winding on the parallel side and the transformer core on the series side. The parallel side converter of the unified power flow controller is used to control the bus voltage and reactive support; the series side converter is used to control the series voltage amplitude and phase angle.

[0010] Preferably, the power electronic closing device includes a back-to-back converter and a unified power flow controller, the unified power flow controller and the improved Sen transformer share the excitation winding on the parallel side and the transformer core on the series side, and the capacity of the unified power flow controller is The calculation is as follows:

[0011] in, 、 are the effective values ​​of the voltage of grid 1 and grid 2 respectively; is the phase difference between the two power grids, Control capacity for line flow; The improved Sen transformer includes a parallel excitation winding and two sets of secondary windings in series. The two sets of series windings are combined with different levels to synthesize different output voltage vectors, and the maximum phase shift angle of the improved Sen transformer is for:

[0012] in, is the rated voltage of the secondary winding.

[0013] Preferably, based on the obtained power electronic and electromagnetic hybrid loop closing device, the topology scheme of the power electronic and electromagnetic hybrid loop closing device is obtained by reducing the capacity of the power electronic equipment and optimizing the following: By reducing the capacity of power electronic equipment and optimizing the topology of the hybrid loop closing device, a topology of the hybrid loop closing device based on static synchronous series compensator and improved Sen transformer is obtained.

[0014] Preferably, the output port of the static synchronous series compensator is connected to the isolation transformer in series with the access line, and the isolation transformer and the improved Sen transformer series winding can share an iron core to achieve structural integration.

[0015] Preferably, within the power flow regulation range of the device, the output voltage of the phase-shifting transformer with the smallest error corresponding to the power reference value is calculated first by the reactive power transmitted at the end of the line. Phase with the output voltage of the phase-shifting transformer , and then by changing the equivalent reactance of the line after compensation Realize continuous regulation of line power; The reactive power regulation amount of the device at the end of the line is:

[0016]

[0017] in, is the line active power regulation; is the line reactive power regulation value; is the effective value of the voltage of grid 2; is the phase difference between the two power grids; is the equivalent resistance of the circuit.

[0018] In a second aspect, an embodiment of the present invention provides a system for topological structure deduction and optimization of a ring closing device, comprising: A deduction module is used to deduce a power electronic and electromagnetic hybrid loop closing device based on a power electronic loop closing device and an electromagnetic loop closing device; The optimization module is based on the obtained power electronic and electromagnetic hybrid loop closing device. On the basis of ensuring the power regulation accuracy, the capacity of the power electronic equipment is reduced to optimize the topology scheme of the power electronic and electromagnetic hybrid loop closing device.

[0019] Preferably, in the deduction module, the cost of the power electronic loop closing device is analyzed according to the access mode; the cost of the electromagnetic loop closing device is analyzed according to the number of windings and the connection mode; the power electronic loop closing device and the electromagnetic loop closing device are combined to form a power electronic electromagnetic hybrid loop closing device based on the comprehensive cost, adjustment accuracy and overload capacity. The hybrid power flow controller of the power electronic electromagnetic hybrid loop closing device includes a unified power flow controller and an improved Sen transformer. The output voltage of the hybrid power flow controller is the output voltage vector of the improved Sen transformer. The output voltage vector of the unified power flow controller The vector sum of .

[0020] Preferably, the unified power flow controller and the improved Sen transformer share the excitation winding on the parallel side and the transformer core on the series side. The parallel side converter of the unified power flow controller is used to control the bus voltage and reactive support; the series side converter is used to control the series voltage amplitude and phase angle. The power electronic closing device includes a back-to-back converter and a unified power flow controller. The unified power flow controller and the improved Sen transformer share the excitation winding on the parallel side and the transformer core on the series side. The capacity of the unified power flow controller is The calculation is as follows:

[0021] in, 、 are the effective values ​​of the voltage of grid 1 and grid 2 respectively; is the phase difference between the two power grids, Control capacity for line flow; The improved Sen transformer includes a parallel excitation winding and two sets of secondary windings in series. The two sets of series windings are combined with different levels to synthesize different output voltage vectors, and the maximum phase shift angle of the improved Sen transformer is for:

[0022] in, is the rated voltage of the secondary winding.

[0023] Preferably, in the optimization module, the capacity of the power electronic equipment is reduced, and the topology of the hybrid loop closing device is optimized to obtain a topology of the hybrid loop closing device based on a static synchronous series compensator and an improved Sen transformer.

[0024] Preferably, the output port of the static synchronous series compensator is connected to the isolation transformer in series with the circuit, and the isolation transformer and the improved Sen transformer series winding can share an iron core to achieve structural integration; Within the power flow regulation range of the device, the output voltage of the phase-shifting transformer with the smallest error corresponding to the power reference value is first calculated by the reactive power transmitted at the end of the line. Phase with the output voltage of the phase-shifting transformer , and then by changing the equivalent reactance of the line after compensation Realize continuous regulation of line power; The reactive power regulation amount of the device at the end of the line is:

[0025]

[0026] in, is the line active power regulation; is the line reactive power regulation value; is the effective value of the voltage of grid 2; is the phase difference between the two power grids; is the equivalent resistance of the circuit.

[0027] In a third aspect, a computer device includes a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the steps of the above-mentioned method for topological structure deduction and optimization of a loop-closing device when executing the computer program.

[0028] In a fourth aspect, an embodiment of the present invention provides a computer-readable storage medium, comprising a computer program, which, when executed by a processor, implements the steps of the above-mentioned method for deducing and optimizing the topology structure of a loop-closing device.

