Low-voltage distribution transformer district security domain modeling method and system based on security domain defining method

Abstract

The invention discloses a low-voltage distribution transformer district security domain modeling method and system based on a security domain defining method. The method comprises the following steps: constructing a working point, a security boundary and a security domain of a low-voltage distribution transformer district; constructing a mathematical model of the low-voltage distribution transformer district, and solving edge points on the security domain by using a bisection method; setting the fitting precision from the edge points to the fitted decision boundary, and selecting linearly independent N edge points covering the whole security domain to establish a first initial decision boundary; calculating the distance from each edge point to the initial decision boundary, and judging whether the initial decision boundary meets fitting precision or not: if so, taking the initial decision boundary as a final boundary expression; otherwise, taking the maximum distance point as a segmentation point, grouping all edge points selected when the initial decision boundary is fitted, and performing next fitting on each subset until the fitting precision is qualified; and constructing a model of the security domain according to the security boundary. The method has the advantage that the curvature change point of the security boundary can be determined without depending on observation data.

Description

Technical Field

[0001] The present invention relates to a method for modeling a safety domain of a low-voltage distribution transformer area, and in particular to a method and system for modeling a safety domain of a low-voltage distribution transformer area based on a safety domain definition method. Background Art

[0002] Traditional low-voltage distribution substations are the core of the power distribution network. They are usually powered by a single transformer and a single power supply circuit, resulting in a fragile grid structure and poor power supply quality and stability. Each distribution area is powered independently and lacks the ability to regulate and control power flow. Due to differences in economic structure, seasonal power load fluctuations often occur in the same region. The access of small-scale industrial loads, especially the increase in load rates in some areas due to the "coal to electricity" policy, makes it impossible for adjacent distribution areas to share remaining capacity due to open-loop operation, making the problem of uneven load distribution more significant. With the increase of DC loads such as DC charging stations and DC household appliances, as well as the large-scale and high-proportion access of DC power sources such as solar photovoltaic power generation units, the source-load-storage ratio of DC characteristics continues to rise.

[0003] Therefore, in order to improve the power supply quality in the low-voltage distribution area, a substation safety domain analysis method is needed to provide effective technical support for exploring the potential of the existing distribution network and improving power supply reliability. Summary of the invention

[0004] In view of the above-mentioned deficiencies in the prior art, the present invention proposes a method and system for modeling the safety domain of a low-voltage distribution transformer area based on a safety domain definition method.

[0005] In order to achieve the above object, the present invention provides the following technical solutions:

[0006] A method for modeling a safety domain of a low-voltage distribution transformer area based on a safety domain definition method comprises the following steps:

[0007] The working point is set as the operating status of the low-voltage distribution transformer area at a specific moment, including the power parameters of each node in the power system, and the power parameters include active power and reactive power; the safety domain is set as the sum of all safe working points in the safety state in the low-voltage distribution transformer area; the safety boundary is the boundary of the safety domain;

[0008] Construct a mathematical model of low-voltage distribution transformer area and use the dichotomy method to solve the edge points on the safety domain;

[0009] Set the maximum distance S allowed from all edge points to the fitted decision boundary max , the maximum distance value S max Reflecting the fitting accuracy, select N linearly independent edge points covering the entire safety domain to establish the first initial decision boundary M 0 ;

[0010] Calculate the distance from each edge point to the initial decision boundary M 0 The distance of the edge point with the maximum distance is set to X (0) b , determine the initial decision boundary M 0 Whether the fitting accuracy is met: If the accuracy is met, the initial decision boundary M 0 is the final boundary expression; otherwise, (0) b As the split point, the initial decision boundary M will be fitted 0 All edge points selected at the time are grouped, and the next fitting is performed on each subset separately;

[0011] Calculate the decision boundary M from all edge points to the kth fit k The distance between the edge points and the fitted decision boundary M k The maximum distance is S max Xb→Mk , the corresponding edge point is recorded as X (k) b , compare the maximum distance to S max Xb→Mk Is it less than the maximum distance value S? max ;

[0012] If yes, the safety boundary obtained at this time is the final result, the fitting is completed, and the model of the safety domain is built based on the safety boundary; if no, the safety boundary is obtained based on X. (k) b As the segmentation point, the kth segment fitting decision boundary M k The edge points selected are grouped, and the next fitting process is repeated for each subset until the decision boundary meets the fitting accuracy.

