A method and system for locating transformer winding deformation based on genetic algorithm

Abstract

The present invention proposes a transformer winding deformation positioning method and system based on a genetic algorithm. By constructing a universal equivalent circuit of the winding, windings in different positions are mapped into different units in the circuit. The feasible domain of the circuit elements is constructed using the equivalent inductance and capacitance parameters of the winding and the series-parallel relationship of the elements. The values ​​of the equivalent circuit elements are optimized within the feasible domain based on the genetic algorithm, thereby obtaining equivalent circuits corresponding to windings in different states, thereby realizing a universal diagnostic method for winding deformation fault positioning.

Description

Technical Field

[0001] The invention belongs to the field related to transformer winding diagnosis, and in particular relates to a transformer winding deformation positioning method and system based on genetic algorithm. Background Art

[0002] The statements in this section merely provide background information related to the present invention and do not necessarily constitute prior art.

[0003] Power transformers are one of the important and expensive core equipment in power systems. Whether their operation is reliable or not has a significant impact on the safety and stability of the power grid. According to relevant statistics, windings are the main part where power transformer failures occur. Among winding failures, the vast majority are caused by winding deformation due to strong electric forces generated by short-circuit currents. Therefore, diagnosing the deformation of power transformer windings is an important research topic in the field of power equipment status assessment. At present, according to the industry standard DL / T 911-2016, power systems often use frequency response analysis to diagnose winding deformation. By applying swept-frequency sinusoidal excitation at the head end of the winding, the voltage response is collected at the end of the winding under test, and the frequency response curve containing the mechanical state information of the winding is obtained. The deviation of the normal and deformed winding frequency response curves is calculated through a variety of quantitative criteria, and the severity of the winding deformation is diagnosed according to the size of the relevant criteria. However, the above-mentioned method based on diagnostic criteria has the following disadvantages: 1) There may be problems with the universality of the criteria, that is, for transformers with different voltage levels or different connection groups, the deformation severity represented by the same criterion value is not the same; 2) The criteria are closely related to the degree of deformation of the winding, but are not closely related to the position of the winding deformation, and it is difficult to locate the winding deformation based on the diagnostic criteria. Summary of the invention

[0004] In order to overcome the shortcomings of the above-mentioned prior art, the present invention provides a transformer winding deformation locating method and system based on a genetic algorithm. By constructing a universal equivalent circuit of the winding, windings in different positions are mapped into different units in the circuit, and the feasible domain of the circuit elements is constructed using the equivalent inductance and capacitance parameters of the winding and the series-parallel relationship of the elements. The values ​​of the equivalent circuit elements are optimized within the feasible domain based on the genetic algorithm, thereby obtaining equivalent circuits corresponding to windings in different states, thereby realizing a universal diagnostic method for locating winding deformation faults.

[0005] To achieve the above objectives, one or more embodiments of the present invention provide the following technical solutions: A method for locating transformer winding deformation based on genetic algorithm, characterized in that it comprises the following steps:

[0006] S1: Obtaining equivalent total parameters of a normal transformer winding and a transformer winding under test respectively, and determining a parameter search domain of an equivalent circuit element of the winding based on the equivalent total parameters of the winding;

[0007] S2: using a genetic algorithm to search the parameter search domain of equivalent circuit elements to obtain a plurality of sets of winding equivalent circuit element value sets;

[0008] S3: establishing an objective function by minimizing the deviation between the frequency response curves of several sets of winding equivalent circuit element values ​​and the measured frequency response curves of the windings;

[0009] S4: Determine the optimal set of equivalent circuit element values ​​corresponding to the winding based on the minimum deviation;

[0010] S5: Compare the optimal set of equivalent circuit component values ​​of the transformer winding under test with the optimal set of equivalent circuit component values ​​of a normal transformer winding, and locate the fault of the transformer winding under test.

[0011] Furthermore, before S1, it also includes: connecting the output and input ends of the frequency response characteristic analysis instrument to the high voltage and low voltage ends of the transformer winding respectively, setting the frequency response test band to 1kHz-1MHz, testing to obtain the frequency response curve of the winding and analyzing the number of characteristic frequencies thereof, and determining the number of units in the winding equivalent circuit.

