Flexible interconnection switch configuration method and system fusing alternating current and direct current networking

Abstract

The invention discloses a flexible interconnection switch configuration method and system fusing alternating current and direct current networking, and the method comprises the steps: obtaining topological structure data and load data of a power distribution network, and determining target functions corresponding to different scenes; constructing a simulation model of the power distribution network, and performing second-order cone analysis on the target function to obtain feedback results in different scenes; performing reverse analysis processing on the feedback result to determine flexible interconnection switch configuration strategies corresponding to different scenes; in the actual operation control of the power distribution network, determining a scene according to the real-time operation state data of the power distribution network; and executing a matched flexible interconnection switch configuration strategy according to the determined scene. According to the flexible interconnection switch configuration method for the integrated AC / DC networking provided by the embodiment of the invention, the flexible regulation and control effect of the integrated AC / DC networking is realized by optimizing the configuration of the flexible interconnection switch.

Description

Technical Field

[0001] The present invention relates to the technical field of AC / DC systems, and in particular to a flexible tie switch configuration method and system for integrating AC / DC networking. Background Art

[0002] The Soft Open Point (SOP) technology aims to replace the traditional feeder interconnector based on circuit breakers with controllable power electronic converters, thereby achieving normalized flexible "soft connection" between feeders, and providing flexible, fast and precise power exchange control and power flow optimization capabilities.

[0003] In the prior art, the flexible interconnecting switches are configured in a fixed manner. Such a design is difficult to adapt to different power grid operation flow distributions, resulting in the stable operation of the power grid being affected.

[0004] It can be seen that how to optimize the configuration of the flexible contact switch has become a technical problem that needs to be solved urgently by those skilled in the art. Summary of the invention

[0005] The present invention provides a flexible interconnection switch configuration method and system for integrated AC / DC networking, so as to solve the technical problem of how to optimize the configuration of the flexible interconnection switch, so as to achieve the effect of flexible regulation of the integrated AC / DC networking.

[0006] In order to solve the above technical problems, an embodiment of the present invention provides a flexible tie switch configuration method for integrated AC / DC networking, comprising:

[0007] Obtain the topological structure data and load data of the distribution network and determine the corresponding objective functions under different scenarios;

[0008] Constructing a simulation model of the distribution network, performing a second-order cone analysis on the objective function, and obtaining feedback results under different scenarios;

[0009] Performing reverse analysis on the feedback results to determine the flexible tie switch configuration strategies corresponding to different scenarios;

[0010] In actual operation control of the distribution network, a scenario is determined based on real-time operation status data of the distribution network;

[0011] The matching flexible contact switch configuration strategy is executed according to the determined scenario.

[0012] As one of the preferred solutions, before obtaining the topological structure data and load data of the target distribution network and determining the corresponding objective functions under different scenarios, the flexible tie switch configuration method for integrated AC / DC networking also includes:

[0013] The topology data and the load data are preprocessed, and the preprocessing steps include topology verification and optimization, data cleaning and data transformation.

[0014] As one of the preferred solutions, the simulation model of the distribution network is constructed, and a second-order cone analysis is performed on the objective function to obtain feedback results under different scenarios, including:

[0015] Based on the Monte Carlo algorithm, the topological structure data and the load data of the distribution network are processed to obtain flow sample data, and a simulation model of the distribution network is constructed with the flow sample data;

[0016] The objective function is input into the simulation model to obtain feedback results under different scenarios.

[0017] As one of the preferred solutions, the reverse analysis of the feedback results to determine the flexible tie switch configuration strategies corresponding to different scenarios includes:

[0018] The feedback result is calculated by using the Newton-Raphson iteration method to obtain the correction amount of the state variable of the distribution network, and the correction amount is further reversely analyzed to determine the flexible tie switch configuration strategy corresponding to different scenarios.

[0019] As one of the preferred solutions, the flexible tie switch configuration method for the integrated AC / DC network further includes:

[0020] If the converter capacity of two branch nodes in the integrated AC / DC network is zero, the two branches are not configured with flexible tie switches.

