Parameter identification and correction method and system for full parallel AT traction power supply system model

Abstract

The invention relates to the technical field of traction power supply system modeling, in particular to a parameter identification and correction method and system for a full parallel AT traction power supply system model. The method comprises the steps of establishing an equivalent mathematical model and performing load flow calculation; inputting a locomotive load measured value and a power flow information measured value of each point of the traction power supply system into the equivalent mathematical model; identifying and correcting model parameters of the full-parallel AT tractive power supply system by using PSO in combination with actual measurement data of power flow information and a power flow calculation model; the system comprises a model building module, a measured value input module and an identification correction module. Through the above mode, the PSO is combined with the actual measurement data of the power flow information and the power flow calculation model to complete the identification and correction of the parameters of the full parallel AT traction power supply model, so that the simulation result of the power flow calculation is close to the actual situation as much as possible, and the problem of inaccurate simulation result caused by model parameter deviation and difficult-to-avoid simplification is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of traction power supply system modeling, and in particular to a parameter identification and correction method of a full-parallel AT traction power supply system model and a system thereof. Background Art

[0002] The current idea of ​​establishing a mathematical model of the traction power supply system is to determine the parameter calculation method and precise mathematical model of each component based on the electrical characteristics of each component; combined with the network topology of the traction power supply system, an equivalent mathematical model of the entire traction power supply system is established.

[0003] The traditional power flow calculation method is no longer suitable for the development requirements of the current traction power supply system, and the remaining optimization algorithms also require a large amount of data and precision instruments. In comparison, the continuous linear power flow calculation method is the most appropriate in the traction power supply system.

[0004] Since the traditional traction power supply system model adopts a calculation method with preset fixed parameters and does not take into account the errors of various parameters in the actual system, the inaccuracy of the model parameters will cause the accumulation of errors in the power flow calculation results, resulting in insufficient accuracy of the traction power supply system model. Summary of the invention

[0005] The purpose of the present invention is to provide a parameter identification and correction method for a full-parallel AT traction power supply system model and its system, aiming to solve the technical problem in the prior art that the traditional traction power supply system model adopts a calculation method with preset fixed parameters, does not take into account the errors existing in various parameters in the actual system, and therefore the inaccuracy of the model parameters will cause the accumulation of errors in the power flow calculation results, resulting in insufficient accuracy of the traction power supply system model.

[0006] To achieve the above object, the present invention adopts a parameter identification and correction method of a full parallel AT traction power supply system model, comprising the following steps:

[0007] An equivalent mathematical model is established through the mathematical model of each component of the full parallel AT traction power supply system and the network topology structure to perform power flow calculation;

[0008] Input the measured values ​​of locomotive load and the measured values ​​of power flow information at each point of the traction power supply system into the equivalent mathematical model;

[0009] PSO is used in combination with measured data of power flow information and power flow calculation model to identify and correct the model parameters of the full parallel AT traction power supply system.

[0010] Among them, in the step of using PSO combined with measured data of power flow information and power flow calculation model to identify and correct the model parameters of the full parallel AT traction power supply system:

[0011] Using subsystem parameters to identify the parameter values ​​of each subsystem;

[0012] Limit the range of parameter variation and correct the overall parameters.

[0013] Among them, in the step of using subsystem parameters to identify the parameter values ​​of each subsystem:

[0014] PSO is used to identify parameters through the measured values ​​of each subsystem combined with its equivalent mathematical model, and the results are used as the initial values ​​for overall parameter correction.

[0015] Among them, in the step of using PSO to identify parameters by combining the measured values ​​of each subsystem with its equivalent mathematical model and taking the results as the initial values ​​of the overall parameter correction:

[0016] Parameter identification of the three subsystems of power system, traction substation and AT:

[0017] The measured state quantity of the power system subsystem is the power system voltage U ss and current I ss , the identification parameter is the power system equivalent impedance Z s , the PSO fitness function is set to:

[0018]

[0019] Where i represents the i-th sampling point, N represents the number of sampling points, and m represents the actual measured value. All physical quantities in the formula are calculated using per-unit values.

