Wideband harmonic optimization configuration method and system for power distribution network

Abstract

The invention provides a broadband harmonic optimization configuration method and system for a power distribution network. The method comprises the following steps: establishing an optimization model which takes the minimum global broadband harmonic distortion rate of the power distribution network and the minimum investment and operation cost of treatment equipment as a comprehensive target; determining constraint conditions of the optimization model, wherein the constraint conditions comprise a node voltage total harmonic distortion rate and a limit value of each harmonic distortion rate, a governance equipment installation capacity and position candidate set constraint, and a power grid power flow safe operation constraint; and solving the optimization model by adopting a multi-target intelligent optimization algorithm, and outputting an optimal configuration scheme of the harmonic treatment equipment, the optimal configuration scheme comprising the type, the installation position and the rated capacity of the treatment equipment. According to the method, efficient suppression and treatment economical efficiency of 2-150 times of broadband harmonic waves can be effectively balanced, and the problems that in a traditional method, treatment frequency bands are limited, economical efficiency is poor, and safety is difficult to cooperate are solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of harmonic optimization, and particularly relates to a power distribution network wideband harmonic optimization configuration method and system. BACKGROUND

[0002] With the wide application of power electronic technology, the harmonic pollution problem in the power distribution network is increasingly serious, and the harmonic spectrum presents a widening trend from the traditional low frequency band to the medium and high frequency band (such as 2-150 times). Wideband harmonics not only cause deterioration of power quality and equipment overheating loss, but also may cause system resonance, which seriously threatens the safety of the power grid. At present, harmonic control mainly relies on the installation of filtering devices at specific nodes, however, the existing configuration method mainly focuses on solving the harmonic problem of a single frequency or low frequency band, and generally takes the harmonic control effect and economic cost as two independent targets for step-by-step optimization. This method is difficult to cope with the complexity of wideband harmonics, and often cannot achieve effective suppression of wideband harmonics in the entire power distribution network under the premise of global economic optimization.

[0003] In addition, the traditional optimization configuration method does not comprehensively consider the constraints of the installation location and capacity of the control equipment when modeling, and lacks collaborative analysis with the safe operation of power flow, resulting in that the planning scheme may be insufficient in adaptability or cause new safety problems in the actual system. At the same time, when solving such complex nonlinear optimization problems, the conventional algorithm is easy to fall into local optimum, and it is difficult to quickly and accurately obtain a system-level solution that achieves the best balance between harmonic suppression effect and investment cost. Therefore, there is an urgent need for an optimization configuration method that can comprehensively consider the characteristics of wideband harmonics, multiple constraint conditions and comprehensive economy. SUMMARY

[0004] The present application aims to provide a power distribution network wideband harmonic optimization configuration method and system, which aims to solve the problem that the planning scheme of the traditional optimization configuration method may be insufficient in adaptability or cause new safety problems in the actual system.

[0005] In a first aspect, the present application provides a power distribution network wideband harmonic optimization configuration method, which comprises:

[0006] establishing an optimization model with the minimum of the global wideband harmonic distortion rate of the power distribution network and the minimum of the investment and operation cost of the control equipment as the comprehensive target, wherein the wideband harmonic includes 2-150 times of fundamental frequency harmonic and interharmonic;

[0007] determining the constraint conditions of the optimization model, the constraint conditions including the node voltage total harmonic distortion rate and the harmonic distortion rate limit value, the installation capacity and location candidate set constraint of the control equipment, and the power flow safe operation constraint;

[0008] The multi-objective intelligent optimization algorithm is used to solve the optimization model, and an optimal configuration scheme of the harmonic control equipment is output, the optimal configuration scheme including the type, installation position and rated capacity of the control equipment.

[0009] In some embodiments, the step of establishing the optimization model with the minimum global broadband harmonic distortion rate and the lowest investment and operation cost of the control equipment as the comprehensive target includes:

[0010] The optimization model is constructed according to the following formula:

[0011] min (α1·T g +α2·C t );

[0012] Wherein, α1 and α2 are greater than 0, and are weights, α1+α2=1, T g is the global broadband harmonic distortion rate, and C t is the investment and operation cost of the control equipment.

