Power system load transfer method and system

Abstract

The invention discloses a power system load transfer method and system, and the method comprises the steps: building a main-distribution integrated power grid model when a fault of a power system is detected; determining a load transfer fitness objective function corresponding to the power grid model; representing a load transfer scheme in response to the load transfer fitness objective function based on the selected coding scheme; in the process of processing the load transfer optimization problem of the power system by adopting a genetic algorithm technology, selecting an individual with the highest fitness from a final population, and decoding the individual into an optimal load transfer scheme; and verifying the optimal load transfer scheme, and executing the verified optimal load transfer scheme. According to the power system load transfer method and system provided by the invention, the heritage algorithm is applied to the power system load transfer process, so that the load transfer can be accurately analyzed, and the intelligent and automatic process of power grid control is promoted.

Description

Technical Field

[0001] The present invention relates to the technical field of power grid control, and in particular to a method and system for load transfer in a power system. Background Art

[0002] In the power system, when one or more main transformers in a substation are out of power due to planned maintenance or faults, it is necessary to transfer the 10kV line load under the main transformer to the opposite line in time to ensure the continuity and stability of power supply.

[0003] In the existing technology, load transfer is performed when a power system failure occurs, relying on the subjective experience of the staff. This method has extremely low accuracy, is prone to errors, and cannot quickly determine whether the opposite line and main transformer will be overloaded due to the increase in load.

[0004] It can be seen that how to improve the accuracy of load transfer in the power system has become a technical problem that needs to be urgently solved by those skilled in the art. Summary of the invention

[0005] The present invention provides a method and system for load transfer in an electric power system. By applying a legacy algorithm to the load transfer process of the electric power system, the load transfer can be accurately analyzed, thereby reducing the probability of failure of the electric power system after the load transfer, and promoting the intelligentization and automation of power grid control.

[0006] In order to solve the above technical problems, an embodiment of the present invention provides a method for load transfer in a power system, comprising:

[0007] When a power system fault is detected, a main and distribution integrated power grid model is constructed based on power system parameters;

[0008] Determining a load transfer fitness objective function corresponding to the power grid model, wherein the load transfer fitness objective function at least reflects minimizing load loss, minimizing the number of switch operations, or maximizing load recovery rate;

[0009] representing a load transfer scheme responsive to the load transfer fitness objective function based on a selected encoding scheme;

[0010] In the process of using genetic algorithm technology to deal with the optimization problem of load transfer in power system, the individuals with the highest fitness are selected from the final population and decoded into the optimal load transfer scheme;

[0011] The optimal load transfer scheme is verified, and the verified optimal load transfer scheme is executed.

[0012] As one of the preferred solutions, the power system parameters at least include the topological relationship between the 10kV line and the main transformer, the maximum load of the 10kV line, the limit of the 10kV line, the maximum load of the main transformer and the limit of the main transformer.

[0013] As one preferred solution, the method of expressing the load transfer solution in response to the load transfer fitness objective function based on the selected encoding solution includes:

[0014] Determining a sub-load transfer scheme for each line based on the load transfer fitness objective function;

[0015] Each of the sub-load transfer schemes is represented by a corresponding integer array, wherein the integer array is represented as follows:

[0016] [m1_1,m2_1,…,mn_x]…[m1_2,m2_2,…,mn_x]

[0017] Where mi_x represents the load transfer scheme corresponding to the xth line in the target line to which the i-th line is transferred.

[0018] As one of the preferred solutions, the encoding scheme is a binary encoding scheme, a real number encoding scheme or a mixed encoding scheme.