[0020] The measured state quantity of the traction substation subsystem is the voltage U on both sides of the traction transformer tps and current I tps , the identification parameter is the equivalent impedance Z of the primary side of the traction transformer 1 , Excitation impedance Z m And the turns ratio k, a, b are variables related to the equivalent impedance of the primary and secondary sides of the traction transformer, and the calculation formula is:

[0021] a=2Z 1 +k 2 Z 2 ,b=Z 1 +k 2 Z 2 ;

[0022] The PSO fitness function is set as:

[0023]

[0024] The measured state quantity of the AT subsystem is the AT voltage U AT and current I AT , the identification parameter is AT equivalent impedance ZAT , the PSO fitness function is set to:

[0025]

[0026] Among them, in the step of limiting the parameter variation range and correcting the overall parameters:

[0027] Based on the initial values ​​of the parameters of each subsystem obtained by subsystem parameter identification, PSO is used to make the parameters of each part take values ​​within ±20% of the initial values. When the parameter values ​​taken minimize the fitness function value, that is, the error between the simulation results of the power flow calculation model and the actual measured value is minimized, the measured state quantity is the voltage U on both sides of the traction transformer. tps Current I tps , AT voltage U AT Current I AT , locomotive voltage U tr Current I tr , the PSO fitness function is:

[0028]

[0029] The present invention also provides a parameter identification and correction system for a full parallel AT traction power supply system model, comprising a model building module, a measured value input module and an identification and correction module, wherein:

[0030] The model building module is used to establish an equivalent mathematical model through the mathematical models of the components of the full parallel AT traction power supply system and the network topology structure to perform power flow calculation;

[0031] The measured value input module is used to input the measured value of the locomotive load and the measured value of the power flow information of each point of the traction power supply system into the equivalent mathematical model;

[0032] The identification and correction module is used to use PSO in combination with measured data of power flow information and a power flow calculation model to identify and correct model parameters of the full parallel AT traction power supply system.

[0033] The present invention discloses a parameter identification and correction method and system for a full-parallel AT traction power supply system model. The model building module, the measured value input module and the identification and correction module are used to perform the following steps: an equivalent mathematical model is established through the mathematical models of the components of the full-parallel AT traction power supply system and the network topology structure to perform power flow calculation; the measured values ​​of the locomotive load and the measured values ​​of the power flow information at each point of the traction power supply system are input into the equivalent mathematical model; PSO is used in combination with the measured data of the power flow information and the power flow calculation model to perform identification and correction of the parameters of the full-parallel AT traction power supply system model; in the above manner, PSO is used in combination with the measured data of the power flow information and the power flow calculation model to complete the identification and correction of the parameters of the full-parallel AT traction power supply model, so that the power flow calculation simulation result is as close as possible to the actual situation, and the problem of inaccurate simulation results caused by model parameter deviation and unavoidable simplification is solved. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, 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.

[0035] Figure 1 It is a flow chart of the steps of the parameter identification and correction method of the full parallel AT traction power supply system model of the present invention.

[0036] Figure 2 It is a structural principle diagram of the high-fidelity model architecture of the present invention.

[0037] Figure 3 It is a schematic diagram of the steps of double-layer model parameter correction of the present invention.

[0038] Figure 4 It is a schematic diagram comparing the simulation results of the present invention with the measured data.

[0039] Figure 5 It is a schematic diagram comparing the simulation results after changing the position and power of the locomotive of the present invention with the measured data.

[0040] Figure 6 It is a structural principle diagram of the parameter identification and correction system of the full parallel AT traction power supply system model of the present invention.

[0041] Figure 7 It is a structural principle diagram of the electronic equipment of the present invention.

[0042] 601-model building module, 602-measurement value input module, 603-identification and correction module. DETAILED DESCRIPTION

[0043] Here, exemplary embodiments are described in detail, and examples thereof are shown in the accompanying drawings. When the following description refers to the drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The implementations described in the following exemplary embodiments do not represent all implementations consistent with the present application.

[0044] The terms used in this application are for the purpose of describing specific embodiments only and are not intended to limit this application. The singular forms of "a", "said" and "the" used in this application and the appended claims are also intended to include plural forms unless the context clearly indicates other meanings. It should also be understood that the term "and / or" used herein refers to and includes any or all possible combinations of one or more associated listed items.

[0045] See also Figure 1 to Figure 3 The present invention provides a parameter identification and correction method for a full parallel AT traction power supply system model, comprising the following steps:

[0046] Step 1: Establish an equivalent mathematical model through the mathematical models of the components of the full-parallel AT traction power supply system and the network topology structure to perform power flow calculation.

[0047] In this implementation, high-fidelity modeling is applied to establish a high-fidelity model of the traction power supply system, and its architecture is as follows: Figure 2 As shown; an equivalent mathematical model is established through the mathematical models of the components of the full-parallel AT traction power supply system and the network topology structure to perform power flow calculation.

