A method for calculating the feasible region of active-reactive-voltage regulation at a power distribution gateway.

Abstract

This invention relates to a method for calculating the feasible region of active-reactive-voltage regulation at a distribution network gateway. The method includes the following steps: acquiring basic operational data of the distribution network's internal system; constructing a static security model of the distribution network based on AC power flow equations; constraining the feasible region using the static security model; and calculating the feasible region based on the basic operational data of the distribution network's internal system using a feasible region identification algorithm based on convex hull expansion. The feasible region identification algorithm, after initializing the feasible region vertex set by selecting several main directions, continuously approximates the actual active-reactive-voltage regulation feasible region of the distribution network by outwardly translating the boundary of an existing approximate polyhedron, searching for new vertices of the feasible region, and updating the approximate polyhedron with the newly searched vertices. Compared with existing technologies, this invention can quickly and accurately determine the feasible region of active-reactive-voltage regulation in a distribution network.

Description

Technical Field

[0001] This invention relates to the field of power system dispatching and operation, and in particular to a method for calculating the feasible region of active-reactive-voltage regulation at the distribution gateway. Background Technology

[0002] With the rapid development and large-scale integration of various distributed resources such as distributed photovoltaics, wind power, small gas turbines, demand response resources, user-side energy storage, and electric vehicles, the power system landscape is being reshaped, and the power grid is transitioning from centralized to distributed. The traditional decoupled dispatch and operation mode of the transmission and distribution networks is no longer suitable for the output of distributed resources. Furthermore, the current wholesale electricity market only allows large-capacity generating units to participate, making it difficult for distributed resources within the distribution network to directly participate in electricity market competition and resource optimization, thus hindering the effective utilization of distributed resources. At the same time, the increased proportion of distributed energy within the distribution network also exacerbates the volatility and instability of the power system, potentially causing safety issues such as voltage exceeding limits and power flow congestion. Against this backdrop, how to efficiently aggregate distributed resources within the distribution network, enabling them to participate in optimized power system operation while simultaneously ensuring the safe and reliable operation of the distribution network, has become a pressing practical problem that needs to be solved in power system dispatch and operation and the development of distributed resources.

[0003] When participating in the optimal dispatching of the power system, a distribution network system containing distributed generation facilities can be considered equivalent to a power plant. It can adjust the active and reactive power output and voltage levels at the grid connection points based on dispatching instructions from the grid dispatching agency or the clearing results of the electricity spot market. This allows distributed resources within the distribution network to participate in the optimal operation of the power system and the optimal allocation of resources in the spot market. Treating the distribution network system as a traditional power plant participating in the optimization of the transmission system and the electricity spot market requires knowing the feasible range of active and reactive power output that the root nodes of the distribution network can provide. Existing literature has studied pricing strategies and methods for distributed resource participation in distribution network collaborative optimization, but these do not fully consider various safety constraints within the distribution network. Some methods have proposed a two-layer dispatching model for distributed resource participation in electricity market optimization that considers distribution network safety, but this model requires the assumption that the costs and physical parameters of other generation equipment are known, which cannot meet practical application needs. Other methods have studied mechanisms for utilizing the distribution network to provide reactive power support and auxiliary services, but they do not consider the variation in the allowable reactive power output range of the distribution network under different active power outputs. The paper "An Efficient Method for Estimating Capability Curve of Virtual Power Plant" calculates and characterizes the two-dimensional output feasible region of the distribution network (PQ) under the constraint of safe operation of the distribution network. However, it does not consider the output range of the voltage of the transmission-distribution network associated nodes, making it impossible to apply to the optimization scheduling process of the transmission network and the spot market. Since the power output and voltage levels of loads and distributed resources in the distribution system fluctuate, the output capacity of the distribution network is time-varying, requiring estimation of the adjustment feasible region of the distribution gateway in each scheduling interval.

[0004] Chinese patent CN118970953A discloses a method, apparatus, computer equipment, and storage medium for determining the feasible region of a microgrid. The method includes: acquiring basic operational data of the microgrid; constructing a static security constraint model of the microgrid based on operational constraints, distributed resource operational constraints, and distributed resource cost constraints determined from the basic operational data; constructing a power cost feasible region model of the microgrid using constraint aggregation theory based on the static security constraint model; and determining the power cost feasible region of the microgrid based on the feasible region model. However, this method uses a vertex enumeration algorithm to calculate the feasible region, resulting in low computational efficiency and low reliability of the results.