[0013] In some embodiments, the global broadband harmonic distortion rate is obtained according to the following formula:

[0014]

[0015] Wherein, U h is the effective value of the hth harmonic voltage, and U1 is the effective value of the fundamental harmonic voltage.

[0016] The investment and operation cost of the control equipment is obtained according to the following formula:

[0017]

[0018] Wherein, N is the total number of control equipment, C inv,i is the investment cost of the ith equipment, and C op，i is the annual operation cost of the ith equipment.

[0019] In some embodiments, the step of determining the constraint conditions of the optimization model, the constraint conditions including the total harmonic distortion rate and the harmonic distortion rate limit value of each node voltage, the installation capacity and location candidate set constraint of the control equipment, and the safe operation constraint of power flow includes:

[0020] The limit value of the total harmonic distortion rate of each node voltage and the harmonic voltage content rate is set;

[0021] The upper limit of the single and total installation capacity of the active control equipment is set, and the installation position is selected from the pre-determined sensitive node candidate set.

[0022] In some embodiments, the step of establishing the optimization model with the comprehensive objective of minimizing the global wideband harmonic distortion rate of the power distribution network and minimizing the total investment and operation cost of the harmonic control devices further comprises:

[0023] initializing a population and generating a set of random solutions, wherein each solution vector is used to represent a harmonic control configuration scheme, and the solution vector includes type codes of the harmonic control devices, installation location codes, and capacity parameters;

[0024] iteratively optimizing by performing the following process until a termination condition is met:

[0025] calculating a comprehensive objective function value of each configuration scheme corresponding to an individual in the population, wherein the comprehensive objective function value is a weighted sum of the global harmonic distortion rate of the power distribution network and the total investment and operation cost of the harmonic control devices;

[0026] based on the fitness value of the individual, using a roulette wheel selection method or a tournament selection method to select excellent individuals as parents from the current population;

[0027] performing a single-point crossover or a simulated binary crossover operation on the selected parent individuals with a preset crossover probability to generate new child individuals;

[0028] performing a bit mutation or a polynomial mutation operation on the generated child individuals with a preset mutation probability to introduce new genetic characteristics;

[0029] merging the newly generated child individuals with the parent individuals, or directly replacing the original population with the newly generated child individuals to form a new generation population;

[0030] repeating the iterative optimization process until a preset maximum number of iterations is reached or the change in the comprehensive objective function value tends to be stable;

[0031] decoding the individual with the optimal fitness value in the final population to output the coded harmonic control device type, installation location, and rated capacity as the optimal configuration scheme.

[0032] In a second aspect, the present application provides a wideband harmonic optimization configuration system for a power distribution network, which comprises:

[0033] an optimization model construction module configured to establish an optimization model with the comprehensive objective of minimizing the global wideband harmonic distortion rate of the power distribution network and minimizing the total investment and operation cost of the harmonic control devices, wherein the wideband harmonic includes 2-150 times of power frequency harmonics and interharmonics;

[0034] a constraint condition construction module configured to determine the constraint conditions of the optimization model, wherein the constraint conditions include the total harmonic distortion rate and the harmonic distortion rate limit value of each harmonic of the node voltage, the installation capacity and location candidate set constraint of the harmonic control devices, and the safe operation constraint of the power grid power flow;

[0035] A solving module is configured to solve the optimization model by using a multi-objective intelligent optimization algorithm, and output an optimal configuration scheme of the harmonic control device, the optimal configuration scheme including a type, an installation position and a rated capacity of the harmonic control device.

[0036] In a third aspect, the present application provides a storage medium, which stores one or more programs, and the program is executed by a processor to implement the power distribution network broadband harmonic optimization configuration method.

[0037] In a fourth aspect, the present application provides an electronic device, which includes a memory and a processor, wherein:

[0038] The memory is configured to store a computer program;

[0039] The processor is configured to execute the computer program stored in the memory to implement the power distribution network broadband harmonic optimization configuration method.