[0029] In a fifth aspect, a chip comprises a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the steps of the above-mentioned method for deducing and optimizing the topology structure of the loop-closing device when executing the computer program.

[0030] In a sixth aspect, an embodiment of the present invention provides an electronic device, comprising a computer program, which, when executed by the electronic device, implements the steps of the above-mentioned method for deducing and optimizing the topology structure of the ring-closing device.

[0031] In the seventh aspect, a topology structure of a loop closing device includes a static synchronous series compensator and an improved Sen transformer; the output port of the static synchronous series compensator is connected to the isolation transformer in series with the access line, and the series windings of the isolation transformer and the improved Sen transformer share an iron core to achieve structural integration; the input power supply is connected to the DC load after passing through the series winding, secondary winding, isolation transformer and rectifier bridge.

[0032] Preferably, three-phase AC power is connected to the series winding, and the output end of the series winding is connected to the secondary winding. The secondary winding includes two groups of terminals. The ends of the first group of terminals are connected to form a neutral point and are grounded, and the head ends of the other group of terminals are interconnected to serve as output nodes; the output end of the secondary winding is coupled to the isolation transformer through a magnetic core to achieve electrical isolation of input / output; the neutral point and the head end output node of the secondary winding are jointly connected to a diode rectifier bridge to convert AC power into DC output; the secondary side of the isolation transformer outputs three-phase AC power to supply subsequent circuits.

[0033] Preferably, the improved Sen transformer is equivalent to a voltage source with adjustable amplitude and phase, and the static synchronous series compensator is equivalent to an adjustable line reactance; the reactive power adjustment amount of the device at the end of the line is:

[0034]

[0035] in, 、 are the voltages of the two grids; is the phase difference between the two power grids; is the output voltage of the phase-shifting transformer; is the equivalent reactance of the series side converter, i.e., SSSC; is the equivalent line impedance.

[0036] Compared with the prior art, the present invention has at least the following beneficial effects: A method for deducing and optimizing the topological structure of a loop closing device is proposed. By comprehensively analyzing the device cost and functional requirements, power electronic, electromagnetic and hybrid loop closing devices are classified and evolved respectively, and a hybrid loop closing device with the best comprehensive cost and functionality is deduced. Based on the hybrid loop closing device topology scheme, a new hybrid loop closing device topology scheme is further optimized and deduced.

[0037] Furthermore, the various types of loop closing device topology schemes are divided into power electronic, electromagnetic and hybrid loop closing devices according to their component structures, and the cost- and functionality-oriented loop closing device evolution methods under different loop closing devices are given respectively, and the hybrid loop closing device is optimized.

[0038] Furthermore, a topology optimization scheme was further constructed based on the selected hybrid loop closing device, and a new hybrid loop closing device topology scheme based on SSSC and HVST was deduced.

[0039] Furthermore, based on the existing hybrid ring closing device topology solution, with cost reduction as the orientation, a new hybrid ring closing device topology solution based on SSSC and HVST is constructed.

[0040] Furthermore, simulations verified the feasibility of using a new hybrid ring closing device for line power flow regulation, achieving continuous regulation of line active power with smaller device capacity and cost.

[0041] It can be understood that the beneficial effects of the second to seventh aspects mentioned above can be found in the relevant description of the first aspect mentioned above, and will not be repeated here.

[0042] In summary, this invention addresses the high cost and weak overload capacity of existing converter-based power electronic loop closing devices. By developing a cost-oriented method for loop closing devices, the method evolves from power electronic, electromagnetic, to hybrid power electronic and electromagnetic loop closing devices. Based on this, a topology optimization method for hybrid loop closing devices is further developed. This novel hybrid loop closing device topology derived using this method maintains power flow control accuracy while reducing costs.

[0043] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following is a brief introduction to the drawings required for use in the embodiments of the present application. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0045] Figure 1 The topology scheme and equivalent circuit diagram of the back-to-back converter (BTB-VSC) are shown below; Figure 2 The topology and equivalent circuit diagram of the unified power flow controller (UPFC) are shown below. Figure 3 This is the topology diagram of the Sen transformer (ST); Figure 4 To improve the topology scheme of Sen transformer (HVST); Figure 5 This is a comparison chart of the output voltage range and phase shift angle between ST and HVST; Figure 6 This is the topology diagram of the hybrid power flow controller (HPFC); Figure 7 This is the voltage vector diagram of the HPFC output (taking regulation level 1 as an example); Figure 8 The topology diagram of the new hybrid power flow controller based on SSSC and ST; Figure 9 This is the equivalent circuit diagram of a new hybrid power flow controller based on SSSC and ST; Figure 10 This is the compensation voltage and current waveform of the series side of the new hybrid loop closing device; Figure 11 This is the line power waveform after compensation by the new hybrid loop closing device; Figure 12 A schematic diagram of a computer device provided in accordance with an embodiment of the present invention; Figure 13 The present invention is a block diagram of an electronic device according to an embodiment of the present invention.

[0046] Among them, 60. Computer device; 61. Processor; 62. Memory; 63. Computer program; 600. Electronic device; 610. Processing unit; 620. Storage unit; 6201. Random access memory unit; 6202. Cache memory unit; 6203. Read-only memory unit; 6204. Program / Utility; 6205. Program module; 630. Bus; 640. Display unit; 650. Input / output interface; 660. Network adapter; 700. External device. DETAILED DESCRIPTION

[0047] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0048] In the description of the present invention, it is to be understood that the terms “include” and “comprise” indicate the presence of the described features, wholes, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, wholes, steps, operations, elements, components and / or collections thereof.

