Line loss metering method and system using minimum energy gateway

Abstract

The invention relates to the technical field of smart power grids, and discloses a line loss metering method and system using a minimum energy gateway, and the method comprises the steps: building a mathematical model according to a low-voltage power distribution network area topological graph, and the mathematical model comprises an objective function, a state constraint, an inference constraint, a degree constraint and a budget constraint; solving the model, calculating out-degree of each node, defining node priority, and calculating a constraint equation of each node according to a mathematical model; determining a placement scheme of the energy gateway by calculating power information; and calculating an electric energy quality line loss power factor, and evaluating the line loss of the low-voltage transformer area. According to the method, the line loss of the whole transformer area network can be accurately calculated, and the evaluation target of the line loss of the low-voltage transformer area is effectively realized. The accuracy of line loss monitoring is improved, and a new solution is provided for intelligent management of the power distribution network.

Description

Technical Field

[0001] The present invention relates to the field of smart grid technology, and in particular to a line loss metering method and system using a minimum energy gateway. Background Art

[0002] In the evolution of modern power systems, the innovation of digital and intelligent technologies has become the core driving force in the global energy sector. With the rapid development of information technology, intelligent management of power systems has become particularly important, especially in the distribution network, which is the key link between the power grid and end users and is called the "last mile" of power transmission. Its operating efficiency and power supply reliability play a decisive role in the overall performance of the power system. Especially in low-voltage distribution networks, due to the large number of substations and complex network structures, the demand for digital and intelligent management is particularly urgent. One of the concentrated manifestations of this demand is the intelligent monitoring and precise management of line losses.

[0003] Line loss mainly comes from power quality problems such as reactive power, harmonics and three-phase imbalance. Its essence is the energy loss generated in the form of heat energy during the transmission of current. Line loss rate, as an important technical indicator reflecting the efficiency of power grid operation, directly affects the economy and stability of the power system. Among them, the main factors affecting the intelligent monitoring and precise management of line loss are: the relationship between the low-voltage distribution network transformer and the user meter does not correspond, various electricity theft behaviors lead to increased line loss, and traditional technical means cannot monitor the size of line loss in real time. Therefore, the use of low-voltage metering units to carry out intelligent monitoring and management of low-voltage distribution networks has become an effective means to solve this problem.

[0004] Energy gateway is a key device for real-time monitoring and management of line loss in modern distribution networks. With the continuous improvement of the level of intelligent power grid, the application of energy gateway has become an important part of the optimization and management of distribution network. Its main function is to accurately calculate line loss by accurately measuring the current, voltage and power parameters of the low-voltage distribution network. Through real-time collection and analysis of these key parameters, the energy gateway can identify the root causes of line loss, such as harmonic interference, excessive reactive power, three-phase imbalance or power theft. The occurrence of each abnormal situation will have a serious impact on the operating efficiency and power quality of the power grid. Through intelligent sampling and analysis, the energy gateway can quickly identify and locate these problems, provide accurate fault diagnosis and decision-making basis for power grid companies, thereby helping operation and maintenance personnel to grasp the operating status of the distribution network in real time and effectively improve the monitoring and management capabilities of the power system.

[0005] In the low-voltage distribution network, due to the large number of substations and complex network structure, especially the diverse user loads and uneven geographical distribution in some substations, the monitoring and management of the entire distribution network faces great challenges. If the line loss of the entire substation is to be managed, the traditional method usually requires the installation of an energy gateway in each branch for data collection. Although this approach can ensure the accuracy of the measurement, it also has the problem of high deployment cost and difficulty in implementation. First, the number of substations in the distribution network is huge, and there may be multiple branches in a single substation. The traditional method requires the installation of an energy gateway in each branch. In this way, not only the equipment procurement and installation costs are greatly increased, but also the subsequent maintenance and management work will face more complexity. Secondly, the traditional installation method often cannot effectively adapt to the rapid changes and upgrades of the distribution network, resulting in difficulty in achieving efficient resource allocation and cost control in actual operation.