[0048] Step 2: Input the measured values ​​of locomotive load and the measured values ​​of power flow information at each point of the traction power supply system into the equivalent mathematical model.

[0049] In this embodiment, a small amount of locomotive load measured values ​​obtained from tests in the actual system, including locomotive position and power and measured values ​​of flow information at each point of the traction power supply system, are input from the actual system into the model through information interaction.

[0050] Step 3: Use PSO combined with measured data of power flow information and power flow calculation model to identify and correct the model parameters of the full parallel AT traction power supply system.

[0051] In this embodiment, although PSO has the ability to globally optimize complex system parameters, it still faces some problems when directly applied to the overall parameter correction of the traction power supply system. First, it is easy to fall into premature convergence and local optimality. The randomly generated particle swarm may also cause the power flow calculation to not converge. In addition, the calculation time cost is high when PSO is used in complex systems. In order to avoid these problems, the present invention adopts a parameter correction strategy that combines a two-layer model, i.e., subsystem parameter identification and overall parameter correction, such as Figure 3 As shown in the figure, PSO is used in combination with measured data of power flow information and power flow calculation model to identify and correct the model parameters of the full parallel AT traction power supply system.

[0052] Among them, in the identification and correction of the model parameters of the full parallel AT traction power supply system using PSO combined with the measured data of power flow information and the power flow calculation model, the specific process is as follows:

[0053] Using subsystem parameters to identify the parameter values ​​of each subsystem;

[0054] Limit the range of parameter variation and correct the overall parameters.

[0055] Among them, in identifying the parameter values ​​of each subsystem using subsystem parameters:

[0056] PSO is used to identify parameters through the measured values ​​of each subsystem combined with its equivalent mathematical model, and the results are used as the initial values ​​of the overall parameter correction; the structure of the traction power supply system of the full parallel AT power supply mode mainly includes the power system subsystem, the traction substation subsystem, and the traction network subsystem. There is no monitoring device on the traction network, which can only be installed in the AT station. Therefore, the parameters of the three subsystems of the power system, traction substation, and AT are identified:

[0057] The measured state quantity of the power system subsystem is the power system voltage U ss and current I ss , the identification parameter is the power system equivalent impedance Z s , the PSO fitness function is set to:

[0058]

[0059] Where i represents the i-th sampling point, N represents the number of sampling points, and m represents the actual measured value. All physical quantities in the formula are calculated using per-unit values.

[0060] The measured state quantity of the traction substation subsystem is the voltage U on both sides of the traction transformer tps and current I tps , the identification parameter is the equivalent impedance Z of the primary side of the traction transformer 1 , Excitation impedance Z mAnd the turns ratio k, a, b are variables related to the equivalent impedance of the primary and secondary sides of the traction transformer, and the calculation formula is:

[0061] a=2Z 1 +k 2 Z 2 ,b=Z 1 +k 2 Z 2 ;

[0062] The PSO fitness function is set as:

[0063]

[0064] The measured state quantity of the AT subsystem is the AT voltage U AT and current I AT , the identification parameter is AT equivalent impedance Z AT , the PSO fitness function is set to:

[0065]

[0066] Among them, in limiting the range of parameter changes and correcting the overall parameters:

[0067] When performing overall parameter correction, the parameter variation range is limited to a certain range to avoid the generation of random particles that lead to non-convergence of power flow calculations and to solve the problems of falling into local optimality and high time cost.

[0068] Based on the initial values ​​of the parameters of each subsystem obtained by subsystem parameter identification, PSO is used to make the parameters of each part take values ​​within ±20% of the initial values. When the parameter values ​​taken minimize the fitness function value, that is, the error between the simulation results of the power flow calculation model and the actual measured value is minimized, that is, the similarity between the model and the real system is the highest. The measured state quantity is the voltage U on both sides of the traction transformer. tps Current I tps , AT voltage U AT Current I AT , locomotive voltage U tr Current I tr , the PSO fitness function is:

[0069]

[0070] Since the traditional full parallel AT traction power supply system model uses preset parameters, the parameters of the power flow calculation model may be inaccurate. Therefore, the present invention proposes a method of using PSO combined with the measured value of power flow information and the power flow calculation model to identify and correct the parameters of the traction power supply system model, and obtain a high-fidelity model of the traction power supply system. The high-fidelity model simulation results are compared with the measured data. Figure 4As shown, it can be seen that the error between the high-fidelity model simulation value and the measured data is very small, indicating that PSO is effective in identifying and correcting system parameters.

