A method and system for evaluating power grid load model

Abstract

The present invention provides a method and system for evaluating a power grid load model, the method comprising: after investigating the power grid load characteristics, statistically analyzing the load equipment types, the proportions of various types of load equipment and equipment type parameters corresponding to the substation based on the survey data; calculating the static load model parameters and the dynamic motor load model parameters respectively according to the load equipment types, the proportions of various types of load equipment and equipment type parameters corresponding to the substation, and constructing a comprehensive load model of the substation; simulating and verifying the comprehensive load model of the substation, and evaluating the stability of the original power grid load model based on the comprehensive load model of the substation. The scheme realizes the evaluation of the stability characteristics of the power grid load model, and can directly and accurately obtain the stability of the power grid load model, which is conducive to improving the stability and reliability of the power system.

Description

Technical Field

[0001] The present invention relates to the field of power system security, and in particular to a power grid load model evaluation method and system. Background Art

[0002] With the improvement of the interconnection degree of power grids, the dynamic stability and voltage stability of power grids have become more and more prominent, and the impact of load models on the simulation results of system stability characteristics can no longer be ignored. Due to the influence of factors such as the access of a large number of distributed power sources and changes in load structure, the adaptability of existing load models in power grids has been reduced, and it has become one of the main bottlenecks in improving the accuracy of system stability characteristics simulation.

[0003] A large number of experiments have shown that load characteristics play an important role in the system simulation calculation results. Different load models have different degrees of influence on the system's transient stability, dynamic stability, voltage stability and other stability issues. However, it is difficult to directly and accurately know the stability of the existing power grid load model, which is not convenient for adaptive adjustment of the power grid load model. Summary of the invention

[0004] In view of this, an embodiment of the present invention provides a method and system for evaluating a power grid load model to solve the problem of being unable to accurately obtain the stability of the power grid load model.

[0005] In a first aspect of an embodiment of the present invention, a method for evaluating a power grid load model is provided, comprising:

[0006] After investigating the load characteristics of the power grid, the types of load equipment corresponding to the substation, the proportion of each type of load equipment, and equipment type parameters are statistically analyzed based on the survey data;

[0007] According to the load equipment type corresponding to the substation, the proportion of each type of load equipment and the equipment type parameters, the static load model parameters and the dynamic motor load model parameters are calculated respectively, and the substation comprehensive load model is constructed;

[0008] The substation comprehensive load model is simulated and verified, and the stability of the original power grid load model is evaluated based on the substation comprehensive load model.

[0009] In a second aspect of an embodiment of the present invention, a power grid load model evaluation system is provided, comprising:

[0010] The statistical analysis module is used to investigate the load characteristics of the power grid and then statistically analyze the load equipment types, proportions of each type of load equipment and equipment type parameters corresponding to the substation based on the survey data;

[0011] A parameter calculation module is used to calculate static load model parameters and dynamic motor load model parameters according to the load equipment type corresponding to the substation, the proportion of each type of load equipment and equipment type parameters, and to construct a comprehensive load model of the substation;

[0012] The model evaluation module is used to simulate and verify the substation comprehensive load model and evaluate the stability of the original power grid load model based on the substation comprehensive load model.

[0013] In a third aspect of an embodiment of the present invention, an electronic device is provided, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the steps of the method described in the first aspect of the embodiment of the present invention when executing the computer program.

[0014] According to a fourth aspect of an embodiment of the present invention, a computer-readable storage medium is provided, wherein the computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the steps of the method provided in the first aspect of the embodiment of the present invention are implemented.

[0015] In the embodiment of the present invention, after investigating the load characteristics of the power grid, the load equipment type corresponding to the substation, the proportion of each type of load equipment and the equipment type parameters are statistically analyzed based on the survey data, and the corresponding static load model parameters and dynamic motor load model parameters are calculated respectively, and the substation comprehensive load model is constructed, and the substation comprehensive load model is simulated and verified, and the stability of the original power grid load model is evaluated. In this way, the adaptability of the existing power grid load model can be evaluated, and its stability can be accurately determined. The evaluation method is simple and efficient, ensures the accuracy of the simulation, is convenient for improving the adaptability of the power grid load model parameters, and improves the stability of the power system. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0017] Figure 1 A schematic diagram of a flow chart of a power grid load model evaluation method provided by an embodiment of the present invention;

[0018] Figure 2 Another schematic diagram of a flow chart of a power grid load model evaluation method provided by an embodiment of the present invention;

[0019] Figure 3A schematic diagram of the structure of a power grid load model evaluation system provided by one embodiment of the present invention;

[0020] Figure 4 A schematic structural diagram of an electronic device provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0021] In order to make the purpose, features and advantages of the present invention more obvious and easy to understand, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the embodiments described below are only part of the embodiments of the present invention, not all of the embodiments. 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. The principles and features of the present invention are described below in conjunction with the drawings. The examples are only used to explain the present invention and are not used to limit the scope of the present invention.