[0006] Therefore, optimizing the deployment strategy of energy gateways has become the key to improving the management efficiency of distribution networks and reducing costs. By accurately calculating and estimating the losses of the substation topology network, the number of energy gateways can be reduced while ensuring data accuracy, thereby achieving the monitoring and management of the entire substation with a minimum number of energy gateways. This strategy can not only significantly reduce the cost of equipment installation and operation and maintenance, but also effectively improve the intelligence level and operation efficiency of the distribution network. In order to achieve this goal, this paper will explore the mathematical models and strategies for optimizing the deployment of energy gateways, combining the substation topology, load distribution and power transmission characteristics, and determine the best energy gateway installation plan through simulation and optimization algorithms, in order to minimize costs while ensuring accurate monitoring and efficient management of distribution network line losses. Summary of the invention

[0007] In view of the above existing problems, the present invention is proposed.

[0008] Therefore, the present invention provides a line loss metering method using a minimum of energy gateways, which can solve the problem of excessive number of equipment and high cost in traditional line loss metering. Through mathematical model optimization, accurate line loss monitoring with a minimum of energy gateways can be achieved. At the same time, the location of the energy gateway is reasonably configured to achieve resource optimization and economy. In addition, by comprehensively evaluating the line loss in the low-voltage area, improving power quality management, and improving the efficiency of the distribution network, the data monitoring needs of the modern smart grid are met, and the power information of the section without the energy gateway is calculated to enhance the overall monitoring capability.

[0009] To solve the above technical problems, the present invention provides the following technical solutions: a line loss metering method using the least energy gateway, comprising: establishing a mathematical model according to a low-voltage distribution network substation topology diagram, including an objective function, state constraints, inference constraints, degree constraints and budget constraints; solving the model, calculating the out-degree of each node, defining the node priority, and calculating the constraint equation of each node according to the mathematical model; determining the placement plan of the energy gateway by inferring power information; calculating the power factor of the power quality line loss, and evaluating the line loss in the low-voltage substation.

[0010] As a preferred solution of the line loss measurement method using the least energy gateway described in the present invention, the objective function includes setting x ij is a decision variable, indicating whether to install an energy gateway on road section ij:

[0011]

[0012] Among them, if installed, then x ij =1, otherwise x ij =1, E is the set of sections in the substation topology network, and the formula represents the minimum number of energy gateways to be installed, while meeting the monitoring requirements of each section in the distribution network.

[0013] As a preferred solution of a line loss metering method using a minimum energy gateway described in the present invention, the state constraints include that each section can only be in one state at any time and cannot have multiple states at the same time, state 1 needs to rely on direct equipment monitoring, state 2 is related to the power conservation of node i, and state 3 depends on the power conservation of node j;

[0014] Since the power information of each road section can only be obtained in one way, it is impossible to be in multiple states at the same time:

[0015]

[0016] The inference constraints include that, according to the node power conservation, an ordinary node i can usually only infer the power of one road section, and the power of any road section cannot be inferred from the centroid point i, so there is the following formula:

[0017]

[0018] Among them, λ i is a decision variable, which is 1 when node i is an ordinary node and 0 when node i is a centroid point. N is the set of nodes in the substation topology network.

[0019] As a preferred solution of the line loss metering method using the least energy gateway described in the present invention, wherein: the degree constraint includes, in network optimization, limiting the topology of the network by introducing the priority of the node and the out-degree constraint, ensuring the directionality of the road section by setting the priority of the node, and avoiding the occurrence of loops in the optimization process;

[0020] Using variable z ij Define node priority. If the road segment between nodes i and j is from i to j, then z ij =1, otherwise, z ij =0; define the out-degree of node i as δ i , then the following constraints apply to node i:

[0021]

[0022] Among them, d out (i) is the out-degree of node i, that is, the number of road segments starting from node i;

[0023] The budget constraint includes setting the budget of the distribution network to B, that is, the total cost of installing all energy gateways must not exceed the current budget, and introducing constraints so that the total installation cost of all energy gateways does not exceed the budget; the installation cost constraint of the energy gateway is expressed as:

[0024]

[0025] Among them, b ij Represents the cost of installing an energy gateway on road section ij.

