Distributed voltage control method and device under transmission and distribution cooperation and medium

Abstract

The invention discloses a distributed voltage control method and device under transmission and distribution cooperation and a medium, and the method comprises the following steps: S1, obtaining the basic parameter information of a transmission and distribution system; s2, establishing a distributed voltage reactive power control model with minimum power transmission network loss and power distribution network loss; s3, decomposing the reactive voltage control model of the power transmission and distribution system into control sub-models about a power transmission network and a power distribution network; and S4, performing decomposition by using the step S3 to obtain a control sub-model, constructing a solving framework for solving based on the parameter information in the step S1, and finally obtaining a distributed voltage control strategy. According to the method, the power transmission and distribution system network loss minimization is set as an optimization target, so that the power generation cost can be reduced and the new energy consumption can be improved while the system voltage safety is ensured. Compared with a centralized method, the distributed solving method for optimizing the network loss in the whole power transmission and distribution system ensures safe operation of the system and reduces the calculation complexity at the same time.

Description

Technical Field

[0001] The present invention relates to the technical field of distributed voltage reactive power control, and in particular to a distributed voltage control method, device and medium under transmission and distribution coordination. Background Art

[0002] With the integration of distributed energy resources, distribution networks are evolving into active distribution networks. The huge capacity of distributed generation systems such as wind power and photovoltaic generators makes the distribution network more complex and difficult to control. Reactive power optimization aims to minimize power losses in the power grid while ensuring safety constraints such as voltage amplitude limits and transmission line power flow limits. Traditionally, reactive power optimization of transmission and distribution networks is separated. When optimizing the transmission network, the boundary node is regarded as a PQ node, which means that the distribution network under it remains unchanged. In contrast, the boundary node is formulated as a reference node for reactive power optimization in the distribution network. When distributed generators are injected into the distribution network on a large scale, overvoltage problems will occur, which may cause distributed generator chain blackouts. Therefore, the voltage regulation capability of the transmission system must be fully utilized to help ADN eliminate its overvoltage problems and reduce network losses.

[0003] However, ADNs lack sufficient voltage regulation capabilities when operating alone and cannot effectively solve voltage problems. Although some studies have proposed distributed reactive power optimization methods, these methods often converge slowly. In addition, although some studies have proposed coordinated voltage control structures between transmission and distribution systems, these methods usually only obtain feasible results rather than optimal solutions. Therefore, a distributed solution framework that can ensure both optimality and safety is needed.

[0004] To this end, this application specifically proposes a distributed voltage control method under transmission and distribution coordination to solve the above technical problems.

[0005] The above contents are only used to assist in understanding the technical solution of the present application, and do not constitute an admission that the above contents are the closest prior art. Summary of the invention

[0006] The main purpose of the present invention is to provide a distributed voltage control method under transmission and distribution coordination to solve the technical problems raised in the background technology.

[0007] The present invention adopts the following technical solutions to solve the above technical problems: A distributed voltage control method under transmission and distribution coordination comprises the following steps: S1. Obtain basic parameter information of the transmission and distribution system; S2. Establish a distributed voltage and reactive power control model with minimum transmission network loss and distribution network loss; S3, decomposing the distributed voltage and reactive power control model into control sub-models about the transmission network and the distribution network; S4, use S3 to decompose and obtain the control sub-model, build a solution framework based on the parameter information in S1, and finally obtain the distributed voltage control strategy.

[0008] Furthermore, step S1 specifically includes parameter information of the transmission network and parameter information of the distribution network; Step 1.1, obtaining parameter information of the transmission network: The set of transmission network nodes is denoted as , the connected distribution network set is recorded as ; The conductance of the branch between any connected i-th node and j-th node and electrosusceptor ; Active power of the load on the i-th node at time t and reactive power , the active power of the generator and reactive power ; Step 1.2: Obtain basic information of the distribution network: The node set of the kth distribution network is recorded as , the resistance of the branch between any i-th node and j-th node Reactance ; Active power of the load at the i-th node in the k-th distribution network and reactive power , the active power of the generator and reactive power .