[0022] The terms "including" and other expressions with similar meanings in the specification or claims of the present invention and the above-mentioned drawings are intended to cover non-exclusive inclusions, such as a process, method or system, or device comprising a series of steps or units is not limited to the listed steps or units.

[0023] See also Figure 1 , Figure 1 A schematic flow chart of a power grid load model evaluation method provided by an embodiment of the present invention includes:

[0024] S101. After investigating the load characteristics of the power grid, statistically analyze the load equipment types, proportions of each type of load equipment, and equipment type parameters corresponding to the substation based on the survey data;

[0025] The grid load is classified according to its nature, and a census is conducted on the load characteristics of the grid. The load types are divided into seven categories: ordinary industrial load, residential commercial load, industrial, residential and commercial mixed load, industrial, residential, commercial and agricultural mixed load, residential, commercial and agricultural mixed load, high-energy consumption load and other load types.

[0026] Among them, according to the actual situation of each region, a detailed investigation of the distribution network, load composition and load characteristics of typical load sites is carried out, and the proportion of each electrical equipment in each load type is calculated. The load types include ordinary industrial load, residential commercial load, industrial, residential and commercial mixed load, industrial, residential, commercial and agricultural mixed load, residential, commercial and agricultural mixed load, high-energy consumption load and other load types, a total of seven categories.

[0027] For example, taking a substation of ordinary industrial load type as an example, the types of equipment involved in a 220kV substation and the proportion of each type of equipment are as follows:

[0028]

[0029] Table 1

[0030] S102, according to the load equipment type corresponding to the substation, the proportion of each type of load equipment and equipment type parameters, respectively calculate the static load model parameters and the dynamic motor load model parameters, and construct a comprehensive load model of the substation;

[0031] The load characteristics are usually given by the relationship curves of active power and reactive power relative to voltage and frequency. In order to obtain the mathematical model for power flow and stability calculations, certain approximations must be made.

[0032] Specifically, the relationship curves of active power and reactive power with respect to voltage and frequency are linearized; based on a specific load value, the static characteristic parameters corresponding to the static load model are calculated.

[0033] For load, the relationship curves of active power and reactive power relative to voltage and frequency can be linearized to obtain:

[0034]

[0035]

[0036] Among them These are load characteristic parameters. For given voltage and frequency, these characteristic parameters are fixed.

[0037] For a certain load, it is required to give the characteristic parameters and power factor of the entire load, that is, the and PF, so that the static characteristic parameters of the entire load can be determined.

[0038] When the load contains a motor, it is necessary to calculate the proportion of the motor power to the total load power, the motor parameters, and the load characteristic parameters other than the motor load. The motor parameters mainly include stator resistance Rs, stator reactance Xs, excitation reactance Xm, rotor resistance Rr, rotor reactance Xr, low-voltage release voltage Vi, low-voltage release delay Ti, mechanical torque coefficients A and B, inertia time constant TJ, and load factor LFm.

[0039] Thus, static load model parameters and dynamic motor load model parameters can be obtained.

[0040] Furthermore, static load model parameters and dynamic motor load model parameters in different load types are calculated to obtain the comprehensive load model of the substation.

[0041] Comprehensive calculations are performed on all equipment types to obtain a set of load model parameters. When the dynamic characteristics of the load are considered, motor load models and static load models are used to represent them.