[0026] As a preferred solution of the line loss metering method using the least energy gateway described in the present invention, the calculation of the out-degree of each node includes solving the above mathematical model using a specific low-voltage area topology diagram, and only considering the out-degree of each node:

[0027] δ1=δ2=δ3=δ4=δ5=2, δ6=1

[0028] The node priorities are defined as follows:

[0029] z 12 =z 13 =z 14 =z 15 =z 16 =1

[0030] z 23 =z 24 =z 25 =z 26 =1

[0031] z 34 =z 35=z 36 =1

[0032] z 45 =z 46 =1

[0033] z 56 =1

[0034] According to the constraint equations of each node, nodes 7, 8, 9, 10, 11, and 12 are all user nodes, that is, sink nodes, with an out-degree of 0. There is no need to write constraint equations. Finally, the following conclusions are obtained:

[0035] x 12 =x 23 =x 34 =x 45 =x 56 =x 69 =1

[0036] x 210 =x 37 =x 48 =x 511 =x 612 =0

[0037] but

[0038]

[0039] By accurately selecting nodes and road sections and combining the power conservation law and budget constraints, the deployment of energy gateways can be minimized and optimal cost control can be achieved while meeting monitoring requirements.

[0040] As a preferred solution of the line loss measurement method using the least energy gateway described in the present invention, the power information is estimated by estimating the power information for the road section where no energy gateway is placed in the following manner to meet the line loss assessment requirements of the distribution network. The specific method is as follows:

[0041]

[0042] Where P is power.

[0043] As a preferred solution of a line loss metering method using the least energy gateways described in the present invention, wherein: the calculation of the power quality line loss power factor includes, after determining the placement plan of the energy gateway, arranging the energy gateway to measure the active and reactive power of each line section, and obtaining the following four power quality line loss power factors in the case of a three-phase system:

[0044]

[0045] Among them, PF ePIndicates the fundamental positive sequence active line loss power factor, PF eQ Indicates reactive line loss power factor, PF eU Indicates the unbalanced line loss power factor, PF eH Indicates the harmonic line loss power factor, S eLoss Indicates the apparent power of bus loss, S1 + Indicates the fundamental positive sequence apparent power, S ePU Indicates the apparent power of unbalanced line loss, S ePH Indicates the apparent power of harmonic line loss, P1 + Indicates the basic positive sequence active power, Q1 + Represents the basic positive sequence reactive power, S U1 is the unbalanced apparent power, D eI is the current distortion power;

[0046] The above four types of power quality line loss power factors can be used to fully evaluate the line loss in the low-voltage area.

[0047] As a preferred solution of a line loss metering system using the least energy gateway described in the present invention, it includes: a mathematical model module, a node out-degree calculation module, a power estimation module, an energy gateway placement solution module, and a power quality assessment module;

[0048] The mathematical model module is used to establish and define the objective function, state constraints, inference constraints, degree constraints and budget constraints to form a mathematical framework for the entire line loss measurement;

[0049] The node out-degree calculation module is responsible for calculating the out-degree of each node in the network, determining the priority of each node, and deriving relevant constraint equations based on this to optimize the deployment of the energy gateway;

[0050] The power estimation module estimates the power information of the road section where the energy gateway is not installed based on the existing installation scheme and network topology to support the evaluation of line loss;

[0051] The energy gateway placement solution module determines the optimal layout location of the energy gateway to ensure that the energy gateway can meet monitoring requirements and minimize deployment costs;

[0052] The power quality assessment module assesses the power quality of the low-voltage distribution network through different line loss power factor calculation methods, analyzes various types of line losses, and provides a comprehensive line loss assessment result.

[0053] A computer device comprises a memory and a processor, wherein the memory stores a computer program, and is characterized in that when the processor executes the computer program, steps of a line loss metering method using a minimum energy gateway are implemented.

[0054] A computer-readable storage medium having a computer program stored thereon, characterized in that when the computer program is executed by a processor, the computer program implements the steps of a line loss metering method using a minimum energy gateway.