[0049] It should also be understood that the terms used in the present specification are only for the purpose of describing particular embodiments and are not intended to limit the present invention. As used in the present specification and the appended claims, the singular forms "a", "an", and "the" are intended to include the plural forms unless the context clearly indicates otherwise.

[0050] It should be further understood that the term "and / or" as used in the present specification and the appended claims refers to and includes any and all possible combinations of one or more of the associated listed items. For example, A and / or B may represent: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the character " / " in the present invention generally indicates that the associated objects are in an "or" relationship.

[0051] It should be understood that although the terms "first," "second," and "third" may be used to describe preset ranges in embodiments of the present invention, these preset ranges should not be limited to these terms. These terms are merely used to distinguish one preset range from another. For example, without departing from the scope of embodiments of the present invention, the first preset range may also be referred to as the second preset range, and similarly, the second preset range may also be referred to as the first preset range.

[0052] The word "if," as used herein, may be interpreted as "at the time of" or "when" or "in response to determining" or "in response to detecting," depending on the context. Similarly, the phrases "if it is determined" or "if (stated condition or event) is detected" may be interpreted as "when it is determined" or "in response to the determination" or "when detecting (stated condition or event)" or "in response to detecting (stated condition or event)," depending on the context.

[0053] The accompanying drawings illustrate various schematic diagrams of structures according to embodiments disclosed herein. These figures are not drawn to scale; for clarity, some details are exaggerated and some details may be omitted. The shapes of the various regions and layers shown in the figures, as well as their relative sizes and positional relationships, are merely exemplary and may deviate in practice due to manufacturing tolerances or technical limitations. Those skilled in the art may design regions / layers with different shapes, sizes, and relative positions as needed.

[0054] To ensure that distribution network loop closing devices can regulate power flow while reducing technical costs, this paper provides a loop closing device topology deduction and optimization method based on a differentiated classification of typical loop closing device topology schemes, guided by the improvement of cost and overload capacity. This method addresses the high cost and weak overload capacity of existing power electronic loop closing devices based on converters. This method, guided by cost, constructs a deduction method for loop closing devices ranging from power electronic, electromagnetic, to hybrid power electronic and electromagnetic loop closing devices. Based on this, a topology optimization method for hybrid loop closing devices is further constructed. The loop closing device topology scheme deduced using this method reduces costs while ensuring power flow regulation accuracy.

[0055] Example 1 The present invention provides a method for deducing and optimizing the topological structure of a ring closing device, comprising the following steps: S1. The specific steps of the deduction method of the loop closing device from the power electronic type, electromagnetic type to the power electronic electromagnetic hybrid loop closing device are as follows: S101. Analyze the economic efficiency of the power electronic loop closing device based on the access mode; Typical power electronic loop closing devices include back-to-back converters (BTB-VSC) and unified power flow controllers (UPFC). The topology and equivalent circuit of BTB-VSC are as follows: Figure 1 As shown in the figure, the topology of UPFC and the equivalent circuit are as follows: Figure 2 As shown in the figure, the former is connected to the distribution network in back-to-back parallel connection, while the latter is connected to the distribution network in series and parallel connection. Different access methods lead to differences in device capacity, which further affects the cost.

[0056] according to Figure 1 It can be seen that the line power flow control capacity all flows through the BTB-VSC, and its capacity calculation method is as follows: (1) in, To regulate the capacity of the line flow.

[0057] according to Figure 2 It can be seen that the power flow control capacity undertaken by UPFC is related to the size of the power grid at both ends. Its capacity calculation method (ignoring line resistance) is as follows: (2) in, 、 are the effective values ​​of the voltage of grid 1 and grid 2 respectively; is the phase difference between the two power grids.

[0058] Given the same power flow control capacity at two voltage levels and at the same line flow control capacity, the UPFC requires less capacity than the BTB-VSC, resulting in a smaller size and lower cost. Therefore, in power electronic loop closures, the evolution from back-to-back parallel connection to series-parallel connection can reduce costs.

[0059] S102. Analyze the cost of the electromagnetic loop closing device based on the number of windings and the connection method; The topology of Sen transformer (ST) is as follows Figure 3 As shown in the figure, the topology of the improved Sen transformer (HVST) is as follows Figure 4 As shown in the figure, the whole system consists of a parallel excitation winding and two sets of secondary windings in series. The two sets of series windings are combined to form different output voltage vectors through different levels. It can be seen that the number of secondary windings in the HVST is reduced from 9 to 6 compared to the ST.

[0060] When ST and HVST have the same secondary winding rated voltage ( ), the output voltage range and phase shift angle comparison of the two are as follows: Figure 5 Taking regulation level 1 as an example, the number of ST output voltage vectors is 7, and the number of HVST output voltage vectors is 9.

[0061] The maximum phase shift angle of ST is: (3) The maximum phase shift angle of HVST is: (4) It can be seen that compared to ST, HVST reduces the number of secondary windings while increasing the number of voltage output vectors and the maximum phase shift angle. Therefore, reducing the number of windings and changing the wiring method can reduce the cost of electromagnetic loop closing devices.

[0062] S103. A power electronic electromagnetic hybrid loop closing device is obtained by deducing the comprehensive cost, regulation accuracy and overload capacity.

[0063] The power electronic electromagnetic hybrid loop closing device combines the advantages of power electronic loop closing devices and electromagnetic loop closing devices. The power electronic electromagnetic hybrid loop closing device is composed of a large-capacity electromagnetic loop closing device and a small-capacity power electronic loop closing device. Compared with the power electronic loop closing device, it reduces the excessive volume and cost of the large-capacity power electronic device and improves the overload capacity; compared with the electromagnetic loop closing device, it enhances the adjustment accuracy.