[0012] Furthermore, in S1, the specific method for obtaining the equivalent total parameters of the normal transformer winding and the transformer winding under test is:

[0013] Short-circuit the transformer winding head and the secondary winding head respectively, connect the impedance analyzer head and the transformer winding head and the secondary winding respectively, test the impedance value under 50Hz sinusoidal excitation, and obtain the equivalent total parallel capacitance value;

[0014] When the secondary winding of the transformer is short-circuited, the first and second ends of the impedance analyzer are connected to the high-voltage and low-voltage ends of the winding under test respectively. The swept-frequency impedance curve of the winding is obtained and fitted, and the equivalent total inductance and equivalent total series capacitance of the transformer winding are calculated.

[0015] Furthermore, in S1, the series-parallel relationship of different elements in the transformer winding equivalent circuit is analyzed, and the parameter search domain of the equivalent circuit elements is determined by analyzing the correlation characteristics between the circuit elements and the winding equivalent total parallel capacitance, equivalent total inductance and series capacitance values, as well as the number of units in the determined winding equivalent circuit.

[0016] Furthermore, in S2, a genetic algorithm is used to search for equivalent circuit elements in a parameter search domain of equivalent circuit elements to obtain several sets of winding equivalent circuit element value sets.

[0017] Furthermore, in S3, an equivalent circuit model of the winding is constructed using PSPICE simulation software based on an equivalent circuit element value set, and a PSPICE circuit element assignment program is constructed in a MATLAB compilation environment to obtain frequency response curves corresponding to different equivalent circuit element value sets.

[0018] Furthermore, in S3, the objective function is:

[0019]

[0020] Among them, OF is the objective function value, l is the frequency point number of the frequency response test, H mi With H si They are respectively the measured frequency response data value and the equivalent circuit frequency response data value at the i-th frequency point.

[0021] A second aspect of the present invention provides a transformer winding deformation diagnosis system based on a genetic algorithm, comprising:

[0022] Winding equivalent parameter acquisition module: it is configured to obtain equivalent total parameters of normal transformer winding and tested transformer winding respectively, and determine the parameter search domain of equivalent circuit elements of winding based on the equivalent total parameters of winding;

[0023] A winding equivalent circuit element value set determination module, which is configured to use a genetic algorithm to search the parameter search domain of the equivalent circuit element to obtain several sets of winding equivalent circuit element value sets;

[0024] An objective function determination module is configured to establish an objective function by minimizing the deviation between the frequency response curves of several sets of winding equivalent circuit element value sets and the measured frequency response curves of the windings;

[0025] An optimal circuit element value combination determination module, which is configured to determine an optimal equivalent circuit element value set corresponding to the winding based on a minimum deviation;

[0026] The fault determination module is configured to compare the optimal equivalent circuit component value set of the transformer winding under test with the optimal equivalent circuit component value set of the normal transformer winding to locate the fault of the transformer winding under test.

[0027] A third aspect of the present invention provides a computer-readable storage medium for storing computer instructions, which, when executed by a processor, complete the steps of the above method.

[0028] A fourth aspect of the present invention provides an electronic device, comprising a memory and a processor, and computer instructions stored in the memory and executed on the processor, wherein the steps of the above method are completed when the computer instructions are executed by the processor.

[0029] One or more of the above technical solutions have the following beneficial effects:

[0030] The present invention maps windings at different positions into different units in the circuit by constructing a universal equivalent circuit of the windings, constructs a feasible domain of circuit elements using the equivalent inductance and capacitance parameters of the windings and the series-parallel relationship of the elements, and optimizes the values ​​of the equivalent circuit elements within the feasible domain based on a genetic algorithm, thereby obtaining equivalent circuits corresponding to windings in different states, thereby realizing a universal diagnostic method for locating winding deformation faults.

[0031] Advantages of additional aspects of the present invention will be given in part in the following description, and in part will become obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] The accompanying drawings in the specification, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0033] Figure 1 This is a flow chart of a transformer winding deformation positioning method according to an embodiment of the present invention;

[0034] Figure 2 1 is a general equivalent circuit diagram of the transformer winding of the first embodiment. DETAILED DESCRIPTION

[0035] It should be noted that the following detailed descriptions are exemplary and are intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meanings as those commonly understood by those skilled in the art to which the present invention belongs.

