Partition network loss allocation method, apparatus and device for AC-DC hybrid system, and storage medium

Abstract

The invention discloses a partition network loss allocation method, apparatus and device for an AC / DC system, and a storage medium. The method comprises the steps of obtaining an AC line parameter, a DC converter parameter and a DC line parameter of the AC / DC system; according to the alternating-current line parameters, the direct-current converter parameters and the direct-current line parameters, a preset alternating-current and direct-current Newton-Raphson method is used for carrying out power flow calculation on the alternating-current and direct-current system, and key indexes are obtained; according to the key index, solving an active power distribution coefficient matrix of each load of each generator node by using a preset power flow tracking algorithm based on a downstream distribution matrix; constructing a target modularity function according to the active distribution coefficient matrix; according to the target modularity function, performing partition solving on the AC-DC system to obtain a partitioned AC-DC system; solving the network loss coefficient of each node in the partitioned AC / DC system according to a preset improved average network loss coefficient; and determining a power scheduling optimization strategy according to the network loss coefficient of each node.

Description

Technical Field

[0001] The present invention relates to the technical field of power system analysis and operation, and in particular to a partitioned network loss allocation method, device, equipment and storage medium for an AC / DC hybrid system. Background Art

[0002] With the development of power systems, especially the large-scale integration of renewable energy and the growing demand for cross-regional power exchange, high-voltage direct current (HVDC) transmission technology, including conventional direct current (LCC-HVDC) and flexible direct current (VSC-HVDC), is playing an increasingly important role in modern power grids, forming a complex AC / DC hybrid grid structure. While this structure improves system stability and transmission efficiency, it also brings new challenges to grid analysis, operation, and management, especially in terms of grid zoning and network loss allocation.

[0003] Grid zoning is the process of dividing a large interconnected power grid into several relatively independent, yet closely connected sub-regions. Reasonable zoning is crucial for power system planning (e.g., regional power source coordination planning), operation (e.g., voltage and frequency zoning control, and stability zoning assessment), dispatching (e.g., zoning reserve sharing), market operations (e.g., forming congestion management zones and determining zoning electricity prices), and fault recovery (e.g., guiding black start and islanding).

[0004] Network loss allocation aims to fairly and reasonably allocate the active power losses incurred during power transmission to the power system participants (such as generators, loads, and inter-regional transactions) responsible for these losses. Accurate and fair loss allocation is crucial for cost recovery, price signal transmission, and incentivizing users to reduce losses in the power market environment.

[0005] Existing technologies lack solutions for regional division and network loss allocation in AC / DC hybrid power grids, resulting in inaccurate network loss calculation and allocation results, causing unfair allocation results. Power generation companies and power users may not be able to bear their actual network loss responsibilities, affecting the economic rationality and fairness of power market transactions; AC / DC systems lack reasonable regional division methods, and it is difficult to divide the system into relatively independent functional areas with close internal connections and sparse external areas according to the characteristics of AC / DC hybrid power grids. This will bring difficulties to regional coordinated control, fault isolation, safety and stability analysis, etc., reducing the flexibility and reliability of the power grid. Summary of the Invention

[0006] In order to solve the above problems existing in the prior art, the present invention provides a method, device, equipment and storage medium for allocating partitioned network losses in an AC / DC system.

[0007] In order to achieve the above-mentioned purpose, the technical solution of the embodiment of the present invention is:

[0008] In a first aspect, the present invention provides a method for allocating partitioned network losses in an AC / DC system, the method comprising:

[0009] Obtaining AC line parameters, DC converter parameters, and DC line parameters of the AC / DC system;

[0010] According to the AC line parameters, the DC converter parameters and the DC line parameters, a preset AC / DC Newton-Raphson method is used to calculate the power flow of the AC / DC system to obtain key indicators;

[0011] According to the key indicators, the active power distribution coefficient matrix of each load at each generator node is solved using a preset power flow tracking algorithm based on the downstream distribution matrix;

[0012] Constructing a target modularity function according to the active power distribution coefficient matrix; partitioning the AC / DC system according to the target modularity function to obtain a partitioned AC / DC system;

[0013] According to the preset improved average network loss coefficient, solving the network loss coefficient of each node in the partitioned AC / DC system;

[0014] A power scheduling optimization strategy is determined based on the network loss coefficient of each node.

[0015] In a second aspect, the present invention provides a partitioned network loss allocation device for an AC / DC system, the device comprising:

[0016] An acquisition module, used to acquire AC line parameters, DC converter parameters and DC line parameters of the AC / DC system;

[0017] a calculation module, configured to calculate the power flow of the AC / DC system using a preset AC / DC Newton-Raphson method according to the AC line parameters, the DC converter parameters, and the DC line parameters to obtain key indicators;

[0018] A solution module is used to solve the active power distribution coefficient matrix of each load at each generator node according to the key indicators using a preset power flow tracking algorithm based on a downstream distribution matrix;

[0019] A construction module is used to construct a target modularity function according to the active power distribution coefficient matrix; partition the AC / DC system according to the target modularity function to obtain a partitioned AC / DC system;

[0020] The solving module is further configured to solve the network loss coefficient of each node in the partitioned AC / DC system according to a preset improved average network loss coefficient;

[0021] The calculation module is used to determine the power scheduling optimization strategy according to the network loss coefficient of each node.

[0022] In some embodiments, the operation module is further used to construct an AC node admittance matrix based on the AC line parameters, the DC converter parameters and the DC line parameters; classify the nodes on the AC / DC system into types according to the AC node admittance matrix and the node type to obtain the divided nodes; construct a DC network power imbalance and a DC Jacobian matrix of the DC system according to the DC converter parameters and the DC line parameters; use a preset Newton iteration method to update the relevant parameters on the DC side according to the DC network power imbalance and the DC Jacobian matrix to obtain updated parameters; the updated parameters The parameters include DC side voltage, current, transformer ratio and converter control angle; according to the AC line parameters, the active power flow, reactive power flow and injection power imbalance of the nodes in the AC system are calculated, and the AC Jacobian matrix of the AC system is assembled; the node voltage amplitude and phase angle are iteratively corrected by the preset AC / DC Newton-Raphson method and the AC Jacobian matrix; DC iteration and AC iteration are alternately performed in the same cycle until the correction increments of the DC and AC variables are both less than the preset convergence accuracy, and the key indicators are output; the key indicators include bus voltage amplitude, phase angle, generator output, DC and AC system power flows and total network loss.