[0013] Furthermore, the safety boundary includes all working points in a critical safety state, and the working points in a critical safety state represent the points in the safety domain that are closest to the unsafe state.

[0014] Furthermore, the mathematical model in the low voltage distribution transformer area is expressed as follows:

[0015] Y e U n =I n

[0016] where Y e is the node admittance matrix; U n and I n are the vectors consisting of node voltage and injected current respectively.

[0017] Furthermore, the initial decision boundary M 0 It can be expressed as:

[0018]

[0019] Among them, M 0 is the initial decision boundary equation; b 0 M 0 Fitting parameter; β i M 0 ; N is the dimension of the mathematical model.

[0020] Furthermore, the edge point X on the security domain b To the initial decision boundary M 0 The distance is expressed as:

[0021]

[0022] Where X b =[x 1 ,…,x i ,…,x N ]; for A vector of for The 2-norm of ;

[0023] The fitting accuracy is expressed as follows:

[0024]

[0025] Furthermore, the method for judging whether the k-th segment fitting is finished is:

[0026] Set the distance from the kth decision boundary M k The edge point with the largest distance is X (k) b , if the maximum distance S max Xb→Mk Less than the maximum distance value S max If the accuracy is met, the safety margin obtained at this time is the final result and the fitting process ends; otherwise, X (k) b As the new segmentation point, the edge points selected during the k-th segment fitting are grouped to generate N new decision boundaries, and the k+1-th segment fitting process is continued.

[0027] Furthermore, the security domain boundary is expressed as follows:

[0028]

[0029] where x i is the working point element, Ω DPA is a security domain set, X *is the new working point,

[0030] Indicates the working point A safe working point located within a safe area.

[0031] Furthermore, the security domain model is expressed as follows:

[0032]

[0033] in is a safe working point, which must satisfy the equilibrium constraint and safety constraints P n , Q n are respectively the active power and reactive power injected into the node; U n max , U n min are the vectors consisting of the upper and lower limits of the node voltage respectively; P n , Q n are the vectors composed of active and reactive power injected into the node respectively; P n max , P n min and Q n max , Q n min S is the vector consisting of the upper and lower limits of active and reactive power injected into the node respectively; b is the vector of branch apparent power, S b max is the vector of branch capacities.

[0034] A low-voltage distribution transformer area safety domain modeling system based on the safety domain definition method includes a low-voltage distribution transformer area construction unit, a mathematical model unit and a solution unit;

[0035] The low-voltage distribution transformer area construction unit is used to construct the working point, safety boundary and safety domain of the low-voltage distribution transformer area. The working point is set as the operating status of the low-voltage distribution transformer area at a specific moment, including the power parameters of each node in the power system. The power parameters include active power and reactive power; the safety domain is set as the sum of all safe working points in the low-voltage distribution transformer area in a safe state; the safety boundary is the limit of the safety domain. The safety boundary includes all working points in a critical safety state. The working point in a critical safety state represents the point in the safety domain that is closest to the unsafe state;

[0036] The mathematical model unit is used to construct the mathematical model of the low-voltage distribution transformer area. The mathematical model is expressed as follows:

[0037] Y c Un =I n

[0038] where Y e is the node admittance matrix; U n and I n are the vectors composed of node voltage and injected current respectively;

[0039] The solving unit is used to solve the edge points on the safety domain by applying the dichotomy method and to construct a model of the safety domain according to the safety boundary;

[0040] The maximum distance value S allowed for all edge points to the fitting decision boundary is set in the solution unit max , the maximum distance value S max Reflecting the fitting accuracy, select N linearly independent edge points covering the entire safety domain to establish the first initial decision boundary M 0 ;

[0041] The solving unit first calculates the distance from each edge point to the initial decision boundary M 0 The distance of the edge point with the maximum distance is set to X (0) b. Determine the initial decision boundary M 0 Whether the fitting accuracy is met: If the accuracy is met, the initial decision boundary M 0 is the final boundary expression; otherwise, (0) b is the split point, and the initial decision boundary M will be fitted. 0 All edge points selected at the time are grouped, and the next fitting is performed on each subset separately;

[0042] The solving unit calculates the decision boundary M from all edge points to the kth fitting k The distance between the edge points and the fitted decision boundary M k The maximum distance is S max Xb→Mk , the corresponding edge point is recorded as X (k) b , compare the maximum distance to S max Xb→Mk Is it less than the maximum distance value S? max ;

[0043] If yes, the safety boundary obtained at this time is the final result, the fitting is completed, and the model of the safety domain is built based on the safety boundary; if no, the safety boundary is obtained based on X. (k) b As the segmentation point, the kth segment fitting decision boundary M k The edge points selected at the time are grouped and the next fitting process is repeated for each subset until the decision boundary meets the fitting accuracy.