[0040] Compared with the prior art, the present application has the following advantages:

[0041] The present application establishes a comprehensive objective function by fusing the global broadband harmonic distortion rate minimization and the device investment and operation cost minimization, and couples multiple conditions such as the node voltage distortion rate limit, the device installation constraint and the power grid power flow safe operation, and automatically solves the optimal configuration scheme by using an intelligent optimization algorithm, so as to realize the optimal balance between the efficient suppression and governance economy of the 2-150 broadband harmonics under the premise of strictly guaranteeing the safety of the power grid, and effectively solve the problems of the limited governance frequency band, the poor economy and the difficult coordination of safety in the traditional method. BRIEF DESCRIPTION OF DRAWINGS

[0042] Figure 1 A flow chart of a power distribution network broadband harmonic optimization configuration method according to an embodiment of the present application is shown in the figure.

[0043] Figure 2 A structure schematic diagram of a power distribution network broadband harmonic optimization configuration system according to an embodiment of the present application is shown in the figure.

[0044] The following specific embodiments will further illustrate the present application in combination with the above-mentioned figures. DETAILED DESCRIPTION

[0045] In order to make the purposes, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below. Obviously, the described embodiments are some but not all of the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts should fall into the scope of the present application. Unless otherwise defined, the technical terms or scientific terms used herein should be understood as the common meanings of the terms by those of ordinary skill in the art to which the present application belongs. The terms such as "comprise" and the like used herein are intended to cover the elements or objects recited in the terms before the terms and their equivalents, and do not exclude other elements or objects.

[0046] As shown in Figure 1 An embodiment of the present application provides a power distribution network broadband harmonic optimization configuration method, which comprises steps S101 to S103, wherein:

[0047] Step S101: An optimization model with the minimum global broadband harmonic distortion rate of the power distribution network and the minimum operation cost of the treatment equipment investment as the comprehensive target is established, wherein the broadband harmonic includes 2-150 power frequency harmonics and interharmonics.

[0048] It should be noted that in this step, firstly, two optimization targets are defined: one is the optimal technical performance, that is, minimizing the "global broadband harmonic distortion rate (THD)" of the entire power distribution network, which requires the model to comprehensively evaluate the overall pollution degree of all power frequency harmonics and interharmonics from 2 to 150 to the power grid, rather than focusing on only one or a few harmonics, thereby ensuring the comprehensiveness of the treatment effect; the other is the optimal economic benefit, that is, minimizing the "treatment equipment investment operation cost", which includes the initial purchase cost of active / passive filters and other equipment and the subsequent operation and maintenance energy consumption cost.

[0049] Specifically, in some embodiments, the optimization model is constructed according to the following formula:

[0050] min (α1·T g +α2·C t );

[0051] Wherein, α1 and α2 are greater than 0, and are weights, α1+α2=1, T g is the global broadband harmonic distortion rate, and C t is the treatment equipment investment operation cost.

[0052] In addition, in some embodiments, the global broadband harmonic distortion rate is obtained according to the following formula:

[0053]

[0054] wherein U h is the effective value of the hth harmonic voltage, and U1 is the effective value of the fundamental voltage;

[0055] In addition, in some embodiments, the operation cost of the governance equipment investment is obtained according to the following formula:

[0056]

[0057] wherein N is the total number of governance equipment, C inv,i is the investment cost of the ith equipment, C op,i is the annual operation cost of the ith equipment.