[0071] By changing the position and power of the locomotive, the accuracy of the high-fidelity model of the full parallel AT traction power supply system after parameter identification is verified. The simulation results are compared with the measured data. Figure 5 As shown in the figure, it can be seen that after changing the position and power of the locomotive, the error between the simulation results of the high-fidelity model and the measured data is very small, indicating that the high-fidelity model of the full-parallel AT traction power supply system can simulate the actual system more accurately.

[0072] Since PSO directly used for overall parameter correction of the traction power supply system model may fall into premature convergence, local optimum and long calculation time, a parameter correction method combining a two-layer model, i.e., subsystem parameter identification and overall parameter correction, is adopted.

[0073] Corresponding to the aforementioned embodiment of the parameter identification and correction method of the full-parallel AT traction power supply system model, the present application also provides an embodiment of the parameter identification and correction system of the full-parallel AT traction power supply system model.

[0074] Figure 6 1 is a block diagram of a parameter identification and correction system for a full parallel AT traction power supply system model according to an exemplary embodiment. Figure 6 , the system may include:

[0075] The present invention also provides a parameter identification and correction system for a full parallel AT traction power supply system model, comprising a model building module 601, a measured value input module 602 and an identification and correction module 603, wherein:

[0076] The model building module 601 is used to establish an equivalent mathematical model through the mathematical models of the components of the full parallel AT traction power supply system and the network topology structure to perform power flow calculation;

[0077] The measured value input module 602 is used to input the measured value of the locomotive load and the measured value of the power flow information of each point of the traction power supply system into the equivalent mathematical model;

[0078] The identification and correction module 603 is used to use PSO in combination with measured data of power flow information and a power flow calculation model to identify and correct model parameters of the full parallel AT traction power supply system.

[0079] In this embodiment, the model building module, the measured value input module and the identification and correction module are used to perform the following steps: an equivalent mathematical model is established through the mathematical model of each component of the full parallel AT traction power supply system and the network topology structure to perform power flow calculation; the measured value of the locomotive load and the measured value of the power flow information at each point of the traction power supply system are input into the equivalent mathematical model; PSO is used in combination with the measured data of the power flow information and the power flow calculation model to perform identification and correction of the model parameters of the full parallel AT traction power supply system; through the above method, PSO is used in combination with the measured data of the power flow information and the power flow calculation model to complete the identification and correction of the parameters of the full parallel AT traction power supply model, so that the power flow calculation simulation results are as close as possible to the actual situation, thereby improving the accuracy of modeling and power flow calculation.

[0080] Regarding the system in the above embodiment, the specific manner in which each module performs operations has been described in detail in the embodiment of the method, and will not be elaborated here.

[0081] For the system embodiment, since it basically corresponds to the method embodiment, the relevant parts can refer to the partial description of the method embodiment. The device embodiment described above is only schematic, wherein the units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, they may be located in one place, or they may be distributed on multiple network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the present application. A person of ordinary skill in the art can understand and implement it without creative work.

[0082] Accordingly, the present application also provides an electronic device, comprising: one or more processors; a memory for storing one or more programs; when the one or more programs are executed by the one or more processors, the one or more processors implement the parameter identification and correction method of the full parallel AT traction power supply system model as described above. Figure 7 As shown, it is a hardware structure diagram of any device with data processing capability where a parameter identification and correction system of a full parallel AT traction power supply system model provided by an embodiment of the present invention is located, except Figure 7 In addition to the processor, memory and network interface shown, any device with data processing capability in which the apparatus in the embodiment is located may also include other hardware, generally based on the actual functions of the device with data processing capability, which will not be described in detail.

[0083] Accordingly, the present application also provides a computer-readable storage medium having computer instructions stored thereon, which, when executed by a processor, implement the parameter identification and correction method of the full-parallel AT traction power supply system model as described above. The computer-readable storage medium may be an internal storage unit of any device with data processing capability described in any of the foregoing embodiments, such as a hard disk or a memory. The computer-readable storage medium may also be an external storage device, such as a plug-in hard disk, a smart memory card (Smart Media Card, SMC), an SD card, a flash card (Flash Card), etc. equipped on the device. Furthermore, the computer-readable storage medium may also include both an internal storage unit and an external storage device of any device with data processing capability. The computer-readable storage medium is used to store the computer program and other programs and data required by any device with data processing capability, and may also be used to temporarily store data that has been output or is to be output.