[0009] Further, step S2 specifically includes: Establish a distributed voltage and reactive power control model with minimum transmission network loss and distribution network loss, including: objective function, transmission network constraint, distribution network constraint and coupling boundary constraint; Step 2.1: Use formula (1) to construct Objective function of the distributed voltage and reactive power control model at each moment : (1) Step 2.2, construct power flow constraints and safety constraints of the transmission network; Step 2.2.1, use equations (2) to (5) to obtain the power flow constraints of the transmission network; (2) (3) (4) (5) In formula (2) to formula (5), represents the active power of the branch between node i and node j in the transmission network at time t; and They represent the voltage amplitudes of nodes i and j in the transmission network at time t respectively; It represents the voltage phase angle difference between the branch between node i and node j in the transmission network at time t; represents the reactive power of the branch between node i and node j in the transmission network at time t; Step 2.2.2, use equations (6) to (9) to obtain the transmission network security constraints; (6) (7) (8) (9) In formula (6) to formula (9), and represents the lower and upper limits of the actual power output of the generator at node i in the transmission network at time t; and represents the lower and upper limits of the reactive power output of the generator at node i in the transmission network at time t; and represents the lower and upper limits of the voltage amplitude of node i in the transmission network at time t; It represents the transmission capacity of the branch between node i and node j in the transmission network at time t; Step 2.3, construct distribution network power flow constraints and safety constraints; Step 2.3.1, use equations (10) to (13) to obtain the power flow constraints of the distribution network; (10) (11) (12) (13) In formula (10) to formula (13), and They represent the active power and reactive power of the branch between node i and node j in the distribution network respectively; represents the current amplitude of the branch between node i and node j in the distribution network; represents the voltage amplitude of node i in the distribution network; and They represent the active power and reactive power output of the generator at the node i of the distribution network respectively; and They represent the active power and reactive power output of the generator at the node j of the distribution network respectively; and represents the actual power and reactive power demand of the load at the distribution network node j; Step 2.3.2, use equations (14) to (17) to obtain the distribution network security constraints; (14) (15) (16) (17) In formula (13) to formula (16), and represents the lower and upper limits of the actual power output of the generator at node i in the distribution network; and represents the lower and upper limits of the reactive power output of the generator at node i in the distribution network; and Represents the lower and upper limits of the voltage amplitude at node i in the distribution network; It represents the upper limit of the current amplitude of the branch between node i and node j in the distribution network; Step 2.4: Use equations (18) to (20) to construct boundary constraints between the transmission network and the distribution network, including the equality of voltage, active power and reactive power; (18) (19) (20) In formula (18) to formula (20), represents the voltage amplitude of the boundary node in the transmission network connected to the kth distribution network; represents the voltage amplitude of the root node in the kth distribution network connected to the transmission network; represents the active power of the boundary nodes in the transmission network connected to the kth distribution network; represents the active power of the root node in the kth distribution network connected to the transmission network; represents the reactive power of the boundary nodes in the transmission network connected to the kth distribution network; represents the reactive power of the root node in the kth distribution network connected to the transmission network.

[0010] Further, step S3 specifically includes: Step 3.1, establish a transmission network voltage control model, including objective function, power flow constraints and safety constraints; Step 3.1.1, construct the objective function of the transmission network voltage control model using equation (21); (twenty one) Step 3.1.2, construct the power flow constraints of the transmission network using equations (2)-(5); Step 3.1.3, construct the security constraints of the transmission network using equations (6)-(9); Step 3.2, establish a distribution network voltage control model, including objective function, power flow constraints and safety constraints; Step 3.2.1: Use equation (22) to construct the objective function of the distribution network voltage control model: (twenty two) Step 3.2.2, construct the power flow constraints of the distribution network using equations (10)-(13); Step 3.2.3: Use equations (14)-(17) to construct the security constraints of the distribution network.

[0011] Further, step S4 specifically includes: Step 4.1, given the initial information of the transmission network and distribution network; Step 4.1.1: For the transmission network, given the generator power output at the initial time , Load active power and load reactive power ; Step 4.1.2: For the distribution network, given the initial generator power output , Load active power and load reactive power ; Step 4.2: In the inner loop, the transmission network and the distribution network are optimized independently; Step 4.2.1: Each distribution network has a boundary node voltage according to the transmission network. and power , using the cplex solver to optimize and adjust the reactive power output of its generator ; Step 4.2.2: According to the boundary node power provided by the distribution network and , the transmission network is optimized again using the cplex solver to adjust the power output of the generator , in order to minimize the losses in the transmission network.