[0042] For example, in summer, the motor parameters and static load parameters in the motor+static load model of a 220 kV substation are respectively shown in the following table:

[0043]

[0044] Table 2

[0045] ZP% ZQ% IP% IQ % PP% PQ% R* X* 10 10 85 85 5 5 0.003 0.07

[0046] Table 3

[0047] In the table, Tj represents the motor inertia time constant, Rs represents the motor stator resistance, Xs represents the motor stator reactance, Xm represents the motor excitation reactance, Rr represents the motor rotor resistance, Xr represents the motor rotor reactance, R* represents the distribution network branch resistance, X* represents the distribution network branch reactance, ZP% represents the constant impedance component in the static active load composition, ZQ% represents the constant impedance component in the static reactive load composition, IP% represents the constant current component in the static active load composition, IQ% represents the constant current component in the static reactive load composition, PP% represents the constant power component in the static active load composition, and PQ% represents the constant power reactance component in the static reactive load composition.

[0048] Calculate the characteristic parameters under different load types, integrate all types of loads, and obtain the comprehensive load parameters.

[0049] Exemplarily, the model parameters of the power grid SLM (distribution network comprehensive load model) are shown in the following table:

[0050]

[0051] Table 4(a)

[0052]

[0053]

[0054] Table 4(b)

[0055] Table 4(a) is a statistical table of motor proportions and static load ZIP proportions of various types of SLM models in the power grid. The highest proportion of motors is in ordinary industrial loads, which is 75%; followed by 50% for industrial, residential and commercial mixed loads and 45% for industrial, residential and agricultural mixed loads, and the lowest is 30% for residential and commercial loads. From the load survey, it can also be seen that there is a large proportion of motors in industrial loads, and there are also many motors used in agriculture, which accounts for the second largest proportion, while motors for residential and commercial electrical equipment account for a relatively small proportion. In terms of static loads, the power grid part adopts a constant current model, and finally, IP% accounts for the largest proportion in the static models of the three types of loads.

[0056] Table 4(b) shows other motor parameters and distribution network resistance and reactance parameters. Industrial loads generally have higher load rates and larger inertia time constants Tj, while commercial and residential loads have smaller load rates. General industrial and industrial residential agricultural models have the highest load rates and inertia time constants Tj, while commercial and residential models have the lowest; the stator reactance, rotor reactance, and magnetizing reactance of industrial SLM models are generally higher than those of residential and commercial models, while the stator resistance and rotor resistance are lower than those of residential and commercial models.

[0057] S103: Perform simulation verification on the substation comprehensive load model to evaluate the stability of the substation comprehensive load model.

[0058] Specifically, Figure 2 As shown, in S201, the validity of the load model is verified. By simulation calculation, the difference between the substation comprehensive load model and the original load model is compared, the variation range of various difference values ​​is calculated, and the stability of the original power grid load model is evaluated, that is, the adaptability of the stability characteristics of the power grid load model is evaluated.

[0059] Furthermore, in S202, the substation comprehensive load model replaces the original power grid load model. Based on the substation comprehensive load model, the transient power angle stability, transient voltage stability and dynamic stability characteristics of the power grid are analyzed. The difference in stability characteristics before and after the replacement model is compared in the same way to analyze the application effect of the model.

[0060] The SLM load model of the distribution network obtained by load modeling replaces the original load model of the power grid. On the basis of the SLM load model, the transient power angle stability, transient voltage stability and dynamic stability characteristics of the power grid are analyzed. The difference in stability characteristics before and after the model replacement is compared in the same way, and the application effect of the model is compared and analyzed to draw conclusions on the adaptability evaluation of the load model.

[0061] In this embodiment, based on the statistical analysis of the survey data, the load data of various equipment are calculated, and then the static model parameters and motor load model parameters are determined, and a comprehensive load model is constructed, and the stability of the original model is evaluated based on the comprehensive load model. In this way, the stability-specific adaptability evaluation of the power grid load model is realized simply and efficiently, which is convenient for improving the stability of the power system.

[0062] It should be understood that the serial numbers of the steps in the above embodiments do not imply a sequence of execution, and the execution sequence of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present invention.

[0063] Figure 3 A schematic diagram of a power grid load model evaluation system provided by an embodiment of the present invention, the system comprising:

[0064] The statistical analysis module 310 is used to conduct a statistical analysis of the load equipment types, the proportion of each type of load equipment and equipment type parameters corresponding to the substation based on the survey data after investigating the load characteristics of the power grid;

[0065] Furthermore, the statistical analysis module 310 also includes: calculating the proportion of each electrical equipment in each load type, wherein the load types include ordinary industrial load, residential commercial load, industrial residential commercial mixed load, industrial residential commercial agricultural mixed load, residential commercial agricultural mixed load, high energy consumption load and other load types, a total of seven categories.

