Power grid reactive compensation method and system based on unbalanced electric quantity of bus

Abstract

The invention discloses a bus unbalanced electric quantity-based power grid reactive compensation method and system, and the method comprises the steps: building a power grid power flow model based on the photovoltaic, energy storage and load data of an access bus, and obtaining the power output of each assembly under different conditions; constructing a multi-objective optimization model based on the power output relationship of each component under different conditions; and calculating and solving the multi-target optimization model to obtain the minimum operation cost of the power grid under the multi-target operation condition so as to perform optimal scheduling. By optimizing reactive compensation of the power grid, effective utilization of photovoltaic resources can be promoted, safe and stable operation of the power grid is guaranteed, and maximization of economic benefits is achieved.

Description

Technical Field

[0001] This invention relates to the technical field of reactive power compensation for power grids, and in particular to a method and system for reactive power compensation for power grids based on unbalanced bus power. Background Technology

[0002] Modern photovoltaic (PV) inverters, leveraging flexible control technology, possess a certain degree of reactive power regulation capability. By controlling the output and absorption of reactive power, they regulate voltage amplitude, opening up a new dimension of collaborative control for traditional voltage regulation equipment. Meanwhile, in the actual operation of distribution networks, bus power imbalance frequently occurs. How to comprehensively consider the output of PV devices and the bus power imbalance, and precisely regulate PV output and power purchase based on actual needs to ensure that the bus voltage remains within a safe range, has become crucial for ensuring the safe and stable operation of the distribution network.

[0003] Currently, most studies treat the reactive power provided by photovoltaic (PV) power generation as an obligation rather than a tradable commodity. While this approach effectively regulates PV output and encourages its participation in distribution network voltage regulation, it harms the interests of PV owners, potentially making them unwilling to contribute PV resources for regulation. Therefore, to fully tap the potential of PV resources and incentivize their reactive power contribution, it is necessary to conduct cost modeling for the reactive power provided by PV resources. Based on this, and considering the costs of PV resource participation in regulation, a reactive power regulation model that fits the realities of the electricity market can be constructed. In the actual operation of the distribution network, the three objectives of minimizing network losses, minimizing voltage deviation, and minimizing three-phase imbalance are conflicting and mutually exclusive, but all are necessary goals to be achieved in the actual operation of the distribution network. Therefore, balancing the trade-offs between these objectives and finding a compromise solution to maximize benefits is of practical significance. Summary of the Invention

[0004] In view of the aforementioned existing problems, this invention is proposed. Therefore, this invention provides a power grid reactive power compensation method and system based on bus imbalance power to solve the problem of photovoltaic resource allocation caused by the increasing photovoltaic penetration rate.

[0005] To solve the above-mentioned technical problems, the present invention provides the following technical solution:

[0006] In a first aspect, embodiments of the present invention provide a power grid reactive power compensation method based on bus unbalanced power, including: establishing a power grid power flow model based on photovoltaic, energy storage and load data connected to the bus, and obtaining the power output of each component under different conditions;

[0007] Based on the power output relationship of each component under different conditions, a multi-objective optimization model is constructed;

[0008] The multi-objective optimization model is calculated and solved to obtain the minimum operating cost under the multi-objective operating conditions of the power grid, so as to carry out optimal scheduling.

[0009] As a preferred embodiment of the power grid reactive power compensation based on bus unbalanced power as described in this invention, the power grid power flow model established based on photovoltaic, energy storage and load data connected to the bus includes: power transmission lines from node j to other child nodes k, and power transmission lines from node i to node j.

[0010] The power transmission line transmits active power P ij and reactive power Q ij The resistance and reactance of the power transmission line are r and r, respectively. ij and x ij Node j connects multiple photovoltaic devices, energy storage devices, and loads.

[0011] As a preferred embodiment of the reactive power compensation of the power grid based on the unbalanced power of the bus as described in this invention, the following is included before constructing a multi-objective optimization model based on the power output relationship of each component under different conditions: establishing a cost model for reactive power compensation of the power grid based on the actual output status of photovoltaics and the unbalanced power of the bus, combined with other operating costs; the cost model takes minimizing the voltage safety cost and the voltage regulation economic cost as the objective function, and power constraints as the constraint condition.