[0012] Step 4.3: According to equations (18)-(20), the distribution network and the transmission network exchange boundary information; Step 4.4, use formula (23) to calculate the inner loop convergence index; (twenty three) In formula (23), Indicates the set convergence threshold; if it is satisfied, execute step 4.5; otherwise, return to step 4.2; Step 4.5: Use equation (24) to check the convergence of the outer loop by adjusting the Lagrange multiplier and the penalty coefficient; (twenty four) In formula (24), is the outer loop convergence threshold set; if it is met, the iteration process stops; otherwise, return to step 4.2.

[0013] On the other hand, the present invention further discloses a computer-readable storage medium storing a computer program, wherein when the computer program is executed by a processor, the processor executes the steps of the above method.

[0014] On the other hand, the present invention further discloses a computer device, including a memory and a processor, wherein the memory stores a computer program, and when the computer program is executed by the processor, the processor executes the steps of the above method.

[0015] It can be seen from the above technical solution that the present invention provides a distributed voltage control method under transmission and distribution coordination to solve a series of problems such as inaccurate voltage control caused by the inability of existing methods to obtain optimal solutions, so as to obtain a distributed voltage reactive power control scheme with minimized network losses of the transmission and distribution system, thereby making the voltage of the active distribution network stable and operating safely.

[0016] Compared with the prior art, the present invention has the following advantages: 1. The present invention sets the minimization of network losses in the power transmission and distribution system as the optimization goal, which can reduce the power generation cost and improve the consumption of new energy while ensuring the system voltage safety.

[0017] 2. The distributed solution method proposed by the present invention for optimizing network losses in the overall power transmission and distribution system reduces the computational complexity while ensuring the safe operation of the system, compared with the centralized method. 3. The present invention ensures the convergence of the decomposition and coordination process by decomposing the reactive power optimization problem into a main problem (transmission network problem) and several sub-problems (lower-level distribution network problems).

[0018] It should be understood that the content described in this section is not intended to identify the key or important features of the embodiments of the present invention, nor is it intended to limit the scope of the present invention. Other features of the present invention will become easy to understand through the following description. Of course, it is not necessary to achieve all of the advantages described above simultaneously for any product implementing the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The drawings constituting a part of the present application are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings: Figure 1 is a structural diagram of the power transmission and distribution system of the present invention; Figure 2 A topological diagram of the IEEE 33-node power distribution system of the present invention; Figure 3 It is the principle diagram of voltage control of the present invention; Figure 4 It is a distributed solution framework for voltage and reactive power control of the power transmission and distribution system of the present invention. DETAILED DESCRIPTION

[0020] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments. In the absence of conflict, the embodiments in this application and the features in the embodiments can be combined with each other. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0021] like Figure 1 As shown, the distributed voltage control method under transmission and distribution coordination proposed in the embodiment of the present invention includes the following steps: S1. Obtain basic parameter information of the transmission and distribution system; S2. Establish a distributed voltage and reactive power control model with minimum transmission network loss and distribution network loss; S3, decomposing the reactive power and voltage control model of the power transmission and distribution system into control sub-models for the transmission network and the distribution network; S4, use S3 to decompose and obtain the control sub-model, build a solution framework based on the parameter information in S1, and finally obtain the distributed voltage control strategy.

