A partial discharge electrical positioning system and method for a power transformer

Abstract

The present invention provides a partial discharge electrical positioning system and method for a power transformer. The system includes a model construction module for constructing a simulation model according to the type, technical parameters and environmental parameters of the power transformer; a compensation factor acquisition module for obtaining a compensation factor according to the aging coefficient of the power transformer and the simulation model; a real-time ultrasonic acquisition module for acquiring the real-time ultrasonic signal of the power transformer and compensating the real-time ultrasonic signal according to the compensation factor; and an electrical positioning module for positioning the partial discharge position of the power transformer according to the compensated real-time ultrasonic signal. The present invention takes into account the influence of the transformer aging and damage factors on the ultrasonic positioning accuracy, solves the problem that the existing ultrasonic-based transformer partial discharge positioning methods do not consider the transformer aging and damage factors, and the positioning accuracy needs to be further improved, and can improve the accuracy of the partial discharge electrical positioning of the transformer.

Description

Technical Field

[0001] The present invention relates to the technical field of transformers, and more specifically, to a system and method for electrical localization of partial discharge in a power transformer. Background Art

[0002] Power transformers are one of the most important devices in power plants and substations, and their safety has an important impact on the power grid and social stability. Due to reasons such as design and manufacturing, process materials, operation and maintenance, and operating environment, internal insulation faults of transformers occur from time to time. In the initial stage of internal insulation faults of transformers, partial discharges generally occur, and it is very necessary to locate the partial discharge signals.

[0003] The propagation speed of ultrasonic waves in a medium is closely related to the elastic properties and density of the medium. The transmission of ultrasonic waves inside a transformer needs to pass through composite media such as cardboard, oil, and steel plates. After a transformer has been used for a long time, the density and elastic properties of the composite media such as cardboard, oil, and steel plates inside it will inevitably change due to aging and damage. That is to say, the transmission speed of ultrasonic waves inside a transformer will change due to aging and damage, affecting the accuracy of the localization of partial discharge points in the transformer.

[0004] Through a large number of searches, the applicant found some typical prior arts. For example, the Chinese invention patent with the application number 201210270858.0 discloses a method for detecting partial discharge in a transformer, which can judge the propagation path and propagation speed of ultrasonic waves through two electric pulse signals, and can also judge the specific type of partial discharge source. Another example is the Chinese invention patent with the application number 201210353417.1, which discloses a method for detecting and locating partial discharge in a transformer. By using the obtained ultrasonic signals in combination with the hyperbolic surface localization method, the position of the partial discharge point can be determined, realizing the full-digital localization of the partial discharge point in the transformer. It can be seen that the existing methods for localizing partial discharge in transformers based on ultrasonic technology do not take into account the factors of transformer aging and damage, and the accuracy of their localization needs to be further improved. Summary of the Invention

[0005] Based on this, in order to solve the problem that the existing methods for localizing partial discharge in transformers based on ultrasonic waves do not take into account the factors of transformer aging and damage, and the accuracy of localization needs to be further improved, the present invention provides a system and method for electrical localization of partial discharge in a power transformer, and its specific technical solutions are as follows:

[0006] A system for electrical localization of partial discharge in a power transformer includes a model construction module, a compensation factor acquisition module, a real-time ultrasonic acquisition module, and an electrical localization module.

[0007] The model construction module is used to construct a simulation model according to the type, technical parameters and environmental parameters of the power transformer.

[0008] The compensation factor acquisition module is used to acquire the compensation factor according to the aging coefficient of the power transformer and the simulation model.

[0009] The real-time ultrasonic acquisition module is used to acquire the real-time ultrasonic signal of the power transformer and compensate the real-time ultrasonic signal according to the compensation factor.

[0010] The electrical positioning module is used to locate the partial discharge position of the power transformer according to the compensated real-time ultrasonic signal.