[0023] In some embodiments, the solution module is also used to distribute the network loss on the lossy network line to the nodes at both ends of the line as loads, thereby simplifying the lossy network and obtaining a lossless network; based on the lossless network and the key indicators, the total injected active power of each node is calculated using the active power transmitted on the branch and the active load of each node; based on the total injected active power and the preset power flow tracking algorithm based on the downstream distribution matrix, the downstream distribution matrix between nodes is calculated; based on the preset proportional sharing principle and the downstream distribution matrix between nodes, the active power distribution of each generator to each load is calculated, and the active power distribution coefficient matrix is ​​calculated.

[0024] In some embodiments, the solution module is further used to construct the target modularity function based on the power flow tracking method; according to preset partitioning rules and preset constraints, the target modularity function is partitioned and solved to obtain the partitioned AC / DC system.

[0025] In some embodiments, the target modularity function is expressed as:

[0026]

[0027] Where M is the modularity function based on power flow tracking, m is the sum of edge weights, i and j are the nodes in the system, k is the ij is the active power distribution coefficient of the downstream tracking method, k i and k j are the weighted degrees of nodes i and j, δ ij It is a binary variable, which takes the value of 1 to indicate that nodes i and j are in the same partition, and 0 otherwise.

[0028] In some embodiments, the calculation module is also used to allocate the total active power loss of the interconnecting line to each partition according to the primary allocation coefficient based on the partitioned AC / DC system, so as to obtain the primary allocation line loss; calculate the secondary allocation coefficient based on the primary allocation line loss; allocate the total active power loss to each node according to the secondary allocation coefficient to obtain the secondary allocation line loss; adjust the power flow of the microgrid and the distribution network according to the preset load redistribution strategy, the primary allocation line loss and the secondary allocation line loss, and generate the power scheduling optimization strategy.

[0029] In some embodiments, the generator active output constraint is: Where, P i is the lower limit of active output of generator i, P i is the active power output of generator i, is the upper limit of active output of generator i;

[0030] Generator reactive output constraints: Where, Q i is the lower limit of reactive power output of generator i, Q i is the reactive power output of generator i, is the upper limit of reactive power output of generator i;

[0031] Each node must belong to one and only one partition: Where N is the node set, i is any node in it, S is the partition set, s is any partition in it, and v is the node partition variable. When node i belongs to partition s, v is =1, otherwise, v is =0;

[0032] Each partition has at least one generator: Where k is any generator node, u is the generator node partition variable, when the generator node k belongs to partition s, u ks =1, otherwise, u ks =0;

[0033] Line flow constraints: Where, P Ll is the lower limit of active power allowed to be transmitted by line l, P Ll is the active power transmitted by line l, is the upper limit of active power allowed to be transmitted on line l;

[0034] Minimum number of nodes for a partition: Where n is the number of nodes, s is any partition, i is the node in partition s, w is the node variable in the partition, and when node i belongs to partition s, w ik =1, otherwise, w ik =0;

[0035] Connectivity constraints: Where C ij is the adjacency matrix;

[0036] DC line constraints: z is +z js =1; where i and j are the starting point and end point of the DC line respectively, s is any partition, and z is the DC line node variable. When node i belongs to partition s, z is =1, otherwise, z is =0.

[0037] In a third aspect, an embodiment of the present invention provides an electronic device, comprising: a memory for storing executable instructions; and a processor for implementing the above-mentioned partitioned network loss allocation method for AC / DC systems when executing the executable instructions stored in the memory.

[0038] In a fourth aspect, an embodiment of the present invention provides a computer-readable storage medium storing executable instructions for causing a processor to execute the executable instructions to implement the above-mentioned partitioned network loss allocation method for AC / DC systems.

[0039] The present invention provides a partitioned network loss allocation method for an AC / DC system. First, AC line parameters, DC converter parameters, and DC line parameters of the AC / DC system are obtained; a preset AC / DC Newton-Raphson method is used to calculate the power flow of the AC / DC system to obtain key indicators; based on the key indicators, a preset power flow tracking algorithm based on a downstream distribution matrix is ​​used to solve the active power distribution coefficient matrix of each load at each generator node; a target modularity function is constructed based on the active power distribution coefficient matrix; based on the target modularity function, the AC / DC system is partitioned and solved to obtain a partitioned AC / DC system; based on a preset improved average network loss coefficient, the network loss coefficient of each node in the partitioned AC / DC system is solved; and based on the network loss coefficient of each node, a power scheduling optimization strategy is determined. In this way, the present invention can prepare to calculate the power distribution and flow path of each node in the AC / DC hybrid power grid, especially the power contribution from the generator to the load and loss, by performing AC / DC power flow calculations and applying a power flow tracking algorithm based on the downstream distribution matrix, thereby laying the foundation for the subsequent accurate allocation of network losses; secondly, a modularity index integrating the power flow tracking distribution coefficient is proposed, and the power grid is partitioned by considering the optimization model with unique constraints of the AC / DC system, thereby achieving a regional division that is more in line with the operating characteristics of the AC / DC hybrid power grid and improving the rationality and effectiveness of the partitioning results; thirdly, by implementing a two-stage network loss allocation method, including allocation between regions based on the tie line loss and the primary loss coefficient, and allocation to the node within the region based on the secondary loss coefficient, the total network loss of the AC / DC hybrid power grid can be more accurately and fairly allocated to specific generators and load entities, thereby solving the inaccuracy and unfairness of the existing methods in dealing with the network loss allocation of AC / DC systems. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 1. It is a structural diagram of a partitioned network loss sharing system for an AC / DC system provided by an embodiment of the present invention;

[0041] Figure 2 This is a flow chart of a method for allocating network losses in a zoned AC / DC system provided by an embodiment of the present invention;