[0022] The specific steps include: Step 1: Obtain basic parameter information of the transmission and distribution system, including: parameter information of the transmission network and parameter information of the distribution network; Step 1.1, obtaining parameter information of the transmission network: exist Figure 1 The transmission and distribution system shown in the figure includes one transmission system and three distribution systems. There are three power stations in the transmission network, and the maximum output power of the power stations is 220MW, 100MW and 25MW respectively. The node set of the transmission network is recorded as , the connected distribution network set is recorded as ; The conductance of the branch between any connected i-th node and j-th node and electrosusceptor ; Active power of the load on the i-th node at time t and reactive power , the active power of the generator and reactive power ; Step 1.2: Obtain basic information of the distribution network: Figure 2 The distribution system shown in Figure 1 includes 33 nodes and 8 photovoltaic devices. The node set of the kth (k=1,2,3) distribution network is recorded as , the resistance of the branch between any i-th node and j-th node Reactance ; Active power of the load at the i-th node in the k-th distribution network and reactive power , the active power of the generator and reactive power ; Step 2: According to Figure 3 The voltage control principle diagram shown in the figure establishes a distributed voltage reactive power control model with the minimum transmission network loss and distribution network loss, including: objective function, transmission network constraint, distribution network constraint and coupling boundary constraint; Step 2.1: Use formula (1) to construct Objective function of the distributed voltage and reactive power control model at each moment : (1) Step 2.2, construct power flow constraints and safety constraints of the transmission network; Step 2.2.1, use equations (2) to (5) to obtain the power flow constraints of the transmission network; (2) (3) (4) (5) In formula (2) to formula (5), represents the active power of the branch between node i and node j in the transmission network at time t; and They represent the voltage amplitudes of nodes i and j in the transmission network at time t respectively; It represents the voltage phase angle difference between the branch between node i and node j in the transmission network at time t; represents the reactive power of the branch between node i and node j in the transmission network at time t; Step 2.2.2, use equations (6) to (9) to obtain the transmission network security constraints; (6) (7) (8) (9) In formula (6) to formula (9), and represents the lower and upper limits of the actual power output of the generator at node i in the transmission network at time t, which are taken as 0 and 160MW respectively; and represents the lower and upper limits of the reactive power output of the generator at node i in the transmission network at time t, which are taken as -50MW and 100MW respectively; and represents the lower and upper limits of the voltage amplitude of node i in the transmission network at time t, which are taken as 0.9 pu and 1.1 pu respectively; represents the transmission capacity of the branch between node i and node j in the transmission network at time t, which is taken as 200MW; Step 2.3, construct distribution network power flow constraints and safety constraints; Step 2.3.1, use equations (10) to (13) to obtain the power flow constraints of the distribution network; (10) (11) (12) (13) In formula (10) to formula (13), and They represent the active power and reactive power of the branch between node i and node j in the distribution network respectively; represents the current amplitude of the branch between node i and node j in the distribution network; represents the voltage amplitude of node i in the distribution network; and They represent the active power and reactive power output of the generator at the node i of the distribution network respectively; and They represent the active power and reactive power output of the generator at the node j of the distribution network respectively; and represents the actual power and reactive power demand of the load at the distribution network node j; Step 2.3.2, use equations (14) to (16) to obtain the distribution network security constraints; (14) (15) (16) In formula (14) to formula (16), and represents the lower and upper limits of the actual power output of the generator at node i in the distribution network, which are taken as 0 and 15MW respectively; and represents the lower and upper limits of the reactive power output of the generator at node i in the distribution network, which are taken as -5MW and 12MW respectively; and represents the lower and upper limits of the voltage amplitude of node i in the distribution network, which are taken as 0.9pu and 1.1pu respectively. Step 2.4, the root bus connected to the transmission network is usually represented as a source on the distribution network side, and a boundary load bus on the transmission network side, so we use Equations (17)-(19) to construct the boundary constraints between the transmission network and the distribution network, including the equality of voltage, active power and reactive power; (17) (18) (19) In formula (17) to formula (19), represents the voltage amplitude of the boundary node in the transmission network connected to the kth distribution network; represents the voltage amplitude of the root node in the kth distribution network connected to the transmission network; represents the active power of the boundary nodes in the transmission network connected to the kth distribution network; represents the active power of the root node in the kth distribution network connected to the transmission network; represents the reactive power of the boundary nodes in the transmission network connected to the kth distribution network; represents the reactive power of the root node in the kth distribution network connected to the transmission network; Step 3, decomposing the reactive power and voltage control model of the power transmission and distribution system into sub-models about the transmission network and the distribution network; Step 3.1, establish a transmission network voltage control model, including objective function, power flow constraints and safety constraints; Step 3.1.1: Use equation (20) to construct the objective function of the transmission network voltage control model: (20) Step 3.1.2, construct the power flow constraints of the transmission network using equations (2)-(5); Step 3.1.3, construct the security constraints of the transmission network using equations (6)-(9); Step 3.2, establish a distribution network voltage control model, including objective function, power flow constraints and safety constraints; Step 3.2.1: Use equation (21) to construct the objective function of the distribution network voltage control model: (twenty one) Step 3.2.2, construct the power flow constraints of the distribution network using equations (10)-(13); Step 3.2.3, construct the security constraints of the distribution network using equations (14)-(16); Step 4: According to Figure 4 The distributed solution framework for voltage and reactive power control of the transmission and distribution system shown in the figure solves the optimization problems of the transmission network and the distribution network separately, and uses coupled boundary constraints to ensure coordination between them. Each subsystem (transmission network and distribution network) makes optimization decisions independently, and finally solves the global problem through information interaction and coordination. A distributed solution framework is constructed using iterative interaction Step 4.1, given the initial information of the transmission network and distribution network; Step 4.1.1: For the transmission network, given the generator power output at the initial time , Load active power and load reactive power ; Step 4.1.2: For the distribution network, given the initial generator power output , Load active power and load reactive power ; Step 4.2: In the inner loop, the transmission network and the distribution network are optimized independently; Step 4.2.1: Each distribution network has a boundary node voltage according to the transmission network. and power , using the cplex solver to optimize and adjust the reactive power output of its generator ; Step 4.2.2: According to the boundary node power provided by the distribution network and , the transmission network is optimized again using the cplex solver to adjust the power output of the generator , in order to minimize the losses in the transmission network.

