Method and device for dissipating space charges of solid insulator in combined electric appliance

Abstract

The invention discloses a space charge dissipation method and device for a solid insulator in a combined electric appliance. The method comprises the following steps: for different types of solid insulators such as an insulating pull rod, a basin-type insulator, a supporting insulator and the like, measuring surface potential attenuation data of the insulators after corona charging at the same temperature in combination with atom types, contents and chemical bond proportions of the insulators, quantitatively calculating trap levels and trap densities of the insulators, and calculating the trap density of the insulators. The method comprises the following steps: measuring the actual size of a combined electric appliance insulator, calculating the number of deep trap charges, regulating and controlling the focus of an X-ray generation device, the type of a filter and the rotating speed of an anode, accurately positioning the insulator needing X-ray irradiation, and regulating and controlling the tube voltage, tube current and exposure time of the X-ray generation device by combining the trap level and trap density of the insulator. Therefore, the space charges of the insulator can be quickly, safely and effectively dissipated.

Description

Technical Field

[0001] This invention belongs to the field of gas-solid interface electrical insulation, specifically relating to a method and apparatus for dissipating space charge in solid insulating components inside a combined electrical appliance. Background Technology

[0002] The accumulation of space charge in solid insulation components has become a bottleneck problem restricting the safe and stable operation of combined electrical equipment (GE). Before surface flashover or internal breakdown of the insulation components, the local electric field distortion is significantly enhanced after the charge falls into the deep trap, which provides impetus for the development of electron avalanche. At this time, the weak sporadic partial discharge signal is difficult to detect effectively, resulting in the inaccurate capture of the electric field distortion effect after local charge accumulation. In addition, the operating GE is an armored and enclosed structure, and the charge accumulation effect of solid insulation components in the strong electromagnetic field environment inside is difficult to suppress effectively by visual means. This leads to the gradual accumulation of insulation defects inside the GIS. Especially during the switching operation, under the combined excitation of multiple physical effects such as mechanical vibration and transient overvoltage, problems of combined electrical equipment caused by insulation breakdown occur frequently.

[0003] The internal structure of GIS is complex, with a wide variety of solid insulating components of different shapes. Relying solely on magnetic field suppression and step-type repair materials to smooth the surface potential is insufficient to fundamentally eliminate the presence of space charge. Adaptive adjustment of surface charge levels tends to passively dissipate charge, and the nonlinear region ages continuously during the long-term operation of the combined electrical equipment, gradually weakening its ability to dissipate charge. Summary of the Invention

[0004] To address the problems of breakdown and flashover caused by local electric field distortion in existing combined electrical appliances, the present invention aims to propose a method and apparatus for dissipating space charge in solid insulating components inside combined electrical appliances.

[0005] To achieve the objectives of this invention, the technical solution provided by this invention is as follows:

[0006] First aspect

[0007] This application provides a method for dissipating space charge in solid insulating components inside a combined electrical appliance, comprising the following steps:

[0008] Step 1: Theoretical calculation and experimental testing of the atomic types, content, and chemical bond ratio of the insulating components;

[0009] Step 2: Cut a flat insulating sample of a certain size, perform surface corona charging at a fixed temperature, measure and record the real-time dynamic value of the surface potential decay of the sample, and plot the isothermal surface potential decay curve.

[0010] Step 3: Calculate the deep and shallow trap energy levels and trap density on the sample surface;

[0011] Step 4: Measure and calculate the actual dimensional parameters of the insulation components;

[0012] Step 5: Calculate the actual number of deep-trapped charges in the insulating component;

[0013] Step 6: Determine the specific location of X-ray irradiation to quickly and effectively dissipate space charge on the insulating components.

[0014] Furthermore, in step 1, the types of insulating components include insulating tie rods, basin insulators, support insulators, etc.; calculation and testing are carried out in conjunction with the initial raw material ratio and preparation conditions in the production stage, taking into account parameters such as temperature, humidity, type and content of additives, and cooling time.

[0015] Further, in step 2, the insulating component is a rectangle with a side length of 1cm-10cm; the fixed temperature range is 200℃-400℃; the surface corona charging uses a ±10-20kV adjustable needle electrode, a ±3-8kV adjustable grid electrode, and an adjustable charging time of 10-100min; the real-time dynamic value of the sample surface potential decay is obtained by immediately transferring the test to below the electrostatic voltmeter probe after charging is completed, keeping the temperature constant, measuring, recording, and plotting the isothermal surface potential decay curve, where the horizontal axis is time and the vertical axis is the potential value.

[0016] Furthermore, in step 3, the deep and shallow trap energy levels and trap density on the sample surface are calculated by performing calculus on the plotted isothermal surface potential decay curve.