[0042] Figure 3 This is a flow chart of a first method for allocating network losses in an AC / DC hybrid system provided by an embodiment of the present invention;

[0043] Figure 4 This is a flow chart of a second method for allocating network losses in a zoned AC / DC hybrid system provided by an embodiment of the present invention;

[0044] Figure 5 1 is a flow chart of a third method for allocating network losses in a zoned AC / DC hybrid system provided by an embodiment of the present invention;

[0045] Figure 6 1 is a flow chart of a fourth method for allocating network losses in a zoned AC / DC hybrid system provided by an embodiment of the present invention;

[0046] Figure 7 1 is a flow chart of a fifth method for allocating network losses in a zoned AC / DC hybrid system provided by an embodiment of the present invention;

[0047] Figure 8 This is a schematic diagram of the structure of a partitioned network loss sharing device for an AC / DC system provided by an embodiment of the present invention;

[0048] Figure 9 It is a schematic diagram of the structure of an electronic device provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0049] In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings. The described embodiments should not be regarded as limiting 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.

[0050] In the following description, references to "some embodiments" describe a subset of all possible embodiments. However, it is understood that "some embodiments" can be the same subset or different subsets of all possible embodiments, and can be combined with each other without conflict. Unless otherwise defined, all technical and scientific terms used in the embodiments of the present invention have the same meaning as commonly understood by those skilled in the art to which the embodiments of the present invention belong. The terms used in the embodiments of the present invention are for the purpose of describing the embodiments of the present invention only and are not intended to limit the present invention.

[0051] In the embodiments of the present invention, the term "module" or "unit" refers to a computer program or a part of a computer program that has a predetermined function and works together with other related parts to achieve a predetermined goal, and can be implemented in whole or in part by using software, hardware (such as processing circuits or memories), or a combination thereof. Similarly, a processor (or multiple processors or memories) can be used to implement one or more modules or units. In addition, each module or unit can be part of an overall module or unit that includes the function of the module or unit.

[0052] Before further explaining the embodiments of the present invention in detail, the nouns and terms involved in the embodiments of the present invention are explained. The nouns and terms involved in the embodiments of the present invention are subject to the following interpretations.

[0053] 1) AC / DC Systems: In power systems, alternating current (AC) and direct current (DC) are the two primary modes of power transmission. AC refers to current whose direction and magnitude change periodically over time, while DC is current whose direction and magnitude remain constant. AC / DC systems are those capable of handling both currents simultaneously and include key equipment such as AC generators, transformers, rectifiers, and inverters.

[0054] The following describes an exemplary application of a partitioned network loss allocation device for an AC / DC system according to an embodiment of the present invention. The partitioned network loss allocation device for an AC / DC system provided by an embodiment of the present invention can be implemented as a terminal or a server. In one implementation, the partitioned network loss allocation device for an AC / DC system provided by an embodiment of the present invention can be implemented as various types of terminals, such as laptop computers, tablet computers, desktop computers, and mobile devices. In another implementation, the partitioned network loss allocation device for an AC / DC system provided by an embodiment of the present invention can also be implemented as a server, wherein the server can be an independent physical server, or a server cluster or distributed system composed of multiple physical servers, or a cloud server that provides basic cloud computing services such as cloud services, cloud databases, cloud computing, cloud functions, cloud storage, network services, cloud communications, middleware services, domain name services, security services, content delivery networks (CDNs), and big data and artificial intelligence platforms. The terminal and the server can be connected directly or indirectly via wired or wireless communication, which is not limited in the embodiment of the present invention. The following describes an exemplary application of the partitioned network loss allocation device for an AC / DC system as a server.

[0055] See also Figure 1 , Figure 1 : is a structural diagram of the partitioned network loss sharing system 10 for the AC / DC system provided in an embodiment of the present invention. The embodiment of the present invention can provide a partitioned network loss sharing platform for the AC / DC system, and the partitioned network loss sharing platform for the AC / DC system can be implemented as a partitioned network loss sharing application for the AC / DC system. The partitioned network loss sharing system 10 for the AC / DC system provided in an embodiment of the present invention includes a terminal 110, a network 120, and a server 130, wherein the server 130 is a server of the partitioned network loss sharing application for the AC / DC system. The server 130 can constitute the partitioned network loss sharing device for the AC / DC system of the embodiment of the present invention. The terminal 110 is connected to the server 130 via the network 120, and the network 120 can be a wide area network or a local area network, or a combination of the two.

[0056] In some embodiments, please refer to Figure 1When performing partitioned network loss allocation for an AC / DC hybrid system, terminal 110 sends the AC / DC system network loss allocation task to server 130 via network 120. In response to the AC / DC system network loss allocation task sent by terminal 110, server 130 obtains the AC / DC system's AC line parameters, DC converter parameters, and DC line parameters. Based on the AC line parameters, DC converter parameters, and DC line parameters, server 130 uses a preset AC / DC Newton-Raphson method to calculate the AC / DC system's power flow to obtain key indicators. Based on the key indicators, server 130 uses a preset power flow tracking algorithm based on a downstream distribution matrix to calculate the active power distribution coefficient matrix for each load at each generator node. Based on the active power distribution coefficient matrix, a target modularity function is constructed. Based on the target modularity function, the AC / DC system is partitioned and solved to obtain a partitioned AC / DC system. Based on a preset improved average network loss coefficient, the network loss coefficient of each node in the partitioned AC / DC system is calculated. Based on the network loss coefficient of each node, a power scheduling optimization strategy is determined. After obtaining the power scheduling optimization strategy, server 130 sends the strategy to terminal 110 via network 120.

[0057] The embodiment of the present invention provides a method for allocating network loss in a zoned AC / DC system. Figure 2 , Figure 2 This is a flow chart of a method for allocating network loss in a zoned AC / DC system provided by an embodiment of the present invention, which combines Figure 2 The steps shown are explained.

[0058] Step S210: Acquire AC line parameters, DC converter parameters, and DC line parameters of the AC / DC system.