[0058] Step S102: determining the constraint conditions of the optimization model, the constraint conditions including the total harmonic distortion rate of node voltage and the limit value of each harmonic distortion rate, the installation capacity and location candidate set constraint of the governance equipment, and the safe operation constraint of power grid power flow;

[0059] It should be noted that the constraint conditions are mainly divided into three categories: the first category is the power quality constraint, which requires that the total harmonic distortion rate of each node in the optimized power grid and the harmonic content rate of each specific frequency must be lower than the limit value specified in the national standard (such as GB / T 14549), which is a hard indicator for the eligibility of the scheme; the second category is the engineering actual constraint, which limits the total installation capacity and single capacity of the governance equipment to be lower than the upper limit provided by the manufacturer, and the installation location must be selected from a pre-screened “location candidate set” (such as the vicinity of the harmonic source, the sensitive node of the power grid, or the resonance risk point), which avoids impractical equipment selection and installation point selection; the third category is the power grid safety constraint, which requires that after the configuration scheme is implemented, the power flow distribution (such as node voltage and branch current) of the entire distribution network still needs to be kept within the safe operation range, so as to prevent new voltage out-of-limit or equipment overload and other safety problems caused by harmonic governance itself.

[0060] Specifically, the limit value of the total harmonic distortion rate of each node voltage and the harmonic voltage content rate of each frequency is set; and the upper limit of the single and total installation capacity of the active governance equipment is set, and the installation location is limited to be selected from the pre-determined sensitive node candidate set.

[0061] Step S103: solving the optimization model by using a multi-objective intelligent optimization algorithm, and outputting an optimal configuration scheme of the harmonic governance equipment, the optimal configuration scheme including the type, installation location, and rated capacity of the governance equipment.

[0062] In this step, since the model target is nonlinear, the variables are discrete (equipment type and location), and the solution space is large, it is difficult to effectively solve the model by using traditional mathematical methods, and therefore a multi-objective intelligent optimization algorithm (such as NSGA-II genetic algorithm) is selected for searching.

[0063] Specifically, in some embodiments, the solving algorithm is: initializing a population, generating a set of random solutions, wherein each solution vector is used to represent a harmonic governance configuration scheme, and the solution vector includes type code, installation location code and capacity parameter of the governance device;

[0064] iterative optimization, the following process is performed until the termination condition is met:

[0065] Calculate the comprehensive objective function value of each individual in the population corresponding to the configuration scheme, and the comprehensive objective function value is the weighted sum of the global harmonic distortion rate of the power distribution network and the total investment and operation cost of the governance device;

[0066] Based on the fitness value of the individual, a roulette selection method or a tournament selection method is used to select excellent individuals from the current population as parents;

[0067] The selected parent individuals are subjected to single-point crossover or simulated binary crossover operation with a preset crossover probability to generate new child individuals;

[0068] The generated child individuals are subjected to bit mutation or polynomial mutation operation with a preset mutation probability to introduce new gene features;

[0069] The newly generated child individuals are combined with the parent individuals, or directly replace the original population to form a new generation population;

[0070] Repeat the iterative optimization process until the preset maximum number of iterations or the change trend of the comprehensive objective function value is stable;

[0071] Decode the individual with the optimal fitness in the final population, and output the coded governance device type, installation location and rated capacity as the optimal configuration scheme.

[0072] In summary, according to the power distribution network broadband harmonic optimization configuration method described above, by establishing a comprehensive objective function that integrates the minimization of global broadband harmonic distortion rate and the minimization of device investment and operation cost, and coupling multiple conditions such as node voltage distortion rate limit, device installation constraint and power flow safe operation, an intelligent optimization algorithm is used to automatically solve the optimal configuration scheme, which realizes the optimal balance between efficient suppression and governance economy of 2-150 broadband harmonics under the premise of strictly ensuring the safety of the power grid, and effectively solves the problems of limited governance frequency band, poor economy and difficult coordination of safety in traditional methods.

[0073] As shown in Figure 2 An embodiment of the present application proposes a power distribution network broadband harmonic optimization configuration system, which comprises:

[0074] An optimization model construction module 10 is configured to establish an optimization model with the minimum global wideband harmonic distortion rate of the power distribution network and the minimum investment and operation cost of the harmonic control device as the comprehensive target, wherein the wideband harmonic includes 2-150 times of power frequency harmonic and inter-harmonic;

[0075] A constraint condition construction module 20 is configured to determine the constraint conditions of the optimization model, and the constraint conditions include the total harmonic distortion rate and the harmonic distortion rate limit value of the node voltage, the constraint of the candidate set of the installation capacity and position of the harmonic control device, and the safe operation constraint of the power flow of the power grid.