[0017] Furthermore, in step 4, the actual size parameters include the length, width, radius, and thickness of the insulating component, and the calculation is carried out with reference to the design drawings of the specific type of insulating component.

[0018] Furthermore, in step 5, the calculation of the actual number of deep trap charges in the insulating component is obtained by comparing the sample size and the actual insulating component size, and by calculating based on the trap energy level and trap density of the sample size.

[0019] Furthermore, in step 6, the specific location is determined in conjunction with the design drawings of the target combined electrical appliance, the type of insulation component, and the specific dimensions; the rapid and effective dissipation of space charge in the insulation component is achieved through the tube voltage, tube current, and exposure time of conditional X-ray irradiation.

[0020] Second aspect

[0021] This application provides a space charge dissipation device for solid insulating components inside a combined electrical appliance. The device is used to implement the method described above, including: an X-ray tube, a signal detection and conversion system, and an electrical signal processing and analysis system.

[0022] The X-ray tube includes a cathode filament and an anode rare metal target. The cathode filament releases a large number of electrons through the thermionic emission effect under current conditions, which bombard the anode metal target. The initial electrons released from the cathode are accelerated by a high voltage field and then bombard the anode rare metal target, which has a high secondary electron emission coefficient, at extremely high speeds. At this time, more than 99% of the energy is converted into heat energy (which needs to be dissipated by a cooling system), and only about 1% of the energy is used to generate X-rays through "bremsstrahlung radiation" (electron deceleration) and "characteristic radiation" (electron transition). The X-rays are emitted through the "window" (low-attenuation material, such as beryllium) of the anode target and then the shape of the X-ray beam is limited by a "collimator" (made of lead) to avoid interference from excess X-rays.

[0023] The signal detection and conversion system, based on the energy attenuation characteristics of X-rays when they penetrate different insulating components and metal shells, converts the X-ray intensity signal, which reflects the energy attenuation characteristics, into an electrical signal. It uses a flat panel detector to generate a charge signal by ionizing a semiconductor material with a low bandgap width, and then the charge is collected by electrodes and converted into an electrical signal.

[0024] The electrical signal processing and analysis system first preprocesses the electrical signal by correcting noise in the signal detection and conversion system and eliminating X-ray inhomogeneity and dark current interference. Then, it performs post-processing on the electrical signal. Finally, on the system display interface, a data-driven coupling algorithm with embedded physical field mechanisms is used to provide feedback on the space charge suppression effect after X-rays act on the metal shell and solid insulating parts, optimize and control the experimental parameters of the X-ray tube, and improve the rapid dissipation effect of charge.

[0025] Furthermore, the electrical signal is post-processed using methods such as comparison optimization, edge enhancement, and Fourier transform.

[0026] Furthermore, the experimental parameters such as tube voltage, tube current, and exposure time of the X-ray tube were optimized and controlled.

[0027] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0028] (1) Precise detection and quantitative analysis: Based on the calculus calculation of the isothermal surface potential decay curve, the energy levels and trap density of deep / shallow traps are quantitatively obtained. Combined with the actual size of the insulating part (length, width, thickness, etc.), the number of deep trap charges is accurately calculated, which completely solves the problem that traditional methods are difficult to quantify the charge accumulation state and provides data support for targeted dissipation.

[0029] (2) Active rapid dissipation breaks through the structural limitations of armored enclosed combined electrical appliances. It can penetrate the metal shell and act on the internal insulation components without disassembling the equipment, avoiding the interference and damage to the equipment by traditional methods. At the same time, it solves the industry pain point that deep trap charges are difficult to eliminate, and greatly reduces the risk of surface flashover and internal breakdown of insulation components.

[0030] (3) Dynamically optimize X-ray irradiation parameters (focus, filter, tube voltage, etc.) to avoid unnecessary ray interference, ensure the dissipation process is safe and controllable, and adapt to the structural differences of different types of insulating components (insulating rods, basin insulators, support insulators, etc.) to improve technical adaptability and long-term operational stability.

[0031] (4) No need to change the original structural design of the combined electrical appliances, it can adapt to the charge management needs of equipment in operation or to be put into operation, and its scope of application covers the entire life cycle operation and maintenance scenarios of the combined electrical appliances in the power system.