[0059] In some embodiments, AC line parameters include resistance, inductance, capacitance, conductance, and susceptance. In AC lines, resistance is a physical quantity that measures the resistance to current passing through a conductor. Due to the skin effect and proximity effect of AC current, AC resistance is typically greater than DC resistance. Resistance causes electrical energy to be lost as heat during transmission and is a key parameter affecting AC transmission efficiency and power quality.

[0060] The inductance of AC lines is primarily determined by factors such as the conductor geometry and spacing, as well as the surrounding dielectric. This inductance causes voltage drop and reactive power loss, significantly impacting the system's voltage distribution and stability. It also affects the transmission efficiency and power quality of the AC lines.

[0061] Capacitors generate reactive power in AC lines, affecting the voltage distribution and stability of the system, and also having a certain impact on the transmission characteristics of the AC lines.

[0062] Susceptance is a parameter that comprehensively considers the effects of inductance and capacitance on the reactive power transmission characteristics of AC lines. It reflects the transmission capacity and characteristics of reactive power in AC lines and is one of the key parameters in the analysis and design of AC transmission systems.

[0063] In some embodiments, DC line parameters include resistance, inductance, capacitance, and conductance. Unlike AC resistance, DC resistance is immune to skin effect and proximity effect. However, resistance remains a significant factor contributing to power loss in DC transmission systems, particularly in long-distance, high-voltage DC transmission lines, where power loss due to resistance requires precise calculation and control.

[0064] Step S220 , calculating the power flow of the AC / DC system using a preset AC / DC Newton-Raphson method according to the AC line parameters, the DC converter parameters, and the DC line parameters to obtain key indicators.

[0065] In some embodiments, the preset AC / DC Newton-Raphson method is a numerical calculation method for AC / DC system power flow calculations. In AC / DC systems, this method comprehensively considers the characteristics of components such as AC lines and DC converters, transforming the AC / DC system power flow problem into a set of nonlinear equations. Key system indicators, such as node voltage and power, are then obtained through iterative solution.

[0066] In some embodiments, power flow calculations analyze and calculate power flows in AC / DC systems. Given system operating conditions, such as generator output, load demand, AC line parameters, DC converter parameters, and DC line parameters, information such as voltage and current at each node in the system, as well as power distribution along each line, is calculated. Power flow calculations are crucial for assessing the operating status of AC / DC systems, analyzing their stability and safety, and performing system planning and scheduling.

[0067] In some embodiments, key indicators refer to important parameters obtained in power flow calculations that can reflect the operating status of the AC / DC system, such as node voltage amplitude, phase angle, line active power and reactive power, generator output, etc.

[0068] Step S230 , according to the key indicators, using a preset power flow tracking algorithm based on a downstream distribution matrix, to solve the active power distribution coefficient matrix of each load at each generator node.

[0069] In some embodiments, the active power allocation coefficient matrix is ​​a matrix whose elements represent the active power allocation ratio of each generator node to each load node. Derived from this matrix through a power flow tracking algorithm, it is possible to clearly determine the contribution of each generator to different loads, thereby facilitating the rational allocation of each generator's output, optimizing the operation of the power system, and improving the system's economy and reliability.

[0070] Step S240 , constructing a target modularity function according to the active power distribution coefficient matrix; partitioning the AC / DC system according to the target modularity function to obtain a partitioned AC / DC system.

[0071] In some embodiments, the target modularity function is constructed to partition the AC / DC system. Typically, based on information such as the system's topology and power flow distribution, the system is divided into distinct regions with the goal of maximizing modularity. This ensures close connections between nodes within each region, while connections between different regions are relatively weak. By optimizing the target modularity function, the optimal partitioning scheme for the system can be found, facilitating more effective analysis, control, and management of the system.

[0072] Step S250 , solving the network loss coefficient of each node in the partitioned AC / DC system according to the preset improved average network loss coefficient.

[0073] In some embodiments, the preset improved average loss coefficient is a parameter derived from an improvement to the traditional average loss coefficient. By introducing correction factors such as line resistance, reactance, and power flow distribution, it can more accurately reflect the contribution of different nodes to system loss, providing a more accurate basis for rationally allocating network losses and optimizing system operation.

[0074] In some embodiments, the nodes include load nodes, generator nodes, and balancing nodes.

[0075] In some embodiments, each node's network loss coefficient represents each node's contribution to active and reactive network losses. This parameter, calculated by pre-setting a modified average network loss coefficient, reflects the power loss at that node during system operation due to factors such as power transmission and line resistance.

[0076] Step S260: determining a power scheduling optimization strategy based on the network loss coefficient of each node.

[0077] In some embodiments, a power dispatch optimization strategy refers to a series of methods and measures used to optimize the power distribution and transmission methods among various power generation nodes, transmission lines, and load nodes within the power system during operation, in order to achieve goals such as reducing network losses, improving system economics, and ensuring power supply reliability and stability. This strategy must comprehensively consider multiple factors, including the system's real-time operating status, equipment parameters, constraints, and user needs.

[0078] In this way, the present invention can prepare to calculate the power distribution and flow path of each node in the AC / DC hybrid power grid, especially the power contribution from the generator to the load and loss, by performing AC / DC power flow calculations and applying a power flow tracking algorithm based on the downstream distribution matrix, thereby laying the foundation for the subsequent accurate allocation of network losses; secondly, a modularity index integrating the power flow tracking distribution coefficient is proposed, and the power grid is partitioned by considering the optimization model with unique constraints of the AC / DC system, thereby achieving a regional division that is more in line with the operating characteristics of the AC / DC hybrid power grid and improving the rationality and effectiveness of the partitioning results; thirdly, by implementing a two-stage network loss allocation method, including allocation between regions based on the tie line loss and the primary loss coefficient, and allocation to the node within the region based on the secondary loss coefficient, the total network loss of the AC / DC hybrid power grid can be more accurately and fairly allocated to specific generators and load entities, thereby solving the inaccuracy and unfairness of the existing methods in dealing with the network loss allocation of AC / DC systems.

[0079] In some embodiments, the above step S220 further includes the following steps S221 to S227:

[0080] Step S221 : constructing an AC node admittance matrix according to the AC line parameters, the DC converter parameters, and the DC line parameters.