[0064] The topology of the hybrid power flow controller (HPFC) based on UPFC and HVST is as follows: Figure 6 As shown in Figure 1, the UPFC and HVST share the excitation winding on the parallel side and the transformer core on the series side to achieve structural integration. The voltage vector diagram of the HPFC output is shown in Figure 1. Figure 7 As shown (taking regulation level 1 as an example). The HPFC output voltage is the HVST output voltage vector and UPFC output voltage vector The vector sum can cover any position within the small circle, making up for the deficiency of discrete adjustment of electromagnetic closing loop device.

[0065] S2. Topology optimization method for power electronic electromagnetic hybrid loop closing device, the specific steps are as follows; S201. On the basis of ensuring power regulation accuracy, with the core focus on reducing the capacity of power electronic equipment, optimize the topology of the existing power electronic and electromagnetic hybrid loop closing device; In the HPFC topology based on UPFC and HVST, the UPFC's parallel-side converter is used to control the bus voltage and reactive support; the series-side converter is used to control the series voltage amplitude and phase angle. It can be seen that the series-side converter is the core device for maintaining the accuracy of power flow regulation. Although removing the parallel-side converter reduces the reactive compensation capability of the device to a certain extent, it can still ensure the continuity of power flow regulation and is more cost-effective. Therefore, a new power electronic electromagnetic hybrid closed-loop device topology solution based on SSSC (Static Synchronous Series Compensator) and HVST is optimized, such as Figure 8 As shown, the output port of the SSSC is connected to the isolation transformer in series with the circuit, and the isolation transformer and the HVST series winding can share the core to achieve structural integration.

[0066] The topology of a novel power electronic electromagnetic hybrid loop closing device includes a static synchronous series compensator and an improved Sen transformer; the output port of the static synchronous series compensator is connected in series with an isolation transformer to the line, and the series windings of the isolation transformer and the improved Sen transformer share an iron core to achieve structural integration; the input power is connected to a DC load after passing through the series winding, secondary winding, isolation transformer and rectifier bridge.

[0067] Specifically, three-phase AC power is connected to the series winding, and the output end of the series winding is connected to the secondary winding. The secondary winding includes two sets of terminals. The ends of the first set of terminals are connected to form a neutral point and are grounded, and the head ends of the other set of terminals are interconnected as output nodes; the output end of the secondary winding is coupled to the isolation transformer through a magnetic core to achieve electrical isolation of input / output; the neutral point and the head end output node of the secondary winding are jointly connected to a diode rectifier bridge to convert AC power into DC output; the secondary side of the isolation transformer outputs three-phase AC power to supply subsequent circuits.

[0068] S202. Analyze the effectiveness and accuracy of power flow control of the new hybrid loop closing device based on SSSC and HVST. The equivalent circuit of the new power electronic electromagnetic hybrid loop closing device connected to the distribution network is as follows: Figure 9 As shown in Figure 3, the HVST is equivalent to a voltage source with adjustable amplitude and phase, and the SSSC is equivalent to an adjustable line reactance.

[0069] in, 、 are the voltages of the two grids; is the phase difference between the two power grids; is the output voltage of the phase-shifting transformer; is the equivalent reactance of the series side converter, i.e., SSSC; is the equivalent line impedance.

[0070] The reactive power transmitted at the end of the line is: (5) (6) in, .

[0071] The reactive power regulation amount of the device at the end of the line is: (7) (8) Within the power flow regulation range of the device, first calculate the power reference value with the minimum error by using equations (5) and (6). and ,because Continuously adjustable, then by changing This allows for continuous regulation of line power. The resulting hybrid loop-closing device maintains the accuracy and overload capacity of power flow regulation while reducing the capacity and volume of power electronics compared to existing hybrid loop-closing devices, further reducing costs.

[0072] Those skilled in the art will appreciate that various aspects of the present invention may be implemented as systems, methods, or program products. Accordingly, various aspects of the present invention may be implemented in the following forms: entirely in hardware, entirely in software (including firmware, microcode, etc.), or in a combination of hardware and software, collectively referred to herein as "circuits," "modules," or "platforms."

[0073] Example 2 The present invention provides a loop-closing device topology structure deduction and optimization system, which can be used to implement the above-mentioned loop-closing device topology structure deduction and optimization method. Specifically, the loop-closing device topology structure deduction and optimization system includes a deduction module and an optimization module.

[0074] Among them, the deduction module deduces a power electronic and electromagnetic hybrid loop closing device based on the power electronic loop closing device and the electromagnetic loop closing device; The cost of the power electronic closing device is analyzed according to the access method; the cost of the electromagnetic closing device is analyzed according to the number of windings and the connection method; the power electronic closing device and the electromagnetic closing device are combined to form a power electronic electromagnetic hybrid closing device based on the comprehensive cost, adjustment accuracy and overload capacity. The hybrid power flow controller of the power electronic electromagnetic hybrid closing device includes a unified power flow controller and an improved Sen transformer. The output voltage of the hybrid power flow controller is the output voltage vector of the improved Sen transformer. The output voltage vector of the unified power flow controller The vector sum of .

[0075] The unified power flow controller and the improved Sen transformer share the excitation winding on the parallel side and the transformer core on the series side. The parallel side converter of the unified power flow controller is used to control the bus voltage and reactive power support; the series side converter is used to control the series voltage amplitude and phase angle. The power electronic closing device includes a back-to-back converter and a unified power flow controller. The unified power flow controller and the improved Sen transformer share the excitation winding on the parallel side and the transformer core on the series side. The capacity of the unified power flow controller is The calculation is as follows:

[0076] in, 、 are the effective values ​​of the voltage of grid 1 and grid 2 respectively; is the phase difference between the two power grids, Control capacity for line flow; The improved Sen transformer includes a parallel excitation winding and two sets of secondary windings in series. The two sets of series windings are combined with different levels to synthesize different output voltage vectors, and the maximum phase shift angle of the improved Sen transformer is for:

[0077] in, is the rated voltage of the secondary winding.