[0005] Therefore, a fast and accurate algorithm for estimating the feasible region of active-reactive-voltage regulation in distribution networks is needed to update it in a timely manner to support the safety, economy, and flexibility of optimized power system scheduling and operation. Summary of the Invention

[0006] The purpose of this invention is to overcome the shortcomings of the existing technology by providing a method for calculating the feasible region of active-reactive-voltage regulation at the distribution network gateway. This method aggregates the operational constraints of various distributed resources within the distribution network and the safety operation constraints of the distribution network into explicit constraints on the active, reactive, and voltage outputs of the root node of the distribution network. Through a feasible region identification algorithm based on convex hull expansion, the feasible region of active-reactive-voltage regulation of the distribution network that is allowed for safe operation can be characterized. This allows the distribution network to participate in the optimized scheduling and operation of the power system and the clearing of the electricity spot market, just like a synchronous generator. It also ensures that the scheduling and clearing results of the distribution network do not violate the internal safety operation constraints of the distribution network, which is beneficial to improving the safety, economy, and flexibility of power system operation.

[0007] The objective of this invention can be achieved through the following technical solutions: According to a first aspect of the present invention, a method for calculating the feasible region of active-reactive-voltage regulation at a power distribution gateway is provided, the method comprising the following steps: Obtain basic operational data of the internal system of the power distribution network; A static security model of the distribution network based on the AC power flow equation is constructed. The feasible region is constrained by the static security model of the distribution network. Based on the basic data of the internal system operation of the distribution network, the feasible region of active power-reactive power-voltage regulation of the distribution network is calculated by using a feasible region identification algorithm based on convex hull expansion. The feasible region identification algorithm initializes the set of feasible region vertices by selecting several main directions. It then continuously approximates the real feasible region of active power-reactive power-voltage regulation of the distribution network by translating the boundary of the existing approximate polyhedron outward, searching for new vertices of the feasible region, and updating the approximate polyhedron with the newly searched vertices.

[0008] The basic data for the operation of the distribution network internal system includes the distribution network connection topology, the conductance and susceptance parameters of distribution lines and transformers, the transmission capacity limit of distribution lines, the upper and lower limits of node voltages allowed for safe operation, the upper and lower limits of active and reactive power output of distributed power sources within the distribution network and their changes in power generation over time, and the active and reactive load forecasts of load nodes within the distribution network and their changes in demand over time.

[0009] The static security model of the distribution network includes power flow equations for distribution lines, power balance equations for distribution network nodes, power flow constraints on distribution lines and transformers, voltage constraints on distribution network nodes, and output range constraints on distributed generation nodes.

[0010] The power flow equation for the distribution line is: , , In the formula, , They are nodesi and nodes j The active and reactive power flow of the distribution lines between them; , They are nodes i and nodes j The series susceptance and series conductance of the power distribution circuit between them; , They are nodes i and nodes j The voltage amplitude; For nodes i and nodes j The voltage phase angle difference; It is a set of node numbers. Represents nodes i A set of node numbers that are directly connected by power distribution lines.

[0011] The power balance equations for the distribution network nodes are as follows: , , In the formula, , These are nodes i The active and reactive power outputs of distributed generation, , These are nodes i Active and reactive loads, , These are the active and reactive power outputs of the power distribution network. It is the set of node numbers that are directly connected to the root node via power distribution lines. , These are nodes j The active and reactive power flow of the distribution lines between the root node and the main node.

[0012] The power flow constraints on the distribution lines and transformers are as follows: , In the formula, , These are the apparent power transmission limits for the distribution line ij and the distribution transformer, respectively.

[0013] The voltage constraint condition for the distribution network nodes is as follows: , In the formula, , They are nodes i The upper and lower limits of the permissible voltage amplitude. For nodes ivoltage amplitude, It is a set of node numbers.

[0014] The output range constraint of the distributed generation node is as follows: , In the formula, , These are nodes i The upper and lower limits of active power output of distributed generation. , These are nodes i The upper and lower limits of reactive power output of distributed generation. , These are nodes i The active and reactive power outputs of distributed generation, It is a set of node numbers.