[0044] Furthermore, the initial decision boundary M0 It can be expressed as:

[0045]

[0046] Among them, M 0 is the initial decision boundary equation; b 0 M 0 Fitting parameter; β i M 0 Variable; N is the dimension of the mathematical model;

[0047] Edge point X on the security domain b To the initial decision boundary M 0 The distance is expressed as:

[0048]

[0049] Where X b =[x 1 ,…,x i ,…,x N ]; for A vector of for The 2-norm of ;

[0050] The fitting accuracy is expressed as follows:

[0051]

[0052] The security domain boundary is expressed as follows:

[0053]

[0054] Where: x i is the working point element, Ω DPA is a security domain set, X * is the new working point,

[0055] Indicates the working point A safe working point located within the safety zone;

[0056] The security domain model is expressed as follows:

[0057]

[0058] in is a safe working point, which must satisfy the equilibrium constraint and safety constraints P n , Q n are respectively the active power and reactive power injected into the node; Un max , U n min are the vectors consisting of the upper and lower limits of the node voltage respectively; P n , Q n are the vectors composed of active and reactive power injected into the node respectively; P n max , P n min and Q n max , Q n min S is the vector consisting of the upper and lower limits of active and reactive power injected into the node respectively; b is the vector of branch apparent power, S b max is the vector of branch capacities.

[0059] In the above technical solution, the low voltage distribution transformer area safety domain modeling method based on the safety domain definition method provided by the present invention has the following beneficial effects:

[0060] The method for modeling the safety domain of the low-voltage distribution transformer area of ​​the present invention can obtain the boundary where the curvature of the safety boundary changes without observation. To a certain extent, it avoids the iterative solution process of nonlinear equations and saves calculation time. The advantage of this method is that it does not need to rely on observation data to determine the curvature change point of the safety boundary, avoids the iterative calculation process when solving nonlinear equations, and significantly reduces the calculation time. This technology theoretically provides an analytical means for the reliable and stable operation of the low-voltage distribution transformer area. BRIEF DESCRIPTION OF THE DRAWINGS

[0061] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For ordinary technicians in this field, other drawings can also be obtained based on these drawings.

[0062] Figure 1 A flowchart of a method for modeling a safety domain of a low-voltage distribution transformer area based on a safety domain definition method provided by the present invention;

[0063] Figure 2 This is a flow chart of the high-order boundary fitting method provided by the present invention. DETAILED DESCRIPTION

[0064] In order to enable those skilled in the art to better understand the technical solution of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings.

[0065] A safety domain modeling method for low voltage distribution transformer area based on safety domain definition method in this implementation mode is as follows: Figure 1 As shown, the following steps are included:

[0066] Step 1: Construct the concepts of working point, safety boundary and safety domain of low voltage distribution transformer area.

[0067] The working point is set as the operating status of the low-voltage distribution transformer area at a specific moment, including the power parameters of each node in the power system, including active power and reactive power; the safety domain is set as the sum of all safe working points in the low-voltage distribution transformer area; the safety boundary is the boundary of the safety domain. It consists of all working points in critical safety states, which represent the points in the safety domain that are closest to the unsafe state.

[0068] Through clear safety domain-related concepts, non-professionals can have a deeper understanding of the importance of stability in the substation area, so as to better standardize work behavior, ensure the safety of staff, prevent unnecessary accidents and protect substation equipment. The construction of the concepts of work point, safety boundary and safety domain provides a theoretical basis and practical guidance for the safe operation and management of low-voltage distribution substations.