[0078] The optimization module, based on the obtained power electronic and electromagnetic hybrid loop closing device, optimizes the topology of the power electronic and electromagnetic hybrid loop closing device by reducing the capacity of the power electronic equipment while ensuring the power regulation accuracy.

[0079] By reducing the capacity of power electronic equipment and optimizing the topology of the hybrid loop closing device, a topology of the hybrid loop closing device based on static synchronous series compensator and improved Sen transformer is obtained.

[0080] The output port of the static synchronous series compensator is connected to the isolation transformer in series with the line. The isolation transformer and the improved Sen transformer series winding can share the iron core to achieve structural integration. Within the power flow regulation range of the device, the output voltage of the phase-shifting transformer with the smallest error corresponding to the power reference value is first calculated by the reactive power transmitted at the end of the line. Phase with the output voltage of the phase-shifting transformer , and then by changing the equivalent reactance of the line after compensation Realize continuous regulation of line power; The reactive power regulation amount of the device at the end of the line is:

[0081]

[0082] in, is the line active power regulation; is the line reactive power regulation value; is the effective value of the voltage of grid 2; is the phase difference between the two power grids; is the equivalent resistance of the circuit.

[0083] Example 3 The present invention provides a terminal device, which includes a processor and a memory, wherein the memory is used to store a computer program, the computer program includes program instructions, and the processor is used to execute the program instructions stored in the computer storage medium. The processor may be a central processing unit (CPU), or may be other general-purpose processors, graphics processing units (GPUs), tensor processing units (TPUs), digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. It is the computing core and control core of the terminal, which is suitable for implementing one or more instructions, specifically suitable for loading and executing one or more instructions to implement corresponding method processes or corresponding functions; the processor described in the embodiment of the present invention can be used for the operation of the closed-loop device topology structure deduction and optimization method, including: A power electronic and electromagnetic hybrid loop closing device is deduced based on the power electronic loop closing device and the electromagnetic loop closing device; based on the obtained power electronic and electromagnetic hybrid loop closing device, the topology scheme of the power electronic and electromagnetic hybrid loop closing device is optimized with the reduction of the capacity of the power electronic equipment as the core.

[0084] See also Figure 12The terminal device is a computer device. The computer device 60 of this embodiment includes: a processor 61, a memory 62, and a computer program 63 stored in the memory 62 and executable by the processor 61. When executed by the processor 61, the computer program 63 implements the loop-closing device topology structure deduction and optimization method of the embodiment. To avoid repetition, a detailed description is omitted here. Alternatively, when executed by the processor 61, the computer program 63 implements the functions of each model / unit in the loop-closing device topology structure deduction and optimization system of the embodiment. To avoid repetition, a detailed description is omitted here.

[0085] The computer device 60 may be a desktop computer, a notebook computer, a PDA, a cloud server, or other computing devices. The computer device 60 may include, but is not limited to, a processor 61 and a memory 62. It will be understood by those skilled in the art that Figure 12 This is merely an example of the computer device 60 and does not constitute a limitation of the computer device 60 . The computer device 60 may include more or fewer components than shown in the figure, or a combination of certain components, or different components. For example, the computer device may also include input and output devices, network access devices, buses, etc.

[0086] The processor 61 may be a central processing unit (CPU), or other general-purpose processors, a graphics processing unit (GPU), a tensor processing unit (TPU), a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor may be a microprocessor or any conventional processor, etc.

[0087] The memory 62 may be an internal storage unit of the computer device 60, such as a hard disk or memory of the computer device 60. The memory 62 may also be an external storage device of the computer device 60, such as a plug-in hard disk, a smart media card (SMC), a secure digital (SD) card, a flash card, etc. equipped on the computer device 60.

[0088] Furthermore, the memory 62 may include both an internal storage unit of the computer device 60 and an external storage device. The memory 62 is used to store computer programs and other programs and data required by the computer device. The memory 62 may also be used to temporarily store data that has been output or is about to be output.

[0089] See also Figure 13 The terminal device is an electronic device 600, which is implemented as a general-purpose computing device. The components of the electronic device may include, but are not limited to, at least one processing unit 610, at least one storage unit 620, a bus 630 connecting different platform components (including the storage unit 620 and the processing unit 610), and a display unit 640.

[0090] The storage unit stores program codes, which can be executed by the processing unit 610 , so that the processing unit 610 executes the steps according to various exemplary embodiments of the present invention described in the above method part of this specification.

[0091] The storage unit 620 may include a readable medium in the form of a volatile storage unit, such as a random access memory unit (RAM) 6201 and / or a cache memory unit 6202 , and may further include a read-only memory unit (ROM) 6203 .

[0092] The storage unit 620 may also include a program / utility 6204 having a set (at least one) of program modules 6205, such program modules 6205 including but not limited to: an operating system, one or more application programs, other program modules, and program data, each of which or some combination may include an implementation of a network environment.

[0093] Bus 630 may represent one or more of several types of bus structures, including a memory bus or memory controller, a peripheral bus, an accelerated graphics port, a processing unit, or a local bus using any of a variety of bus architectures.