[0081] Step S222 : Classify the nodes on the AC / DC system into different types according to the AC node admittance matrix and the node types to obtain the divided nodes.

[0082] Step S223 : constructing a DC network power imbalance and a DC Jacobian matrix of the DC system according to the DC converter parameters and the DC line parameters.

[0083] Step S224: Using a preset Newton iteration method, the relevant parameters of the DC side are updated according to the DC network power imbalance and the DC Jacobian matrix to obtain updated parameters; the updated parameters include the DC side voltage, current, transformer ratio and converter control angle.

[0084] Step S225 , calculating the active power flow, reactive power flow and injection power imbalance of nodes in the AC system according to the AC line parameters, and assembling the AC Jacobian matrix of the AC system.

[0085] Step S226 , iteratively correcting the node voltage amplitude and phase angle using the preset AC / DC Newton-Raphson method and the AC Jacobian matrix.

[0086] Step S227, alternately performing DC iteration and AC iteration in the same loop until the correction increments of the DC and AC variables are both less than the preset convergence accuracy, and outputting the key indicators; the key indicators include bus voltage amplitude, phase angle, generator output, DC and AC system power flow and total network loss.

[0087] In some embodiments, the above step S230 further includes the following steps S231 to S234:

[0088] Step S231 : Allocate the network loss on the lossy network line to the nodes at both ends of the line as loads, thereby simplifying the lossy network and obtaining a lossless network.

[0089] Step S232 : Calculate the total injected active power of each node according to the lossless network and the key indicator using the active power transmitted on the branch and the active load of each node.

[0090] Step S233 : calculating the downstream distribution matrix between nodes according to the total injected active power and the preset power flow tracking algorithm based on the downstream distribution matrix.

[0091] Step S234 , calculating the active power distribution of each generator to each load according to the preset proportional sharing principle and the inter-node downstream distribution matrix, and calculating the active power distribution coefficient matrix.

[0092] In some embodiments, the above step S240 further includes the following steps S241 to S242:

[0093] Step S241 : constructing the target modularity function based on the power flow tracking method according to the active power distribution coefficient matrix.

[0094] Step S242 : partitioning and solving the target modularity function according to preset partitioning rules and preset constraints to obtain the partitioned AC / DC system.

[0095] In some embodiments, the target modularity function in step S240 is expressed as:

[0096]

[0097] Where M is the modularity function based on power flow tracking, m is the sum of edge weights, i and j are the nodes in the system, k is the ij is the active power distribution coefficient of the downstream tracking method, k i and k j are the weighted degrees of nodes i and j, δ ij It is a binary variable, which takes the value of 1 to indicate that nodes i and j are in the same partition, and 0 otherwise.

[0098] In some embodiments, the above step S260 further includes the following steps S261 to S264:

[0099] Step S261 : Based on the partitioned AC / DC system, the total active power loss of the tie line is allocated to each partition according to a primary allocation coefficient to obtain a primary allocated line loss.

[0100] Step S262: Calculate a secondary apportionment coefficient based on the primary apportionment line loss.

[0101] Step S263: Allocate the total active power loss to each node according to the secondary allocation coefficient to obtain a secondary allocated line loss.

[0102] Step S264: According to the preset load redistribution strategy, the primary shared line loss and the secondary shared line loss, the power flow of the microgrid and the distribution network is adjusted to generate the power dispatch optimization strategy.

[0103] The following describes an exemplary application of an embodiment of the present invention in a practical application scenario.

[0104] See also Figure 3 The present invention provides a method for allocating network losses in an AC / DC hybrid system, comprising the following steps:

[0105] S1: Based on the relevant data information of the AC / DC system, the AC / DC iterative Newton method is used to calculate and solve the power flow of the AC / DC system to obtain the output of each generator and the power flow on the line.

[0106] In this embodiment, the relevant data information includes AC line parameters, DC converter parameters, DC line parameters, generator information (voltage, active power), and node load information.

[0107] S2: Use the power flow tracking algorithm based on the downstream distribution matrix to solve the active power distribution of each generator node to each load, that is, solve the active power distribution coefficient matrix of each generator node and each load node.

[0108] S3: The calculated active power distribution coefficient matrix is ​​used to replace the adjacency matrix of the modularity function Q value in the GN algorithm to obtain the modularity function based on the power flow tracking method, and it is used as the objective function to solve and obtain the optimal partitioning result.

[0109] S4: For AC / DC systems with multiple access entities, the network loss coefficient of each participating entity is obtained using the improved average network loss coefficient method, and the line active power loss allocated to each participating entity node is calculated.

[0110] See also Figure 4 The specific steps of solving the AC / DC system power flow results in step S1 above include:

[0111] S101: Obtain line parameters based on the data in the example, construct the AC node admittance matrix, and classify the node types.

[0112] In the present invention, AC line parameters, DC converter parameters and DC line parameters are read according to the data in the calculation example, an AC node admittance matrix is ​​constructed, and PQ, PV and balance nodes are divided according to the node type.

[0113] S102: Constructing a corresponding Jacobian matrix according to the DC commutation parameters and the DC line parameters, and using the Newton iteration method to update the DC side voltage, current, transformer ratio and converter control angle.

[0114] In the present invention, the DC network power imbalance and the corresponding Jacobian matrix are constructed according to the DC converter parameters and the DC line parameters, and the DC side voltage, current, transformer ratio and converter control angle are updated using the Newton iteration method.

[0115] S103: Calculate the power flow, injected power, and Jacobian matrix of the node based on the AC line parameters, and calculate the node voltage according to the Newton-Raphson method.

[0116] In the present invention, the imbalance of active and reactive power flows and injected power at the node is calculated based on the AC line parameters, the Jacobian matrix is ​​assembled, the node voltage amplitude and phase angle are iteratively corrected by the Newton-Raphson method, and the tributary iteration and AC iteration are alternately performed in the same cycle until the correction increments of the DC and AC variables are less than the convergence accuracy. After convergence, key indicators such as bus voltage amplitude, phase angle, generator output, DC and AC system flows and total network loss are output.