[0069] Step 2: Construct a mathematical model of the low-voltage distribution transformer area, and use the dichotomy method to solve the edge points on the safety domain; Construct a mathematical model of the low-voltage distribution transformer area, and then use the dichotomy method to determine the edge points on the safety domain of the area. During the modeling and analysis process, by adjusting the parameters in the model, the working point moves within the safety domain until it approaches the edge point. The dichotomy method has the advantages of accuracy, speed and flexibility, which greatly increases the efficiency of building mathematical models. At the same time, it can well adapt to the situation when the parameters of the area change, and increase the applicability of the system model.

[0070] Step 3: Set the maximum distance S allowed from all edge points to the fitted decision boundary max , the maximum distance value S max Reflecting the fitting accuracy, select N linearly independent edge points covering the entire safety domain to establish the first initial decision boundary M 0 .

[0071] This part is an important part of establishing the security domain model. Establishing an accurate initial decision boundary can shorten the time of security boundary fitting, speed up the model convergence, and make the model closer to practical applications.

[0072] Among them, the maximum distance value S maxIt indicates the maximum value allowed for the distance from all edge points to the decision boundary of the fitting process. It reflects the accuracy of the decision boundary fitting and serves as the termination criterion for the piecewise fitting process. This can avoid redundant calculations, reduced efficiency and waste of resources.

[0073] Among them, the initial decision boundary M of the first fitting 0 , select as many linearly independent N edge points as possible, which can cover the entire domain range widely for fitting. The more edge points selected, the more accurately the boundaries of the entire domain can be reflected, providing a comprehensive reference framework for the subsequent fitting and prediction of the safety boundary, and simplifying the subsequent steps of fitting the safety boundary.

[0074] Step 4: Calculate the distance from each edge point to the initial decision boundary M 0 The distance of the edge point with the maximum distance is set to X (0) b , determine the initial decision boundary M 0 Whether the fitting accuracy is met: If the accuracy is met, the initial decision boundary M 0 is the final boundary expression; otherwise, (0) b As the split point, the initial decision boundary M will be fitted 0 All edge points selected at the time are grouped and the next fitting is performed on each subset separately.

[0075] This is the core step in establishing the security domain model. It ensures that the model can accurately capture the boundaries of the security domain while maintaining computational efficiency and model applicability by evaluating fitting accuracy, determining segmentation points, and guiding further fitting.

[0076] Step 5: Calculate the decision boundary M from all edge points to the kth fitting k The distance between the edge points and the fitted decision boundary M k The maximum distance is S max Xb→Mk , the corresponding edge point is recorded as X (k) b , compare the maximum distance to S max Xb→Mk Is it less than the maximum distance value S? max ;

[0077] If yes, the safety margin obtained at this time is the final result, the fitting is completed, and the process goes to step 6; if no, the safety margin is obtained by X. (k) b As the segmentation point, the kth segment fitting decision boundary M kThe edge points selected are grouped, and step 5 is repeated to perform the next fitting on each subset; the applicability and flexibility of the model are increased, so that the model can be adjusted according to specific actual data, and the results are closer to accuracy.

[0078] Step 6: Build a security domain model based on the security boundary.

[0079] Preferably, in step one:

[0080] The safety domain refers to the sum of all possible safe operating points in the low-voltage distribution transformer area under certain operating restrictions and conditions; these operating restrictions and conditions may include electrical parameters such as voltage, current, power factor, temperature, load, and physical conditions such as equipment status, environmental factors, etc.

[0081] The safety boundary includes all operating points in a critical safety state, which represent the points in the safety domain closest to an unsafe state. This means that any operation beyond these points may cause the system to enter an unsafe state, which may cause a failure, accident, or equipment damage.

[0082] Preferably, in step 2, the mathematical model of the low voltage distribution transformer area is expressed as follows:

[0083] Y e U n =I n

[0084] where Y e U is the node admittance matrix; it is a key parameter that contains the admittance information of all nodes in the network. Admittance is the reciprocal of resistance and is used to describe the node's ability to accept current. n and I n They are vectors composed of node voltage and injection current respectively. They directly affect the transmission efficiency of the substation system and the operating status of the equipment. Through in-depth analysis of these key parameters, we can better understand and control the dynamic behavior of the low-voltage distribution substation and ensure the stability and security of power supply.