[0011] The partial discharge electrical positioning system of the power transformer constructs a simulation model according to the type, technical parameters and environmental parameters of the power transformer, obtains the compensation factor by using the simulation model and the aging coefficient of the power transformer, and compensates the real-time ultrasonic signal according to the compensation factor. It takes into account the influence of the transformer aging and damage factors on the ultrasonic positioning accuracy, solves the problem that the existing ultrasonic-based transformer partial discharge positioning methods do not consider the transformer aging and damage factors, and the positioning accuracy needs to be further improved, and can improve the accuracy of the partial discharge electrical positioning of the transformer.

[0012] Further, the model construction module includes a parameter acquisition unit and a construction unit.

[0013] The parameter acquisition unit is used to acquire the types, technical parameters and environmental parameters of multiple power transformers.

[0014] The construction unit is used to construct different simulation models according to the types, technical parameters and environmental parameters of multiple power transformers.

[0015] Further, the compensation factor acquisition module includes a fault ultrasonic acquisition unit, a prediction positioning unit, an actual positioning unit, an aging coefficient acquisition unit and a compensation factor acquisition unit.

[0016] The fault ultrasonic acquisition unit is used to acquire the fault ultrasonic signals of multiple faulty power transformers of the same type; the prediction positioning unit is used to acquire the predicted fault positions of the faulty power transformers by the fault ultrasonic.

[0017] The actual positioning unit is used to acquire the actual fault positions of the faulty power transformers; the aging coefficient acquisition unit is used to acquire the aging coefficients of the faulty power transformers; the compensation factor acquisition unit is used to acquire the compensation factor according to the aging coefficients, predicted fault positions and actual fault positions of the faulty power transformers.

[0018] Further, the electrical positioning module includes a first acquisition unit and a first positioning unit.

[0019] The first acquisition unit is used to acquire the propagation path, propagation speed, and propagation time of the compensated real-time ultrasonic signal; the first positioning unit is used to locate the partial discharge position of the power transformer according to the propagation path, propagation speed, and propagation time of the compensated real-time ultrasonic signal.

[0020] A method for electrical positioning of partial discharge in a power transformer includes the following steps:

[0021] S1. Construct a simulation model according to the type, technical parameters, and environmental parameters of the power transformer.

[0022] S2. Obtain a compensation factor according to the aging coefficient of the power transformer and the simulation model.

[0023] S3. Obtain the real-time ultrasonic signal of the power transformer, and compensate the real-time ultrasonic signal according to the compensation factor.

[0024] S4. Locate the partial discharge position of the power transformer according to the compensated real-time ultrasonic signal.

[0025] Further, in step S1, the specific method for constructing the simulation model according to the type, technical parameters, and environmental parameters of the power transformer includes the following steps:

[0026] S10. Obtain the types, technical parameters, and environmental parameters of multiple power transformers.

[0027] S11. Construct different simulation models according to the types, technical parameters, and environmental parameters of multiple power transformers.

[0028] Further, in step S2, the specific method for obtaining the compensation factor according to the aging coefficient of the power transformer and the simulation model includes the following steps:

[0029] S20. Obtain the fault ultrasonic signals of multiple faulty power transformers of the same type.

[0030] S21. Obtain the predicted fault positions of the faulty power transformers for the fault ultrasonic waves.

[0031] S22. Obtain the actual fault positions of the faulty power transformers.

[0032] S23. Obtain the aging coefficient of the faulty power transformer.

[0033] S24. Obtain the compensation factor according to the aging coefficient, predicted fault position, and actual fault position of the faulty power transformer.

[0034] Further, in step S4, the specific method for locating the partial discharge position of the power transformer according to the compensated real-time ultrasonic signal includes the following steps:

[0035] S40, obtain the propagation path, propagation speed, and propagation time of the compensated real-time ultrasonic signal.

[0036] S41, locate the partial discharge position of the power transformer according to the propagation path, propagation speed, and propagation time of the compensated real-time ultrasonic signal.