[0117] See also Figure 5 The specific steps of generating the active power distribution coefficient matrix in the above step S2 include:

[0118] S201: Simplify the lossy network into a lossless network according to the node and bus parameters of the system.

[0119] In the present invention, according to the node parameters and bus parameters of the AC / DC hybrid system, the losses on the line are evenly distributed to the starting point and end point of the line as the loads of the starting point and end point, so that the AC / DC hybrid system is simplified into a lossless network.

[0120] S202: Based on the simplified lossless network, a downstream distribution matrix and an active power distribution coefficient matrix of the generator node to the load are calculated according to the active power of the branch and the load of the node.

[0121] In the present invention, based on the simplified lossless network, the total injected active power of node i is calculated using the active power transmitted on branch ij and the active load of node i, and then the downstream distribution matrix A between nodes is calculated. Then, the proportional sharing principle is applied to obtain the active power distribution of generator i to load p, and the distribution coefficient matrix of generator i to load p is obtained.

[0122] See also Figure 6 The specific steps of generating the optimal partitioning result in step S3 include:

[0123] S301: Constructing a modularity function M based on the power flow tracking method based on the active power distribution coefficient matrix of the GN algorithm and the downstream tracking method.

[0124] S302: According to the requirements of the partitioning, appropriate constraints are designed, and the objective function and the constraints are solved to obtain the optimal partitioning result.

[0125] In the present invention, based on the GN algorithm in the community discovery algorithm, it is a splitting method. The core idea of ​​the GN algorithm is to split the network into communities by gradually removing the edges with the highest number of boundaries, and maximize the modularity function Q to improve the quality of community division. The modularity function Q is a commonly used effect indicator of network partitioning, and the formula is as follows: k i represents the weighted degree of node i; k j represents the weighted degree of node j; δ ij represents a binary variable, which takes 1 to indicate that nodes i and j are in the same partition, otherwise it takes 0; e ij represents the adjacency matrix; m represents the sum of edge weights.

[0126] The modularity function M based on power flow tracking is the adjacency matrix e of the original modularity function Q ij Replaced by the system's active power distribution coefficient k ij , and take M as the objective function:

[0127] According to the requirements and rules of the preset partitioning, the constraints are determined, including that each node can only have one partition, each partition contains at least one generator power upper and lower limit constraint, line safety operation constraint, minimum number of nodes in each partition constraint, topological connectivity constraint, and DC line must be used as a tie line constraint; the solution is performed based on the objective function and the constraints, and the optimal partitioning result is output.

[0128] See also Figure 7 The specific steps of generating the optimal partitioning result in step S4 include:

[0129] S401: Based on the partitioned AC / DC hybrid system, the total active power loss of the tie line is allocated to each partition according to the primary allocation coefficient.

[0130] In this embodiment, based on the partitioned AC / DC hybrid system, the AC lines and DC lines connecting different partitions are identified. These are the tie lines between regions. The active power losses of all tie lines are summarized, and the active power of the equivalent power source and load of each partition is calculated. The active power losses of all tie lines are allocated to each partition according to the primary allocation coefficient. The network loss coefficient λ of participant i is calculated as follows:

[0131] Among them, P loss is the line loss of the entire network, P i is the active power of participating node i.

[0132] In an AC / DC hybrid system, the main entities participating in network loss sharing are power supply and load. The calculation formulas for the line loss coefficients of power supply and load are:

[0133] Among them, λ G and λ L are the line loss coefficients of power supply and load respectively; a represents the total number of power supply nodes; b represents the total number of load nodes.

[0134] According to the line loss coefficient of the participating entities, the line loss L borne by a certain type of participating entity can be calculated. j For: L j =λ j P j .

[0135] S402: After calculating the secondary allocation coefficient based on the primary allocated line loss obtained by partition, the total active power loss in the partition is allocated to each node according to the secondary allocation coefficient to obtain the active power loss allocated to each node by the system.

[0136] In this embodiment, the total loss within the partition is calculated based on the loss allocated to each partition once and the line loss of each partition, and the line loss coefficient of the secondary allocation is calculated. The network loss that each node should bear is calculated based on the line loss coefficient of the secondary allocation.

[0137] S403: Based on the load redistribution plan, adjust the power flow between the microgrid and the distribution network, perform new power allocation and transmission path adjustment, and generate a power scheduling optimization plan.

[0138] In this embodiment, the constraints include:

[0139] Generator active output constraints: in, P i is the lower limit of active output of generator i, P iis the active power output of generator i, is the upper limit of active output of generator i.

[0140] Generator reactive output constraints: in, Q i is the lower limit of reactive power output of generator i, Q i is the reactive power output of generator i, is the upper limit of reactive power output of generator i.

[0141] Each node must belong to one and only one partition: Where N is the node set, i is any node in it, S is the partition set, s is any partition in it, and v is the node partition variable. When node i belongs to partition s, v is =1, otherwise, v is =0.

[0142] Each partition has at least one generator: Where k is any generator node, u is the generator node partition variable, when the generator node k belongs to partition s, u ks =1, otherwise, u ks =0.

[0143] Line flow constraints: Where, P Ll is the lower limit of active power allowed to be transmitted by line l, P Ll is the active power transmitted by line l, is the upper limit of active power allowed to be transmitted on line 1.

[0144] Minimum number of nodes for a partition: Where n is the number of nodes, s is any partition, i is the node in partition s, w is the node variable in the partition, and when node i belongs to partition s, w ik =1, otherwise, w ik =0.

[0145] Connectivity constraints: Where C ij is the adjacency matrix.

[0146] DC line constraints: z is +z js =1; where i and j are the starting point and end point of the DC line respectively, s is any partition, and z is the DC line node variable. When node i belongs to partition s, z is =1, otherwise, z is =0.