[0085] Preferably, the initial decision boundary M in step 4 0 It can be expressed as:

[0086]

[0087] Among them, M 0 is the initial decision boundary equation; b 0 M 0 Fitting parameters, these coefficients are determined through the fitting process, the purpose is to make the decision boundary as close as possible to the edge of the safe domain; β i M0 variables, which can be node voltages, injected currents, etc. N is the dimension of the mathematical model.

[0088] Preferably, in step 4, the edge point X on the security domain b To the initial decision boundary M 0 The distance is expressed as:

[0089]

[0090] Where X b =[x 1 ,…,x i ,…,x N ]; for The vector of for The 2-norm of ;

[0091] The fitting accuracy is expressed as follows:

[0092]

[0093] Preferably, in step 5, the method for judging whether the k-th segment fitting is finished is:

[0094] Set the distance from the kth decision boundary M k The edge point with the largest distance is X (k) b , if the maximum distance is S max Xb→Mk Less than the maximum distance value S max If the accuracy is met, the safety margin obtained at this time is the final result and the fitting process ends; otherwise, X (k) b As new segmentation points, the edge points selected during the kth segment fitting are grouped to generate N new decision boundaries, and the k+1th segment fitting process is continued. By iteratively refining the decision boundary, the accuracy of the model can be gradually improved until the preset accuracy requirements are met, making the model closer to practical applications. In addition, this iterative refinement process also helps to identify and process abnormal points or noise that may be ignored in the initial fitting, enhancing the model's anti-interference ability.

[0095] Preferably, the security domain boundary is expressed as follows:

[0096]

[0097] where x i is the working point element, representing a specific operating state of the low-voltage distribution transformer area; Ω DPA is a security domain set, X * is the new working point, Indicates the working point The safe working point is located in the safety region. ε is the judgment operator. If Make but is a boundary point, all Constitute a safety margin. If ε*>0, then It has positive criticality and is located at the upper boundary; if ε*<0, then By determining which operating points are on the boundary, the safe operation of the low-voltage distribution transformer area can be better understood and managed.

[0098] Preferably, the security domain model is expressed as follows:

[0099]

[0100] in is a safe working point, which must satisfy the equilibrium constraint and safety constraints P n , Q n are respectively the active power and reactive power injected into the node; U n max , U n min are the vectors consisting of the upper and lower limits of the node voltage respectively; P n , Q n are the vectors composed of active and reactive power injected into the node respectively; P n max , P n min and Q n max , Q n min S is the vector consisting of the upper and lower limits of active and reactive power injected into the node respectively; b is the vector of branch apparent power, S b max is the vector of branch capacities.

[0101] In addition, the balance constraint refers to the power balance condition in the low-voltage distribution transformer area, that is, at any given time, the total power generation in the area system must be equal to the total load power. Safety constraints refer to the restrictions set on various parameters (such as voltage, current, power, etc.) in the area system in order to ensure the safe operation of the low-voltage distribution transformer area;

[0102] A low-voltage distribution transformer area safety domain modeling system based on a safety domain definition method comprises a low-voltage distribution transformer area construction unit, a mathematical model unit and a solution unit.

[0103] Among them, the low-voltage distribution transformer area construction unit is used to construct the working point, safety boundary and safety domain of the low-voltage distribution transformer area. The working point is set as the operating status of the low-voltage distribution transformer area at a specific moment, including the power parameters of each node in the power system, and the power parameters include active power and reactive power; the safety domain is set as the sum of all safe working points in the low-voltage distribution transformer area in a safe state; the safety boundary is the limit of the safety domain. The safety boundary includes all working points in a critical safety state. The working point in a critical safety state represents the point in the safety domain that is closest to the unsafe state.

[0104] Among them, the mathematical model unit is used to construct the mathematical model of the low-voltage distribution transformer area, and the mathematical model is expressed as follows:

[0105] Y c U n =I n

[0106] where Y e is the node admittance matrix; U n and I n are the vectors consisting of node voltage and injected current respectively.

[0107] The solving unit is used to solve the edge points on the safety domain by applying the dichotomy method and to construct a model of the safety domain according to the safety boundary.