[0055] Beneficial effects of the invention: The research focus of this patent is to explore the optimal configuration strategy of energy gateways, aiming to achieve the minimum deployment of line loss monitoring in substations. In the study, the constraints of the model were simplified according to the out-degree characteristics of the nodes. This method not only improves the computational efficiency of the model, but also enhances the practicability of the model. In addition, this method also introduces budget constraints, making the model closer to the needs of actual application scenarios. This method shows obvious innovation in the simplification of model constraints and the addition of budget constraints. Through these improvements, this method not only determines the minimum necessary number of energy gateways, but also accurately points out their specific installation locations. It has been verified in practice that the placement scheme proposed by this method can accurately calculate the line loss of the entire substation network, effectively achieving the evaluation target of low-voltage substation line loss. This achievement not only improves the accuracy of line loss monitoring, but also provides a new solution for the intelligent management of distribution networks. BRIEF DESCRIPTION OF THE DRAWINGS

[0056] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work. Among them:

[0057] Figure 1 A schematic flow chart of a line loss metering method using a minimum energy gateway is provided for one embodiment of the present invention.

[0058] Figure 2 A low voltage area topology diagram of a line loss metering method using a minimum energy gateway provided by an embodiment of the present invention.

[0059] Figure 3 A schematic diagram of the installation location of energy gateways in a low-voltage substation area for a line loss metering method using a minimum number of energy gateways provided by an embodiment of the present invention.

[0060] Figure 4 A schematic diagram of working modules of a line loss metering system using a minimum energy gateway provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0061] In order to make the above-mentioned purposes, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in conjunction with the drawings of the specification. Obviously, the described embodiments are part of the embodiments of the present invention, but not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary persons in the art without creative work should fall within the scope of protection of the present invention.

[0062] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein, and those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0063] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The term "in one embodiment" that appears in different places in this specification does not necessarily refer to the same embodiment, nor is it a separate or selective embodiment that is mutually exclusive with other embodiments.

[0064] The present invention is described in detail with reference to schematic diagrams. When describing the embodiments of the present invention, for the sake of convenience, the cross-sectional diagrams showing the device structure will not be partially enlarged according to the general scale, and the schematic diagrams are only examples, which should not limit the scope of protection of the present invention. In addition, in actual production, the three-dimensional dimensions of length, width and depth should be included.

[0065] At the same time, in the description of the present invention, it should be noted that the directions or positional relationships indicated by the terms "upper, lower, inner and outer" are based on the directions or positional relationships shown in the drawings, which are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as limiting the present invention. In addition, the terms "first, second or third" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0066] In the present invention, unless otherwise clearly specified and limited, the terms "install, connect, connect" should be understood in a broad sense, for example: it can be a fixed connection, a detachable connection or an integral connection; it can also be a mechanical connection, an electrical connection or a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0067] Example 1, reference Figure 1 - Figure 3, which is the first embodiment of the present invention, provides a line loss metering method using a minimum energy gateway, including:

[0068] S1: A mathematical model is established based on the low-voltage distribution network area topology diagram, including objective function, state constraints, inference constraints, degree constraints and budget constraints.

[0069] Furthermore, let x ij is a decision variable, indicating whether to install an energy gateway on road section ij:

[0070]

[0071] Among them, if installed, then x ij =1, otherwise x ij =1, E is the set of sections in the substation topology network, and the formula represents the minimum number of energy gateways to be installed, while meeting the monitoring requirements of each section in the distribution network.

[0072] It should be noted that, like the BM model, there are three states for the road segment between nodes i and j: the first is that an energy gateway (x ij =1), the device monitors key parameters such as current, voltage and power in real time, so that the power information of the section can be directly obtained. In this state, the energy gateway can provide accurate power data, eliminating the uncertainty of relying on speculation and calculation, and ensuring the high accuracy of real-time monitoring. The second is that the power on section ij can be inferred based on the power conservation law of node i (here the inference decision variable is set If it cannot be inferred, it is 0), because according to the law of conservation of power, if the power input and output of node i are known, combined with its connection relationship with adjacent nodes, the power value on the section can be inferred by calculation. The third is that the power on the section can be inferred according to the law of conservation of power of node j.