[0012] As a preferred embodiment of the reactive power compensation of the power grid based on the unbalanced power of the busbar as described in this invention, the multi-objective optimization model is constructed based on the power output relationship of each component under different conditions, including: based on the cost model, introducing network loss cost and three-phase unbalance cost to construct a multi-objective optimization model; the network loss cost is calculated based on the current between branches in the distribution network and the cost coefficient corresponding to the unit network loss, and the three-phase unbalance cost is determined based on the three-phase voltage difference corresponding to the node and the cost coefficient corresponding to the unit three-phase unbalance degree.

[0013] As a preferred embodiment of the reactive power compensation of the power grid based on bus imbalance described in this invention, the cost model is expressed as follows:

[0014] minωC stable +(1-ω)C pay

[0015] P G,m,o ≥P G,m

[0016] P G,m,min ≤P G,m ≤P G,m,max

[0017] Among them, PG,m To output active power, P G,m,o P is the active power output when no reactive power is provided. G,m,min and P G,m,max To output the minimum and maximum active power, C stable and C pay These represent voltage safety cost and voltage regulation economic cost, respectively, with ω being the cost coefficient.

[0018] The beneficial effects of this preferred technical solution are that by focusing on the economic operation of the power system, emphasizing the safety and stability of the power grid, and obtaining the most effective operation strategy, the power grid can achieve the goal of economic operation while ensuring safety and stability.

[0019] As a preferred embodiment of the reactive power compensation for power grids based on bus imbalance described in this invention, the objective function of the multi-objective optimization model is expressed as:

[0020] minω1C stable +ω2C pay +ω3C loss +ω4C unbalance

[0021] ω1+ω2+ω3+ω4=1

[0022]

[0023] Among them, C loss and C unbalance For network loss cost and three-phase imbalance cost, δ is the cost coefficient corresponding to unit network loss, I ij V represents the current between branches ij in the distribution network. A V B and V C Let ε be the three-phase voltage corresponding to the node, and ε be the cost coefficient corresponding to a unit three-phase unbalance.

[0024] As a preferred embodiment of the reactive power compensation of the power grid based on the unbalanced power of the bus as described in this invention, the multi-objective optimization model further includes: establishing a constraint model including voltage based on the actual distribution network structure and power flow constraints;

[0025] The constraint model is represented as:

[0026]

[0027] V i,min ≤V i ≤V i,max

[0028] k G,m,1 +k G,m,2 =1

[0029] k ES,n,1 +k ES,n,2 =1

[0030] Among them, S G,m and S ES,n P represents the apparent power of photovoltaic device m and energy storage device n, respectively. ES,n and Q ES,n P represents the active power output and reactive power output of energy storage device n, respectively. G,m and Q G,m These represent the active power output and reactive power output of the photovoltaic device m, respectively, V i,min and V i,max These represent the minimum and maximum voltage values ​​for the corresponding bus, k. G,m,1 and k G,m,2 k is used to describe the different operating modes of photovoltaic device m. ES,n,1 and k ES,n,2 Used to describe the different operating modes of energy storage device n.

[0031] The beneficial effects of this preferred technical solution are that the constraints ensure that the photovoltaic device and energy storage device will not exceed their apparent power limits when providing active and reactive power, and guarantee that the bus voltage fluctuates within the allowable range. Furthermore, by setting the k-coefficient, the operating modes of the photovoltaic device and energy storage device can be flexibly adjusted to meet different operational needs.

[0032] Secondly, the present invention provides a power grid reactive power compensation system based on bus unbalanced power, including: a power grid power flow model establishment module, used to establish a power grid power flow model based on photovoltaic, energy storage and load data connected to the bus, and obtain the power output of each component under different conditions;

[0033] A multi-objective optimization model construction module is used to construct a multi-objective optimization model based on the power output relationship of the various components under different conditions.

[0034] The optimization scheduling module is used to calculate and solve the multi-objective optimization model to obtain the minimum operating cost under the multi-objective operation conditions of the power grid, so as to perform optimal scheduling.

[0035] Thirdly, the present invention provides an electronic device, comprising:

[0036] Memory and processor;

[0037] The memory is used to store computer-executable instructions, and the processor is used to execute the computer-executable instructions. When the computer-executable instructions are executed by the processor, they implement the steps of the power grid reactive power compensation method based on bus unbalanced power.