[0036] Embodiment 1

[0037] like Figure 1-2 As shown, this embodiment discloses a transformer winding deformation positioning method based on a genetic algorithm, comprising the following steps:

[0038] S1: Obtaining equivalent total parameters of a normal transformer winding and a transformer winding under test respectively, and determining a parameter search domain of an equivalent circuit element of the winding based on the equivalent total parameters of the winding;

[0039] S2: using a genetic algorithm to search the parameter search domain of equivalent circuit elements to obtain a plurality of sets of winding equivalent circuit element value sets;

[0040] S3: establishing an objective function by minimizing the deviation between the frequency response curves of several sets of winding equivalent circuit element values ​​and the measured frequency response curves of the windings;

[0041] S4: Determine the optimal set of equivalent circuit element values ​​corresponding to the winding based on the minimum deviation;

[0042] S5: Compare the optimal set of equivalent circuit component values ​​of the transformer winding under test with the optimal set of equivalent circuit component values ​​of a normal transformer winding, and locate the fault of the transformer winding under test.

[0043] like Figure 2 As shown, in this embodiment, by constructing a universal equivalent circuit of all windings of the transformer, windings at different positions in the transformer are mapped to different units in the universal equivalent circuit.

[0044] Connect the output and input of the frequency response characteristic analyzer to the high-voltage and low-voltage ends of the transformer winding respectively, set the frequency response test band to 1kHz-1MHz, obtain the frequency response curve of the winding and analyze the number of its characteristic frequencies (resonance peaks) to determine the number of units in the equivalent circuit of the winding under test;

[0045] In S1 of this embodiment, the first and second ends of the transformer winding and the second end of the secondary winding are short-circuited respectively, the first and second ends of the impedance analyzer are connected to the winding to be tested and the secondary winding respectively, the impedance value under 50 Hz sinusoidal excitation is tested, and the equivalent total parallel capacitance value is directly calculated;

[0046] When the secondary winding of the transformer is short-circuited, the first and second ends of the impedance analyzer are connected to the high-voltage and low-voltage ends of the winding respectively. The swept-frequency impedance curve of the winding is obtained and fitted, and the equivalent total inductance and equivalent total series capacitance of the winding are indirectly calculated.

[0047] Based on the above, the equivalent total parameters of the transformer winding are obtained, which include the equivalent total parallel capacitance, the equivalent total inductance and the equivalent total series capacitance. Then, the series-parallel relationship of different components in the universal equivalent circuit of the transformer winding is analyzed. Based on the correlation characteristics of the series-parallel relationship of different components and the equivalent total parameters of the transformer winding and the determined number of circuit units, the parameter search domain of the universal equivalent circuit elements is constructed.

[0048] In this embodiment S2, a genetic algorithm is used to optimize the calculation of equivalent circuit elements within the feasible domain of circuit elements. The number of individuals in the population is set to 2000, the number of individual coding bits is set to 20, the crossover probability is set to 0.9, the mutation probability is set to 0.05, the evolutionary generation is set to 1000, and a set of 2000 sets of circuit element values ​​is obtained in each generation.

[0049] In this embodiment S3, based on S2, several groups of winding equivalent circuit element value sets are obtained, and equivalent circuit models are respectively constructed for the several groups of winding equivalent circuit element value sets using PSPICE simulation software. In the MATLAB compilation environment, a PSPICE circuit element assignment program is constructed to assign values ​​to the several groups of winding equivalent circuit element value sets, and obtain frequency response curves corresponding to the several groups of winding equivalent circuit element value sets.

[0050] The objective function of the optimization process is constructed based on the deviation of the measured frequency response curve of the winding and the frequency response curve obtained by the equivalent circuit model. The established objective function is:

[0051]

[0052] Among them, OF is the objective function value, l is the frequency point number of the frequency response test, H mi With H si are respectively the measured frequency response data value at the i-th frequency point and the frequency response data value corresponding to the equivalent circuit model.

[0053] Formula (1) is used to evaluate the degree of fit of different equivalent circuit models constructed by several sets of winding equivalent circuit element value sets when simulating the measured winding respectively.

[0054] Repeat S2-S3 to screen out a set of winding equivalent circuit element values ​​with the smallest objective function value, and construct a winding equivalent circuit model with the highest fitting degree as the optimal equivalent circuit corresponding to the measured winding.