[0032] (5) Avoid unplanned outages and maintenance caused by the accumulation of insulation defects, reduce the operation and maintenance costs of the power system, and ensure the safe and stable operation of the power grid. Attached Figure Description

[0033] Figure 1 This is a schematic diagram of the method flow provided in an embodiment of the present invention;

[0034] Figure 2 This is an isothermal surface potential decay curve diagram in an embodiment of the present invention;

[0035] Figure 3 This is a diagram showing the deep and shallow trap energy levels and trap density of the epoxy resin used to support the insulator in an embodiment of the present invention;

[0036] Figure 4 This is a design drawing of the target combined electrical appliance in an embodiment of the present invention. Detailed Implementation

[0037] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0038] like Figure 1 As shown, this embodiment of the invention provides a method for dissipating space charge in solid insulating components inside a combined electrical appliance, comprising the following steps:

[0039] Step 1: Theoretical calculation and experimental testing of the atomic types, content, and chemical bond ratio of the insulating components;

[0040] Taking epoxy resin cast support insulators as an example, considering the initial raw material ratios of bisphenol A, epichlorohydrin, catalyst, solvent, refining additives, curing agent, and curing accelerator, as well as the preparation conditions such as casting temperature, cooling time, and curing temperature, first-principles simulation calculations were performed and experimental testing was conducted using an X-ray photoelectron spectroscopy instrument. By comparing the calculation and test results, the atomic types, contents, and chemical bond ratios of epoxy resin insulators were scientifically and accurately obtained, as shown in Table 1.

[0041] Table 1. Atom types, content, and chemical bond percentages of epoxy resin insulation components

[0042]

[0043] Step 2: Cut a flat insulating sample of a certain size, perform surface corona charging at a fixed temperature, measure and record the real-time dynamic value of the surface potential decay of the sample, and plot the isothermal surface potential decay curve.

[0044] The selected epoxy resin specimen for the supporting insulator was a square with a side length of 3cm. The constant temperature during the test was 200℃. A needle electrode with a voltage of -15kV and a grid electrode with a voltage of -5kV were used, and the sample was charged for 30 minutes. After charging, the test was immediately transferred to a position below the probe of an electrostatic voltmeter. The temperature was kept constant, and the isothermal surface potential decay curve was measured, recorded, and plotted. The horizontal axis represents time, and the vertical axis represents the potential value. Figure 2 As shown.

[0045] Step 3: By performing calculus calculations on the plotted isothermal surface potential decay curves, the deep and shallow trap energy levels and trap density on the sample surface are obtained, such as... Figure 3 As shown.

[0046] Step 4: Based on the design drawings of the supporting insulator, calculate the actual parameters of the insulator, such as its length, width, radius, and thickness.

[0047] Step 5: Compare the dimensions of the sample and the actual insulating component. Based on the calculated trap energy level and trap density of the sample size, obtain the number of deep trap charges in the actual insulating component.

[0048] Step 6: Based on the design drawings, supporting insulator type, and specific dimensions of the target combined electrical appliance, determine the specific location for X-ray irradiation, and adjust the tube voltage, tube current, and exposure time to achieve rapid and effective dissipation of space charge on the insulator. Figure 4 As shown.

[0049] In addition, this application also provides a space charge dissipation device for solid insulating components inside a combined electrical appliance. The device comprises three parts: an X-ray tube, a signal detection and conversion system, and an electrical signal processing and analysis system. The X-ray tube includes a cathode filament and an anode rare metal target. The cathode filament releases a large number of electrons through the thermionic emission effect under current-carrying conditions, bombarding the anode metal target. The initial electrons released from the cathode are accelerated by a high-voltage field and then bombard the anode rare metal target, which has a high secondary electron emission coefficient, at extremely high speeds, generating X-rays. The X-rays are emitted through the beryllium material of the anode target and then collimated to limit the beam shape, avoiding interference from excess rays. The signal detection and conversion system, based on the energy attenuation characteristics of X-rays penetrating different insulating components and metal shells, converts the X-ray intensity signal, which reflects the energy attenuation characteristics, into an electrical signal. A flat panel detector is used, which generates a charge signal through ionization of low-bandgap semiconductor materials such as selenium. The charge is then collected by electrodes and converted back into an electrical signal. The electrical signal processing and analysis system first preprocesses the electrical signal by correcting noise in the signal detection and conversion system and eliminating X-ray inhomogeneity and dark current interference. Then, it performs post-processing on the electrical signal using methods such as contrast optimization, edge enhancement, and Fourier transform. Finally, on the system display interface, a data-driven coupling algorithm with embedded physical field mechanisms is used to provide feedback on the space charge suppression effect after X-rays act on the metal shell and solid insulating parts, and to optimize and control experimental parameters such as tube voltage, tube current, and exposure time of the X-ray tube to improve the rapid dissipation effect of charge.

[0050] Finally, it should be noted that the above embodiments are merely illustrative and explanatory of the present invention, and are not intended to limit the present invention to the scope of the described embodiments. Furthermore, those skilled in the art will understand that the present invention is not limited to the above embodiments, and many more variations and modifications can be made based on the teachings of the present invention, all of which fall within the scope of protection claimed by the present invention.