[0019] As one of the preferred solutions, verifying the optimal load transfer solution and executing the verified optimal load transfer solution includes:

[0020] Based on the preset physical constraints of the power grid, the optimal load transfer scheme is verified to obtain a first verification result, wherein the physical constraints of the power grid at least include 10kV line capacity constraints, transformer capacity constraints and power flow distribution constraints;

[0021] Based on the preset power grid operation constraint conditions, verifying the optimal load transfer scheme to obtain a second verification result, wherein the power grid operation constraint conditions at least include relay protection and automatic device constraints;

[0022] Compare and analyze the first verification result and the second verification result based on big data analysis technology;

[0023] After detecting that the comparison and analysis results are in compliance with the safe operation regulations and dispatching principles of the power grid, the optimal load transfer plan is executed.

[0024] Another embodiment of the present invention provides a power system load transfer system, comprising:

[0025] A model module is used to construct a main and distribution integrated power grid model based on power system parameters when a power system fault is detected;

[0026] A fitness function module, used to determine a load transfer fitness objective function corresponding to the power grid model, wherein the load transfer fitness objective function at least reflects minimizing load loss, minimizing the number of switch operations, or maximizing load recovery rate;

[0027] A coding representation module, for representing a load transfer scheme responsive to the load transfer fitness objective function based on a selected coding scheme;

[0028] A genetic algorithm module is used to select the individual with the highest fitness from the final population and decode it into an optimal load transfer scheme in the process of using the genetic algorithm technology to process the power system load transfer optimization problem;

[0029] An execution module is used to verify the optimal load transfer scheme and execute the verified optimal load transfer scheme.

[0030] As one of the preferred solutions, the power system parameters at least include the topological relationship between the 10kV line and the main transformer, the maximum load of the 10kV line, the limit of the 10kV line, the maximum load of the main transformer and the limit of the main transformer.

[0031] As one of the preferred solutions, the encoding representation module includes:

[0032] A determination unit, configured to determine a sub-load transfer scheme for each line based on the load transfer fitness objective function;

[0033] An array unit is used to represent each of the sub-load transfer schemes using a corresponding integer array, wherein the integer array is represented as follows:

[0034] [m1_1,m2_1,…,mn_x]…[m1_2,m2_2,…,mn_x]

[0035] Where mi_x represents the load transfer scheme corresponding to the xth line in the target line to which the i-th line is transferred.

[0036] As one of the preferred solutions, the encoding scheme is a binary encoding scheme, a real number encoding scheme or a mixed encoding scheme.

[0037] As one preferred solution, the execution module includes:

[0038] A first verification unit is used to verify the optimal load transfer scheme based on a preset physical constraint condition of the power grid to obtain a first verification result, wherein the physical constraint condition of the power grid at least includes a 10 kV line capacity constraint, a transformer capacity constraint and a power flow distribution constraint;

[0039] A second verification unit is used to verify the optimal load transfer scheme based on a preset power grid operation constraint condition to obtain a second verification result, wherein the power grid operation constraint condition at least includes a relay protection and an automatic device constraint;

[0040] A comparison unit, configured to compare and analyze the first verification result and the second verification result based on a big data analysis technology;

[0041] The execution unit is used to execute the optimal load transfer plan after detecting that the comparison and analysis results are in line with the safe operation regulations and dispatching principles of the power grid.

[0042] Compared with the prior art, the embodiments of the present invention have the following advantages:

[0043] (1) This solution uses a genetic algorithm to simulate the process of natural selection and inheritance, and can search for the optimal solution in a large solution space. In the load transfer of the power system, an optimal load distribution method can be found, which significantly improves the efficiency and reliability of the power system. Through the optimization of the genetic algorithm, it can ensure that the power system can still operate stably after the load transfer and meet the power supply needs of users;

[0044] (2) By adopting genetic algorithms, various resources of the power system, such as generators and transmission lines, can be dispatched more flexibly to adapt to different load demands, which in turn helps to improve the response capacity of the power system, enabling it to better respond to emergencies and emergency situations, and promote the intelligent and automated process of power grid control. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 is a flow chart of a method for power system load transfer in one embodiment of the present invention;

[0046] Figure 2 It is a structural block diagram of a power system load transfer system in one embodiment of the present invention. DETAILED DESCRIPTION

[0047] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. The purpose of providing these embodiments is to make the disclosure of the present invention more thorough and comprehensive. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0048] In the description of this application, the terms "first", "second", "third", etc. are used for descriptive purposes only and are not to be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first", "second", "third", etc. may explicitly or implicitly include one or more of the feature. In the description of this application, unless otherwise specified, "plurality" means two or more.