[0021] The embodiment of the present invention provides a flexible tie switch configuration system integrating AC and DC networking, including:

[0022] The acquisition module is used to obtain the topological structure data and load data of the distribution network and determine the corresponding objective functions under different scenarios;

[0023] A construction module is used to construct a simulation model of the distribution network, perform a second-order cone analysis on the objective function, and obtain feedback results under different scenarios;

[0024] A reverse module, used for performing reverse analysis on the feedback results to determine the flexible tie switch configuration strategies corresponding to different scenarios;

[0025] A determination module, used to determine a scenario according to real-time operation status data of the distribution network in actual operation control of the distribution network;

[0026] The execution module is used to execute the matching flexible tie switch configuration strategy according to the determined scenario.

[0027] As one of the preferred solutions, before obtaining the topological structure data and load data of the target distribution network and determining the corresponding objective functions under different scenarios, the flexible tie switch configuration system for integrated AC / DC networking further includes:

[0028] The preprocessing module is used to preprocess the topology data and the load data, wherein the preprocessing steps include topology verification and optimization, data cleaning and data transformation.

[0029] As one of the preferred solutions, the simulation model of the distribution network is constructed, and a second-order cone analysis is performed on the objective function to obtain feedback results under different scenarios, including:

[0030] Based on the Monte Carlo algorithm, the topological structure data and the load data of the distribution network are processed to obtain flow sample data, and a simulation model of the distribution network is constructed with the flow sample data;

[0031] The objective function is input into the simulation model to obtain feedback results under different scenarios.

[0032] As one of the preferred solutions, the reverse analysis of the feedback results to determine the flexible tie switch configuration strategies corresponding to different scenarios includes:

[0033] The feedback result is calculated by using the Newton-Raphson iteration method to obtain the correction amount of the state variable of the distribution network, and the correction amount is further reversely analyzed to determine the flexible tie switch configuration strategy corresponding to different scenarios.

[0034] As one of the preferred solutions, the flexible tie switch configuration system for integrated AC / DC networking also includes:

[0035] The coordination module is used for not configuring flexible tie switches for the two branches if the converter capacity of the two branch nodes in the integrated AC / DC network is zero.

[0036] Compared with the prior art, the embodiments of the present invention have the following advantages:

[0037] (1) The present invention optimizes the configuration of flexible tie switches to adapt to different power grid operation flow distributions and improve the access flexibility of distributed renewable energy;

[0038] (2) By optimizing the configuration of flexible interconnection switches and integrating flexible interconnection of AC and DC networks, the grid structure is optimized and the stability of grid operation is ensured. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1It is a schematic diagram of a flexible contact switch implementation device in one embodiment of the present invention;

[0040] Figure 2 It is a schematic flow chart of a method for configuring a flexible tie switch for integrated AC / DC networking in one embodiment of the present invention;

[0041] Figure 3 It is a structural schematic diagram of a flexible tie switch configuration system for integrated AC / DC networking in one embodiment of the present invention.

[0042] Reference numerals:

[0043] Among them, 11, acquisition module; 12, construction module; 13, reverse module; 14, determination module; 15, execution module. DETAILED DESCRIPTION

[0044] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. The purpose of providing these embodiments is to make the disclosure of the present invention more thorough and comprehensive. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0045] In the description of this application, the terms "first", "second", "third", etc. are used for descriptive purposes only and are not to be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first", "second", "third", etc. may explicitly or implicitly include one or more of the feature. In the description of this application, unless otherwise specified, "plurality" means two or more.

[0046] In the description of the present application, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be a connection between the two elements. The terms "vertical", "horizontal", "left", "right", "upper", "lower" and similar expressions used herein are only for illustrative purposes, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. The term "and / or" used herein includes any and all combinations of one or more related listed items. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0047] In the description of this application, it should be noted that, unless otherwise defined, all technical and scientific terms used in the present invention have the same meaning as those commonly understood by those skilled in the art. The terms used in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood by specific circumstances.

[0048] Traditional distribution networks mainly adopt the AC power supply mode. With the gradual implementation of the national energy conservation and emission reduction strategy and the continuous advancement of related technologies, electric energy substitution and clean substitution have become the mainstream. DC power sources and DC loads such as photovoltaics are constantly increasing, the grid structure is becoming increasingly complex, and the multiple sources, loads and storage in the distribution system show characteristics such as nonlinearity and randomness. The distribution network form has been upgraded under the background of dual carbon.