[0015] The constraint of the feasible region based on the static security model of the distribution network specifically includes: Based on the static security model of the distribution network, a certain security concept is determined. Feasible domain of static security constraints for distribution networks F ,Right now: F , in, , , , They are respectively based on , , , A vector of elements. For nodes i voltage amplitude, For nodes i voltage phase angle, , These are nodes i The active and reactive power outputs of distributed generation, These are the active and reactive power outputs of the distribution network, respectively. Based on the feasible region of the static security constraints of the distribution network, the variables are eliminated. Only retain variables Determine the feasible region Ω for active-reactive-voltage regulation of the distribution network: Ω , in, This refers to the root node voltage of the distribution network; The above formula represents any set of power output conditions of the distribution network within the feasible region Ω of active power-reactive power-voltage regulation. There exists at least one set This makes this set of variables It belongs to the feasible region of static security constraints of the distribution network .

[0016] The feasible region identification algorithm based on convex hull expansion performs the following steps: 3-1) Data Acquisition and Input: Obtain basic operational data of the distribution network system and the error limits of the pre-set feasible domain for active-reactive-voltage regulation of the distribution network. ; 3-2) Initialization of vertex set and convex hull: Selecting in three-dimensional space , , , , , , A total of 8 main directions were used to explore the feasible domains for active power-reactive power-voltage regulation in the distribution network. The vertex calculation completes the initialization of the feasible region vertex set and the feasible region approximate polyhedron. The initial vertices are calculated by solving the following optimization problem: , , in, These are the active and reactive power outputs of the power distribution network. The root node voltage of the distribution network. , , , They are respectively based on , , , A vector of elements. For nodes i voltage amplitude, For nodes i voltage phase angle, , These are nodes i The active and reactive power outputs of distributed generation, F For the feasible region of static security constraints of the distribution network, These are the optimization coefficients for active power, reactive power, and voltage in the distribution network, respectively, with values ​​of 1 or -1. This constitutes the combination of coefficients of the objective function for the optimization problem, which take values ​​sequentially. , , , , , , ; The optimization problem is solved by a nonlinear optimization algorithm or by calling a nonlinear optimization solver, and the optimal solution to the corresponding optimization problem is denoted as . That is, the first m 1 initial vertex; form a set of initial vertices. And initialize the set of feasible region vertices to The set of equations for each boundary of the polyhedron formed by the initial vertices is denoted as the boundary set to be searched. ;right The average value is calculated from the middle vertex. ; 3-3) Initialize the newly added boundary set It is an empty set, that is ; 3-4) Search the feasible region for active-reactive-voltage regulation of the distribution network. The process of finding new vertices and updating the approximate polyhedron includes vertex search, convex hull update, and boundary set determination, as detailed below: 3-4-1) Perform convex hull expansion: by translating the boundary set to be searched outwards. Boundary search Boundary points; for the boundary set to be searched The first in k There are several boundaries, and the equation of each boundary is: The computational model for vertex search is as follows: , , in, , , These are the boundary sets to be searched. The Middle k The coefficients of active power, reactive power, and voltage in the boundary equations of the distribution network. The boundary set to be searched The Middle k The constant coefficients in the boundary equations of each boundary; The computational model for the vertex search described above is solved using a nonlinear optimization algorithm or by calling a nonlinear optimization solver. The optimal solution is denoted as... The optimal value is denoted as The improvement amount is calculated using the following formula: , 3-4-2) Update the vertex set: Add the vertices represented by the calculated optimal solution to the feasible region vertex set. ,Right now ; 3-4-3) Determine whether the newly added boundary set needs to be updated: if Calculate separately and , Equation of a given straight line , Add it to the new boundary set ,Right now Otherwise, do not update the newly added boundary set; 3-5) Determine whether the boundary set to be searched has been traversed. All boundaries: If it has not yet been traversed If the boundary is reached, then return to step 3-4-1 and use... The first in k +1 boundary to perform vertex search; otherwise, jump to steps 3-6). 3-6) Determine if the algorithm has terminated: After performing vertex search on all boundary equations, determine Whether the set is empty is used to determine whether the algorithm terminates. if The boundary set to be searched Updated to ,Right now And return to step 3-3) for the updated Vertex search is performed on the boundary of the boundary; if If the vertex set fails to reach its maximum value, the algorithm terminates; at this point, the vertex set... The polyhedron determined by the vertices in the calculation results is the feasible region for active-reactive-voltage regulation of the distribution network.

[0017] According to a second aspect of the present invention, an electronic device is provided, including a memory and a processor, wherein the memory stores a computer program, and the processor executes the program to implement the method described thereon.