[0108] The maximum distance value S allowed for all edge points to the fitting decision boundary is set in the solution unit max , the maximum distance value S max Reflecting the fitting accuracy, select N linearly independent edge points covering the entire safety domain to establish the first initial decision boundary M 0 ;

[0109] The solving unit first calculates the distance from each edge point to the initial decision boundary M 0 The distance of the edge point with the maximum distance is set to X (0) b. Determine the initial decision boundary M 0 Whether the fitting accuracy is met: If the accuracy is met, the initial decision boundary M 0 is the final boundary expression; otherwise, (0) b is the split point, and the initial decision boundary M will be fitted. 0 All edge points selected at the time are grouped, and the next fitting is performed on each subset separately;

[0110] The solving unit calculates the decision boundary M from all edge points to the kth fitting k The distance between the edge points and the fitted decision boundary M k The maximum distance is S max Xb→Mk , the corresponding edge point is recorded as X(k) b , compare the maximum distance to S max Xb→Mk Is it less than the maximum distance value S? max ;

[0111] If yes, the safety boundary obtained at this time is the final result, the fitting is completed, and the model of the safety domain is built based on the safety boundary; if no, the safety boundary is obtained based on X. (k) b As the segmentation point, the kth segment fitting decision boundary M k The edge points selected at the time are grouped and the next fitting process is repeated for each subset until the decision boundary meets the fitting accuracy.

[0112] Specifically, set the distance from the kth decision boundary M k The edge point with the largest distance is X (k) b ,if If the accuracy is met, the safety margin obtained at this time is the final result and the fitting process ends; otherwise, X (k) b As new segmentation points, the edge points selected during the kth segment fitting are grouped to generate N new decision boundaries, and the k+1th segment fitting process is continued. By iteratively refining the decision boundary, the accuracy of the model can be gradually improved until the preset accuracy requirements are met, making the model closer to practical applications. In addition, this iterative refinement process also helps to identify and process abnormal points or noise that may be ignored in the initial fitting, enhancing the model's anti-interference ability.

[0113] Preferably, the initial decision boundary M 0 It can be expressed as:

[0114]

[0115] Among them, M 0 is the initial decision boundary equation; b 0 M 0 Fitting parameter; β i M 0 ; N is the dimension of the mathematical model.

[0116] Edge point X on the security domain b To the initial decision boundary M 0 The distance is expressed as:

[0117]

[0118] Where X b =[x 1 ,…,xi ,…,x N ]; for A vector of for The 2-norm of ;

[0119] The fitting accuracy is expressed as follows:

[0120]

[0121] The security domain boundary is expressed as follows:

[0122]

[0123] Where: x i is the working point element, Ω DPA is a security domain set, X * is the new working point,

[0124] Indicates the working point A safe working point located within a safe area.

[0125] The security domain model is expressed as follows:

[0126]

[0127] in is a safe working point, which must satisfy the equilibrium constraint and safety constraints P n , Q n are respectively the active power and reactive power injected into the node; U n max , U n min are the vectors consisting of the upper and lower limits of the node voltage respectively; P n , Q n are the vectors composed of active and reactive power injected into the node respectively; P n max , P n min and Q n max , Q n min S is the vector consisting of the upper and lower limits of active and reactive power injected into the node respectively; b is the vector of branch apparent power, S b max is the vector of branch capacities.

[0128] In addition, the security domain model can also help identify potential risk points, such as voltage fluctuations, power imbalances, and other issues, which may lead to a decrease in system stability or even cause power outages. By identifying and analyzing these risk points, measures can be taken in advance, such as adjusting power generation plans, optimizing load distribution, and enhancing grid regulation capabilities, to improve system flexibility and reliability. This model-based approach not only improves the security of the power system, but also provides a more stable and predictable operating environment for the power market, thereby supporting the implementation of a wider range of energy management and optimization strategies. In this way, the security domain model has become an important tool for the safe operation and efficiency optimization of the power system.

[0129] Those skilled in the art will appreciate that the embodiments of the present application may be provided as methods, systems, or computer program products. Therefore, the present application may adopt the form of complete hardware embodiments, complete software embodiments, or embodiments in combination with software and hardware. Moreover, the present application may adopt the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) that contain computer-usable program code. The scheme in the embodiments of the present application may be implemented in various computer languages, for example, object-oriented programming language Java and literal scripting language JavaScript, etc.

[0130] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, 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 generate 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 flowchart and / or block diagram. 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.

[0131] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate 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 A function specified in one or more boxes.