[0094] The electronic device 600 may also communicate with one or more external devices 700 (e.g., a keyboard, a pointing device, a Bluetooth device, etc.), one or more devices that enable a user to interact with the electronic device 600, and / or any device that enables the electronic device 600 to communicate with one or more other computing devices (e.g., a router, a modem). Such communication may occur via an input / output interface 650. Furthermore, the electronic device 600 may also communicate with one or more networks (e.g., a local area network, a wide area network, and / or a public network, such as the Internet) via a network adapter 660. The network adapter 660 may communicate with other modules of the electronic device 600 via a bus 630. It should be understood that, although not shown in the figures, other hardware and / or software modules may be used in conjunction with the electronic device 600, including but not limited to microcode, device drivers, redundant processing units, external disk drive arrays, RAID systems, tape drives, and data backup storage platforms.

[0095] Example 4 The present invention also provides a storage medium, specifically a computer-readable storage medium. The computer-readable storage medium is a memory device in a terminal device, used to store programs and data. It is understood that the computer-readable storage medium herein may include both the built-in storage medium in the terminal device and, of course, the extended storage medium supported by the terminal device. It may be any tangible medium containing or storing a program that can be used by or in conjunction with an instruction execution system, apparatus, or device. The computer-readable storage medium provides storage space that stores the terminal's operating system. Furthermore, the storage space also stores one or more instructions suitable for being loaded and executed by a processor. These instructions may be one or more computer programs (including program code). It should be noted that more specific examples of the computer-readable storage medium herein include: an electrical connection having one or more wires, a portable disk, a hard disk, a random access memory, a read-only memory, an erasable programmable read-only memory, an optical fiber, a portable compact disk read-only memory, an optical storage device, a magnetic storage device, or any suitable combination thereof.

[0096] Computer-readable storage media also include data signals propagated in baseband or as part of a carrier wave, which carry readable program code. Such propagated data signals can take a variety of forms, including but not limited to electromagnetic signals, optical signals, or any suitable combination of the above. The readable storage medium can also be any readable medium other than a readable storage medium, which can send, propagate, or transmit programs for use by or in conjunction with an instruction execution system, device, or device. The program code contained on the readable storage medium can be transmitted using any appropriate medium, including but not limited to wireless, wired, optical cable, radio frequency, etc., or any suitable combination of the above.

[0097] The program code for performing the operations of the present invention may be written in any combination of one or more programming languages, including object-oriented programming languages ​​such as Java, C++, and the like, as well as conventional open-source programming languages ​​such as "C" or similar programming languages. The program code may be executed entirely on the user computing device, partially on the user device, as a stand-alone software package, partially on the user computing device and partially on a remote computing device, or entirely on a remote computing device or server. In cases involving a remote computing device, the remote computing device may be connected to the user computing device via any type of network, including a local area network or a wide area network, or may be connected to an external computing device (e.g., via the Internet using an Internet service provider).

[0098] The processor may load and execute one or more instructions stored in a computer-readable storage medium to implement the corresponding steps of the method for topological structure deduction and optimization of the ring closing device in the above embodiment; the processor may load and execute the following steps: A power electronic and electromagnetic hybrid loop closing device is deduced based on the power electronic loop closing device and the electromagnetic loop closing device; based on the obtained power electronic and electromagnetic hybrid loop closing device, the topology scheme of the power electronic and electromagnetic hybrid loop closing device is optimized with the reduction of the capacity of the power electronic equipment as the core.

[0099] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings herein can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the claimed invention, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0100] The following simulation results based on the 10kV distribution network application scenario illustrate the effectiveness of the new device in precise power flow control. Among them, the phase difference between the two power grids is 30°; the line impedance is 6+ j 3.14Ω; at 2s, the line active power command value suddenly changes from 14MW to 22MW, and at 3s, the line active power command value suddenly changes from 22MW to 16MW.

[0101] The voltage and current on the series side of the new hybrid closing device are as follows: Figure 10 As shown, the line has reactive power as Figure 11 As shown in Figure 2, it can be seen that when the power command changes, the series compensation voltage of the device changes, thereby making the line active power accurately follow the command value and realizing continuous control of active power.

[0102] In summary, the present invention provides a method for deducing and optimizing the topology structure of a loop closing device and related devices. This method addresses the high cost and limited project promotion of existing loop closing devices based on power electronics technology. It constructs a method for deducing and optimizing the topology of a loop closing device based on comprehensive cost and functionality. Based on this method, a new hybrid loop closing device based on SSSC and HVST is derived, which reduces costs while achieving continuous regulation of the line active power.

[0103] Those skilled in the art can clearly understand that, for the convenience and brevity of description, only the division of the above-mentioned functional units and modules is used as an example for illustration. In actual applications, the above-mentioned functions can be distributed and completed by different functional units and modules as needed, that is, the internal structure of the device can be divided into different functional units or modules to complete all or part of the functions described above. The functional units and modules in the embodiment can be integrated into one processing unit, or each unit can exist physically alone, or two or more units can be integrated into one unit. The above-mentioned integrated unit can be implemented in the form of hardware or in the form of software functional units. In addition, the specific names of the functional units and modules are only for the convenience of distinguishing each other, and are not used to limit the scope of protection of this application. The specific working process of the units and modules in the above-mentioned system can refer to the corresponding process in the aforementioned method embodiment, and will not be repeated here.

[0104] In the above embodiments, the description of each embodiment has its own focus. For parts that are not described or recorded in detail in a certain embodiment, reference can be made to the relevant description of other embodiments.

[0105] Those skilled in the art will appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed in the present invention can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professionals and technicians can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of the present invention.