[0049] If the AC power supply mode is still used, more converters will be needed, which is not conducive to the economic construction of the distribution network. The operating loss of the converter will also reduce the operating efficiency of the distribution network and increase the carbon emissions of the distribution network. At the same time, the penetration of distributed power sources and loads in various regions is inconsistent, the load rate is uneven in time and space, and the cross-regional power regulation capacity is insufficient. When a fault occurs, resources between regions cannot quickly support each other, which can easily expand the scope of the accident and reduce system reliability. Traditional AC distribution networks have become increasingly difficult to meet the electricity demand of diversified development. Connecting DC sources and loads to DC distribution networks to form AC and DC distribution networks can alleviate the above problems. Therefore, AC and DC networking is an important development direction for future power grids under the background of dual carbon.

[0050] There are four major advantages of flexible interconnection between different lines in AC / DC networking: First, it can optimize the grid structure, improve the flexibility of distributed renewable energy access, realize the coordinated and complementary consumption of multiple types of renewable energy and electric vehicles, and improve equipment utilization through flexible control of power electronics technology. Second, the DC distribution system can directly supply power to DC loads, reduce the AC-DC conversion link, effectively reduce the loss of power conversion, and improve energy utilization efficiency. Third, through the closed-loop operation of different AC power supply partitions or multiple AC lines in the multi-port flexible direct link, while effectively isolating the impact of various AC faults, it can realize the rapid switching of multiple power sources in the event of a fault, thereby improving the power supply reliability of the system. Fourth, compared with AC distribution, DC distribution has advantages in power supply radius, transmission capacity, operating efficiency, and reducing carbon emissions, which can solve the "bottleneck" problem of capacity expansion and transformation in old areas of some urban distribution networks.

[0051] The DC distribution network is interconnected with the existing AC distribution network through power electronic devices such as flexible interconnection switches (soft open point, SOP). Flexible interconnection switches are multifunctional power electronic devices installed at the position of traditional switches. Unlike traditional switch-type mechanical control, they control power electronic switches through active power and reactive power provided by converter terminals to control power flow. Replacing interconnection switches in distribution networks with flexible interconnection switches can balance feeder output, improve power flow distribution, reduce network losses, and increase voltage levels. Flexible interconnection switches can effectively reduce short-circuit currents by isolating DC lines and instantaneously controlling currents. The power control of flexible interconnection switches is more reliable, and real-time optimal control of distribution networks can be achieved. When a fault occurs, the fault recovery mode of the flexible interconnection switch is adopted, and the time for fault isolation and power restoration can be shortened in conjunction with distribution network protection.

[0052] At present, an embodiment of the present invention provides a flexible tie switch implementation device for integrating AC and DC networking. For details, please refer to Figure 1 , Figure 1 The figure shows a schematic diagram of a flexible contact switch implementation device in one embodiment of the present invention.

[0053] There are three main types of flexible tie switch implementation devices: back-to-back voltage source converters (B2B VSC), unified power flow controller (UPFC) and static series synchronous compensator (SSSC).

[0054] In actual application, in order to meet the needs of distribution networks in different situations, it is necessary to select the most suitable structure from different topologies. The main features of the three typical structures of flexible tie switches are shown in the following table.

[0055]

[0056]

[0057] To achieve interconnection between distribution networks, the key lies in the configuration of flexible interconnection switches, and the configuration strategy will change with the changes in the system's operating status and control objectives.

[0058] Considering the carbon reduction application background, the distribution network containing flexible interconnecting switches needs to have good power regulation capability, distributed power supply absorption capability, line loss optimization capability, fault isolation capability and carbon emission reduction capability. Therefore, the subsequent configuration method selects B2B-VSC flexible interconnecting switches as the main research object. The flexible interconnecting switch configuration method and system integrating AC / DC networking are mainly suitable for B2B-VSC flexible interconnecting switches.

[0059] The B2B-VSC flexible tie switch mainly includes the rotor-side converter, the grid-side converter, the DC bus and the control system. Its working principle and steps are as follows:

[0060] The rotor-side converter converts the AC power of the power grid into DC power and stores it in the DC bus; the grid-side converter converts the DC power in the DC bus into AC power suitable for grid access. The DC bus connects the two inverters and transmits the DC power generated by the rotor-side converter to the grid-side converter. The control system is mainly used to monitor and control the operation of the back-to-back converters, including the adjustment and protection of parameters such as current, voltage, and frequency.