[0038] Fourthly, the present invention provides a computer-readable storage medium storing computer-executable instructions that, when executed by a processor, implement the steps of the power grid reactive power compensation method based on bus imbalance power.

[0039] Compared with existing technologies, the beneficial effects of this invention are as follows: This invention establishes a power flow model that includes photovoltaics, energy storage, and loads, constructs a cost model based on actual power output, and considers a multi-objective optimization objective function that minimizes network losses, voltage deviations, and three-phase imbalance. Based on the distribution network structure and power flow constraints, it sets constraints including voltage and current, and finally integrates these elements into a mixed integer linear programming problem to obtain the optimal scheduling scheme. This can improve the safety and economy of distribution network operation, while fully exploring and utilizing the potential of photovoltaic resources. Attached Figure Description

[0040] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. Wherein:

[0041] Figure 1 This is a flowchart of a power grid reactive power compensation method and system based on bus unbalanced power, according to an embodiment of the present invention.

[0042] Figure 2 This is a schematic diagram of a power flow model of a power grid reactive power compensation method and system based on bus unbalanced power, according to an embodiment of the present invention.

[0043] Figure 3 This is a diagram showing the relationship between active power output and reactive power output of a power grid reactive power compensation method and system based on bus unbalanced power, as described in one embodiment of the present invention. Detailed Implementation

[0044] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. 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 protection scope of the present invention.

[0045] Example 1

[0046] Reference Figures 1-3This is one embodiment of the present invention, which provides a power grid reactive power compensation method based on bus imbalance, such as... Figure 1 As shown, it includes:

[0047] S100: Establish a power flow model of the power grid based on photovoltaic, energy storage and load data connected to the bus, and obtain the power output of each component under different conditions;

[0048] S200: Based on the power output relationship of each component under different conditions, a multi-objective optimization model is constructed;

[0049] S300: Calculate and solve the multi-objective optimization model to obtain the minimum operating cost under the multi-objective operation conditions of the power grid, so as to carry out optimal scheduling.

[0050] It should be noted that modern photovoltaic inverters, with the help of flexible control technology, possess a certain degree of reactive power regulation capability. By controlling the output and absorption of reactive power, they can regulate the voltage amplitude, opening up a new dimension of collaborative control for traditional voltage regulation equipment. Meanwhile, in the actual operation of distribution networks, bus power imbalance problems frequently occur. By comprehensively considering the output status of photovoltaic (PV) devices and the imbalance of power supply to the bus, and by precisely regulating PV output and power purchase based on actual needs to ensure that the bus voltage remains within a safe range, this application is crucial for ensuring the safe and stable operation of the distribution network. This application establishes a typical distribution network model, considering PV, energy storage, and loads connected to the bus, and establishes corresponding power flow relationships. Based on the actual output status of PV devices, a PV device output cost model is established, and a power purchase cost model is established considering the imbalance of power supply to the bus. Other costs and actual operating conditions are also considered to form a cost model. A power flow constraint model including voltage and current amplitude constraints is established based on the actual distribution system. These constraints and cost models are then used as an optimization solution model under these constraints to obtain the minimum operating cost under multi-objective operating conditions including the imbalance of power supply to the bus, thus addressing the issue of rational utilization of PV resources due to increased PV penetration.

[0051] In this embodiment of the application, the establishment of the power flow model of the power grid based on the photovoltaic, energy storage and load data of the access bus in step S100 includes: power transmission lines from node j to other child nodes k, and power transmission lines from node i to node j.

[0052] Power transmission lines transmit active power P ij and reactive power Q ij The resistance and reactance of the power transmission line are r and r, respectively. ij and x ij Node j connects multiple photovoltaic devices, energy storage devices, and loads.

[0053] In an optional embodiment, the established power flow model including photovoltaics, energy storage, and load is as follows: Figure 2 As shown, where P ij and Q ij Let r represent the active power and reactive power of branch ij, respectively. ij and x ij P represents the resistance and reactance of branch ij, respectively. jk and Q jk P represents the active and reactive power from bus j to k. G,m and Q G,m P represents the active and reactive power output of the photovoltaic device m. L,j and Q L,j These represent the active and reactive power demands of bus j, respectively, P. ES,n and Q ES,n These represent the active and reactive power outputs of energy storage device n, respectively, Φ j This represents the set of sub-buses belonging to bus j.