[0049] In the description of the present application, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be a connection between the two elements. The terms "vertical", "horizontal", "left", "right", "upper", "lower" and similar expressions used in this article are only for illustrative purposes, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. The term "and / or" used in this article includes any and all combinations of one or more related listed items. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0050] In the description of this application, it should be noted that, unless otherwise defined, all technical and scientific terms used in the present invention have the same meaning as those commonly understood by those skilled in the art. The terms used in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood by specific circumstances.

[0051] An embodiment of the present invention provides a method for transferring loads in a power system. For details, see Figure 1 , Figure 1 The figure shows a flow chart of a method for power system load transfer in one embodiment of the present invention, which includes steps S1 to S5:

[0052] S1. When a power system fault is detected, a main and distribution integrated power grid model is constructed based on power system parameters;

[0053] S2. Determine a load transfer fitness objective function corresponding to the power grid model, wherein the load transfer fitness objective function at least reflects minimizing load loss, minimizing the number of switch operations, or maximizing load recovery rate;

[0054] S3, representing the load transfer scheme responsive to the load transfer fitness objective function based on the selected encoding scheme;

[0055] S4. In the process of using genetic algorithm technology to deal with the power system load transfer optimization problem, the individual with the highest fitness is selected from the final population and decoded into the optimal load transfer solution;

[0056] S5. Verify the optimal load transfer plan and execute the verified optimal load transfer plan.

[0057] In the embodiment of the present invention, it should be noted that a main-distribution integrated power grid model needs to be established, preferably, it is constructed according to power system parameters, specifically as follows:

[0058] (1) 10kV line: the maximum load of the line within a period of time, the line limit, and whether there are important users on the line;

[0059] (2) Main transformer: the maximum load of the main transformer within a period of time, the main transformer limit.

[0060] In the above embodiment, it is necessary to generate the contact relationship of the 10kV line. The 10kV contact relationship information includes the current line, the opposite contact line, the contact switch, whether the contact switch can be remotely controlled, and the contact relationship between the 10kV line and the main transformer is generated, that is, it is necessary to know how many 10kV lines are under the main transformer, which will not be repeated here. In the above embodiment, the load transfer fitness objective function reflects at least one of the following constraint objectives: minimizing the load gap; balancing the loads of each line to avoid overload or uneven load; minimizing the time and complexity of the transfer operation; load overload: the number of overloads of the line and the main transformer is small, the overload amount is small, and the overload time is short; load gap: the load gap is minimized. Preferably, the fitness function is usually a comprehensive objective function, in the following form. Among them, w1, w2, w3, w4 are weights that determine the importance of different optimization objectives.

[0061] F(individual) = w1×main transformer overload + w2×line overload + w3×overload duration + w4*load gap

[0062] Furthermore, in the above embodiment, based on the load transfer fitness objective function, the sub-load transfer scheme of each line is determined. Then, the gene encoding method of the individual is defined. For this problem, an integer array can be used to represent the load transfer scheme of each line, specifically: each sub-load transfer scheme is represented by a corresponding integer array, wherein the integer array is represented as follows:

[0063] [m1_1,m2_1,…,mn_x]…[m1_2,m2_2,…,mn_x]

[0064] Where mi_x represents the load transfer scheme corresponding to the xth line in the target line to which the i-th line is transferred.

[0065] For example, if x1 can be transferred to {m1_1,m1_2}, and x2 can be transferred to {m2_1,m2_2,m2_3}, then an individual may be [m1_1,m2_2,…] or [m1_2,m2_3} and so on.