[0037] Further, a computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the electrical positioning method for partial discharge of the power transformer is implemented. Description of the Drawings

[0038] The present invention can be further understood from the following description in conjunction with the drawings. The components in the drawings are not necessarily drawn to scale, but the focus is on showing the principles of the embodiments. In different views, the same reference numerals designate corresponding parts.

[0039] Figure 1 is a schematic diagram of the overall structure of an electrical positioning system for partial discharge of a power transformer in an embodiment of the present invention;

[0040] Figure 2 is a schematic diagram of the overall process of an electrical positioning method for partial discharge of a power transformer in an embodiment of the present invention. Detailed Embodiments

[0041] In order to make the objectives, technical solutions, and advantages of the present invention clearer and more understandable, the present invention will be further described in detail below in conjunction with its embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and do not limit the protection scope of the present invention.

[0042] It should be noted that when an element is referred to as being "fixed to" another element, it can be directly on the other element or there may also be an intermediate element. When an element is considered to be "connected" to another element, it can be directly connected to the other element or there may be an intermediate element at the same time. The terms "vertical", "horizontal", "left", "right" and similar expressions used herein are only for the purpose of illustration and do not represent the only implementation.

[0043] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the technical field to which this invention belongs. The terms used in the description of the present invention herein are for the purpose of describing specific embodiments only and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more of the related listed items.

[0044] In the present invention, the "first" and "second" do not represent specific quantities and orders, but are only used for name distinction.

[0045] As Figure 1 shown, an electrical positioning system for partial discharge of a power transformer in an embodiment of the present invention includes a model construction module, a compensation factor acquisition module, a real-time ultrasonic acquisition module, and an electrical positioning module.

[0046] The model construction module is used to construct a simulation model according to the type, technical parameters, and environmental parameters of the power transformer.

[0047] Here, the technical parameters include but are not limited to rated capacity, rated voltage, rated current, no-load loss, no-load current, load loss, impedance voltage, and phase number frequency, etc. The environmental parameters include the temperature and humidity of the working environment.

[0048] For power transformers with the same technical parameters, environmental parameters, and the same type, the model construction module constructs a corresponding simulation model.

[0049] The same environmental parameters mean that the working environment temperature and humidity of the transformer are respectively within the same preset temperature value range and preset humidity value range.

[0050] In this way, by constructing a corresponding simulation model for power transformers with the same technical parameters, environmental parameters, and the same type, the constructed simulation model can accurately reflect the actual working conditions of the power transformer.

[0051] Specifically, the model construction module includes a parameter acquisition unit and a construction unit.

[0052] The parameter acquisition unit is used to acquire the types, technical parameters, and environmental parameters of multiple power transformers. The construction unit is used to construct different simulation models according to the types, technical parameters, and environmental parameters of multiple power transformers.

[0053] The compensation factor acquisition module is used to acquire a compensation factor according to the aging coefficient of the power transformer and the simulation model.

[0054] Here, the aging coefficient of the power transformer represents the aging degree of the power transformer. Specifically, the specific method for obtaining the aging coefficient of the power transformer includes the following steps:

[0055] In the first step, multiple first ultrasonic signals and corresponding running times of power transformers with the same technical parameters, environmental parameters, and the same type are obtained through ultrasonic sensors installed at different positions.

[0056] Among them, each power transformer with the same technical parameters, environmental parameters, and the same type corresponds to multiple ultrasonic sensors installed at different positions, and each ultrasonic sensor collects the first ultrasonic signals of the standard power transformer at different running times.

[0057] In the second step, calculate the actual propagation time and actual propagation speed of the first ultrasonic signal collected by each ultrasonic sensor of the power transformer at the same running time, and calculate the simulated propagation time and simulated propagation speed of the first ultrasonic signal corresponding to the simulated model of the power transformer at the same running time.