[0054] In this embodiment of the application, before constructing a multi-objective optimization model based on the power output relationship of each component under different conditions in step S200, the following steps are taken: establishing a cost model for grid reactive power compensation based on the actual output status of photovoltaic power and the unbalanced power of the bus and combined with other operating costs; the cost model takes minimizing voltage security cost and voltage regulation economic cost as objective function and power constraint as constraint condition.

[0055] In this embodiment of the application, step S200, based on the power output relationship of each component under different conditions, constructs a multi-objective optimization model, including: based on the cost model, introducing network loss cost and three-phase imbalance cost, and constructing a multi-objective optimization model; the network loss cost is calculated based on the current between branches in the distribution network and the cost coefficient corresponding to the unit network loss, and the three-phase imbalance cost is determined based on the three-phase voltage difference corresponding to the node and the cost coefficient corresponding to the unit three-phase imbalance.

[0056] In an optional embodiment, the relationship between the active power output and reactive power output of the photovoltaic device m is as follows: Figure 3 As shown, if the photovoltaic (PV) device is dispatched to provide reactive power, the PV device will reduce its active power output. The compensation calculation for this reduction in active power output is expressed as follows:

[0057] C G,m =α(P G,m,o -P G,m )Δt

[0058] Where α is the unit active power compensation price, P G,m To output active power, P G,m,oThe active power output is when no reactive power is provided, and Δt is the operating time.

[0059] It should be noted that, based on the power flow model established in step S100, a minimum cost objective function for maintaining voltage security is established, taking into account photovoltaic, energy storage, load, and unbalanced power supply on the bus.

[0060] In this embodiment of the application, the cost model in step S200 is represented as follows:

[0061] minωC stable +(1-ω)C pay

[0062] P G,m,o ≥P G,m

[0063] P G,m,min ≤P G,m ≤P G,m,max

[0064] Among them, P G,m To output active power, P G,m,o P is the active power output when no reactive power is provided. G,m,min and P G,m,max To output the minimum and maximum active power, C stable and C pay These represent voltage safety cost and voltage regulation economic cost, respectively, with ω being the cost coefficient.

[0065] It should be noted that the cost factor reflects the degree of importance attached to voltage safety; the higher the value, the more importance is attached to voltage safety.

[0066] Specifically, the calculation of voltage safety costs and voltage regulation economic costs is expressed as follows:

[0067]

[0068] C pay =C PV +C ES +C extra

[0069] C PV =C G,m

[0070]

[0071] R ES,n,reactive =p ES,n [k ES,n,1 (Q ES,n,o -Q ES,n )+k ES,n,2 (Q ES,n -QES,n,o )]

[0072]

[0073] Among them, V i Let β be the voltage at bus i, β be the voltage fluctuation cost coefficient, and C be the voltage at bus i. PV C is the cost of power output paid to the owners of the photovoltaic resources involved in regulation. ES R is the cost of power output paid to the owners of the energy storage devices that participate in regulation. ES,n,reactive To provide reactive power to energy storage devices, θ ES,n For the cost per unit of reactive power, k ES,n,1 and k ES,n,2 It is a 01 variable, when k ES,n,1 For 1, k ES,n,2 A value of 0 indicates that the energy storage device provides negative reactive power, exhibiting inductive load behavior. ES,n,2 For 1, k ES,n,1 A value of 0 indicates that the energy storage device provides reactive power, Q. ES,n,o and Q ES,n C corresponds to the reactive power output of the energy storage device when it is not participating in dispatch and when it is participating in dispatch, respectively. extra P represents the cost of purchasing electricity from the upstream power grid when the active power cannot meet the system load, i.e., when there is an imbalance in the bus power supply. L,j For the active power demand at bus j, P G,m and P ES,n It provides active power output for photovoltaic and energy storage.

[0074] In an optional embodiment, a multi-objective optimization objective function is established based on the linear weighting method, which includes minimizing network loss, minimizing voltage deviation, and minimizing three-phase imbalance. Based on the cost model established in step S200, network loss cost and three-phase imbalance cost are further added.

[0075] In another alternative embodiment, particle swarm optimization can also be used to handle multi-objective optimization problems.