[0066] The embodiment of the present invention uses a genetic algorithm. The objective function and modeling have been described above, and the following mainly describes the steps of the genetic algorithm in detail.

[0067] 1. Initialize the population: Randomly generate a set of load transfer schemes as the initial population. Each scheme corresponds to an individual whose genotype is determined by the coding scheme. The population size is usually set to 50 to 200 individuals. Each individual represents a different load transfer combination. It should be emphasized that the constraints of the problem should be observed during generation, for example, the load of each line can only be transferred to the specified opposite line.

[0068] 2. Fitness evaluation: Calculate the fitness value of each individual according to the objective function and constraints. The higher the fitness value, the better the load transfer scheme.

[0069] 3. Selection operation: Select a certain number of excellent individuals as parents according to the fitness value to generate the next generation. Use Roulette Wheel Selection or Tournament Selection to select excellent individuals, and the probability is proportional to their fitness. The higher the individual fitness, the greater the probability of being selected.

[0070] 4. Crossover operation: Perform a crossover operation on the selected parent individuals to generate new offspring individuals. The crossover operation can be performed using single-point crossover, multi-point crossover, uniform crossover and other methods. Single-point crossover: Randomly select two individuals, select a crossover point in their gene sequences, exchange their subsequent parts, and generate two new individuals. Multi-point crossover: Multiple crossover points can be selected to increase genetic diversity. It should be noted that the crossover operation will generate new load transfer schemes that inherit some of the characteristics of the parent generation.

[0071] 5. Mutation operation: Perform mutation operation on the newly generated offspring individuals to increase the diversity of the population. The mutation operation can adopt methods such as bit flipping and real number mutation. Specifically, some positions in the individual genes can be randomly adjusted, such as randomly changing the transfer target line of a certain line. The mutation rate is usually low (such as 1% to 5%) to avoid destroying the existing excellent solutions.

[0072] 6. Iterative update: Replace some or all individuals in the population with the newly generated offspring individuals to form a new generation of population. Repeat the fitness evaluation, selection, crossover and mutation operations until the predetermined number of iterations is reached or the termination condition is met. For example, the set maximum number of generations (such as 100 generations) is reached. The fitness function reaches a certain target value (such as a predetermined level of power loss or load balance). The fitness of the population converges, indicating that no better individuals are generated.

[0073] After the optimal load transfer scheme is obtained through the above genetic algorithm, the embodiment of the present invention also needs to verify it. Specifically, the verification includes two steps, which are as follows:

[0074] Based on the preset physical constraints of the power grid, the optimal load transfer scheme is verified to obtain a first verification result, wherein the physical constraints of the power grid include at least 10kV line capacity constraints, transformer capacity constraints and power flow distribution constraints.

[0075] Based on the preset power grid operation constraint conditions, the optimal load transfer scheme is verified to obtain a second verification result, wherein the power grid operation constraint conditions at least include relay protection and automatic device constraints.

[0076] A comparison analysis is performed on the first verification result and the second verification result based on big data analysis technology. The specific comparison analysis can be performed by specifically analyzing the difference between the first verification result and the second verification result, which will not be further elaborated here.

[0077] After detecting that the comparison and analysis results meet the safe operation regulations and dispatching principles of the power grid, the optimal load transfer plan is executed. Of course, the safe operation regulations and dispatching principles of the power grid are determined by different power systems and distribution network safety requirements, and are not specifically limited in the embodiments of the present invention.

[0078] Another embodiment of the present invention provides a power system load transfer system. For details, see Figure 2 , Figure 2 The structure block diagram of the power system load transfer system in one embodiment of the present invention is shown, which includes:

[0079] Model module 11, used to build a main and distribution integrated power grid model based on power system parameters when a power system fault is detected;

[0080] A fitness function module 12, used to determine a load transfer fitness objective function corresponding to the power grid model, wherein the load transfer fitness objective function at least reflects minimizing load loss, minimizing the number of switch operations, or maximizing load recovery rate;

[0081] A coding representation module 13, for representing a load transfer scheme in response to the load transfer fitness objective function based on a selected coding scheme;

[0082] A genetic algorithm module 14 is used to select the individual with the highest fitness from the final population and decode it into an optimal load transfer solution in the process of processing the power system load transfer optimization problem using the genetic algorithm technology;

[0083] The execution module 15 is used to verify the optimal load transfer scheme and execute the verified optimal load transfer scheme.

