Spatial arrangement method of ultrahigh frequency sensor for transformer and transformer fault detection method

Abstract

The invention discloses an ultrahigh frequency sensor spatial arrangement method for a transformer and a transformer fault detection method, and relates to the field of transformer detection, and the method comprises the steps: constructing a transformer model with the same size as a real transformer, and setting a corresponding fault region on the transformer model according to the fault region of the real transformer; setting a partial discharge signal source in a fault area of the transformer model, and obtaining the signal strength of the fault source; determining a simulation arrangement scheme of the ultrahigh frequency sensor based on the fault source signal intensity and the monitoring range of the ultrahigh frequency sensor; and optimizing the simulation arrangement scheme based on the on-site allowed installation position of the transformer and the insulation margin of the real transformer to obtain an optimal ultrahigh frequency sensor arrangement scheme. According to the invention, the detection precision and anti-interference capability of the ultrahigh frequency sensor can be improved, and effective detection of transformer faults is realized.

Description

Technical Field

[0001] The present application relates to the field of transformer detection, and in particular to a method for spatially arranging ultra-high frequency sensors for transformers and a method for detecting transformer faults. Background Art

[0002] Transformers are important equipment for power transmission in power systems, and their operating stability is of great significance to the safety of power grids and the stability of power supply. The operation of power equipment is characterized by a long cycle. In order to improve the stability of power supply in the power system, reliable monitoring of the operating status of transformers has become a top priority. Among the existing online detection methods, ultra-high frequency has become a common monitoring method due to its advantages of high signal frequency band and fast response speed to high-frequency signals accompanying early faults. The existing layout scheme of ultra-high frequency sensors only considers the spatiotemporal distribution characteristics of ultra-high frequency signals inside the transformer, which will cause the sensor layout to be too dispersed or concentrated, without considering the detection accuracy and sensitivity of the sensor. An overly dispersed layout may cause fault signals in some areas to fail to be captured in time, while an overly concentrated layout may lead to redundancy. Summary of the invention

[0003] The purpose of this application is to provide a spatial arrangement method of ultra-high frequency sensors for transformers and a transformer fault detection method, which can improve the detection accuracy and anti-interference ability of ultra-high frequency sensors and realize effective detection of transformer faults.

[0004] To achieve the above objectives, this application provides the following solutions:

[0005] In a first aspect, the present application provides a method for spatially arranging a UHF sensor for a transformer, comprising:

[0006] Constructing a transformer model of the same size as the real transformer, and setting a corresponding fault area on the transformer model according to the fault area of ​​the real transformer;

[0007] Setting a partial discharge signal source in the fault area of ​​the transformer model to obtain the fault source signal strength;

[0008] Determining a simulation arrangement scheme of the UHF sensor based on the fault source signal strength and the monitoring range of the UHF sensor;

[0009] The simulation arrangement scheme is optimized based on the allowable installation position of the transformer on site and the insulation margin of the real transformer to obtain the optimal UHF sensor arrangement scheme.

[0010] In a second aspect, the present application provides a transformer fault detection method, comprising:

[0011] Arrange the UHF sensor according to the above-mentioned method for spatially arranging the UHF sensor for the transformer;

[0012] Transformer faults are detected based on the measurement signal of the UHF sensor.

[0013] According to the specific embodiments provided in this application, this application discloses the following technical effects:

[0014] The present application provides a method for spatially arranging ultra-high frequency sensors for transformers and a method for detecting transformer faults. By constructing a transformer model of the same size as a real transformer and setting faults based on the fault area of ​​the real transformer, the ultra-high frequency signal distribution of the transformer model is ensured to be accurately equivalent to that of the real transformer; by comprehensively considering the monitoring range of the ultra-high frequency (UHF) sensor, the insulation margin of the real transformer and the transformer on-site installation position allowed, the optimal UHF sensor arrangement scheme is determined, and the reliability of the UHF sensor arrangement scheme is ensured. At the same time, through the time difference analysis of UHF sensors at different monitoring positions (monitoring points), effective discrimination of interference signals and fault signals is achieved, which greatly improves the anti-interference ability of the UHF sensor and realizes effective detection of transformer faults. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0016] Figure 1 A schematic diagram of a flow chart of a method for spatially arranging ultra-high frequency sensors for transformers provided in one embodiment of the present application;

[0017] Figure 2 A schematic diagram of the process for determining the simulation layout plan;

[0018] Figure 3 Schematic diagram of the process for determining the optimal UHF sensor layout;

[0019] Figure 4 This is a schematic diagram of the relationship between the sets of monitoring points. DETAILED DESCRIPTION

[0020] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0021] In practical applications, UHF sensors are limited by the structure of the transformer itself, and their installation positions are limited, especially dielectric window UHF sensors, and are also limited by the insulation margin of the transformer. Therefore, accurate sensitivity analysis needs to be combined with the physical characteristics and layout of the UHF sensor, and cannot rely solely on the time and space distribution. This application proposes a spatial layout method for UHF sensors for transformers and a transformer fault detection method, which provides new technical ideas and solutions for solving the optimal layout scheme and anti-interference technology of UHF sensors in online monitoring of transformers, and has important engineering practical value.