[0066] The parameter calculation module 320 is used to calculate the static load model parameters and the dynamic motor load model parameters according to the load equipment type corresponding to the substation, the proportion of each type of load equipment and the equipment type parameters, and construct a comprehensive load model of the substation;

[0067] Among them, the relationship curves of active power and reactive power with respect to voltage and frequency are linearized; based on specific load values, the static characteristic parameters corresponding to the static load model are calculated.

[0068] The static load model parameters and dynamic motor load model parameters in different load types are calculated to obtain the comprehensive load model of the substation.

[0069] The model evaluation module 330 is used to simulate and verify the substation comprehensive load model, and evaluate the stability of the original power grid load model based on the substation comprehensive load model.

[0070] Specifically, the difference between the substation comprehensive load model and the original load model is compared, the variation range of various difference values ​​is calculated, and the stability of the original power grid load model is evaluated.

[0071] Furthermore, the substation comprehensive load model replaces the original power grid load model. Based on the substation comprehensive load model, the transient power angle stability, transient voltage stability and dynamic stability characteristics of the power grid are analyzed, and the difference in stability characteristics before and after the replacement model is compared in the same way.

[0072] Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working processes of the above-described systems and modules can refer to the corresponding processes in the aforementioned method embodiments, and will not be repeated here.

[0073] Figure 4 1 is a schematic diagram of the structure of an electronic device provided by an embodiment of the present invention. The electronic device is used for evaluating the stability of a power grid load model and is usually a computer. Figure 4 As shown, the electronic terminal device 4 of this embodiment includes: a memory 410, a processor 420 and a system bus 430, wherein the memory 410 includes an executable program 4101 stored thereon, and those skilled in the art can understand that Figure 4 The electronic device structure shown in the figure does not constitute a limitation of the electronic device, and may include more or less components than shown in the figure, or combine certain components, or arrange the components differently.

[0074] Combine the following Figure 4 A detailed introduction to the various components of electronic equipment:

[0075] The memory 410 can be used to store software programs and modules, and the processor 420 executes various functional applications and data processing of the electronic device by running the software programs and modules stored in the memory 410. The memory 410 may mainly include a program storage area and a data storage area, wherein the program storage area may store an operating system, an application required for at least one function, etc.; the data storage area may store data (such as cache data) created according to the use of the electronic device, etc. In addition, the memory 410 may include a high-speed random access memory, and may also include a non-volatile memory, such as at least one disk storage device, a flash memory device, or other volatile solid-state storage devices.

[0076] The memory 410 includes an executable program 4101 of the network request method, and the executable program 4101 can be divided into one or more modules / units, which are stored in the memory 410 and executed by the processor 420 to achieve accident prediction, etc. The one or more modules / units can be a series of computer program instruction segments that can complete specific functions, and the instruction segments are used to describe the execution process of the computer program 4101 in the electronic device 4. For example, the computer program 4101 can be divided into a statistical analysis module, a parameter calculation module, and a model evaluation module.

[0077] The processor 420 is the control center of the electronic device. It uses various interfaces and lines to connect various parts of the entire electronic device. It executes various functions of the electronic device and processes data by running or executing software programs and / or modules stored in the memory 410, and calling data stored in the memory 410, so as to monitor the overall status of the electronic device. Optionally, the processor 420 may include one or more processing units; preferably, the processor 420 may integrate an application processor and a modem processor, wherein the application processor mainly processes the operating system, application programs, etc., and the modem processor mainly processes wireless communications. It is understandable that the above-mentioned modem processor may not be integrated into the processor 420.

[0078] The system bus 430 is used to connect the various functional components inside the computer, and can transmit data information, address information, and control information. Its types can be, for example, PCI bus, ISA bus, VESA bus, etc. The instructions of the processor 420 are transmitted to the memory 410 through the bus, and the memory 410 feeds back data to the processor 420. The system bus 430 is responsible for the data and instruction exchange between the processor 420 and the memory 410. Of course, the system bus 430 can also be connected to other devices, such as network interfaces, display devices, etc.

[0079] In the embodiment of the present invention, the executable program executed by the processor 420 included in the electronic device includes:

[0080] After investigating the load characteristics of the power grid, the types of load equipment corresponding to the substation, the proportion of each type of load equipment, and equipment type parameters are statistically analyzed based on the survey data;

[0081] According to the load equipment type corresponding to the substation, the proportion of each type of load equipment and the equipment type parameters, the static load model parameters and the dynamic motor load model parameters are calculated respectively, and the substation comprehensive load model is constructed;

[0082] The substation comprehensive load model is simulated and verified, and the stability of the original power grid load model is evaluated based on the substation comprehensive load model.