[0132] The above description is only by way of illustration of certain exemplary embodiments of the present invention. It is undoubted that those skilled in the art can modify the described embodiments in various ways without departing from the spirit and scope of the present invention. Therefore, the above drawings and descriptions are illustrative in nature and should not be construed as limiting the scope of protection of the claims of the present invention.

Claims

1. A low voltage distribution transformer area safety domain modeling method based on the safety domain definition method is characterized by: The steps include: The working point is set as the operating status of the low-voltage distribution transformer area at a specific moment, including the power parameters of each node in the power system, and the power parameters include active power and reactive power; the safety domain is set as the sum of all safe working points in the safety state in the low-voltage distribution transformer area; the safety boundary is the boundary of the safety domain; Construct a mathematical model of low-voltage distribution transformer area and use the dichotomy method to solve the edge points on the safety domain; Set the maximum distance S allowed from all edge points to the fitted decision boundary max , the maximum distance value S max Reflecting the fitting accuracy, select N linearly independent edge points covering the entire safety domain to establish the first initial decision boundary M 0 ; Calculate the distance from each edge point to the initial decision boundary M 0 The distance of the edge point with the maximum distance is set to X (0) b , determine the initial decision boundary M 0 Whether the fitting accuracy is met: If the accuracy is met, the initial decision boundary M 0 is the final boundary expression; otherwise, (0) b As the split point, the initial decision boundary M will be fitted 0 All edge points selected at the time are grouped, and the next fitting is performed on each subset separately; Calculate the decision boundary M from all edge points to the kth fit k The distance between the edge points and the fitted decision boundary M k The maximum distance is S max Xb→Mk , the corresponding edge point is recorded as X (k) b , compare the maximum distance S max Xb→Mk Is it less than the maximum distance value S? max ; If yes, the safety boundary obtained at this time is the final result, the fitting is completed, and the model of the safety domain is built based on the safety boundary; if no, the safety boundary is obtained based on X. (k) b As the segmentation point, the kth segment fitting decision boundary M k The edge points selected are grouped, and the next fitting process is repeated for each subset until the decision boundary meets the fitting accuracy.

2. The method for modeling the safety domain of a low-voltage distribution transformer area based on the safety domain definition method according to claim 1 is characterized in that: The safety boundary includes all working points in critical safety state, and the working points in critical safety state represent the points in the safety domain that are closest to the unsafe state.

3. The method for modeling the safety domain of a low-voltage distribution transformer area based on the safety domain definition method according to claim 1 is characterized in that: The mathematical model in the low voltage distribution transformer area is expressed as follows: Y e U n =I n where Y e is the node admittance matrix; U n and I n are the vectors consisting of node voltage and injected current respectively.

4. The method for modeling the safety domain of a low-voltage distribution transformer area based on the safety domain definition method according to claim 1 is characterized in that: Initial decision boundary M 0 It can be expressed as: Among them, M 0 is the initial decision boundary equation; b 0 M 0 Fitting parameter; β i M 0 ; N is the dimension of the mathematical model.

5. The method for modeling the safety domain of a low-voltage distribution transformer area based on the safety domain definition method according to claim 4 is characterized in that: Edge point X on the security domain b To the initial decision boundary M 0 The distance is expressed as: Where X b =[x1,…,x i ,…,x N ]; for A vector of for The 2-norm of ; The fitting accuracy is expressed as follows:

6. The method for modeling the safety domain of a low-voltage distribution transformer area based on the safety domain definition method according to claim 1 is characterized in that: The method to determine whether the kth segment fitting is completed is: Set the distance from the kth decision boundary M k The edge point with the largest distance is X (k) b , if the maximum distance S max Xb→Mk Less than the maximum distance value S max If the accuracy is met, the safety margin obtained at this time is the final result and the fitting process ends; otherwise, X (k) b As the new segmentation point, the edge points selected during the k-th segment fitting are grouped to generate N new decision boundaries, and the k+1-th segment fitting process is continued.

7. The method for modeling the safety domain of a low-voltage distribution transformer area based on the safety domain definition method according to claim 3 is characterized in that: The security domain boundary is expressed as follows: where x i is the working point element, Ω DPA is a security domain set, X * For the new working point, Indicates the working point A safe working point located within a safe area.