[0058] In the third step, according to the difference DV1 between the actual propagation time and the simulated propagation time and the running time T1, calculate the aging coefficient ac = DV1 / T1, or according to the difference DV2 between the actual propagation speed and the simulated propagation speed and the running time T2, calculate the aging coefficient ac = DV2 / T2.

[0059] Here, the aging coefficient is expressed as the ratio of the ultrasonic propagation speed or time change value of the power transformer to the actual running time.

[0060] The real-time ultrasonic acquisition module is used to acquire the real-time ultrasonic signal of the power transformer and compensate the real-time ultrasonic signal according to the compensation factor.

[0061] After obtaining the aging coefficient, the compensation factor can be obtained according to the simulated model. That is, for the power transformer at different running times, due to the inevitable changes in the density and elastic properties of the composite media such as cardboard, oil, and steel plate inside due to aging and damage, the compensation for the change in ultrasonic propagation speed or propagation time is carried out.

[0062] In order to better obtain the aging coefficient, the aging coefficients at multiple different running times can be used, and then the aging coefficients and the corresponding running times are fitted to obtain the fitting function curve. According to the defect of the fitting function, the aging coefficient of the power transformer to be subjected to partial discharge electrical positioning at other running times is obtained.

[0063] The electrical positioning module is used to locate the partial discharge position of the power transformer according to the compensated real-time ultrasonic signal.

[0064] Of course, it is also possible to first obtain the actual position of the partial discharge fault in the actual power transformer and the corresponding ultrasonic signal, then obtain the corresponding simulated fault position on the simulation model based on the ultrasonic signal, and finally obtain the aging coefficient according to the distance difference between the actual position of the partial discharge fault in the actual power transformer and the corresponding simulated fault position on the simulation model and the proportional value between the actual operation time of the power transformer.

[0065] Here, the electrical positioning module first locates the partial discharge fault position according to the real-time ultrasonic signal, and then compensates and corrects the located partial fault position according to the aging coefficient to obtain the final partial discharge fault position.

[0066] The partial discharge electrical positioning system of the power transformer constructs a simulation model according to the type, technical parameters and environmental parameters of the power transformer, obtains a compensation factor by using the simulation model and the aging coefficient of the power transformer, and compensates the real-time ultrasonic signal according to the compensation factor. It takes into account the influence of the transformer aging and damage factors on the ultrasonic positioning accuracy, solves the problem that the existing ultrasonic-based transformer partial discharge positioning methods do not take into account the transformer aging and damage factors, and the positioning accuracy needs to be further improved, and can improve the accuracy of the partial discharge electrical positioning of the transformer.

[0067] In one embodiment, the compensation factor acquisition module includes a fault ultrasonic acquisition unit, a prediction positioning unit, an actual positioning unit, an aging coefficient acquisition unit and a compensation factor acquisition unit. The electrical positioning module includes a first acquisition unit and a first positioning unit.

[0068] The first acquisition unit is used to acquire the propagation path, propagation speed and propagation time of the compensated real-time ultrasonic signal; the first positioning unit is used to locate the partial discharge position of the power transformer according to the propagation path, propagation speed and propagation time of the compensated real-time ultrasonic signal. Since locating the partial discharge position of the power transformer according to the propagation path, propagation speed and propagation time of the ultrasonic signal is a conventional technical means in the art, it will not be elaborated here.

[0069] The fault ultrasonic acquisition unit is used to acquire the fault ultrasonic signals of multiple faulty power transformers of the same type; the prediction positioning unit is used to acquire the predicted fault positions of the faulty power transformers by the fault ultrasonic signals.

[0070] The actual positioning unit is used to obtain the actual fault location of the faulty power transformer; the aging coefficient acquisition unit is used to obtain the aging coefficient of the faulty power transformer; the compensation factor acquisition unit is used to obtain the compensation factor according to the aging coefficient, predicted fault location and actual fault location of the faulty power transformer.

[0071] In this embodiment, for power transformers of the same type with the same technical parameters and environmental parameters, the aging coefficient = actual operating time / designed service time. When the actual operating time is greater than or equal to the designed service time, the aging coefficient is 1.