[0061] An embodiment of the present invention provides a flexible tie switch configuration method for integrated AC / DC networking. For details, see Figure 2 , Figure 2 The figure shows a flow chart of a flexible tie switch configuration method for integrated AC / DC networking in one embodiment of the present invention, including:

[0062] S1: Obtain the topological structure data and load data of the distribution network and determine the corresponding objective functions under different scenarios;

[0063] S2: constructing a simulation model of the distribution network, performing a second-order cone analysis on the objective function, and obtaining feedback results under different scenarios;

[0064] S3: Perform reverse analysis on the feedback results to determine the flexible tie switch configuration strategies corresponding to different scenarios;

[0065] S4: In actual operation control of the distribution network, determining a scenario according to real-time operation status data of the distribution network;

[0066] S5: Execute a matching flexible tie switch configuration strategy according to the determined scenario.

[0067] In S1, the topological structure data and load data of the distribution network are obtained, and the topological structure data and load data are preprocessed. The preprocessing steps include topological structure verification and optimization, data cleaning and data transformation, etc. After the data is preprocessed, the corresponding objective functions under different scenarios are determined.

[0068] Based on the Monte Carlo algorithm, the topological structure data and load data of the distribution network are processed to obtain the flow sample data, and the simulation model of the distribution network is constructed with the flow sample data; the objective function is input into the simulation model to obtain feedback results under different scenarios.

[0069] The Monte Carlo algorithm simulates the probability distribution of a problem by generating a large number of random samples, and estimates the solution to the problem through statistical processing of these random samples.

[0070] The feedback results include current, voltage, power loss, switching frequency, etc.

[0071] The Newton-Raphson iteration method is used to calculate the feedback results to obtain the correction value of the state variables of the distribution network. The correction value is then reversely analyzed to determine the flexible interconnection switch configuration strategy corresponding to different scenarios.

[0072] The reverse analysis includes: power flow analysis, voltage stability analysis and network loss analysis.

[0073] Power flow analysis: Based on the collected data, reversely deduce the impact of the flexible contact switch on the power flow. Analyze the power transmission of the switch in different states, and the impact of the flexible contact switch action on the system power balance.

[0074] Voltage stability analysis: Evaluate the impact of flexible tie switches on system voltage stability. Through reverse analysis, determine how the switch configuration affects the voltage level at the node and how to improve voltage stability by adjusting the flexible tie switch configuration.

[0075] Network loss analysis: Analyze the impact of flexible contact switches on system network loss. Reversely deduce the network loss of flexible contact switches under different configurations and find the best configuration to reduce loss.

[0076] According to the results of reverse analysis, combined with the operation requirements and constraints of the distribution network, including the operation constraints of flexible tie switches, distribution network safety constraints, distribution network flow constraints and DG operation constraints, the flexible tie switch configuration strategies in different scenarios are determined. These strategies may include the opening or closing of switches, the switching order and time of switches, etc.

[0077] In the actual operation control of the distribution network, the scenario is determined according to the real-time operation status data of the distribution network; and the matching flexible interconnection switch configuration strategy is executed according to the determined scenario.

[0078] If the converter capacity of two branch nodes in the integrated AC / DC network is zero, the two branches are not equipped with flexible tie switches.

[0079] An embodiment of the present invention provides a flexible tie switch configuration system for integrating AC and DC networking. For details, see Figure 3 , Figure 3 The figure shows a schematic diagram of a flexible tie switch configuration system for integrated AC / DC networking in one embodiment of the present invention, including:

[0080] The acquisition module 11 is used to obtain the topological structure data and load data of the distribution network and determine the corresponding objective functions under different scenarios;

[0081] A construction module 12 is used to construct a simulation model of the distribution network, perform a second-order cone analysis on the objective function, and obtain feedback results under different scenarios;

[0082] A reverse module 13, used for performing reverse analysis on the feedback result to determine the flexible tie switch configuration strategy corresponding to different scenarios;

[0083] A determination module 14, used to determine a scenario according to real-time operation status data of the distribution network in actual operation control of the distribution network;

[0084] The execution module 15 is used to execute the matching flexible tie switch configuration strategy according to the determined scenario.