[0055] Repeat steps S1-S4 for the transformer windings in normal state and fault state respectively to obtain the equivalent circuits corresponding to the windings in different states;

[0056] In this embodiment S5, by comparing the set of equivalent circuit element values ​​corresponding to the optimal equivalent circuit obtained for the normal transformer winding with the set of equivalent circuit element values ​​corresponding to the optimal equivalent circuit obtained for the transformer winding to be tested, the position of the changed components is found and its deviation is calculated, the deformation of the winding is intuitively located, and the degree of deformation at different fault locations is evaluated by comparing the change rate of the components.

[0057] Embodiment 2

[0058] The purpose of this embodiment is to provide a computing device, including 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 above method when executing the program.

[0059] Embodiment 3

[0060] The purpose of this embodiment is to provide a computer-readable storage medium.

[0061] A computer-readable storage medium stores a computer program, which executes the steps of the above method when executed by a processor.

[0062] Embodiment 4

[0063] The purpose of this embodiment is to provide a transformer winding deformation diagnosis system based on a genetic algorithm, comprising:

[0064] Winding equivalent parameter acquisition module: it is configured to obtain equivalent total parameters of normal transformer winding and tested transformer winding respectively, and determine the parameter search domain of equivalent circuit elements of winding based on the equivalent total parameters of winding;

[0065] A winding equivalent circuit element value set determination module, which is configured to use a genetic algorithm to search the parameter search domain of the equivalent circuit element to obtain several sets of winding equivalent circuit element value sets;

[0066] An objective function determination module is configured to establish an objective function by minimizing the deviation between the frequency response curves of several sets of winding equivalent circuit element value sets and the measured frequency response curves of the windings;

[0067] An optimal circuit element value combination determination module, which is configured to determine an optimal equivalent circuit element value set corresponding to the winding based on a minimum deviation;

[0068] The fault determination module is configured to compare the optimal equivalent circuit component value set of the transformer winding under test with the optimal equivalent circuit component value set of the normal transformer winding to locate the fault of the transformer winding under test.

[0069] The steps involved in the apparatuses of the above embodiments 2, 3 and 4 correspond to the method embodiment 1, and the specific implementation methods can refer to the relevant description part of embodiment 1. The term "computer-readable storage medium" should be understood as a single medium or multiple media including one or more instruction sets; it should also be understood to include any medium that can store, encode or carry an instruction set for execution by a processor and enable the processor to execute any method in the present invention.

[0070] Those skilled in the art should understand that the modules or steps of the present invention described above can be implemented by a general-purpose computer device, or alternatively, they can be implemented by a program code executable by a computing device, so that they can be stored in a storage device and executed by the computing device, or they can be made into individual integrated circuit modules, or multiple modules or steps therein can be made into a single integrated circuit module for implementation. The present invention is not limited to any specific combination of hardware and software.

[0071] Although the above describes the specific implementation mode of the present invention in conjunction with the accompanying drawings, it is not intended to limit the scope of protection of the present invention. Those skilled in the art should understand that various modifications or variations that can be made by those skilled in the art on the basis of the technical solution of the present invention without creative work are still within the scope of protection of the present invention.

Claims

1. A method for locating transformer winding deformation based on genetic algorithm, characterized in that: The following steps are involved: S1: Obtaining equivalent total parameters of a normal transformer winding and a transformer winding under test respectively, and determining a parameter search domain of an equivalent circuit element of the winding based on the equivalent total parameters of the winding; The specific method for obtaining the equivalent total parameters of the normal transformer winding and the transformer winding under test is: Short-circuit the transformer winding head and the secondary winding head respectively, connect the impedance analyzer head and the transformer winding head and the secondary winding respectively, test the impedance value under 50Hz sinusoidal excitation, and obtain the equivalent total parallel capacitance value; Under the condition that the secondary winding of the transformer is short-circuited, the first and second ends of the impedance analyzer are connected to the high-voltage and low-voltage ends of the winding under test, and the swept-frequency impedance curve of the winding is obtained and fitted to calculate the equivalent total inductance and equivalent total series capacitance of the transformer winding. S2: using a genetic algorithm to search the parameter search domain of equivalent circuit elements to obtain a plurality of sets of winding equivalent circuit element value sets; S3: establishing an objective function by minimizing the deviation between the frequency response curves of several sets of winding equivalent circuit element values ​​and the measured frequency response curves of the windings; S4: Determine the optimal set of equivalent circuit element values ​​corresponding to the winding based on the minimum deviation; S5: Compare the optimal set of equivalent circuit component values ​​of the transformer winding under test with the optimal set of equivalent circuit component values ​​of a normal transformer winding, and locate the fault of the transformer winding under test.