[0023] Step 4.3: According to equations (18)-(20), the distribution network and the transmission network exchange boundary information; Step 4.4, use formula (23) to calculate the inner loop convergence index; (twenty three) In formula (23), Indicates the set convergence threshold, which is taken as 0.01; if it is satisfied, execute step 4.5; otherwise, return to step 4.2; Step 4.5, specifically, the system continuously checks the changes in the boundary power and the objective function value to determine whether it is necessary to continue iterating. Use equation (24) to check the convergence of the outer loop by adjusting the Lagrange multiplier and the penalty coefficient; (twenty four) In formula (24), is the outer loop convergence threshold set, which is set to 0.1; if it is satisfied, the iteration process stops; at this time, the power loss of the transmission network and the distribution network reaches the minimum, and the system enters a stable state. Otherwise, return to step 4.2.

[0024] The embodiment of the present invention obtains the status information of the transmission network and the distribution network through measurement, including node power, branch impedance and other information, understands the power flow process and the working principle of the generators in the transmission network and the distribution network, establishes an optimization problem that minimizes the power loss of the transmission network and the distribution network, and obtains the optimal distributed voltage control strategy through a distributed solution framework of problem decomposition and internal and external loop dual iterative optimization, thereby ensuring the voltage stability of the transmission and distribution system and effectively reducing the power loss of the system.

[0025] On the other hand, the present invention further discloses a computer-readable storage medium storing a computer program, wherein when the computer program is executed by a processor, the processor executes the steps of the above method.

[0026] On the other hand, the present invention further discloses a computer device, including a memory and a processor, wherein the memory stores a computer program, and when the computer program is executed by the processor, the processor executes the steps of the above method.

[0027] In another embodiment provided in the present application, a computer program product including instructions is also provided, which, when executed on a computer, enables the computer to execute any of the distributed voltage control methods under transmission and distribution coordination in the above embodiments.

[0028] It is understandable that the system provided by the embodiment of the present invention corresponds to the method provided by the embodiment of the present invention, and the explanation, examples and beneficial effects of the relevant contents can refer to the corresponding parts in the above method.

[0029] The embodiment of the present application also provides an electronic device, including a processor, a communication interface, a memory and a communication bus, wherein the processor, the communication interface and the memory communicate with each other through the communication bus. Memory, used to store computer programs; The processor is used to implement the above-mentioned distributed voltage control method under transmission and distribution coordination when executing the program stored in the memory.

[0030] The communication bus mentioned in the above electronic device may be a Peripheral Component Interconnect (PCI) bus or an Extended Industry Standard Architecture (EISA) bus, etc. The communication bus may be divided into an address bus, a data bus, a control bus, etc.

[0031] The communication interface is used for communication between the above electronic device and other devices.

[0032] The memory may include a random access memory (RAM) or a non-volatile memory (NVM), such as at least one disk memory. Optionally, the memory may also be at least one storage device located away from the aforementioned processor.

[0033] The above-mentioned processor can be a general-purpose processor, including a central processing unit (CPU), a network processor (NP), etc.; it can also be a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), or other programmable logic devices, discrete gate or transistor logic devices, and discrete hardware components.

[0034] It should also be noted that electronic devices also include terminal devices, which can also be called terminals, user equipment (UE), mobile stations (MS), mobile terminals (MT), etc. Terminal devices can be mobile phones, smart TVs, wearable devices, tablet computers (Pad), computers with wireless transceiver functions, virtual reality (VR) terminal devices, augmented reality (AR) terminal devices, wireless terminals in industrial control, wireless terminals in self-driving, wireless terminals in remote medical surgery, wireless terminals in smart grids, wireless terminals in transportation safety, wireless terminals in smart cities, wireless terminals in smart homes, etc. The embodiments of the present application do not limit the specific technology and specific device form adopted by the terminal devices.