[0018] According to a third aspect of the present invention, a computer-readable storage medium is provided having a computer program stored thereon, which, when executed by a processor, implements the method described thereon.

[0019] Compared with the prior art, the present invention has the following beneficial effects: (1) This invention aggregates the operational constraints of various distributed resources in the distribution network and the safe operation constraints of the distribution network into explicit constraints on the active power, reactive power output and voltage level of the distribution network, and describes the feasible domain of active power-reactive power-voltage regulation of the distribution network that is allowed for safe operation. This allows the distribution network containing distributed resources to participate in the power system optimization scheduling and power spot market clearing like a synchronous generator. It can ensure that the scheduling and clearing results of the distribution network will not violate the safe operation constraints, which is conducive to improving the safety, economy and flexibility of the power system operation.

[0020] (2) This invention employs a convex hull-based identification method to calculate the feasible region of active-reactive-voltage regulation in a distribution network. It first calculates the vertices of the feasible region and constructs a convex hull accordingly, then gradually covers the entire feasible region through boundary expansion. Compared to other polyhedral projection algorithms, the convex hull-based feasible region identification method requires lower computational complexity, faster computation time, and higher computational efficiency, thus meeting the real-time operation requirements of the distribution network system. Attached Figure Description

[0021] Figure 1 This is a flowchart of the method of the present invention; Figure 2 This is a flowchart of a feasible region identification algorithm based on convex hull expansion. Detailed Implementation

[0022] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0023] Unless otherwise defined, the technical or scientific terms used in this application shall have the ordinary meaning understood by one of ordinary skill in the art to which this application pertains. The terms “a,” “an,” “an,” “the,” and similar words used in this application do not indicate quantity limitation and may indicate singular or plural. The terms “comprising,” “including,” “having,” and any variations thereof used in this application are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or device that includes a series of steps or modules (units) is not limited to the listed steps or units, but may also include steps or units not listed, or may include other steps or units inherent to these processes, methods, products, or devices. The terms “connected,” “linked,” “coupled,” and similar words used in this application are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. “Multiple” used in this application refers to two or more. “And / or” describes the relationship between related objects, indicating that three relationships may exist; for example, “A and / or B” can represent: A alone, A and B simultaneously, and B alone. The character " / " generally indicates that the preceding and following objects are in an "or" relationship. The terms "first," "second," and "third" used in this application are merely to distinguish similar objects and do not represent a specific ordering of the objects.

[0024] Example 1 This embodiment provides a method for calculating the feasible region of active-reactive-voltage regulation at a power distribution gateway interface. The method includes the following steps: 1) Obtain basic data on the operation of the internal system of the power distribution network.

[0025] In this embodiment, the basic data for the operation of the distribution network internal system includes the distribution network connection topology, the conductance and susceptance parameters of distribution lines and transformers, the transmission capacity limit of distribution lines, the upper and lower limits of node voltages allowed for safe operation, the upper and lower limits of active and reactive power output of distributed power sources within the distribution network and their power generation changes over time, and the active and reactive load forecasts of load nodes within the distribution network and their demand changes over time.

[0026] 2) Construct a static security model of the distribution network based on the AC power flow equation, and constrain the feasible region with the static security model of the distribution network.

[0027] The static security model of the distribution network includes the power flow equations of the distribution lines, the power balance equations of the distribution network nodes, the power flow constraints on the distribution lines and transformers, the voltage constraints on the distribution network nodes, and the output range constraints of the distributed generation nodes.

[0028] Based on the feasible region of the static security constraints of the distribution network, the feasible region of active-reactive-voltage regulation at the distribution gateway is determined, specifically including: Based on the static security model of the distribution network, a certain security concept is determined. Feasible domain of static security constraints for distribution networks F ,Right now: F , in, , , , They are respectively based on , , , A vector of elements. For nodes i voltage amplitude, For nodes i voltage phase angle, , These are nodes i The active and reactive power outputs of distributed generation, These are the active and reactive power outputs of the distribution network; and the feasible region of the static security constraints of the distribution network. F It contains information on all variables within the distribution network.

[0029] Based on the feasible region of the static security constraints of the distribution network, the variables are eliminated. Only retain variables The feasible region Ω for active-reactive-voltage regulation of the distribution network can be determined: Ω , in, This is the root node voltage of the distribution network.

[0030] The above formula represents any set of power output conditions of the distribution network within the feasible region Ω of active power-reactive power-voltage regulation. There exists at least one set This makes this set of variables It belongs to the feasible region of static security constraints of the distribution network .