[0076] A solution module 30 is configured to solve the optimization model by using a multi-objective intelligent optimization algorithm, and output an optimal configuration scheme of the harmonic control device, wherein the optimal configuration scheme includes the type, installation position and rated capacity of the harmonic control device.

[0077] In another aspect, the application further provides a storage medium having one or more programs stored thereon, and the program is executed by a processor to implement the power distribution network wideband harmonic optimization configuration method.

[0078] In another aspect, the application further provides an electronic device including a memory and a processor, wherein the memory is configured to store a computer program, and the processor is configured to execute the computer program stored in the memory to implement the power distribution network wideband harmonic optimization configuration method.

[0079] Those skilled in the art can understand that the logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as a sequence list of executable instructions for implementing the logic function, which can be specifically implemented in any computer readable medium for use by or in conjunction with an instruction execution system, device or equipment (such as a computer-based system, a system including a processor or other system that can fetch and execute instructions from the instruction execution system, device or equipment). For the purpose of this specification, the "computer readable medium" can be any device that can contain, store, communicate, propagate or transport programs for use by or in conjunction with an instruction execution system, device or equipment, or in conjunction with these instruction execution systems, devices or equipment.

[0080] More specific examples (a non-exhaustive list) of the computer-readable medium include the following: an electrical connection (electronic) having one or more wires, a portable computer diskette (magnetic), a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or Flash memory), an optical fiber, and a portable compact disc read-only memory (CDROM). Additionally, the computer-readable medium can also be paper or another suitable medium upon which the program is printed, as the program can be electronically captured, for example, via an optical scanner, then compiled, interpreted, or otherwise processed, and stored in a computer memory in a form that is then suitable for use by the computer. Note that the computer-readable medium can even be paper or another suitable medium that can be conventional for the use in the computer field.

[0081] It should be understood that aspects of the application can be implemented in hardware, software, firmware or combinations thereof. In the embodiments described above, various steps or methods can be implemented, for example, in software or firmware that is stored in memory and executed by a suitable instruction execution system. For example, if implemented in hardware, and in another embodiment, any of the following techniques, which are well known in the art of making integrated circuits, can be used to implement the application: a discrete logic circuit having logic gates for implementing logic functions upon data signals, an application specific integrated circuit having appropriate combinational logic gates, a programmable gate array (PGA), a field programmable gate array (FPGA), etc.

[0082] While the embodiments of the application have been illustrated and described in detail, it will be clear to those skilled in the art that various modifications and changes can be made to the embodiments without departing from the scope and spirit of the application as set forth in the claims. Moreover, the application has been described with reference to a few embodiments. However, one of ordinary skill in the art appreciates that various modifications and changes can be made without departing from the scope and spirit of the application as set forth in the claims. Accordingly, the disclosure is intended to embrace all such modifications and changes that fall within the scope and spirit of the application, together with all equivalents thereof.

Claims

1. A method for optimizing the configuration of broadband harmonics in a distribution network, characterized in that, The method includes: An optimization model is established with the comprehensive objectives of minimizing the global broadband harmonic distortion rate of the distribution network and minimizing the investment and operating costs of the mitigation equipment. The broadband harmonics include the 2nd to 150th power frequency harmonics and interharmonics. The constraints of the optimization model are determined, including the total harmonic distortion rate and harmonic distortion rate limits of node voltages, the installation capacity and location candidate set of the mitigation equipment, and the power flow safety operation constraints. The optimization model is solved using a multi-objective intelligent optimization algorithm, which outputs the optimal configuration scheme for harmonic mitigation equipment. The optimal configuration scheme includes the type, installation location, and rated capacity of the mitigation equipment.

2. The method for optimizing the configuration of broadband harmonics in a distribution network according to claim 1, characterized in that, The steps for establishing an optimization model with the comprehensive objectives of minimizing the global broadband harmonic distortion rate of the distribution network and minimizing the investment and operating costs of mitigation equipment include: Construct an optimization model based on the following formula: min(α1·T g +α2·C t ); Where α1 and α2 are both greater than 0 and are both weights, α1 + α2 = 1, T g For global broadband harmonic distortion, C t To manage the investment and operating costs of equipment.