[0076] In this embodiment of the application, the objective function of the multi-objective optimization model in step S200 is expressed as:

[0077] minω1C stable +ω2C pay +ω3C loss +ω4C unbalance

[0078] ω1+ω2+ω3+ω4=1

[0079]

[0080] Among them, Closs and C unbalance For network loss cost and three-phase imbalance cost, δ is the cost coefficient corresponding to unit network loss, I ij V represents the current between branches ij in the distribution network. A V B and V C Let ε be the three-phase voltage corresponding to the node, and ε be the cost coefficient corresponding to a unit three-phase unbalance.

[0081] In an optional embodiment, based on the power flow model established in step S100, the active power relationship, reactive power relationship, and bus voltage drop in the system are shown in the following equations:

[0082]

[0083] V j =V i -P ij r ij -Q ij x ij

[0084] In this embodiment of the application, the multi-objective optimization model in step S200 includes: establishing a constraint model including voltage based on the actual distribution network structure and power flow constraints;

[0085] The constraint model is represented as:

[0086]

[0087] V i,min ≤V i ≤V i,max

[0088] k G,m,1 +k G,m,2 =1

[0089] k ES,n,1 +k ES,n,2 =1

[0090] Among them, S G,m and S ES,n P represents the apparent power of photovoltaic device m and energy storage device n, respectively. ES,n and Q ES,n P represents the active power output and reactive power output of energy storage device n, respectively. G,m and Q G,m These represent the active power output and reactive power output of the photovoltaic device m, respectively, V i,min and V i,max These represent the minimum and maximum voltage values ​​for the corresponding bus, k. G,m,1 and k G,m,2k is used to describe the different operating modes of photovoltaic device m. ES,n,1 and k ES,n,2 Used to describe the different operating modes of energy storage device n.

[0091] It should be noted that the constraint model, which includes voltage, is established based on the actual distribution network structure and power flow constraints. This includes active and reactive power output constraints of photovoltaic devices and energy storage devices, bus voltage constraints, and operating state constraints of photovoltaic devices and energy storage devices in absorbing and providing reactive power.

[0092] It should also be noted that the above power flow relationships and constraints are transformed into a cost-minimizing optimization scheduling problem that considers voltage safety, economic cost, network loss cost, and three-phase imbalance cost. The constraints are the standby output, status, and bus voltage amplitude in step S200. The above objective function and constraints are established as a mixed integer linear programming problem, which is solved using a commercial solver to obtain the optimal scheduling scheme under all constraints.

[0093] Example 2, refer to Figures 1-3 This is one embodiment of the present invention, which differs from the first embodiment in that it provides a power grid reactive power compensation system based on bus imbalance, comprising:

[0094] The power grid power flow model building module is used to build a power grid power flow model based on photovoltaic, energy storage and load data connected to the bus, and to obtain the power output of each component under different conditions;

[0095] The multi-objective optimization model building module is used to construct a multi-objective optimization model based on the power output relationship of each component under different conditions.

[0096] The optimization scheduling module is used to calculate and solve the multi-objective optimization model to obtain the minimum operating cost under the multi-objective operation conditions of the power grid, so as to perform optimal scheduling.

[0097] Specifically, each module of the power grid reactive power compensation system based on bus imbalance power in this embodiment implements the steps of the power grid reactive power compensation method based on bus imbalance power in Embodiment 1, for example:

[0098] In one implementation, the power grid reactive power compensation system based on bus unbalanced power can perform the following steps: establishing a power grid power flow model including: power transmission lines from node j to other child nodes k, and power transmission lines from node i to node j;

[0099] Power transmission lines transmit active power P ij and reactive power Q ij The resistance and reactance of the power transmission line are r and r, respectively. ijand x ij Node j connects multiple photovoltaic devices, energy storage devices, and loads.

[0100] A cost model for reactive power compensation of the power grid is established based on the actual output status of photovoltaic power and the unbalanced power of the bus, combined with other operating costs. The cost model takes minimizing the voltage security cost and the voltage regulation economic cost as the objective function, and power constraints as the constraint conditions.

[0101] Based on the cost model, network loss cost and three-phase imbalance cost are introduced to construct a multi-objective optimization model. The network loss cost is calculated based on the current between branches in the distribution network and the cost coefficient corresponding to the unit network loss. The three-phase imbalance cost is determined based on the three-phase voltage difference corresponding to the node and the cost coefficient corresponding to the unit three-phase imbalance.