[0085] The above-mentioned embodiments only express several implementation methods of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the scope of the patent of the present invention. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A flexible tie switch configuration method for integrated AC / DC networking, characterized in that: include: Obtain the topological structure data and load data of the distribution network and determine the corresponding objective functions under different scenarios; Constructing a simulation model of the distribution network, performing a second-order cone analysis on the objective function, and obtaining feedback results under different scenarios; Performing reverse analysis on the feedback results to determine the flexible tie switch configuration strategies corresponding to different scenarios; In actual operation control of the distribution network, a scenario is determined based on real-time operation status data of the distribution network; The matching flexible contact switch configuration strategy is executed according to the determined scenario.

2. The flexible tie switch configuration method for integrated AC / DC networking according to claim 1, characterized in that: Before obtaining the topological structure data and load data of the target distribution network and determining the corresponding objective functions in different scenarios, the flexible tie switch configuration method for integrated AC / DC networking also includes: The topology data and the load data are preprocessed, and the preprocessing steps include topology verification and optimization, data cleaning and data transformation.

3. The flexible tie switch configuration method for integrated AC / DC networking according to claim 1, characterized in that: The simulation model of the distribution network is constructed, and a second-order cone analysis is performed on the objective function to obtain feedback results under different scenarios, including: Based on the Monte Carlo algorithm, the topological structure data and the load data of the distribution network are processed to obtain flow sample data, and a simulation model of the distribution network is constructed with the flow sample data; The objective function is input into the simulation model to obtain feedback results under different scenarios.

4. The flexible tie switch configuration method for integrated AC / DC networking according to claim 1, characterized in that: The reverse analysis of the feedback results to determine the flexible tie switch configuration strategies corresponding to different scenarios includes: The feedback result is calculated by using the Newton-Raphson iteration method to obtain the correction amount of the state variable of the distribution network, and the correction amount is further reversely analyzed to determine the flexible tie switch configuration strategy corresponding to different scenarios.

5. The flexible tie switch configuration method for integrated AC / DC networking according to claim 1, characterized in that: The flexible tie switch configuration method for integrating AC and DC networking also includes: If the converter capacity of two branch nodes in the integrated AC / DC network is zero, the two branches are not configured with flexible tie switches.

6. A flexible tie switch configuration system integrating AC and DC networking, characterized in that: include: The acquisition module is used to obtain the topological structure data and load data of the distribution network and determine the corresponding objective functions under different scenarios; A construction module is used to construct a simulation model of the distribution network, perform a second-order cone analysis on the objective function, and obtain feedback results under different scenarios; A reverse module, used for performing reverse analysis on the feedback results to determine the flexible tie switch configuration strategies corresponding to different scenarios; A determination module, used to determine a scenario according to real-time operation status data of the distribution network in actual operation control of the distribution network; The execution module is used to execute the matching flexible tie switch configuration strategy according to the determined scenario.

7. The flexible tie switch configuration system for integrated AC / DC networking according to claim 6, characterized in that: Before obtaining the topological structure data and load data of the target distribution network and determining the corresponding objective functions under different scenarios, the flexible tie switch configuration system for integrating AC and DC networking further includes: The preprocessing module is used to preprocess the topology data and the load data, wherein the preprocessing steps include topology verification and optimization, data cleaning and data transformation.

8. The flexible tie switch configuration system for integrated AC / DC networking according to claim 6, characterized in that: The simulation model of the distribution network is constructed, and a second-order cone analysis is performed on the objective function to obtain feedback results under different scenarios, including: Based on the Monte Carlo algorithm, the topological structure data and the load data of the distribution network are processed to obtain flow sample data, and a simulation model of the distribution network is constructed with the flow sample data; The objective function is input into the simulation model to obtain feedback results under different scenarios.

9. The flexible tie switch configuration system for integrated AC / DC networking according to claim 6, characterized in that: The reverse analysis of the feedback results to determine the flexible tie switch configuration strategies corresponding to different scenarios includes: The feedback result is calculated by using the Newton-Raphson iteration method to obtain the correction amount of the state variable of the distribution network, and the correction amount is further reversely analyzed to determine the flexible tie switch configuration strategy corresponding to different scenarios.

10. The flexible tie switch configuration system for integrated AC / DC networking according to claim 6, characterized in that: The flexible tie switch configuration system for integrating AC and DC networking also includes: The coordination module is used for not configuring flexible tie switches for the two branches if the converter capacity of the two branch nodes in the integrated AC / DC network is zero.

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