[0072] For multiple power transformers of the same type with the same technical parameters and environmental parameters, when a fault occurs, their actual operating times are often different. After obtaining the fault ultrasonic signal of the faulty power transformer, the corresponding actual operating time and the fault ultrasonic signal are input into the simulation to obtain the predicted fault location.

[0073] Using the distance differences between the aging coefficients, predicted fault locations and actual fault locations of multiple faulty power transformers of the same type for fitting, the fitting function curve related to the aging coefficient and the distance difference can be obtained.

[0074] The compensation factor here refers to the distance difference corresponding to the faulty power transformer under different aging coefficients.

[0075] Different types of power transformers with the same technical parameters and environmental parameters correspond to different fitting function curves. When a partial discharge fault occurs in the power transformer, after positioning the fault location based on ultrasonic technology, and then combining the actual operating time of the power transformer and the fitting function curve, the corresponding compensation factor can be obtained.

[0076] In this way, by obtaining the compensation factor through the aging coefficient, predicted fault location and actual fault location of the faulty power transformer, the fault location can be compensated and corrected when a partial discharge fault occurs in the power transformer to obtain a more accurate fault location.

[0077] As Figure 2 shown, a method for electrical positioning of partial discharge in a power transformer includes the following steps:

[0078] S1, construct a simulation model according to the type, technical parameters and environmental parameters of the power transformer.

[0079] S2, obtain the compensation factor according to the aging coefficient of the power transformer and the simulation model.

[0080] S3, obtain the real-time ultrasonic signal of the power transformer and compensate the real-time ultrasonic signal according to the compensation factor.

[0081] S4. Locate the partial discharge position of the power transformer based on the compensated real-time ultrasonic signal.

[0082] Specifically, in step S1, the specific method for constructing the simulation model according to the type, technical parameters, and environmental parameters of the power transformer includes the following steps:

[0083] S10. Obtain the types, technical parameters, and environmental parameters of multiple power transformers.

[0084] S11. Construct different simulation models according to the types, technical parameters, and environmental parameters of multiple power transformers.

[0085] In step S4, the specific method for locating the partial discharge position of the power transformer based on the compensated real-time ultrasonic signal includes the following steps:

[0086] S40. Obtain the propagation path, propagation speed, and propagation time of the compensated real-time ultrasonic signal.

[0087] S41. Locate the partial discharge position of the power transformer based on the propagation path, propagation speed, and propagation time of the compensated real-time ultrasonic signal.

[0088] The electrical positioning method for partial discharge of the power transformer constructs a simulation model according to the type, technical parameters, and environmental parameters of the power transformer, obtains a compensation factor by using the simulation model and the aging coefficient of the power transformer, and compensates the real-time ultrasonic signal according to the compensation factor. It takes into account the influence of the transformer aging and damage factors on the ultrasonic positioning accuracy, solves the problem that the existing ultrasonic-based transformer partial discharge positioning methods do not consider the transformer aging and damage factors, and the positioning accuracy needs to be further improved, and can improve the accuracy of the electrical positioning of the transformer partial discharge.

[0089] In one embodiment, in step S2, the specific method for obtaining the compensation factor according to the aging coefficient of the power transformer and the simulation model includes the following steps:

[0090] S20. Obtain the fault ultrasonic signals of multiple faulty power transformers of the same type.

[0091] S21. Obtain the predicted fault positions of the faulty power transformers for the fault ultrasonic waves.

[0092] S22. Obtain the actual fault positions of the faulty power transformers.

[0093] S23. Obtain the aging coefficient of the faulty power transformer.

[0094] S24. Obtain a compensation factor according to the aging coefficient of the faulty power transformer, the predicted fault location, and the actual fault location.

[0095] In this way, by obtaining the compensation factor according to the aging coefficient of the faulty power transformer, the predicted fault location, and the actual fault location, when a partial discharge fault occurs in the power transformer, the fault location can be compensated and corrected to obtain a more accurate fault location.