[0084] Furthermore, in the above embodiment, the power system parameters include at least the topological relationship between the 10kV line and the main transformer, the maximum load of the 10kV line, the limit of the 10kV line, the maximum load of the main transformer and the limit of the main transformer.

[0085] Furthermore, in the above embodiment, the coding representation module 13 includes:

[0086] A determination unit, configured to determine a sub-load transfer scheme for each line based on the load transfer fitness objective function;

[0087] An array unit is used to represent each of the sub-load transfer schemes using a corresponding integer array, wherein the integer array is represented as follows:

[0088] [m1_1,m2_1,…,mn_x]…[m1_2,m2_2,…,mn_x]

[0089] Where mi_x represents the load transfer scheme corresponding to the xth line in the target line to which the i-th line is transferred.

[0090] Furthermore, in the above embodiments, the encoding scheme is a binary encoding scheme, a real number encoding scheme or a mixed encoding scheme.

[0091] Furthermore, in the above embodiment, the execution module 15 includes:

[0092] A first verification unit is used to verify the optimal load transfer scheme based on a preset physical constraint condition of the power grid to obtain a first verification result, wherein the physical constraint condition of the power grid at least includes a 10 kV line capacity constraint, a transformer capacity constraint and a power flow distribution constraint;

[0093] A second verification unit is used to verify the optimal load transfer scheme based on a preset power grid operation constraint condition to obtain a second verification result, wherein the power grid operation constraint condition at least includes a relay protection and an automatic device constraint;

[0094] A comparison unit, configured to compare and analyze the first verification result and the second verification result based on a big data analysis technology;

[0095] The execution unit is used to execute the optimal load transfer plan after detecting that the comparison and analysis results are in line with the safe operation regulations and dispatching principles of the power grid.

[0096] The power system load transfer method and system provided by the embodiments of the present invention have the following beneficial effects:

[0097] (1) This solution uses a genetic algorithm to simulate the process of natural selection and inheritance, and can search for the optimal solution in a large solution space. In the load transfer of the power system, an optimal load distribution method can be found, which significantly improves the efficiency and reliability of the power system. Through the optimization of the genetic algorithm, it can ensure that the power system can still operate stably after the load transfer and meet the power supply needs of users;

[0098] (2) By adopting genetic algorithms, various resources of the power system, such as generators and transmission lines, can be dispatched more flexibly to adapt to different load demands, which in turn helps to improve the response capacity of the power system, enabling it to better respond to emergencies and emergency situations, and promote the intelligent and automated process of power grid control.

[0099] The above-mentioned embodiments only express several implementation methods of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the scope of the patent of the present invention. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A method for load transfer in a power system, characterized in that: include: When a power system fault is detected, a main and distribution integrated power grid model is constructed based on power system parameters; Determining a load transfer fitness objective function corresponding to the power grid model, wherein the load transfer fitness objective function at least reflects minimizing load loss, minimizing the number of switch operations, or maximizing load recovery rate; representing a load transfer scheme responsive to the load transfer fitness objective function based on a selected encoding scheme; In the process of using genetic algorithm technology to deal with the optimization problem of load transfer in power system, the individuals with the highest fitness are selected from the final population and decoded into the optimal load transfer scheme; The optimal load transfer scheme is verified, and the verified optimal load transfer scheme is executed.

2. The power system load transfer method according to claim 1, characterized in that: The power system parameters include at least the topological relationship between the 10kV line and the main transformer, the maximum load of the 10kV line, the limit of the 10kV line, the maximum load of the main transformer and the limit of the main transformer.