[0031] The feasible region for active-reactive-voltage regulation of the distribution network realizes the inclusion of all variables related to the distribution network. The safety operation constraints are projected onto variables only related to the root node variables of the distribution network. In the low-dimensional space, the internal state variables of the distribution network are eliminated. and internal decision variables , , This reduces the amount of information that needs to be transmitted for interaction between power transmission and distribution networks. The feasible region Ω for active-reactive-voltage regulation in a distribution network is a bounded region in three-dimensional space. This model aggregates the operational constraints of various distributed resources within the distribution network, as well as the safety constraints of the distribution network, into a feasible region concerning the active and reactive power outputs and the root node voltage of the distribution network. This ensures that any constraint-satisfied operation... Distribution network output status All of these can be executed by the power distribution system without violating static safety constraints.

[0032] 3) Based on the basic data of the internal system operation of the distribution network, the feasible region identification algorithm based on convex hull expansion is used to calculate the active-reactive-voltage regulation feasible region of the distribution gateway. The feasible region identification algorithm initializes the feasible region vertex set by selecting several main directions, and then continuously approximates the real active-reactive-voltage regulation feasible region of the distribution network by translating the boundary of the existing approximate polyhedron outward, searching for new vertices of the feasible region, and using the newly searched vertices to update the approximate polyhedron.

[0033] like Figure 2 As shown, the feasible region identification algorithm based on convex hull expansion performs the following steps: 3-1) Data Acquisition and Input: Obtain basic operational data of the distribution network system and the error limits of the pre-set feasible domain for active-reactive-voltage regulation of the distribution network. (Typical values ​​range from 0.01 to 0.05, and can be set according to the required accuracy of the calculation). 3-2) Initialization of vertex set and convex hull: Selecting in three-dimensional space , , , , , , A total of 8 main directions were used to explore the feasible domains for active power-reactive power-voltage regulation in the distribution network. The vertex calculation completes the initialization of the feasible region vertex set and the feasible region approximate polyhedron. The initial vertices are calculated by solving the following optimization problem: , , in, These are the optimization coefficients for active power, reactive power, and voltage in the distribution network, respectively, with values ​​of 1 or -1. This constitutes the combination of coefficients of the objective function for the optimization problem, which take values ​​sequentially. , , , , , , ; The optimization problem is solved using a nonlinear optimization algorithm (such as the primal-dual interior-point method) or by calling a nonlinear optimization solver (such as IPOPT), and the optimal solution to the corresponding optimization problem is obtained, denoted as . That is, the first m 1 initial vertex; form a set of initial vertices. And initialize the set of feasible region vertices to The set of equations for each boundary of the polyhedron formed by the initial vertices is denoted as the boundary set to be searched. ;right The average value is calculated from the middle vertex. ; 3-3) Initialize the newly added boundary set It is an empty set, that is ; 3-4) Search the feasible region for active-reactive-voltage regulation of the distribution network. The process of finding new vertices and updating the approximate polyhedron includes vertex search, convex hull update, and boundary set determination, as detailed below: 3-4-1) Perform convex hull expansion: by translating the boundary set to be searched outwards. Boundary search Boundary points; for the boundary set to be searched The first in k There are several boundaries, and the equation of each boundary is: The computational model for vertex search is as follows: , , in, , , These are the boundary sets to be searched. The Middle k The coefficients of active power, reactive power, and voltage in the boundary equations of the distribution network. The boundary set to be searched The Middle k The constant coefficients in the boundary equations of each boundary; The computational model for the vertex search described above is solved using a nonlinear optimization algorithm or by calling a nonlinear optimization solver. The optimal solution is denoted as... The optimal value is denoted as The improvement amount is calculated using the following formula: , 3-4-2) Update the vertex set: Add the vertices represented by the calculated optimal solution to the feasible region vertex set. ,Right now ; 3-4-3) Determine whether the newly added boundary set needs to be updated: if Calculate separately and , Equation of a given straight line , Add it to the new boundary set ,Right now Otherwise, do not update the newly added boundary set; 3-5) Determine whether the boundary set to be searched has been traversed. All boundaries: If it has not yet been traversed If the boundary is reached, then return to step 3-4-1 and use... The first in k +1 boundary to perform vertex search; otherwise, jump to steps 3-6). 3-6) Determine if the algorithm has terminated: After performing vertex search on all boundary equations, determine Whether the set is empty is used to determine whether the algorithm terminates. if The boundary set to be searched Updated to ,Right now And return to step 3-3) for the updated Vertex search is performed on the boundary of the boundary; if If the vertex set fails to reach its maximum value, the algorithm terminates; at this point, the vertex set... The polyhedron defined by the vertices in the equation represents the calculated feasible region of active-reactive-voltage regulation for the distribution network. The boundary inequalities of this polyhedron are the linear inequality constraints characterizing the feasible region of active-reactive-voltage regulation at the distribution gateway.