[0035] In the above embodiments, it can be implemented in whole or in part by software, hardware, firmware or any combination thereof. When implemented using software, it can be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, the process or function described in the embodiment of the present application is generated in whole or in part. The computer may be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions may be stored in a computer-readable storage medium, or transmitted from one computer-readable storage medium to another computer-readable storage medium. For example, the computer instructions may be transmitted from a website site, a computer, a server or a data center by wired (e.g., coaxial cable, optical fiber, digital subscriber line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) mode to another website site, computer, server or data center. The computer-readable storage medium may be any available medium that a computer can access or a data storage device such as a server or a data center that includes one or more available media integrated. The available medium may be a magnetic medium (e.g., a floppy disk, a hard disk, a tape), an optical medium (e.g., a DVD), or a semiconductor medium (e.g., a solid-state drive Solid State Disk (SSD)), etc.

[0036] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

[0037] In addition, it should be noted that if the embodiments of the present invention involve directional indications (such as up, down, left, right, front, back...), the directional indications are only used to explain the relative position relationship, movement status, etc. between the components in a certain specific posture. If the specific posture changes, the directional indication will also change accordingly.

[0038] In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the present invention, the descriptions of "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In addition, the meaning of "and / or" appearing in the full text includes three parallel schemes. Taking "A and / or B" as an example, it includes scheme A, or scheme B, or schemes that A and B meet at the same time. In addition, in the embodiments of the present invention, "multiple" refers to more than two. In addition, the technical solutions between the various embodiments can be combined with each other, but it must be based on the ability of ordinary technicians in the field to implement. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

Claims

1. A distributed voltage control method under transmission and distribution coordination, characterized in that: The following steps are included: S1. Obtain basic parameter information of the transmission and distribution system; S2. Establish a distributed voltage and reactive power control model with minimum transmission network loss and distribution network loss; S3, decomposing the distributed voltage and reactive power control model into control sub-models about the transmission network and the distribution network; S4, use S3 to decompose and obtain the control sub-model, build a solution framework based on the parameter information in S1, and finally obtain the distributed voltage control strategy.

2. The distributed voltage control method under transmission and distribution coordination according to claim 1 is characterized in that , Step S1 specifically includes parameter information of the transmission network and parameter information of the distribution network; Step 1.1, obtain the parameter information of the transmission network: The set of transmission network nodes is denoted as , the connected distribution network set is recorded as ; The conductance of the branch between any connected i-th node and j-th node and electrosusceptor ; Active power of the load on the i-th node at time t and reactive power , the active power of the generator and reactive power ; Step 1.2: Get basic information about the distribution network: The node set of the kth distribution network is recorded as , the resistance of the branch between any i-th node and j-th node Reactance ; Active power of the load at the i-th node in the k-th distribution network and reactive power , the active power of the generator and reactive power .