3. The power system load transfer method according to claim 1, characterized in that: The step of expressing the load transfer scheme in response to the load transfer fitness objective function based on the selected encoding scheme includes: Determining a sub-load transfer scheme for each line based on the load transfer fitness objective function; Each of the sub-load transfer schemes is represented by a corresponding integer array, wherein the integer array is represented as follows: [m1_1,m2_1,…,mn_x]…[m1_2,m2_2,…,mn_x] Where mi_x represents the load transfer scheme corresponding to the xth line in the target line to which the i-th line is transferred.

4. The power system load transfer method according to claim 1, characterized in that: The encoding scheme is a binary encoding scheme, a real number encoding scheme, or a hybrid encoding scheme.

5. The power system load transfer method according to claim 1, characterized in that: The verifying the optimal load transfer scheme and executing the verified optimal load transfer scheme includes: Based on the preset physical constraints of the power grid, the optimal load transfer scheme is verified to obtain a first verification result, wherein the physical constraints of the power grid at least include 10kV line capacity constraints, transformer capacity constraints and power flow distribution constraints; Based on the preset power grid operation constraint conditions, verifying the optimal load transfer scheme to obtain a second verification result, wherein the power grid operation constraint conditions at least include relay protection and automatic device constraints; Compare and analyze the first verification result and the second verification result based on big data analysis technology; After detecting that the comparison and analysis results are in compliance with the safe operation regulations and dispatching principles of the power grid, the optimal load transfer plan is executed.

6. A power system load transfer system, characterized in that: include: A model module is used to construct a main and distribution integrated power grid model based on power system parameters when a power system fault is detected; A fitness function module, used to determine a load transfer fitness objective function corresponding to the power grid model, wherein the load transfer fitness objective function at least reflects minimizing load loss, minimizing the number of switch operations, or maximizing load recovery rate; A coding representation module, for representing a load transfer scheme responsive to the load transfer fitness objective function based on a selected coding scheme; A genetic algorithm module is used to select the individual with the highest fitness from the final population and decode it into an optimal load transfer scheme in the process of using the genetic algorithm technology to process the power system load transfer optimization problem; An execution module is used to verify the optimal load transfer scheme and execute the verified optimal load transfer scheme.

7. The power system load transfer system according to claim 6, characterized in that: The power system parameters include at least the topological relationship between the 10kV line and the main transformer, the maximum load of the 10kV line, the limit of the 10kV line, the maximum load of the main transformer and the limit of the main transformer.

8. The power system load transfer system according to claim 6, characterized in that: The coding representation module comprises: A determination unit, configured to determine a sub-load transfer scheme for each line based on the load transfer fitness objective function; An array unit is used to represent each of the sub-load transfer schemes using a corresponding integer array, wherein the integer array is represented as follows: [m1_1,m2_1,…,mn_x]…[m1_2,m2_2,…,mn_x] Where mi_x represents the load transfer scheme corresponding to the xth line in the target line to which the i-th line is transferred.

9. The power system load transfer system according to claim 6, characterized in that: The encoding scheme is a binary encoding scheme, a real number encoding scheme, or a hybrid encoding scheme.

10. The power system load transfer system according to claim 6, characterized in that: The execution module includes: A first verification unit is used to verify the optimal load transfer scheme based on a preset physical constraint condition of the power grid to obtain a first verification result, wherein the physical constraint condition of the power grid at least includes a 10 kV line capacity constraint, a transformer capacity constraint and a power flow distribution constraint; A second verification unit is used to verify the optimal load transfer scheme based on a preset power grid operation constraint condition to obtain a second verification result, wherein the power grid operation constraint condition at least includes a relay protection and an automatic device constraint; A comparison unit, configured to compare and analyze the first verification result and the second verification result based on a big data analysis technology; The execution unit is used to execute the optimal load transfer plan after detecting that the comparison and analysis results are in line with the safe operation regulations and dispatching principles of the power grid.

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