[0034] Example 2 This embodiment, based on Embodiment 1, provides a specific implementation method for the static security model of the distribution network. Among them, The power flow equations for the distribution lines are: , , In the formula, , They are nodes i and nodes j The active and reactive power flow of the distribution lines between them; , They are nodes i and nodesj The series susceptance and series conductance of the power distribution circuit between them; , They are nodes i and nodes j The voltage amplitude; For nodes i and nodes j The voltage phase angle difference; It is a set of node numbers. Represents nodes i A set of node numbers that are directly connected by power distribution lines.

[0035] The power balance equations for distribution network nodes are as follows: , , In the formula, , These are nodes i The active and reactive power outputs of distributed generation, , These are nodes i Active and reactive loads, , These are the active and reactive power outputs of the power distribution network. It is the set of node numbers that are directly connected to the root node via power distribution lines. , These are nodes j The active and reactive power flow of the distribution lines between the root node and the main node.

[0036] The power flow constraints for distribution lines and transformers are as follows: , In the formula, , These are the apparent power transmission limits for the distribution line ij and the distribution transformer, respectively.

[0037] The voltage constraint conditions for distribution network nodes are: , In the formula, , They are nodes i The upper and lower limits of the permissible voltage amplitude.

[0038] The output range constraints of distributed generation nodes are as follows: , In the formula, , These are nodes iThe upper and lower limits of active power output of distributed generation. , These are nodes i The upper and lower limits of reactive power output of distributed generation.

[0039] Example 3 The electronic device of this invention includes a central processing unit (CPU), which can perform various appropriate actions and processes according to computer program instructions stored in read-only memory (ROM) or loaded from a storage unit into random access memory (RAM). The RAM may also store various programs and data required for device operation. The CPU, ROM, and RAM are interconnected via a bus. Input / output (I / O) interfaces are also connected to the bus.

[0040] Multiple components in the device are connected to the I / O interface, including: input units such as keyboards and mice; output units such as various types of displays and speakers; storage units such as disks and optical discs; and communication units such as network interface cards (NICs), modems, and wireless transceivers. The communication unit allows the device to exchange information / data with other devices through computer networks such as the Internet and / or various telecommunications networks.

[0041] The processing unit executes the various methods and processes described above, such as method steps 1)-3). For example, in some embodiments, method steps 1)-3) may be implemented as a computer software program tangibly contained in a machine-readable medium, such as a storage unit. In some embodiments, part or all of the computer program may be loaded and / or installed on the device via ROM and / or a communication unit. When the computer program is loaded into RAM and executed by the CPU, one or more steps of method steps 1)-3) described above may be performed. Alternatively, in other embodiments, the CPU may be configured to execute method steps 1)-3) by any other suitable means (e.g., by means of firmware).

[0042] The functions described above in this document can be performed, at least in part, by one or more hardware logic components. For example, exemplary types of hardware logic components that can be used, without limitation, include: Field Programmable Gate Arrays (FPGAs), Application-Specific Integrated Circuits (ASICs), Application Standard Products (ASSPs), System-on-Chip (SoCs), Complex Programmable Logic Devices (CPLDs), and so on.

[0043] The program code used to implement the methods of the present invention can be written in any combination of one or more programming languages. This program code can be provided to a processor or controller of a general-purpose computer, special-purpose computer, or other programmable data processing device, such that when executed by the processor or controller, the program code causes the functions / operations specified in the flowcharts and / or block diagrams to be implemented. The program code can be executed entirely on the machine, partially on the machine, as a standalone software package partially on the machine and partially on a remote machine, or entirely on a remote machine or server.

[0044] In the context of this invention, a machine-readable medium can be a tangible medium that may contain or store a program for use by or in conjunction with an instruction execution system, apparatus, or device. A machine-readable medium can be a machine-readable signal medium or a machine-readable storage medium. Machine-readable media can include, but are not limited to, electronic, magnetic, optical, electromagnetic, infrared, or semiconductor systems, apparatus, or devices, or any suitable combination of the foregoing. More specific examples of machine-readable storage media include electrical connections based on one or more wires, portable computer disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fibers, portable compact disk read-only memory (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination of the foregoing.