3. The distributed voltage control method under transmission and distribution coordination according to claim 2, characterized in that: Step S2 specifically includes: Establish a distributed voltage and reactive power control model with minimum transmission network loss and distribution network loss, including: objective function, transmission network constraint, distribution network constraint and coupling boundary constraint; Step 2.1: Use formula (1) to construct Objective function of the distributed voltage and reactive power control model at each moment : (1) Step 2.2, construct power flow constraints and safety constraints of the transmission network; Step 2.2.1, use equations (2) to (5) to obtain the power flow constraints of the transmission network; (2) （3） （4） （5） In formula (2) to formula (5), represents the active power of the branch between node i and node j in the transmission network at time t; and They represent the voltage amplitudes of nodes i and j in the transmission network at time t respectively; It represents the voltage phase angle difference between the branch between node i and node j in the transmission network at time t; represents the reactive power of the branch between node i and node j in the transmission network at time t; Step 2.2.2, use equations (6) to (9) to obtain the transmission network security constraints; （6） （7） （8） （9） In formula (6) to formula (9), and represents the lower and upper limits of the actual power output of the generator at node i in the transmission network at time t; and represents the lower and upper limits of the reactive power output of the generator at node i in the transmission network at time t; and represents the lower and upper limits of the voltage amplitude of node i in the transmission network at time t; It represents the transmission capacity of the branch between node i and node j in the transmission network at time t; Step 2.3, construct distribution network power flow constraints and safety constraints; Step 2.3.1, use equations (10) to (13) to obtain the power flow constraints of the distribution network; （10） （11） （12） （13） In formula (10) to formula (13), and They represent the active power and reactive power of the branch between node i and node j in the distribution network respectively; represents the current amplitude of the branch between node i and node j in the distribution network; represents the voltage amplitude of node i in the distribution network; and They represent the active power and reactive power output of the generator at the node i of the distribution network respectively; and They represent the active power and reactive power output of the generator at the node j of the distribution network respectively; and represents the actual power and reactive power demand of the load at the distribution network node j; Step 2.3.2, use equations (14) to (17) to obtain the distribution network security constraints; （14） （15） （16） （17） In formula (13) to formula (16), and represents the lower and upper limits of the actual power output of the generator at node i in the distribution network; and represents the lower and upper limits of the reactive power output of the generator at node i in the distribution network; and Represents the lower and upper limits of the voltage amplitude at node i in the distribution network; It represents the upper limit of the current amplitude of the branch between node i and node j in the distribution network; Step 2.4: Use equations (18) to (20) to construct boundary constraints between the transmission network and the distribution network, including the equality of voltage, active power and reactive power; （18） （19） （20） In formula (18) to formula (20), represents the voltage amplitude of the boundary node in the transmission network connected to the kth distribution network; represents the voltage amplitude of the root node in the kth distribution network connected to the transmission network; represents the active power of the boundary nodes in the transmission network connected to the kth distribution network; represents the active power of the root node in the kth distribution network connected to the transmission network; represents the reactive power of the boundary nodes in the transmission network connected to the kth distribution network; represents the reactive power of the root node in the kth distribution network connected to the transmission network.

4. The distributed voltage control method under transmission and distribution coordination according to claim 3, characterized in that: Step S3 specifically includes: Step 3.1, establish a transmission network voltage control model, including objective function, power flow constraints and safety constraints; Step 3.1.1, construct the objective function of the transmission network voltage control model using equation (21); （21） Step 3.1.2, construct the power flow constraints of the transmission network using equations (2)-(5); Step 3.1.3, construct the security constraints of the transmission network using equations (6)-(9); Step 3.2, establish a distribution network voltage control model, including objective function, power flow constraints and safety constraints; Step 3.2.1: Use equation (22) to construct the objective function of the distribution network voltage control model: （22） Step 3.2.2, construct the power flow constraints of the distribution network using equations (10)-(13); Step 3.2.3: Use equations (14)-(17) to construct the security constraints of the distribution network.

5. The distributed voltage control method under transmission and distribution coordination according to claim 4, characterized in that: Step S4 specifically includes: Step 4.1, given the initial information of the transmission network and distribution network; Step 4.1.1: For the transmission network, given the generator power output at the initial time , Load active power and load reactive power ; Step 4.1.2: For the distribution network, given the initial generator power output , Load active power and load reactive power ; Step 4.2: In the inner loop, the transmission network and the distribution network are optimized independently; Step 4.2.1: Each distribution network has a boundary node voltage according to the transmission network. and power , using the cplex solver to optimize and adjust the reactive power output of its generator ; Step 4.2.2: According to the boundary node power provided by the distribution network and , the transmission network is optimized again using the cplex solver to adjust the power output of the generator , to minimize the losses in the transmission grid; Step 4.3: According to equations (18)-(20), the distribution network and the transmission network exchange boundary information; Step 4.4, use formula (23) to calculate the inner loop convergence index; （23） In formula (23), Indicates the set convergence threshold; if it is satisfied, execute step 4.5; otherwise, return to step 4.2; Step 4.5: Use equation (24) to check the convergence of the outer loop by adjusting the Lagrange multiplier and the penalty coefficient; （24） In formula (24), is the outer loop convergence threshold set; If satisfied, the iteration process stops; Otherwise, return to step 4.

2.

6. A computer-readable storage medium, characterized in that: A computer program is stored, and when the computer program is executed by a processor, the processor is caused to perform the steps of the method according to any one of claims 1 to 5.

7. A computer device, characterized in that: The method comprises a memory and a processor, wherein the memory stores a computer program, and when the computer program is executed by the processor, the processor executes the steps of the method according to any one of claims 1 to 5.

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