[0102] The cost model is expressed as:

[0103] minωC stable +(1-ω)C pay

[0104] P G,m,o ≥P G,m

[0105] P G,m,min ≤P G,m ≤P G,m,max

[0106] Among them, P G,m To output active power, P G,m,o P is the active power output when no reactive power is provided. G,m,min and P G,m,max To output the minimum and maximum active power, C stable and C pay These represent voltage safety cost and voltage regulation economic cost, respectively, with ω being the cost coefficient.

[0107] The objective function of the multi-objective optimization model is expressed as:

[0108] minω1C stable +ω2C pay +ω3C loss +ω4C unbalance

[0109] ω1+ω2+ω3+ω4=1

[0110]

[0111] Among them, C loss and C unbalance For network loss cost and three-phase imbalance cost, δ is the cost coefficient corresponding to unit network loss, I ijV represents the current between branches ij in the distribution network. A V B and V C Let ε be the three-phase voltage corresponding to the node, and ε be the cost coefficient corresponding to a unit three-phase unbalance.

[0112] The multi-objective optimization model also includes: establishing a constraint model that includes voltage based on the actual distribution network structure and power flow constraints;

[0113] The constraint model is represented as:

[0114]

[0115] V i,min ≤V i ≤V i,max

[0116] k G,m,1 +k G,m,2 =1

[0117] k ES,n,1 +k ES,n,2 =1

[0118] Among them, S G,m and S ES,n P represents the apparent power of photovoltaic device m and energy storage device n, respectively. ES,n and Q ES,n P represents the active power output and reactive power output of energy storage device n, respectively. G,m and Q G,m These represent the active power output and reactive power output of the photovoltaic device m, respectively, V i,min and V i,max These represent the minimum and maximum voltage values ​​for the corresponding bus, k. G,m,1 and k G,m,2 k is used to describe the different operating modes of photovoltaic device m. ES,n,1 and k ES,n,2 Used to describe the different operating modes of energy storage device n.

[0119] This embodiment also provides an electronic device applicable to power grid reactive power compensation methods based on bus imbalance, including:

[0120] The system includes a memory and a processor. The memory stores computer-executable instructions, and the processor executes these instructions to implement the power grid reactive power compensation method based on bus imbalance power, as proposed in the above embodiments.

[0121] This embodiment also provides a storage medium storing a computer program that, when executed by a processor, implements the power grid reactive power compensation method based on bus unbalanced power as proposed in the above embodiments.

[0122] The storage medium proposed in this embodiment and the method for implementing reactive power compensation of the power grid based on the unbalanced power of the bus proposed in the above embodiments belong to the same inventive concept. Technical details not described in detail in this embodiment can be found in the above embodiments, and this embodiment has the same beneficial effects as the above embodiments.

[0123] Based on the above description of the embodiments, those skilled in the art should understand that the embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code. The solutions in the embodiments of this application can be implemented using various computer languages, such as the object-oriented programming language Java and the interpreted scripting language JavaScript.

[0124] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this application. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart... Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0125] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0126] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1The steps of the function specified in one or more boxes.

[0127] Although preferred embodiments of this application have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of this application.

[0128] Obviously, those skilled in the art can make various modifications and variations to this application without departing from the spirit and scope of this application. Therefore, if such modifications and variations fall within the scope of the claims of this application and their equivalents, this application also intends to include such modifications and variations.

[0129] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A power grid reactive power compensation method based on bus imbalance, characterized in that, include: A power flow model of the power grid is established based on photovoltaic, energy storage and load data connected to the bus, and the power output of each component under different conditions is obtained. Based on the power output relationship of each component under different conditions, a multi-objective optimization model is constructed; The multi-objective optimization model is calculated and solved to obtain the minimum operating cost under the multi-objective operating conditions of the power grid, so as to carry out optimal scheduling.

2. The power grid reactive power compensation method based on bus imbalance as described in claim 1, characterized in that, The power flow model established based on photovoltaic, energy storage and load data of the access bus includes: power transmission lines from node j to other child nodes k, and power transmission lines from node i to node j. The power transmission line transmits active power P ij and reactive power Q ij The resistance and reactance of the power transmission line are r and r, respectively. ij and x ij Node j connects multiple photovoltaic devices, energy storage devices, and loads.