8. The method for modeling the safety domain of a low-voltage distribution transformer area based on the safety domain definition method according to claim 7 is characterized in that: The security domain model is expressed as follows: in is a safe working point, which must satisfy the equilibrium constraint and safety constraints P n , Q n are respectively the active power and reactive power injected into the node; U n max , U n min are the vectors consisting of the upper and lower limits of the node voltage respectively; P n , Q n are the vectors composed of active and reactive power injected into the node respectively; P n max , P n min and Q n max , Q n min S is the vector consisting of the upper and lower limits of active and reactive power injected into the node respectively; b is the vector of branch apparent power, S b max is the vector of branch capacities.

9. The low voltage distribution transformer area safety domain modeling system based on the safety domain definition method is characterized by: It includes low voltage distribution transformer area construction unit, mathematical model unit and solution unit; The low-voltage distribution transformer area construction unit is used to construct the working point, safety boundary and safety domain of the low-voltage distribution transformer area. The working point is set as the operating status of the low-voltage distribution transformer area at a specific moment, including the power parameters of each node in the power system. The power parameters include active power and reactive power; the safety domain is set as the sum of all safe working points in the low-voltage distribution transformer area in a safe state; the safety boundary is the limit of the safety domain. The safety boundary includes all working points in a critical safety state. The working point in a critical safety state represents the point in the safety domain that is closest to the unsafe state; The mathematical model unit is used to construct the mathematical model of the low-voltage distribution transformer area. The mathematical model is expressed as follows: Y c U n =I n where Y e is the node admittance matrix; U n and I n are the vectors composed of node voltage and injected current respectively; The solving unit is used to solve the edge points on the safety domain by applying the dichotomy method and to construct a model of the safety domain according to the safety boundary; The maximum distance value S allowed for all edge points to the fitting decision boundary is set in the solution unit max , the maximum distance value S max Reflecting the fitting accuracy, select N linearly independent edge points covering the entire safety domain to establish the first initial decision boundary M 0 ; The solving unit first calculates the distance from each edge point to the initial decision boundary M 0 The distance of the edge point with the maximum distance is set to X (0) b , determine the initial decision boundary M 0 Whether the fitting accuracy is met: If the accuracy is met, the initial decision boundary M 0 is the final boundary expression; otherwise, (0) b As the split point, the initial decision boundary M will be fitted 0 All edge points selected at the time are grouped, and the next fitting is performed on each subset separately; The solving unit calculates the decision boundary M from all edge points to the kth fitting k The distance between the edge points and the fitted decision boundary M k The maximum distance is S max Xb→Mk , the corresponding edge point is recorded as X (k) b , compare the maximum distance to S max Xb→Mk Is it less than the maximum distance value S? max ; If yes, the safety boundary obtained at this time is the final result, the fitting is completed, and the model of the safety domain is built based on the safety boundary; if no, the safety boundary is obtained based on X. (k) b As the segmentation point, the kth segment fitting decision boundary M k The edge points selected at the time are grouped and the next fitting process is repeated for each subset until the decision boundary meets the fitting accuracy.

10. The low voltage distribution transformer area safety domain modeling system based on the safety domain definition method according to claim 9 is characterized in that: Initial decision boundary M 0 It can be expressed as: Among them, M 0 is the initial decision boundary equation; b 0 M 0 Fitting parameter; β i M 0 Variable; N is the dimension of the mathematical model; Edge point X on the security domain b To the initial decision boundary M 0 The distance is expressed as: Where X b =[x1,…,x i ,…,x N ]; for A vector of for The 2-norm of ; The fitting accuracy is expressed as follows: The security domain boundary is expressed as follows: Where: x i is the working point element, Ω DPA is a security domain set, X * is the new working point, Indicates the working point A safe working point located within the safety zone; The security domain model is expressed as follows: in is a safe working point, which must satisfy the equilibrium constraint and safety constraints P n , Q n are respectively the active power and reactive power injected into the node; U n max , U n min are the vectors consisting of the upper and lower limits of the node voltage respectively; P n , Q n are the vectors composed of active and reactive power injected into the node respectively; P n max , P n min and Q n max , Q n min S is the vector consisting of the upper and lower limits of active and reactive power injected into the node respectively; b is the vector of branch apparent power, S b max is the vector of branch capacities.

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