[0073] It should be noted that among these three states, each road section can only be in one state at any time and cannot have multiple states at the same time. State 1 needs to rely on direct equipment monitoring, state 2 is related to the power conservation of node i, and state 3 depends on the power conservation of node j;

[0074] Since the power information of each road section can only be obtained in one way, it is impossible to be in multiple states at the same time:

[0075]

[0076] The inference constraints include, first, to avoid two nodes using the same road section as their inference section at the same time, the range of the road section inferred by the node must be clear. In order to ensure the uniqueness of the inference and avoid conflicts, it is first assumed that the road section that a node can infer can only be the road section starting from the node. This is because the law of conservation of power requires a balance between the input and output power of the node, and the inference ability of each node depends on its connection relationship with the adjacent nodes. In other words, a node can usually only infer the power size on the road section it is directly connected to, ensuring that the inferences of each node do not overlap or conflict with each other.

[0077] Therefore, in general, according to the node power conservation principle, an ordinary node i can usually only infer the power size on a road section. The power of any road section cannot be inferred from the centroid i Then we have the following formula:

[0078]

[0079] Among them, λ i is a decision variable, which is 1 when node i is an ordinary node and 0 when node i is a centroid point. N is the set of nodes in the substation topology network.

[0080] The degree constraint includes that in network optimization, in order to avoid the influence of loops in the network on the results, we can effectively restrict the topological structure of the network by introducing node priorities and out-degree constraints. By setting the priority of the node, the directionality of the road section can be ensured and loops can be avoided during the optimization process.

[0081] Using variable z ij Define node priority. If the road segment between nodes i and j is from i to j, then z ij =1, otherwise, z ij =0; define the out-degree of node i as δ i , then the following constraints apply to node i:

[0082]

[0083] Among them, d out (i) is the out-degree of node i, that is, the number of road segments starting from node i;

[0084] The budget constraint includes, considering the installation difficulty and installation cost of energy gateways placed on different road sections, this paper introduces budget constraints when optimizing the energy gateway deployment strategy. In actual operation, the installation of energy gateways involves certain costs and resource investment, especially in low-voltage distribution networks, where there are many road sections and the network structure is complex. Therefore, when deploying energy gateways, in addition to considering the optimal layout plan, budget constraints must also be considered to ensure the economy and feasibility of the plan.

[0085] First, we define the installation cost of each energy gateway. Assume that the installation cost of the energy gateway is related to the characteristics of the road section where it is located, including factors such as geographical location, road section length, and installation complexity. Let the cost of installing an energy gateway on road section ij be b ij ,This cost includes not only the equipment procurement cost but also the ,installation and debugging costs.,For simplicity, it is assumed that the installation cost of the ,energy gateway for each road section is a known constant.

[0086] The budget of the distribution network is set to B, that is, the total cost of installing all energy gateways must not exceed the current budget. The constraint condition is introduced so that the total installation cost of all energy gateways does not exceed the budget. The installation cost constraint of the energy gateway is expressed as:

[0087]

[0088] Among them, b ij Represents the cost of installing an energy gateway on road section ij.

[0089] Based on the above objective function and constraints, the following improved model can be established.

[0090]

[0091] S2: Solve the model, calculate the out-degree of each node, define the node priority, and calculate the constraint equation of each node according to the mathematical model.

[0092] Furthermore, a specific low-voltage area topology is used to solve the above mathematical model, considering only the out-degree of each node:

[0093] δ1=δ2=δ3=δ4=δ5=2,δ6=1 The node priority is defined as:

[0094] z 12 =z 13 =z 14 =z 15 =z 16 =1

[0095] z 23 =z 24 =z 25 =z26 =1

[0096] z 34 =z 35 =z 36 =1

[0097] z 45 =z 46 =1

[0098] z 56 =1

[0099] It should be noted that node 1 (transformer source node):

[0100] State constraints:

[0101] Inferred constraints:

[0102] Degree Constraint:

[0103] Node 2 (ordinary node of branch box):

[0104] State constraints:

[0105] Inferred constraints:

[0106] Degree Constraint:

[0107] Node 3 (ordinary node of branch box):

[0108] State constraints:

[0109] Inferred constraints:

[0110] Degree Constraint:

[0111] Node 4 (ordinary node of branch box):

[0112] State constraints:

[0113] Inferred constraints:

[0114] Degree Constraint:

[0115] Node 5 (ordinary node of branch box):

[0116] State constraints:

[0117] Inferred constraints:

[0118] Degree Constraint:

[0119] Node 6 (ordinary node of branch box):

[0120] State constraints:

[0121] Inferred constraints:

[0122] Degree Constraint:

[0123] According to the constraint equations of each node, nodes 7, 8, 9, 10, 11, and 12 are all user nodes, that is, sink nodes, with an out-degree of 0. There is no need to write constraint equations. Finally, the following conclusions are obtained:

[0124] x 12 =x 23 =x 34 =x 45 =x 56 =x 69 =1

[0125] x 210 =x 37 =x 48 =x 511 =x 612 =0

[0126] but

[0127]

[0128] It should be noted that for the energy gateway installation problem of this simple topology network, after optimization, at least 6 energy gateways need to be placed, which are placed on nodes P1, P3, P5, P7, P9 and P11 respectively. Figure 3 This optimization strategy significantly reduces the number of energy gateways installed, reducing the number of installations by 45.5% compared to the method of installing energy gateways on every road section.

[0129] Specifically, if the traditional method is to install energy gateways on every road section, 11 energy gateways will be needed to ensure the full power monitoring and management needs of the network. However, with the optimized solution, only 6 energy gateways are needed to meet the same monitoring needs. This reduction not only reduces the investment cost of hardware equipment, but also reduces the subsequent maintenance and management costs.

[0130] This optimization effect is due to a deep understanding of the network topology and reasonable design of decision variables. By accurately selecting nodes and sections, and combining the power conservation law and budget constraints, the deployment of energy gateways can be minimized while meeting monitoring requirements, thereby achieving optimal cost control.

[0131] S3: Determine the placement plan of the energy gateway by calculating the power information.

[0132] Furthermore, for the sections without energy gateways (P2, P4, P6, P8, P10), their power information can be estimated in the following way to meet the line loss assessment requirements of the distribution network. The specific method is as follows:

[0133]

[0134] Where P is power.

[0135] S4: Calculate the power factor of power quality line loss and evaluate the line loss in the low voltage area.

[0136] Furthermore, after determining the placement plan of the energy gateway, the energy gateway is arranged to measure the active and reactive power of each line section, and the following four power quality line loss power factors are obtained in the case of a three-phase system:

[0137]

[0138] Among them, PF eP Indicates the fundamental positive sequence active line loss power factor, PF eQ Indicates reactive line loss power factor, PF eU Indicates the unbalanced line loss power factor, PF eH Indicates the harmonic line loss power factor, S eLoss Indicates the apparent power of bus loss, S1 + Indicates the fundamental positive sequence apparent power, S ePU Indicates the apparent power of unbalanced line loss, S ePH Indicates the apparent power of harmonic line loss, P1 + Indicates the basic positive sequence active power, Q1 + Represents the basic positive sequence reactive power, S U1 is the unbalanced apparent power, D eI is the current distortion power;

[0139] The above four types of power quality line loss power factors can be used to fully evaluate the line loss in the low-voltage area.

[0140] Embodiment 2, the second embodiment of the present invention, is different from the previous embodiment in that:

[0141] If the functions are implemented in the form of software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art or the part of the technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium, including several instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the methods described in each embodiment of the present invention. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk, etc., which can store program codes.

[0142] The logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as an ordered list of executable instructions for implementing logical functions, and can be embodied in any computer-readable medium for use by an instruction execution system, device or apparatus (such as a computer-based system, a system including a processor, or other system that can fetch instructions from an instruction execution system, device or apparatus and execute instructions), or in conjunction with such instruction execution systems, devices or apparatuses. For the purposes of this specification, "computer-readable medium" can be any device that can contain, store, communicate, propagate or transmit a program for use by an instruction execution system, device or apparatus, or in conjunction with such instruction execution systems, devices or apparatuses.