[0084] Those skilled in the art will readily appreciate other embodiments of the present application after considering the specification and practicing the contents disclosed herein. The present application is intended to cover any variations, uses or adaptations of the present application, which follow the general principles of the present application and include common knowledge or customary technical means in the art that are not disclosed in the present application.

[0085] It should be understood that the present application is not limited to the exact construction that has been described above and shown in the drawings, and that various modifications and changes may be made without departing from the scope thereof.

Claims

1. A parameter identification and correction method for a full parallel AT traction power supply system model, characterized in that: The steps include: An equivalent mathematical model is established through the mathematical model of each component of the full parallel AT traction power supply system and the network topology structure to perform power flow calculation; Input the measured values ​​of locomotive load and the measured values ​​of power flow information at each point of the traction power supply system into the equivalent mathematical model; PSO is used in combination with measured data of power flow information and power flow calculation model to identify and correct the model parameters of the full parallel AT traction power supply system.

2. The parameter identification and correction method of the full parallel AT traction power supply system model according to claim 1, characterized in that: In the steps of using PSO combined with measured data of power flow information and power flow calculation model to identify and correct the model parameters of the full parallel AT traction power supply system: Using subsystem parameters to identify the parameter values ​​of each subsystem; Limit the range of parameter variation and correct the overall parameters.

3. The parameter identification and correction method of the full parallel AT traction power supply system model according to claim 2 is characterized in that: In the step of identifying the parameter values ​​of each subsystem using the subsystem parameters: PSO is used to identify parameters through the measured values ​​of each subsystem combined with its equivalent mathematical model, and the results are used as the initial values ​​for overall parameter correction.

4. The parameter identification and correction method of the full parallel AT traction power supply system model according to claim 3 is characterized in that: In the step of using PSO to identify parameters by combining the measured values ​​of each subsystem with its equivalent mathematical model and taking the results as the initial values ​​of the overall parameter correction: Parameter identification of the three subsystems of power system, traction substation and AT: The measured state quantity of the power system subsystem is the power system voltage U ss and current I ss , the identification parameter is the power system equivalent impedance Z s , the PSO fitness function is set to: Where i represents the i-th sampling point, N represents the number of sampling points, and m represents the actual measured value. All physical quantities in the formula are calculated using per-unit values. The measured state quantity of the traction substation subsystem is the voltage U on both sides of the traction transformer tps and current I tps The identification parameters are the equivalent impedance Z1 of the primary side of the traction transformer and the excitation impedance Z m And the turns ratio k, a, b are variables related to the equivalent impedance of the primary and secondary sides of the traction transformer, and the calculation formula is: a=2Z1+k 2 Z2,b=Z1+k 2 Z2; The PSO fitness function is set as: The measured state quantity of the AT subsystem is the AT voltage U AT and current I AT , the identification parameter is AT equivalent impedance Z AT , the PSO fitness function is set to:

5. The parameter identification and correction method of the full parallel AT traction power supply system model according to claim 2, characterized in that: In the step of limiting the range of parameter variation and correcting the overall parameters: Based on the initial values ​​of the parameters of each subsystem obtained by subsystem parameter identification, PSO is used to make the parameters of each part take values ​​within ±20% of the initial values. When the parameter values ​​taken minimize the fitness function value, that is, the error between the simulation results of the power flow calculation model and the actual measured value is minimized, the measured state quantity is the voltage U on both sides of the traction transformer. tps Current I tps , AT voltage U AT Current I AT , locomotive voltage U tr Current I tr , the PSO fitness function is:

6. A parameter identification and correction system for a full parallel AT traction power supply system model, applied to the parameter identification and correction method for a full parallel AT traction power supply system model as claimed in claim 1, characterized in that: It includes a model building module, a measured value input module, an identification and correction module, a subsystem parameter value identification module and a parameter restriction module, wherein: The model building module is used to establish an equivalent mathematical model through the mathematical models of the components of the full parallel AT traction power supply system and the network topology structure to perform power flow calculation; The measured value input module is used to input the measured value of the locomotive load and the measured value of the power flow information of each point of the traction power supply system into the equivalent mathematical model; The identification and correction module is used to use PSO in combination with measured data of power flow information and a power flow calculation model to identify and correct model parameters of the full parallel AT traction power supply system.

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