[0096] In one of the embodiments, a computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the electrical positioning method for partial discharge of a power transformer as described above is implemented.

[0097] The technical features of the above-described embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope described in this specification.

[0098] The above-described embodiments only represent several implementation manners of the present invention. The description is relatively specific and detailed, but it should not be construed as a limitation on the scope of the invention patent. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can still be made, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the invention patent should be subject to the appended claims.

Claims

1. A partial discharge electrical positioning system for a power transformer, characterized in that, The partial discharge electrical positioning system for power transformers includes: A model construction module, which is used to construct a simulation model according to the type, technical parameters and environmental parameters of the power transformer, and use the aging coefficients of multiple faulty power transformers of the same type, and the distance differences between the predicted fault positions and the actual fault positions for fitting to obtain a fitting function curve related to the aging coefficient and the distance difference. Different types of power transformers with the same technical parameters and environmental parameters correspond to different fitting function curves; A compensation factor acquisition module, which is used to obtain a compensation factor according to the aging coefficient of the power transformer and the simulation model; A real-time ultrasonic acquisition module, which is used to acquire the real-time ultrasonic signal of the power transformer; An electrical positioning module, which is used to locate the partial discharge position of the power transformer according to the real-time ultrasonic signal, and then correct the located partial fault position according to the compensation factor to obtain the final partial discharge fault position; The compensation factor acquisition module includes an aging coefficient acquisition unit and a compensation factor acquisition unit; The aging coefficient acquisition unit is used to acquire the aging coefficient of the faulty power transformer. For power transformers of the same type with the same technical parameters and environmental parameters, the aging coefficient = actual operating time / designed service time; The compensation factor acquisition unit is used to obtain a compensation factor according to the aging coefficient of the faulty power transformer and the fitting function curve corresponding to the faulty power transformer. The compensation factor is the distance difference corresponding to the aging coefficient.

2. The partial discharge electrical positioning system of a power transformer according to claim 1, characterized in that, The model construction module includes: A parameter acquisition unit, which is used to acquire the types, technical parameters and environmental parameters of multiple power transformers; A construction unit, which is used to construct different simulation models according to the types, technical parameters and environmental parameters of multiple power transformers.

3. A method for electrical positioning of partial discharge in a power transformer, characterized in that, The partial discharge electrical positioning method for power transformers includes the following steps: S1. Construct a simulation model according to the type, technical parameters and environmental parameters of the power transformer, and use the aging coefficients of multiple faulty power transformers of the same type, and the distance differences between the predicted fault positions and the actual fault positions for fitting to obtain a fitting function curve related to the aging coefficient and the distance difference. Different types of power transformers with the same technical parameters and environmental parameters correspond to different fitting function curves; S2. Obtain a compensation factor according to the aging coefficient of the power transformer and the simulation model. Specifically: obtain a compensation factor according to the aging coefficient of the faulty power transformer and the fitting function curve corresponding to the faulty power transformer. The compensation factor is the distance difference corresponding to the aging coefficient. For power transformers of the same type with the same technical parameters and environmental parameters, the aging coefficient = actual operating time / designed service time; S3. Acquire the real-time ultrasonic signal of the power transformer; S4. Locate the partial discharge position of the power transformer according to the real-time ultrasonic signal, and then correct the located partial fault position according to the compensation factor.

4. The electrical positioning method for partial discharge of a power transformer according to claim 3, characterized in that, In step S1, the specific method for constructing a simulation model according to the type, technical parameters and environmental parameters of the power transformer includes the following steps: S10. Acquire the types, technical parameters and environmental parameters of multiple power transformers; S11. Construct different simulation models according to the types, technical parameters and environmental parameters of multiple power transformers.

5. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program, which implements the electrical positioning method for partial discharge of a power transformer according to any one of claims 3-4 when the computer program is executed by a processor.

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