3. The method for optimizing the configuration of broadband harmonics in a distribution network according to claim 2, characterized in that, The global broadband harmonic distortion rate can be obtained using the following formula: Among them, U h U1 is the effective value of the h-th harmonic voltage, and U2 is the effective value of the fundamental voltage. The investment and operating costs of the treatment equipment can be obtained using the following formula: Where N is the total number of treatment devices, C inv,i Let C be the investment cost of the i-th device. op,i Let be the annual operating cost of the i-th device.

4. The method for optimizing the configuration of broadband harmonics in a distribution network according to claim 3, characterized in that, The steps for determining the constraints of the optimization model, including the limits of total harmonic distortion rate and harmonic distortion rate of node voltages, constraints on the installation capacity and location candidate set of mitigation equipment, and constraints on the safe operation of power grid flow, include: Set limits for the total harmonic distortion rate of voltage at each node and the content of each harmonic voltage. Set upper limits for the single unit and total installation capacity of active control equipment, and limit the installation location to be selected from a pre-determined set of sensitive node candidates.

5. The method for optimizing the configuration of broadband harmonics in a distribution network according to claim 4, characterized in that, The step of establishing an optimization model with the combined objectives of minimizing the global broadband harmonic distortion rate of the distribution network and minimizing the investment and operating costs of the mitigation equipment also includes: Initialize the population and generate a set of random solutions, where each solution vector is used to characterize a harmonic mitigation configuration scheme. The solution vector includes the type code, installation location code, and capacity parameters of the mitigation equipment. Iterative optimization, performing the following process until the termination condition is met: Calculate the comprehensive objective function value of the configuration scheme corresponding to each individual in the population. The comprehensive objective function value is the weighted sum of the global harmonic distortion rate of the distribution network and the total investment and operating cost of the mitigation equipment. Based on the fitness value of an individual, a roulette wheel selection method or a tournament selection method is used to select superior individuals from the current population as parents. For the selected parent individuals, perform single-point crossover or simulated binary crossover operations with preset crossover probabilities to generate new offspring individuals; For the generated offspring individuals, perform site mutation or polynomial mutation operations with a preset mutation probability to introduce new gene characteristics; The newly generated offspring individuals are merged with the parent individuals, or the original population is directly replaced to form a new generation of population; Repeat the iterative optimization process until the preset maximum number of iterations is reached or the change in the comprehensive objective function value tends to stabilize. The individual with the best fitness in the final population is decoded, and its encoded governance equipment type, installation location, and rated capacity are output as the optimal configuration scheme.

6. A broadband harmonic optimization configuration system for power distribution networks, characterized in that, The system includes: The optimization model construction module is used to establish an optimization model with the comprehensive objectives of minimizing the global broadband harmonic distortion rate of the distribution network and minimizing the investment and operating costs of the mitigation equipment. The broadband harmonics include the 2nd to 150th power frequency harmonics and interharmonics. The constraint construction module is used to determine the constraints of the optimization model. The constraints include the total harmonic distortion rate and harmonic distortion rate limits of the node voltage, the installation capacity and location candidate set of the governance equipment, and the power flow safety operation constraints. The solution module is used to solve the optimization model using a multi-objective intelligent optimization algorithm and output the optimal configuration scheme of the harmonic control equipment. The optimal configuration scheme includes the type, installation location and rated capacity of the control equipment.

7. A storage medium, characterized in that, The storage medium stores one or more programs, which, when executed by a processor, implement a broadband harmonic optimization configuration method for a power distribution network as described in any one of claims 1-5.

8. An electronic device comprising a memory and a processor, wherein: The memory is used to store computer programs; When the processor executes the computer program stored in the memory, it implements the broadband harmonic optimization configuration method for a power distribution network as described in any one of claims 1-5.

Images