[0106] In the embodiments provided by the present invention, it should be understood that the disclosed devices / terminals and methods can be implemented in other ways. For example, the device / terminal embodiments described above are merely illustrative. For example, the division of the modules or units is merely a logical functional division. In actual implementation, there may be other division methods, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. In addition, the mutual coupling or direct coupling or communication connection shown or discussed can be through some interface, indirect coupling or communication connection of devices or units, and can be electrical, mechanical, or other forms.

[0107] The units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed across multiple network units. Some or all of these units may be selected to achieve the purpose of this embodiment according to actual needs.

[0108] In addition, the functional units in the various embodiments of the present invention may be integrated into a single processing unit, each unit may exist physically separately, or two or more units may be integrated into a single unit. The aforementioned integrated units may be implemented in the form of hardware or software functional units.

[0109] If the integrated module / unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the present invention implements all or part of the process in the above-mentioned embodiment method, and can also be completed by instructing the relevant hardware through a computer program. The computer program can be stored in a computer-readable storage medium. When the computer program is executed by a processor, it can implement the steps of the above-mentioned various method embodiments. Among them, the computer program includes computer program code, and the computer program code can be in source code form, object code form, executable file or some intermediate form. The computer-readable medium may include: any entity or device capable of carrying the computer program code, recording medium, USB flash drive, mobile hard disk, magnetic disk, optical disk, computer memory, read-only memory (ROM), random access memory (RAM), electric carrier signal, telecommunication signal and software distribution medium, etc. It should be noted that the content contained in the computer-readable medium can be appropriately increased or decreased according to the requirements of legislation and patent practice in the jurisdiction. For example, in some jurisdictions, according to legislation and patent practice, computer-readable media do not include electric carrier signals and telecommunication signals.

[0110] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices, and computer program products according to the embodiments of the present application. It should be understood that each process and / or block in the flowchart and / or block diagram, as well as the combination of processes and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 a process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0111] These computer program instructions may also be stored in a computer readable memory that can direct a computer or other programmable data processing device to work in a specific manner, so that the instructions stored in the computer readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1a process or multiple processes and / or boxes Figure 1 The function specified in one or more boxes.

[0112] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operational steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing the instructions executed on the computer or other programmable device for implementing the process. Figure 1 a process or multiple processes and / or boxes Figure 1 A step that specifies a function in one or more boxes.

[0113] The above content is only for explaining the technical idea of ​​the present invention and cannot be used to limit the protection scope of the present invention. Any changes made on the basis of the technical solution in accordance with the technical idea proposed by the present invention shall fall within the protection scope of the claims of the present invention.

Claims

1. A method for deducing and optimizing the topological structure of a ring closing device, characterized in that: The following steps are involved: Based on the power electronic loop closing device and the electromagnetic loop closing device, a power electronic electromagnetic hybrid loop closing device is derived; Based on the obtained power electronic and electromagnetic hybrid loop closing device, a topology scheme of the power electronic and electromagnetic hybrid loop closing device is obtained by reducing the capacity optimization of power electronic equipment.

2. The method for deducing and optimizing the topology of a ring closing device according to claim 1, characterized in that: Based on the power electronic loop closing device and the electromagnetic loop closing device, the power electronic electromagnetic hybrid loop closing device is deduced as follows: The cost of the power electronic closing device is analyzed according to the access method; the cost of the electromagnetic closing device is analyzed according to the number of windings and the connection method; the power electronic closing device and the electromagnetic closing device are combined to form a power electronic electromagnetic hybrid closing device based on the comprehensive cost, adjustment accuracy and overload capacity. The hybrid power flow controller of the power electronic electromagnetic hybrid closing device includes a unified power flow controller and an improved Sen transformer. The output voltage of the hybrid power flow controller is the output voltage vector of the improved Sen transformer. The output voltage vector of the unified power flow controller The vector sum of .

3. The method for deducing and optimizing the topological structure of the ring closing device according to claim 2, characterized in that: The unified power flow controller and the improved Sen transformer share the excitation winding on the parallel side and the transformer core on the series side. The parallel side converter of the unified power flow controller is used to control the bus voltage and reactive support; the series side converter is used to control the series voltage amplitude and phase angle.

4. The method for deducing and optimizing the topological structure of the ring closing device according to claim 2, characterized in that: The power electronic closing device includes a back-to-back converter and a unified power flow controller. The unified power flow controller and the improved Sen transformer share the excitation winding on the parallel side and the transformer core on the series side. The capacity of the unified power flow controller is The calculation is as follows: in, 、 are the effective values ​​of the voltage of grid 1 and grid 2 respectively; is the phase difference between the two power grids, Control capacity for line flow; The improved Sen transformer includes a parallel excitation winding and two sets of secondary windings in series. The two sets of series windings are combined with different levels to synthesize different output voltage vectors, and the maximum phase shift angle of the improved Sen transformer is for: in, is the rated voltage of the secondary winding.

5. The method for deducing and optimizing the topological structure of a ring closing device according to claim 1, characterized in that: Based on the obtained power electronic electromagnetic hybrid loop closing device, the topology scheme of the power electronic electromagnetic hybrid loop closing device is obtained by reducing the capacity of the power electronic equipment and optimizing the following: By reducing the capacity of power electronic equipment and optimizing the topology of the hybrid loop closing device, a topology of the hybrid loop closing device based on static synchronous series compensator and improved Sen transformer is obtained.

6. The method for deducing and optimizing the topological structure of the ring closing device according to claim 5, characterized in that: The output port of the static synchronous series compensator is connected to the isolation transformer in series with the circuit. The isolation transformer and the improved Sen transformer series winding can share an iron core to achieve structural integration.