3. The power grid reactive power compensation method based on bus imbalance as described in claim 2, characterized in that, Based on the power output relationship of each component under different conditions, the multi-objective optimization model is constructed as follows: a cost model for reactive power compensation of the power grid is established based on the actual output status of photovoltaic power and the unbalanced power of the bus, combined with other operating costs; the cost model takes minimizing the voltage security cost and the voltage regulation economic cost as the objective function, and power constraints as the constraint condition.

4. The power grid reactive power compensation method based on bus imbalance as described in claim 3, characterized in that, Based on the power output relationship of the various components under different conditions, a multi-objective optimization model is constructed, including: based on the cost model, introducing network loss cost and three-phase imbalance cost to construct a multi-objective optimization model; the network loss cost is calculated based on the current between branches in the distribution network and the cost coefficient corresponding to the unit network loss, and the three-phase imbalance cost is determined based on the three-phase voltage difference corresponding to the node and the cost coefficient corresponding to the unit three-phase imbalance.

5. The power grid reactive power compensation method based on bus imbalance as described in claim 3 or 4, characterized in that: The cost model is expressed as: minωC stable +(1-ω)C pay P G,m,o ≥P G,m P G,m,min ≤P G,m ≤P G,m,max Among them, P G,m To output active power, P G,m,o P is the active power output when no reactive power is provided. G,m,min and P G,m,max To output the minimum and maximum active power, C stable and C pay These represent voltage safety cost and voltage regulation economic cost, respectively, with ω being the cost coefficient.

6. The power grid reactive power compensation method based on bus imbalance as described in claim 5, characterized in that: The objective function of the multi-objective optimization model is expressed as: minω1C stable +ω2C pay +ω3C loss +ω4C unbalance ω1+ω2+ω3+ω4=1 Among them, C loss and C unbalance For network loss cost and three-phase imbalance cost, δ is the cost coefficient corresponding to unit network loss, I ij V represents the current between branches ij in the distribution network. A V B and V C Let ε be the three-phase voltage corresponding to the node, and ε be the cost coefficient corresponding to a unit three-phase unbalance.

7. The power grid reactive power compensation method based on bus imbalance as described in claim 6, characterized in that, The multi-objective optimization model also includes: establishing a constraint model that includes voltage based on the actual distribution network structure and power flow constraints; The constraint model is represented as: In i,min ≤V i ≤V i,max k G,m,1 +k G,m,2 =1 k ES,n,1 +k ES,n,2 =1 Among them, S G,m and S ES,n P represents the apparent power of photovoltaic device m and energy storage device n, respectively. ES,n and Q ES,n P represents the active power output and reactive power output of energy storage device n, respectively. G,m and Q G,m These represent the active power output and reactive power output of the photovoltaic device m, respectively, V i,min and V i,max These represent the minimum and maximum voltage values ​​for the corresponding bus, k. G,m,1 and k G,m,2 k is used to describe the different operating modes of photovoltaic device m. ES,n,1 and k ES,n,2 Used to describe the different operating modes of energy storage device n.

8. A power grid reactive power compensation system based on bus imbalance, applied to the method described in any one of claims 1-7, characterized in that, include: The power grid power flow model building module is used to build a power grid power flow model based on photovoltaic, energy storage and load data connected to the bus, and to obtain the power output of each component under different conditions; A multi-objective optimization model construction module is used to construct a multi-objective optimization model based on the power output relationship of the various components under different conditions. The optimization scheduling module is used to calculate and solve the multi-objective optimization model to obtain the minimum operating cost under the multi-objective operation conditions of the power grid, so as to perform optimal scheduling.

9. An electronic device, comprising: Memory and processor; The memory is used to store computer-executable instructions, and the processor is used to execute the computer-executable instructions. When the computer-executable instructions are executed by the processor, they implement the steps of the power grid reactive power compensation method based on bus unbalanced power as described in any one of claims 1 to 7.

10. A computer-readable storage medium storing computer-executable instructions that, when executed by a processor, implement the steps of the power grid reactive power compensation method based on bus unbalanced power as described in any one of claims 1 to 7.

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