[0045] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in the present invention, and these modifications or substitutions should all be covered within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A method for calculating the feasible region of active-reactive-voltage regulation at a power distribution gateway, characterized in that, The method includes the following steps: Obtain basic operational data of the internal system of the power distribution network; A static security model of the distribution network based on the AC power flow equation is constructed. The feasible region is constrained by the static security model of the distribution network. Based on the basic data of the internal system operation of the distribution network, the feasible region of active power-reactive power-voltage regulation of the distribution network is calculated by using a feasible region identification algorithm based on convex hull expansion. The feasible region identification algorithm initializes the set of feasible region vertices by selecting several main directions. It then continuously approximates the real feasible region of active power-reactive power-voltage regulation of the distribution network by translating the boundary of the existing approximate polyhedron outward, searching for new vertices of the feasible region, and updating the approximate polyhedron with the newly searched vertices.

2. The method for calculating the feasible region of active-reactive-voltage regulation at a power distribution gateway interface according to claim 1, characterized in that, The basic data for the operation of the distribution network internal system includes the distribution network connection topology, the conductance and susceptance parameters of distribution lines and transformers, the transmission capacity limit of distribution lines, the upper and lower limits of node voltages allowed for safe operation, the upper and lower limits of active and reactive power output of distributed power sources within the distribution network and their changes in power generation over time, and the active and reactive load forecasts of load nodes within the distribution network and their changes in demand over time.

3. The method for calculating the feasible region of active-reactive-voltage regulation at a power distribution gateway interface according to claim 1, characterized in that, The static security model of the distribution network includes power flow equations for distribution lines, power balance equations for distribution network nodes, power flow constraints on distribution lines and transformers, voltage constraints on distribution network nodes, and output range constraints on distributed generation nodes.

4. The method for calculating the feasible region of active-reactive-voltage regulation at a power distribution gateway interface according to claim 3, characterized in that, The power flow equation for the distribution line is: ， ， In the formula, , They are nodes i and nodes j The active and reactive power flow of the distribution lines between them; , They are nodes i and nodes j The series susceptance and series conductance of the power distribution circuit between them; , They are nodes i and nodes j The voltage amplitude; For nodes i and nodes j The voltage phase angle difference; It is a set of node numbers. Represents nodes i A set of node numbers that are directly connected by power distribution lines.

5. The method for calculating the feasible region of active-reactive-voltage regulation at a power distribution gateway interface according to claim 4, characterized in that, The power balance equations for the distribution network nodes are as follows: ， ， In the formula, , These are nodes i The active and reactive power outputs of distributed generation, , These are nodes i Active and reactive loads, , These are the active and reactive power outputs of the power distribution network. It is the set of node numbers that are directly connected to the root node via power distribution lines. , These are nodes j The active and reactive power flow of the distribution lines between the root node and the main node.

6. The method for calculating the feasible region of active-reactive-voltage regulation at a power distribution gateway interface according to claim 5, characterized in that, The power flow constraints on the distribution lines and transformers are as follows: ， In the formula, , These are the apparent power transmission limits for the distribution line ij and the distribution transformer, respectively.

7. The method for calculating the feasible region of active-reactive-voltage regulation at a power distribution gateway interface according to claim 4, characterized in that, The voltage constraint condition for the distribution network nodes is as follows: ， In the formula, , They are nodes i The upper and lower limits of the permissible voltage amplitude. For nodes i voltage amplitude, It is a set of node numbers.

8. The method for calculating the feasible region of active-reactive-voltage regulation at a power distribution gateway interface according to claim 3, characterized in that, The output range constraint of the distributed generation node is as follows: ， In the formula, , These are nodes i The upper and lower limits of active power output of distributed generation. , These are nodes i The upper and lower limits of reactive power output of distributed generation. , These are nodes i The active and reactive power outputs of distributed generation, It is a set of node numbers.