[0022] In order to make the above-mentioned objects, features and advantages of the present application more obvious and easy to understand, the present application is further described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0023] In an exemplary embodiment, Figure 1 As shown, a method for spatial arrangement of ultra-high frequency sensors for transformers is provided, which is executed by a computer device, specifically, it can be executed by a computer device such as a terminal or a server alone, or it can be executed by a terminal and a server together. In the embodiment of the present application, the method is applied to a server as an example for explanation, and includes the following steps S1 to S4. Among them:

[0024] S1: construct a transformer model of the same size as the real transformer, and set a corresponding fault area on the transformer model according to the fault area of ​​the real transformer.

[0025] S2: Setting a partial discharge signal source in the fault area of ​​the transformer model to obtain the fault source signal strength.

[0026] The signal waveform of the partial discharge signal source is a Gaussian pulse signal, so that the ultra-high frequency signal distribution of the transformer model when a typical discharge occurs is consistent with the ultra-high frequency signal distribution of the real transformer.

[0027] S3: Determine the simulation layout of the UHF sensor based on the fault source signal strength and the monitoring range of the UHF sensor. Specifically, it includes: setting multiple monitoring points on the transformer model based on the radius of the monitoring range of the UHF sensor; obtaining the UHF signal strength of each monitoring point, and determining the signal attenuation degree of each monitoring point in combination with the fault source signal strength; deleting the monitoring points whose signal attenuation degree is greater than or equal to the attenuation threshold, and determining the first monitoring point set; determining the simulation layout of the UHF sensor based on the monitoring points in the first monitoring point set.

[0028] like Figure 2As shown, according to the radius R of the monitoring range of the UHF sensor, monitoring points are set at intervals of aR on the surface of the transformer model to obtain the UHF signal strength of different monitoring points on each surface of the transformer model. The measurement method of R is: a signal source with a constant power is used to send a signal, and the measurement signal of the UHF sensor is 20% of the fault source signal strength. The distance between the position and the signal source is recorded, and the average value is taken after multiple measurements, which is R. The value range of the preset value a is 80% to 90%.

[0029] Combined with the fault source signal strength in the fault area, determine whether the signal attenuation of each monitoring point is lower than the attenuation threshold b (40% to 60%), and delete the monitoring points that do not meet the attenuation threshold requirements. After all monitoring points have been judged, all monitoring points that meet the attenuation threshold requirements are combined into the first monitoring point set M to obtain the simulation layout plan of the UHF sensor.

[0030] S4: Optimize the simulation layout scheme based on the transformer on-site allowable installation position and the insulation margin of the real transformer to obtain the optimal UHF sensor layout scheme. Figure 3 As shown, specifically including:

[0031] S41: Screening the monitoring points in the first monitoring point set based on the transformer on-site allowable installation positions to determine a second monitoring point set.

[0032] All monitoring points in the first monitoring point set M are judged, and only the monitoring points located at the positions where the compressor is allowed to be installed on site are retained, which are recorded as the second monitoring point set P.

[0033] S42: Simulate the electric field distribution of the transformer model, and for any monitoring point in the first monitoring point set, determine whether the insulation margin of the real transformer meets the preset requirements, and determine the third monitoring point set based on the judgment result; the monitoring points in the third monitoring point set are all monitoring points where the insulation margin of the real transformer meets the preset requirements.

[0034] A UHF sensor is installed at each monitoring point in the first monitoring point set M, and the electric field distribution of the transformer is simulated to determine whether the insulation margin of the real transformer meets the requirements after the UHF sensor is installed at each monitoring point. Only all monitoring points that meet the insulation margin requirements of the real transformer are retained to obtain the third monitoring point set Q.

[0035] S43: Determine the optimal UHF sensor layout scheme based on the second monitoring point set and the third monitoring point set. Specifically, take the intersection of the second monitoring point set P and the third monitoring point set Q as the fourth monitoring point set N; take the monitoring points in the fourth monitoring point set N that are located on different surfaces and have the lowest attenuation to form the fifth monitoring point set N1; arrange UHF sensors at each monitoring point in the fifth monitoring point set N1 to obtain the optimal UHF sensor layout scheme. The relationship between each monitoring point set is as follows: Figure 4 shown.

[0036] The existing UHF sensor layout scheme does not consider the impact of the UHF sensor installation on the insulation margin and electric field distribution of the real transformer, and the specific installation position may cause the insulation margin of the real transformer to be insufficient, posing a threat to the safe operation of the transformer. Therefore, this application optimizes the layout scheme based on whether the installation position allowed by the transformer site and the monitoring point have an impact on the insulation margin and electric field distribution of the real transformer, thereby ensuring the reliability of the UHF sensor layout scheme.