[0147] Figure 8FIG. 1 is a schematic diagram of the structure of a partitioned network loss sharing device for an AC / DC system provided by an embodiment of the present invention. Figure 8 As shown, the partitioned network loss allocation device 800 of the AC / DC system includes: an acquisition module 801, which is used to obtain AC line parameters, DC converter parameters and DC line parameters of the AC / DC system; an operation module 802, which is used to perform power flow calculation on the AC / DC system according to the AC line parameters, the DC converter parameters and the DC line parameters using a preset AC / DC Newton-Raphson method to obtain key indicators; a solution module 803, which is used to solve the active power distribution coefficient matrix of each load at each generator node according to the key indicators using a preset power flow tracking algorithm based on the downstream distribution matrix; a construction module 804, which is used to construct a target modularity function according to the active power distribution coefficient matrix; partitioning the AC / DC system according to the target modularity function to obtain a partitioned AC / DC system; the solution module 803 is also used to solve the network loss coefficient of each node in the partitioned AC / DC system according to a preset improved average network loss coefficient; and a calculation module 805 is used to determine a power scheduling optimization strategy according to the network loss coefficient of each node.

[0148] It should be noted that the description of the device embodiment of the present invention is similar to the description of the above-mentioned method embodiment, and has similar beneficial effects as the same method embodiment, so it will not be repeated. For technical details not disclosed in the device embodiment, please refer to the description of the method embodiment of the present invention for understanding.

[0149] Based on the above embodiments, an embodiment of the present invention further provides an electronic device, Figure 9 FIG. 1 is a structural diagram of an electronic device according to an embodiment of the present invention. Figure 9 As shown, the hardware entity of the electronic device 900 includes: a memory 901 and a processor 902. The memory 901 stores a computer program that can be run on the processor 902. When the processor 902 executes the program, the steps in the partition network loss allocation of the AC and DC system in the above embodiment are implemented.

[0150] The memory 901 is configured to store instructions and applications executable by the processor 902, and can also cache data to be processed or processed by the processor 902 and various modules in the electronic device 900 (for example, image data, audio data, voice communication data and video communication data), which can be implemented through flash memory (FLASH) or random access memory (Random Access Memory, RAM).

[0151] Based on the foregoing embodiments, an embodiment of the present invention further provides a computer-readable storage medium, which stores a computer program. When the computer program is executed by a processor of an electronic device, it can implement the partitioned network loss allocation method of the AC / DC system provided in any of the foregoing embodiments.

[0152] The above description of the various embodiments tends to emphasize the differences between the various embodiments. The same or similar aspects can be referenced with each other and will not be repeated herein for the sake of brevity.

[0153] The methods disclosed in the various method embodiments provided by the present invention can be arbitrarily combined without conflict to obtain new method embodiments.

[0154] The features disclosed in the various product embodiments provided by the present invention can be arbitrarily combined without conflict to obtain new product embodiments.

[0155] The features disclosed in the various method or device embodiments provided by the present invention can be arbitrarily combined without conflict to obtain new method embodiments or device embodiments.

[0156] It should be noted that the above-mentioned computer-readable storage medium can be a ferroelectric random access memory (FRAM), a read-only memory (ROM), a programmable read-only memory (PROM), an erasable programmable read-only memory (EPROM), an electrically erasable programmable read-only memory (EEPROM), a flash memory, a magnetic surface memory, an optical disc, or a compact disc read-only memory (CD-ROM) and other memories; it can also be various electronic devices that include one or any combination of the above-mentioned memories, such as mobile phones, computers, tablet devices, personal digital assistants, etc.

[0157] It should be noted that, in this article, the terms "comprise", "include" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method or device comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method or device. In the absence of further restrictions, an element defined by the statement "comprises a..." does not exclude the presence of other identical elements in the process, method, article or device comprising the element. In the several embodiments provided by the present invention, it should be understood that the disclosed devices and methods can be implemented in other ways. The device embodiments described above are merely schematic. For example, the division of the units is only a logical function division. In actual implementation, there may be other division methods, such as: multiple units or components can be combined, or can be integrated into another system, or some features can be ignored, or not executed.

[0158] The serial numbers of the above embodiments of the present invention are for description only and do not represent the advantages or disadvantages of the embodiments.

[0159] Through the description of the above embodiments, those skilled in the art can clearly understand that the above-mentioned embodiment methods can be implemented by means of software plus necessary general hardware nodes, or of course by hardware, but in many cases the former is a better embodiment. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art, can be embodied in the form of a software product. The computer software product is stored in a storage medium (such as ROM / RAM, magnetic disk, optical disk), and includes a number of instructions for enabling a terminal device (which can be a mobile phone, computer, server, air conditioner, or network device, etc.) to execute the methods described in the various embodiments of the present invention.

[0160] The present invention is described with reference to flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to embodiments of the present invention. It should be understood that each process and / or block in the flowcharts and / or block diagrams, as well as combinations of processes and / or blocks in the flowcharts 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, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowcharts and / or block diagrams. Figure 1 a process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0161] These computer program instructions may also be stored in a computer readable memory that can direct a computer or other programmable data processing device to work in a specific manner, so that the instructions stored in the computer readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 a process or multiple processes and / or boxes Figure 1 The function specified in one or more boxes.

[0162] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operational steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing the instructions executed on the computer or other programmable device for implementing the process. Figure 1 a process or multiple processes and / or boxes Figure 1 A step that specifies a function in one or more boxes.

[0163] 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 modifications or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in the present invention should be included in the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be based on the scope of protection of the claims.

Claims

1. A method for allocating regional network losses in an AC / DC system, characterized in that: The method comprises: Obtaining AC line parameters, DC converter parameters, and DC line parameters of the AC / DC system; According to the AC line parameters, the DC converter parameters and the DC line parameters, a preset AC / DC Newton-Raphson method is used to calculate the power flow of the AC / DC system to obtain key indicators; According to the key indicators, the active power distribution coefficient matrix of each load at each generator node is solved using a preset power flow tracking algorithm based on the downstream distribution matrix; Constructing a target modularity function according to the active power distribution coefficient matrix; partitioning the AC / DC system according to the target modularity function to obtain a partitioned AC / DC system; According to the preset improved average network loss coefficient, solving the network loss coefficient of each node in the partitioned AC / DC system; A power scheduling optimization strategy is determined based on the network loss coefficient of each node.