9. The method for calculating the feasible region of active-reactive-voltage regulation at a power distribution gateway interface according to claim 1, characterized in that, The constraint of the feasible region based on the static security model of the distribution network specifically includes: Based on the static security model of the distribution network, a certain security concept is determined. Feasible domain of static security constraints for distribution networks Φ ,Right now: Φ ， in, , , , They are respectively based on , , , A vector of elements. For nodes i voltage amplitude, For nodes i voltage phase angle, , These are nodes i The active and reactive power outputs of distributed generation, These are the active and reactive power outputs of the distribution network, respectively. Based on the feasible region constrained by the static security model of the distribution network, the variables are eliminated. Only retain variables Determine the feasible region Ω for active-reactive-voltage regulation of the distribution network: Oh , in, This refers to the root node voltage of the distribution network; The above formula represents any set of power output conditions of the distribution network within the feasible region Ω of active power-reactive power-voltage regulation. There exists at least one This makes this set of variables It belongs to the feasible region of static security constraints of the distribution network .

10. The method for calculating the feasible region of active-reactive-voltage regulation at a power distribution gateway interface according to claim 1, characterized in that, The feasible region identification algorithm based on convex hull expansion performs the following steps: 3-1) Data Acquisition and Input: Obtain basic operational data of the distribution network system and the error limits of the pre-set feasible domain for active-reactive-voltage regulation of the distribution network. ; 3-2) Initialization of vertex set and convex hull: Select in three-dimensional space , , , , , , A total of 8 main directions were used to explore the feasible domains for active power-reactive power-voltage regulation in the distribution network. The vertex calculation completes the initialization of the feasible region vertex set and the feasible region approximate polyhedron. The initial vertices are calculated by solving the following optimization problem: ， ， in, These are the active and reactive power outputs of the power distribution network. The root node voltage of the distribution network. , , , They are respectively based on , , , A vector of elements. For nodes i voltage amplitude, For nodes i voltage phase angle, , These are nodes i The active and reactive power outputs of distributed generation, Φ For the feasible region of static security constraints of the distribution network, These are the optimization coefficients for active power, reactive power, and voltage in the distribution network, respectively, with values ​​of 1 or -1. This constitutes the combination of coefficients of the objective function for the optimization problem, which take values ​​sequentially. , , , , , , ; The optimization problem is solved by a nonlinear optimization algorithm or by calling a nonlinear optimization solver, and the optimal solution to the corresponding optimization problem is denoted as . That is, the first m 1 initial vertex; form a set of initial vertices. And initialize the set of feasible region vertices to The set of equations for each boundary of the polyhedron formed by the initial vertices is denoted as the boundary set to be searched. ;right The average value is calculated from the middle vertex. ; 3-3) Initialize the newly added boundary set It is an empty set, that is ; 3-4) Search the feasible region for active-reactive-voltage regulation of the distribution network. The process of finding new vertices and updating the approximate polyhedron includes vertex search, convex hull update, and boundary set determination, as detailed below: 3-4-1) Perform convex hull expansion: by translating the boundary set to be searched outwards. Boundary search Boundary points; for the boundary set to be searched The first in k There are several boundaries, and the equation of each boundary is: The computational model for vertex search is as follows: ， ， in, , , These are the boundary sets to be searched. The Middle k The coefficients of active power, reactive power, and voltage in the boundary equations of the distribution network. The boundary set to be searched The Middle k The constant coefficients in the boundary equations of each boundary; The computational model for the vertex search described above is solved using a nonlinear optimization algorithm or by calling a nonlinear optimization solver. The optimal solution is denoted as... The optimal value is denoted as The improvement amount is calculated using the following formula: ， 3-4-2) Update the vertex set: Add the vertices represented by the calculated optimal solution to the feasible region vertex set. ,Right now ; 3-4-3) Determine whether the newly added boundary set needs to be updated: if Calculate separately and , Equation of a given straight line , Add it to the new boundary set ,Right now Otherwise, do not update the newly added boundary set; 3-5) Determine whether the boundary set to be searched has been traversed. All boundaries: If it has not yet been traversed If the boundary is reached, then return to step 3-4-1 and use... The first in k +1 boundary to perform vertex search; otherwise, jump to steps 3-6). 3-6) Determine if the algorithm has terminated: After performing vertex search on all boundary equations, determine Whether the set is empty is used to determine whether the algorithm terminates. if The boundary set to be searched Updated to ,Right now And return to step 3-3) for the updated Vertex search is performed on the boundary of the boundary; if If the vertex set fails to reach its maximum value, the algorithm terminates; at this point, the vertex set... The polyhedron determined by the vertices in the calculation results is the feasible region for active-reactive-voltage regulation of the distribution network.

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