[0037] In an exemplary embodiment, a transformer fault detection method is provided, comprising:

[0038] Arrange the UHF sensors according to the above-mentioned spatial arrangement method for UHF sensors for transformers; and detect transformer faults based on the measurement signals of the UHF sensors. Specifically:

[0039] Determine the first wave time difference Δt of the measurement signal of the UHF sensor; when the first wave time difference Δt< time threshold T 1 When the first wave time difference Δt≥ time threshold T 1 When the fault location is judged to be outside the transformer, the measured signal is an interference signal. 1 The setting method is the ratio of the actual transformer length L to the sound speed V in the medium.

[0040] At the same time, through the time difference analysis of UHF sensors at different monitoring positions, effective discrimination between interference signals and fault signals is achieved, which greatly improves the anti-interference ability of UHF sensors and realizes effective detection of transformer faults.

[0041] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0042] This article uses specific examples to illustrate the principles and implementation methods of this application. The description of the above embodiments is only used to help understand the method and core ideas of this application. At the same time, for those skilled in the art, according to the ideas of this application, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting this application.

Claims

1. A method for spatially arranging ultra-high frequency sensors for transformers, characterized in that: include: Constructing a transformer model of the same size as the real transformer, and setting a corresponding fault area on the transformer model according to the fault area of ​​the real transformer; Setting a partial discharge signal source in the fault area of ​​the transformer model to obtain the fault source signal strength; Determining a simulation arrangement scheme of the UHF sensor based on the fault source signal strength and the monitoring range of the UHF sensor; The simulation arrangement scheme is optimized based on the allowable installation position of the transformer on site and the insulation margin of the real transformer to obtain the optimal UHF sensor arrangement scheme.

2. The method for spatially arranging ultra-high frequency sensors for transformers according to claim 1, characterized in that: A partial discharge signal source is set in the fault area of ​​the transformer model so that the ultra-high frequency signal distribution of the transformer model is consistent with the ultra-high frequency signal distribution of the real transformer when a typical discharge occurs.

3. The method for spatially arranging ultra-high frequency sensors for transformers according to claim 1, characterized in that: The signal emitted by the partial discharge signal source is a Gaussian pulse signal.

4. The method for spatially arranging ultra-high frequency sensors for transformers according to claim 1, characterized in that: Determining a simulation arrangement scheme of the UHF sensor based on the fault source signal strength and the monitoring range of the UHF sensor specifically includes: Setting a plurality of monitoring points on the transformer model based on the radius of the monitoring range of the UHF sensor; Obtaining the UHF signal strength of each monitoring point, and determining the signal attenuation degree of each monitoring point in combination with the fault source signal strength; Deleting monitoring points whose signal attenuation is greater than or equal to the attenuation threshold, and determining a first monitoring point set; A simulation arrangement scheme of the UHF sensors is determined based on the monitoring points in the first monitoring point set.

5. The method for spatially arranging ultra-high frequency sensors for transformers according to claim 4, characterized in that: Monitoring points are set at intervals of aR on the surface of the transformer model; R is the radius of the monitoring range of the UHF sensor, and a is a preset value ranging from 80% to 90%.

6. The method for spatially arranging ultra-high frequency sensors for transformers according to claim 4, characterized in that: The simulation layout scheme is optimized based on the transformer on-site allowable installation position and the transformer insulation margin to obtain the optimal UHF sensor layout scheme, which specifically includes: Screening the monitoring points in the first set of monitoring points based on the transformer on-site permitted installation positions to determine a second set of monitoring points; Simulating the electric field distribution of the transformer model, judging whether the insulation margin of the real transformer meets the preset requirements for any monitoring point in the first monitoring point set, and determining the third monitoring point set according to the judgment result; the monitoring points in the third monitoring point set are all monitoring points at which the insulation margin of the real transformer meets the preset requirements; An optimal UHF sensor arrangement scheme is determined based on the second monitoring point set and the third monitoring point set.

7. The method for spatially arranging ultra-high frequency sensors for transformers according to claim 6, characterized in that: Determining an optimal UHF sensor arrangement scheme based on the second monitoring point set and the third monitoring point set specifically includes: Taking the intersection of the second monitoring point set and the third monitoring point set as a fourth monitoring point set; Taking the monitoring points located on different planes and with the smallest attenuation in the fourth monitoring point set to form a fifth monitoring point set; A UHF sensor is arranged at each monitoring point in the fifth monitoring point set to obtain an optimal UHF sensor arrangement scheme.

8. A transformer fault detection method, characterized in that: include Arrange the UHF sensor according to the method for spatial arrangement of UHF sensors for transformers according to any one of claims 1 to 7; Transformer faults are detected based on the measurement signal of the UHF sensor.

9. The transformer fault detection method according to claim 8, characterized in that: Transformer fault detection based on the measurement signal of the UHF sensor includes: Determine the first wave time difference of the measurement signal of the UHF sensor; When the first wave time difference is less than a time threshold, determining that the measurement signal is a fault signal; When the first wave time difference is greater than or equal to a time threshold, it is determined that the measurement signal is an interference signal.

10. The transformer fault detection method according to claim 9, characterized in that: The time threshold is the ratio of the actual transformer length to the sound speed in the medium.

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