[0083] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described or recorded in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0084] As described above, the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features thereof may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for evaluating a power grid load model, It is characterized in that include: After investigating the load characteristics of the power grid, the types of load equipment corresponding to the substation, the proportion of each type of load equipment, and equipment type parameters are statistically analyzed based on the survey data; According to the load equipment type corresponding to the substation, the proportion of each type of load equipment and the equipment type parameters, the static load model parameters and the dynamic motor load model parameters are calculated respectively, and the substation comprehensive load model is constructed; Wherein, constructing the substation comprehensive load model includes: Calculating static load model parameters and dynamic motor load model parameters in different load types to obtain the substation comprehensive load model; Among them, a comprehensive calculation is performed on all equipment types to obtain a set of load model parameters. When the dynamic characteristics of the load are considered, the motor load model and the static load model are used to represent them; Performing simulation verification on the substation comprehensive load model, and evaluating the stability of the original power grid load model based on the substation comprehensive load model; Wherein, the evaluating the stability of the original power grid load model based on the substation comprehensive load model includes: Compare the difference between the substation comprehensive load model and the original load model, calculate the variation range of various difference values, and evaluate the stability of the original power grid load model; Among them, the substation comprehensive load model replaces the original power grid load model, and on the basis of the substation comprehensive load model, the transient power angle stability, transient voltage stability and dynamic stability characteristics of the power grid are analyzed, and the difference in stability characteristics before and after the replacement model is compared in the same way.

2. The method according to claim 1, It is characterized in that The load equipment types, proportions of various types of load equipment and equipment type parameters corresponding to the substation based on the statistical analysis of the survey data also include: Calculate the proportion of each electrical equipment in each load type, where the load types include ordinary industrial load, residential commercial load, industrial residential commercial mixed load, industrial residential commercial agricultural mixed load, residential commercial agricultural mixed load, high energy consumption load and other load types, a total of seven categories.

3. The method according to claim 1, It is characterized in that The calculating of the static load model parameters and the dynamic motor load model parameters respectively according to the load equipment type corresponding to the substation, the proportion of each type of load equipment and the equipment type parameters includes: Linearize the relationship curves of active power and reactive power with respect to voltage and frequency; Based on the specified load value, the static characteristic parameters corresponding to the static load model are calculated.

4. A power grid load model evaluation system, It is characterized in that include: The statistical analysis module is used to investigate the load characteristics of the power grid and then statistically analyze the load equipment types, proportions of each type of load equipment and equipment type parameters corresponding to the substation based on the survey data; A parameter calculation module is used to calculate static load model parameters and dynamic motor load model parameters according to the load equipment type corresponding to the substation, the proportion of each type of load equipment and equipment type parameters, and to construct a comprehensive load model of the substation; Wherein, constructing the substation comprehensive load model includes: Calculating static load model parameters and dynamic motor load model parameters in different load types to obtain the substation comprehensive load model; Among them, a comprehensive calculation is performed on all equipment types to obtain a set of load model parameters. When the dynamic characteristics of the load are considered, the motor load model and the static load model are used to represent them; A model evaluation module, used to simulate and verify the substation comprehensive load model, and evaluate the stability of the original power grid load model based on the substation comprehensive load model; Wherein, the evaluating the stability of the original power grid load model based on the substation comprehensive load model includes: Compare the difference between the substation comprehensive load model and the original load model, calculate the variation range of various difference values, and evaluate the stability of the original power grid load model; Among them, the substation comprehensive load model replaces the original power grid load model, and on the basis of the substation comprehensive load model, the transient power angle stability, transient voltage stability and dynamic stability characteristics of the power grid are analyzed, and the difference in stability characteristics before and after the replacement model is compared in the same way.

5. An electronic device comprising a processor, a memory, and a computer program stored in the memory and running on the processor, It is characterized in that When the processor executes the computer program, the steps of the power grid load model evaluation method as described in any one of claims 1-3 are implemented.

6. A computer-readable storage medium storing a computer program, It is characterized in that When the computer program is executed by a processor, the steps of a power grid load model evaluation method as described in any one of claims 1 to 3 are implemented.

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