2. The method according to claim 1, characterized in that The power flow calculation of the AC / DC system is performed based on the AC line parameters, the DC converter parameters, and the DC line parameters using a preset AC / DC Newton-Raphson method to obtain key indicators, including: constructing an AC node admittance matrix according to the AC line parameters, the DC converter parameters, and the DC line parameters; Classify the nodes on the AC / DC system into different types according to the AC node admittance matrix and the node type to obtain the divided nodes; constructing a DC network power imbalance and a DC Jacobian matrix of the DC system according to the DC converter parameters and the DC line parameters; Using a preset Newton iteration method, the DC side related parameters are updated according to the DC network power imbalance and the DC Jacobian matrix to obtain updated parameters; the updated parameters include the DC side voltage, current, transformer ratio, and converter control angle; Calculating active power flow, reactive power flow and injection power imbalance of nodes in the AC system according to the AC line parameters, and assembling an AC Jacobian matrix of the AC system; Iteratively correcting the node voltage amplitude and phase angle by the preset AC / DC Newton-Raphson method and the AC Jacobian matrix; DC iteration and AC iteration are performed alternately within the same loop until the correction increments of the DC and AC variables are both less than the preset convergence accuracy, and the key indicators are output; the key indicators include bus voltage amplitude, phase angle, generator output, DC and AC system power flow and total network loss.

3. The method according to claim 1, characterized in that According to the key indicators, a preset power flow tracking algorithm based on the downstream distribution matrix is ​​used to solve the active power distribution coefficient matrix of each load at each generator node, including: Distributing the network loss on the lossy network line to the nodes at both ends of the line as loads, thereby simplifying the lossy network and obtaining a lossless network; Calculate the total injected active power of each node based on the lossless network and the key indicators using the active power transmitted on the branch and the active load of each node; Calculating an inter-node downstream distribution matrix according to the total injected active power and the preset power flow tracking algorithm based on the downstream distribution matrix; According to the preset proportional sharing principle and the downstream distribution matrix between nodes, the active power distribution of each generator to each load is calculated, and the active power distribution coefficient matrix is ​​calculated.

4. The method according to claim 1, wherein Partitioning and solving the AC / DC system according to the target modularity function to obtain a partitioned AC / DC system includes: Constructing the target modularity function based on the power flow tracking method; According to preset partitioning rules and preset constraints, the target modularity function is partitioned and solved to obtain the partitioned AC / DC system.

5. The method according to claim 4, characterized in that The target modularity function is expressed as: Where M is the modularity function based on power flow tracking, m is the sum of edge weights, i and j are the nodes in the system, k is the ij is the active power distribution coefficient of the downstream tracking method, k i and k j are the weighted degrees of nodes i and j, δ ij It is a binary variable, which takes the value of 1 to indicate that nodes i and j are in the same partition, and 0 otherwise.

6. The method according to claim 1, characterized in that Determining a power scheduling optimization strategy according to the network loss coefficient of each node includes: According to the partitioned AC / DC system, the total active power loss of the tie line is allocated to each partition according to the primary allocation coefficient to obtain the primary allocated line loss; Calculating a secondary apportionment coefficient based on the primary apportionment line loss; Allocate the total active power loss to each node according to the secondary allocation coefficient to obtain the secondary allocated line loss; According to the preset load redistribution strategy, the primary shared line loss and the secondary shared line loss, the power flow of the microgrid and the distribution network is adjusted to generate the power dispatch optimization strategy.

7. The method according to claim 4, characterized in that The preset constraints include: Generator active output constraints: Where, P i is the lower limit of active power output of generator i, P i is the active power output of generator i, is the upper limit of active output of generator i; Generator reactive output constraints: Where, Q i is the lower limit of reactive power output of generator i, Q i is the reactive power output of generator i, is the upper limit of reactive power output of generator i; Each node must belong to one and only one partition: Where N is the node set, i is any node in it, S is the partition set, s is any partition in it, and v is the node partition variable. When node i belongs to partition s, v is =1, otherwise, v is =0; Each partition has at least one generator: Where k is any generator node, u is the generator node partition variable, when the generator node k belongs to partition s, u ks =1, otherwise, u ks =0; Line flow constraints: Where, P Ll is the lower limit of active power allowed to be transmitted by line l, P Ll is the active power transmitted by line l, is the upper limit of active power allowed to be transmitted on line l; Minimum number of nodes for a partition: Where n is the number of nodes, s is any partition, i is the node in partition s, w is the node variable in the partition, and when node i belongs to partition s, w ik =1, otherwise, w ik =0; Connectivity constraints: Where C ij is the adjacency matrix; DC line constraints: z is +z js =1; where i and j are the starting point and end point of the DC line respectively, s is any partition, and z is the DC line node variable. When node i belongs to partition s, z is =1, otherwise, z is =0.

8. A partitioned network loss sharing device for an AC / DC system, characterized in that: The device comprises: An acquisition module, used to acquire AC line parameters, DC converter parameters and DC line parameters of the AC / DC system; a calculation module, configured to calculate the power flow of the AC / DC system using a preset AC / DC Newton-Raphson method according to the AC line parameters, the DC converter parameters, and the DC line parameters to obtain key indicators; A solution module is used to solve the active power distribution coefficient matrix of each load at each generator node according to the key indicators using a preset power flow tracking algorithm based on a downstream distribution matrix; A construction module is used to construct a target modularity function according to the active power distribution coefficient matrix; partition the AC / DC system according to the target modularity function to obtain a partitioned AC / DC system; The solving module is further configured to solve the network loss coefficient of each node in the partitioned AC / DC system according to a preset improved average network loss coefficient; The calculation module is used to determine the power scheduling optimization strategy according to the network loss coefficient of each node.

9. An electronic device, characterized in that: include: a memory for storing executable instructions; The processor is configured to implement the partitioned network loss allocation method for an AC / DC system according to any one of claims 1 to 7 when executing the executable instructions stored in the memory.

10. A computer-readable storage medium, characterized in that Executable instructions are stored, which are used to cause a processor to execute the executable instructions to implement the partitioned network loss allocation method of the AC / DC system according to any one of claims 1 to 7.

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