2. A method for locating transformer winding deformation based on genetic algorithm as claimed in claim 1, characterized in that: Before S1, it also includes: connecting the output and input ends of the frequency response characteristic analysis instrument to the high voltage and low voltage ends of the transformer winding respectively, setting the frequency response test band to 1kHz-1MHz, testing to obtain the frequency response curve of the winding and analyzing the number of characteristic frequencies thereof, and determining the number of units in the winding equivalent circuit.

3. The method for locating transformer winding deformation based on genetic algorithm according to claim 1, characterized in that: In S1, the series-parallel relationship of different elements in the transformer winding equivalent circuit is analyzed, and the parameter search domain of the equivalent circuit elements is determined by analyzing the correlation characteristics between the circuit elements and the winding equivalent total parallel capacitance, equivalent total inductance and series capacitance values, as well as the number of units in the determined winding equivalent circuit.

4. The method for locating transformer winding deformation based on genetic algorithm according to claim 1, characterized in that: In S2, a genetic algorithm is used to search for equivalent circuit elements in a parameter search domain of equivalent circuit elements to obtain several sets of winding equivalent circuit element value sets.

5. The method for locating transformer winding deformation based on genetic algorithm according to claim 1, characterized in that: In S3, an equivalent circuit model of the winding is constructed using PSPICE simulation software based on an equivalent circuit element value set, and a PSPICE circuit element assignment program is constructed in a MATLAB compilation environment to obtain frequency response curves corresponding to different equivalent circuit element value sets.

6. The method for locating transformer winding deformation based on genetic algorithm as claimed in claim 4, characterized in that: In S3, the objective function is: Among them, OF is the objective function value, l is the frequency point number of the frequency response test, H mi and H si Respectively i The measured frequency response data values ​​at each frequency point and the frequency response data values ​​corresponding to the equivalent circuit model.

7. A transformer winding deformation diagnosis system based on genetic algorithm, characterized in that: include: Winding equivalent parameter acquisition module: it is configured to obtain equivalent total parameters of normal transformer winding and tested transformer winding respectively, and determine the parameter search domain of equivalent circuit elements of winding based on the equivalent total parameters of winding; The specific method for obtaining the equivalent total parameters of the normal transformer winding and the transformer winding under test is: Short-circuit the transformer winding head and the secondary winding head respectively, connect the impedance analyzer head and the transformer winding head and the secondary winding respectively, test the impedance value under 50Hz sinusoidal excitation, and obtain the equivalent total parallel capacitance value; Under the condition that the secondary winding of the transformer is short-circuited, the first and second ends of the impedance analyzer are connected to the high-voltage and low-voltage ends of the winding under test, and the swept-frequency impedance curve of the winding is obtained and fitted to calculate the equivalent total inductance and equivalent total series capacitance of the transformer winding. A winding equivalent circuit element value set determination module, which is configured to use a genetic algorithm to search the parameter search domain of the equivalent circuit element to obtain several sets of winding equivalent circuit element value sets; An objective function determination module is configured to establish an objective function by minimizing the deviation between the frequency response curves of several sets of winding equivalent circuit element value sets and the measured frequency response curves of the windings; An optimal circuit element value combination determination module, which is configured to determine an optimal equivalent circuit element value set corresponding to the winding based on a minimum deviation; The fault determination module is configured to compare the optimal equivalent circuit component value set of the transformer winding under test with the optimal equivalent circuit component value set of the normal transformer winding to locate the fault of the transformer winding under test.

8. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the program is executed by a processor, the steps of a transformer winding deformation positioning method based on a genetic algorithm as described in any one of claims 1 to 6 are implemented.

9. A processing device comprising a memory, a processor and a computer program stored in the memory and executable on the processor, wherein: When the processor executes the program, the steps in the transformer winding deformation positioning method based on genetic algorithm as described in any one of claims 1-6 are implemented.

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