7. The method for deducing and optimizing the topological structure of the ring closing device according to claim 5, characterized in that: Within the power flow regulation range of the device, the output voltage of the phase-shifting transformer with the smallest error corresponding to the power reference value is first calculated by the reactive power transmitted at the end of the line. Phase with the output voltage of the phase-shifting transformer , and then by changing the equivalent reactance of the line after compensation Realize continuous regulation of line power; The reactive power regulation amount of the device at the end of the line is: in, is the line active power regulation; is the line reactive power regulation value; is the effective value of the voltage of grid 2; is the phase difference between the two power grids; is the equivalent resistance of the circuit.

8. A loop closing device topology structure deduction and optimization system, characterized in that: include: A deduction module is used to deduce a power electronic and electromagnetic hybrid loop closing device based on a power electronic loop closing device and an electromagnetic loop closing device; The optimization module, based on the obtained power electronic and electromagnetic hybrid loop closing device, optimizes the topology of the power electronic and electromagnetic hybrid loop closing device by reducing the capacity of the power electronic equipment while ensuring the power regulation accuracy.

9. The loop closing device topology structure deduction and optimization system according to claim 8, characterized in that: In the deduction module, the cost of the power electronic closing device is analyzed according to the access method; the cost of the electromagnetic closing device is analyzed according to the number of windings and the connection method; the power electronic closing device and the electromagnetic closing device are combined to form a power electronic electromagnetic hybrid closing device based on the comprehensive cost, regulation accuracy and overload capacity. The hybrid power flow controller of the power electronic electromagnetic hybrid closing device includes a unified power flow controller and an improved Sen transformer. The output voltage of the hybrid power flow controller is the output voltage vector of the improved Sen transformer. The output voltage vector of the unified power flow controller The vector sum of .

10. The loop closing device topology structure deduction and optimization system according to claim 9, characterized in that: The unified power flow controller and the improved Sen transformer share the excitation winding on the parallel side and the transformer core on the series side. The parallel side converter of the unified power flow controller is used to control the bus voltage and reactive power support; the series side converter is used to control the series voltage amplitude and phase angle. The power electronic closing device includes a back-to-back converter and a unified power flow controller. The unified power flow controller and the improved Sen transformer share the excitation winding on the parallel side and the transformer core on the series side. The capacity of the unified power flow controller is The calculation is as follows: in, 、 are the effective values ​​of the voltage of grid 1 and grid 2 respectively; is the phase difference between the two power grids, Control capacity for line flow; The improved Sen transformer includes a parallel excitation winding and two sets of secondary windings in series. The two sets of series windings are combined with different levels to synthesize different output voltage vectors, and the maximum phase shift angle of the improved Sen transformer is for: in, is the rated voltage of the secondary winding.

11. The loop closing device topology structure deduction and optimization system according to claim 8, characterized in that: In the optimization module, the capacity of the power electronic equipment is reduced, and the topology of the hybrid loop closing device is optimized, and a topology of the hybrid loop closing device based on the static synchronous series compensator and the improved Sen transformer is obtained.

12. The loop closing device topology structure deduction and optimization system according to claim 11, characterized in that: The output port of the static synchronous series compensator is connected to the isolation transformer in series with the line. The isolation transformer and the improved Sen transformer series winding can share the iron core to achieve structural integration. Within the power flow regulation range of the device, the output voltage of the phase-shifting transformer with the smallest error corresponding to the power reference value is first calculated by the reactive power transmitted at the end of the line. Phase with the output voltage of the phase-shifting transformer , and then by changing the equivalent reactance of the line after compensation Realize continuous regulation of line power; The reactive power regulation amount of the device at the end of the line is: in, is the line active power regulation; is the line reactive power regulation value; is the effective value of the voltage of grid 2; is the phase difference between the two power grids; is the equivalent resistance of the circuit.

13. A computer-readable storage medium storing one or more programs, characterized in that: The one or more programs include instructions, which, when executed by a computing device, cause the computing device to perform the method of any one of claims 1 to 7.

14. A computing device, characterized in that include: One or more processors, a memory, and one or more programs, wherein the one or more programs are stored in the memory and configured to be executed by the one or more processors, and the one or more programs include steps for executing the method according to any one of claims 1 to 7.

15. A topological structure of a ring closing device, characterized in that: The invention comprises a static synchronous series compensator and an improved Sen transformer; the output port of the static synchronous series compensator is connected to an isolation transformer in series with the circuit, and the series windings of the isolation transformer and the improved Sen transformer share an iron core to realize structural integration; the input power is connected to a DC load after passing through a series winding, a secondary winding, an isolation transformer and a rectifier bridge.

16. The topological structure of the ring closing device according to claim 15, characterized in that: Three-phase AC power is connected to the series winding, and the output end of the series winding is connected to the secondary winding. The secondary winding includes two sets of terminals. The ends of the first set of terminals are connected to form a neutral point and are grounded, and the head ends of the other set of terminals are interconnected as output nodes; the output end of the secondary winding is coupled to the isolation transformer through a magnetic core to achieve electrical isolation of input / output; the neutral point and the head end output node of the secondary winding are jointly connected to a diode rectifier bridge to convert AC power into DC output; the secondary side of the isolation transformer outputs three-phase AC power to supply subsequent circuits.

17. The topological structure of the ring closing device according to claim 15, characterized in that: The improved Sen transformer is equivalent to a voltage source with adjustable amplitude and phase, and the static synchronous series compensator is equivalent to an adjustable line reactance. The reactive power regulation of the device at the end of the line is: in, 、 are the voltages of the two grids; is the phase difference between the two power grids; is the output voltage of the phase-shifting transformer; is the equivalent reactance of the series side converter, i.e., SSSC; is the equivalent line impedance.

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