[0143] More specific examples of computer-readable media (a non-exhaustive list) include the following: an electrical connection with one or more wires (electronic device), a portable computer disk case (magnetic device), a random access memory (RAM), a read-only memory (ROM), an erasable and programmable read-only memory (EPROM or flash memory), an optical fiber device, and a portable compact disk read-only memory (CDROM). In addition, the computer-readable medium may even be a paper or other suitable medium on which the program is printed, since the program may be obtained electronically, for example, by optically scanning the paper or other medium, followed by editing, deciphering or, if necessary, processing in another suitable manner, and then stored in a computer memory.

[0144] It should be understood that the various parts of the present invention can be implemented by hardware, software, firmware or a combination thereof. In the above-mentioned embodiments, a plurality of steps or methods can be implemented by software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented by hardware, as in another embodiment, it can be implemented by any one of the following technologies known in the art or their combination: a discrete logic circuit having a logic gate circuit for implementing a logic function for a data signal, a dedicated integrated circuit having a suitable combination of logic gate circuits, a programmable gate array (PGA), a field programmable gate array (FPGA), etc.

[0145] Example 3, reference Figure 4 , which is an embodiment of the present invention, provides a line loss metering system using a minimum energy gateway, characterized in that it includes a mathematical model module 1, a node out-degree calculation module 2, a power estimation module 3, an energy gateway placement scheme module 4, and a power quality assessment module 5;

[0146] The mathematical model module 1 is used to establish and define the objective function, state constraints, inference constraints, degree constraints and budget constraints to form a mathematical framework for the entire line loss measurement;

[0147] The node out-degree calculation module 2 is responsible for calculating the out-degree of each node in the network, determining the priority of each node, and deriving relevant constraint equations based on this to optimize the deployment of the energy gateway;

[0148] The power estimation module 3 estimates the power information of the road section where the energy gateway is not installed according to the existing installation scheme and network topology to support the evaluation of line loss;

[0149] The energy gateway placement solution module 4 determines the optimal layout location of the energy gateway to ensure that the energy gateway can meet the monitoring requirements and minimize the deployment cost;

[0150] The power quality assessment module 5 assesses the power quality of the low-voltage distribution network through different line loss power factor calculation methods, analyzes various types of line losses, and provides a comprehensive line loss assessment result.

[0151] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. A line loss measurement method using a minimum energy gateway, characterized in that: include, Establish a mathematical model based on the low-voltage distribution network area topology diagram, including objective function, state constraints, inference constraints, degree constraints and budget constraints; Solve the model, calculate the out-degree of each node, define the node priority, and calculate the constraint equation of each node according to the mathematical model; Determine the placement plan of the energy gateway by calculating power information; Calculate the power factor of power quality line loss and evaluate the line loss in low voltage area.

2. A line loss measurement method using a minimum energy gateway as claimed in claim 1, characterized in that: The objective function includes setting x ij is a decision variable, indicating whether to install an energy gateway on road section ij: Among them, if installed, then x ij =1, otherwise x ij =1, E is the set of sections in the substation topology network, and the formula represents the minimum number of energy gateways to be installed, while meeting the monitoring requirements of each section in the distribution network.

3. A line loss measurement method using a minimum energy gateway as claimed in claim 2, characterized in that: The state constraints include that each road section can only be in one state at any time and cannot have multiple states at the same time. State 1 needs to rely on direct equipment monitoring, state 2 is related to the power conservation of node i, and state 3 depends on the power conservation of node j; Since the power information of each road section can only be obtained in one way, it is impossible to be in multiple states at the same time: The inference constraints include that, according to the node power conservation, an ordinary node i can usually only infer the power of one road section, and the power of any road section cannot be inferred from the centroid point i, so there is the following formula: Among them, λ i is a decision variable, which is 1 when node i is an ordinary node and 0 when node i is a centroid point. N is the set of nodes in the substation topology network.