Claims

1. A method for dissipating space charge in a solid insulating component inside a combined electrical appliance, characterized in that, Includes the following steps: Step 1: Theoretical calculation and experimental testing of the atomic types, content, and chemical bond ratio of the insulating components; Step 2: Cut a flat insulating sample of a certain size, perform surface corona charging at a fixed temperature, measure and record the real-time dynamic value of the surface potential decay of the sample, and plot the isothermal surface potential decay curve. Step 3: Calculate the deep and shallow trap energy levels and trap density on the sample surface; Step 4: Measure and calculate the actual dimensional parameters of the insulation components; Step 5: Calculate the actual number of deep-trapped charges in the insulating component; Step 6: Determine the specific location of X-ray irradiation to quickly and effectively dissipate space charge on the insulating components.

2. The method for dissipating space charge in a solid insulating component inside a combined electrical appliance according to claim 1, characterized in that, In step 1, the types of insulating components include insulating tie rods, basin insulators, and support insulators; calculations and tests are carried out in conjunction with the initial raw material ratio and preparation conditions during the production stage, taking into account parameters such as temperature, humidity, type and content of additives, and cooling time.

3. The method for dissipating space charge in a solid insulating component inside a combined electrical appliance according to claim 1, characterized in that, In step 2, the insulating component is a rectangle with a side length of 1cm-10cm; the fixed temperature range is 200℃-400℃; the surface corona charging uses a ±10-20kV adjustable needle electrode, a ±3-8kV adjustable grid electrode, and an adjustable charging time of 10-100min; the real-time dynamic value of the sample surface potential decay is obtained by immediately transferring the test to below the electrostatic voltmeter probe after charging is completed, keeping the temperature constant, measuring, recording, and plotting the isothermal surface potential decay curve, where the horizontal axis represents time and the vertical axis represents the potential value.

4. The method for dissipating space charge in a solid insulating component inside a combined electrical appliance according to claim 1, characterized in that, In step 3, the deep and shallow trap energy levels and trap density on the sample surface are calculated by performing calculus on the plotted isothermal surface potential decay curve.

5. A method for dissipating space charge in a solid insulating component inside a combined electrical appliance according to claim 1, characterized in that, In step 4, the actual size parameters include the length, width, radius, and thickness of the insulating component, and the calculation is carried out with reference to the design drawings of the specific type of insulating component.

6. A method for dissipating space charge in a solid insulating component inside a combined electrical appliance according to claim 1, characterized in that, In step 5, the number of deep trap charges in the actual insulating component is calculated by comparing the sample size and the actual insulating component size, and by calculating based on the trap energy level and trap density of the sample size.

7. A method for dissipating space charge in a solid insulating component inside a combined electrical appliance according to claim 1, characterized in that, In step 6, the specific location is determined in conjunction with the design drawings of the target combined electrical appliance, the type of insulation component, and the specific dimensions; the rapid and effective dissipation of space charge in the insulation component is achieved through the tube voltage, tube current, and exposure time of conditional X-ray irradiation.

8. A space charge dissipation device for a solid insulating component inside a combined electrical appliance, the device being used to implement the method as described in any one of claims 1-7, characterized in that, include: X-ray tube, signal detection and conversion system, electrical signal processing and analysis system; The X-ray tube includes a cathode filament and an anode rare metal target; The cathode filament releases a large number of electrons through the thermionic emission effect under current conditions, which bombard the anode metal target; the anode rare metal target, the initial electrons released by the cathode are accelerated by a high voltage field and bombard the anode rare metal target with a high secondary electron emission coefficient at extremely high speed. The signal detection and conversion system, based on the energy attenuation characteristics of X-rays when they penetrate different insulating components and metal shells, converts the X-ray intensity signal, which reflects the energy attenuation characteristics, into an electrical signal. It uses a flat panel detector to generate a charge signal by ionizing a semiconductor material with a low bandgap width, and then the charge is collected by electrodes and converted into an electrical signal. The electrical signal processing and analysis system first preprocesses the electrical signal by correcting noise in the signal detection and conversion system and eliminating X-ray inhomogeneity and dark current interference. Then, it performs post-processing on the electrical signal. Finally, on the system display interface, a data-driven coupling algorithm with embedded physical field mechanisms is used to provide feedback on the space charge suppression effect after X-rays act on the metal shell and solid insulating parts, optimize and control the experimental parameters of the X-ray tube, and improve the rapid dissipation effect of charge.

9. A space charge dissipation device for solid insulating components inside a combined electrical appliance according to claim 8, characterized in that, Post-processing of electrical signals is performed using methods such as comparison optimization, edge enhancement, and Fourier transform.

10. A space charge dissipation device for a solid insulating component inside a combined electrical appliance according to claim 8, characterized in that, Optimize and control the experimental parameters of X-ray tube voltage, tube current and exposure time.

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