4. A line loss measurement method using a minimum energy gateway as claimed in claim 3, characterized in that: The degree constraint includes, in network optimization, limiting the topological structure of the network by introducing node priorities and out-degree constraints, ensuring the directionality of the road section by setting the node priorities, and avoiding loops in the optimization process; Using variable z ij Define node priority. If the road segment between nodes i and j is from i to j, then z ij =1, otherwise, z ij =0; define the out-degree of node i as δ i , then the following constraints apply to node i: Among them, d out (i) is the out-degree of node i, that is, the number of road segments starting from node i; The budget constraint includes setting the budget of the distribution network to B, that is, the total cost of installing all energy gateways must not exceed the current budget, and introducing constraints so that the total installation cost of all energy gateways does not exceed the budget; the installation cost constraint of the energy gateway is expressed as: Among them, b ij Represents the cost of installing an energy gateway on road section ij.

5. A line loss measurement method using a minimum energy gateway as claimed in claim 4, characterized in that: The calculation of the out-degree of each node includes solving the above mathematical model using a specific low-voltage area topology diagram, and only considering the out-degree of each node: δ1=δ2=δ3=δ4=δ5=2, δ6=1 The node priorities are defined as follows: With 12 =from 13 =from 14 =from 15 =from 16 =1 With 23 =from 24 =from 25 =from 26 =1 With 34 =from 35 =from 36 =1 With 45 =from 46 =1 z 56 ＝1 According to the constraint equations of each node, nodes 7, 8, 9, 10, 11, and 12 are all user nodes, that is, sink nodes, with an out-degree of 0. There is no need to write constraint equations. Finally, the following conclusions are obtained: x 12 =x 23 =x 34 =x 45 =x 56 =x 69 =1 x 210 =x 37 =x 48 =x 511 =x 612 =0 but By accurately selecting nodes and road sections and combining the power conservation law and budget constraints, the deployment of energy gateways can be minimized and optimal cost control can be achieved while meeting monitoring requirements.

6. A line loss measurement method using a minimum energy gateway as claimed in claim 5, characterized in that: The power information is calculated by calculating the power information for the road section where no energy gateway is placed, in order to meet the line loss assessment requirements of the distribution network. The specific method is as follows: Where P is power.

7. A line loss measurement method using a minimum energy gateway as claimed in claim 6, characterized in that: The calculation of the power quality line loss power factor includes, after determining the placement plan of the energy gateway, arranging the energy gateway to measure the active and reactive power of each line section, and obtaining the following four power quality line loss power factors in the case of a three-phase system: Among them, PF eP Indicates the fundamental positive sequence active line loss power factor, PF eQ Indicates reactive line loss power factor, PF eU Indicates the unbalanced line loss power factor, PF eH Indicates the harmonic line loss power factor, S eLoss It represents the apparent power of bus loss. Indicates the fundamental positive sequence apparent power, S ePU Indicates the apparent power of unbalanced line loss, S ePH Indicates the apparent power of harmonic line loss, P1 + Indicates the basic positive sequence active power, Represents the basic positive sequence reactive power, S U1 is the unbalanced apparent power, D eI is the current distortion power; The above four types of power quality line loss power factors can be used to fully evaluate the line loss in the low-voltage area.

8. A system using a line loss metering method using a minimum energy gateway as claimed in any one of claims 1 to 7, characterized in that: It includes mathematical model module, node out-degree calculation module, power estimation module, energy gateway placement scheme module and power quality assessment module; The mathematical model module is used to establish and define the objective function, state constraints, inference constraints, degree constraints and budget constraints to form a mathematical framework for the entire line loss measurement; The node out-degree calculation module is responsible for calculating the out-degree of each node in the network, determining the priority of each node, and deriving relevant constraint equations based on this to optimize the deployment of the energy gateway; The power estimation module estimates the power information of the road section where the energy gateway is not installed based on the existing installation scheme and network topology to support the evaluation of line loss; The energy gateway placement solution module determines the optimal layout location of the energy gateway to ensure that the energy gateway can meet monitoring requirements and minimize deployment costs; The power quality assessment module assesses the power quality of the low-voltage distribution network through different line loss power factor calculation methods, analyzes various types of line losses, and provides a comprehensive line loss assessment result.

9. A computer device comprising a memory and a processor, wherein the memory stores a computer program, wherein: When the processor executes the computer program, the steps of the method according to any one of claims 1 to 7 are implemented.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 7 are implemented.

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