Method for cleaning oil stains of three-dimensional non-flat structure of power transformation equipment through femtosecond laser

Abstract

The invention discloses a method for cleaning oil stains on a three-dimensional non-flat structure of power transformation equipment by femtosecond laser, which comprises the following steps of: firstly, measuring absorbance of materials on the surfaces of pollution-free power transformation equipment and the power transformation equipment attached with the oil stains in different wave bands by utilizing an ultraviolet-visible near-infrared spectrometer; selecting a wave band with relatively high absorbance of the transformer equipment attached with the oil stain; then, processing parameters of the modulated femtosecond laser cleaning system are determined; and finally, on the basis of the machining parameters, the femtosecond laser cleaning system is used for conducting laser irradiation on the power transformation equipment, so that oil stains of the three-dimensional non-flat structure of the power transformation equipment are cleaned through femtosecond laser. On the basis of the advantage of small heat effect of femtosecond laser, the damage caused by thermal ablation in the conventional laser cleaning method can be avoided. According to the method, the laser cleaning effect can be improved, and heat damage and loss of the laser to the surface of an object can be reduced.

Description

Technical Field

[0001] The invention belongs to the technical field of laser cleaning, in particular to a method for cleaning oil stains of three-dimensional non-planar structures of transformer equipment with femtosecond laser. Background Art

[0002] Substation equipment is widely used in power systems for power transmission, power generation, distribution, voltage stabilization, protection, control and monitoring.

[0003] During the use of substation equipment, oil pollution is a phenomenon that will seriously affect the operation of the equipment and is difficult to avoid. There are many reasons for the generation of oil pollution, such as improper control of the welding production process of substation equipment, welding defects, poor material of sealing gaskets, aging and cracking of gaskets, and reduced oil resistance, oxidation resistance, and high temperature resistance of sealing gaskets. Oil pollution can cause damage to the equipment and adhere to a large amount of dust and other pollutants. These oil pollution and pollutants will affect the normal operation of the equipment and may have serious adverse effects on the equipment itself, such as corrosion of the protective layer of the equipment or reduced insulation of the equipment. If the components of the substation equipment are contaminated by oil pollution, it is easy to cause accidents such as short circuits and arcs, thereby threatening personal and equipment safety. This has become a technical problem that needs to be solved urgently. Summary of the invention

[0004] The purpose of the present invention is to provide a femtosecond laser cleaning method for three-dimensional non-flat structure oil stains of transformer equipment to solve the deficiencies in the prior art. It can avoid the damage of thermal ablation in the current laser cleaning method based on the advantage of small thermal effect of femtosecond laser. This method can not only improve the laser cleaning effect, but also reduce the thermal damage and loss of the laser to the surface of the object.

[0005] An embodiment of the present application provides a method for cleaning oil stains of a three-dimensional non-planar structure of a transformer using a femtosecond laser, the method comprising:

[0006] Placement of substation equipment with oil stains;

[0007] Determine the processing parameters of the femtosecond laser cleaning system;

[0008] Based on the processing parameters, the femtosecond laser cleaning system is used to irradiate the substation equipment with laser, so as to clean the oil stains on the three-dimensional non-planar structure of the substation equipment with the femtosecond laser.

[0009] Optionally, before placing the substation equipment with oil stains attached, the method further includes:

[0010] The UV-visible near-infrared spectrometer is used to measure the absorbance of materials on the surface of non-polluted substation equipment and substation equipment with oil stains in different bands.

[0011] Based on the absorbance, a target band of the femtosecond laser cleaning system is determined; wherein the absorbance of the target band is lower in the non-polluted substation equipment and higher in the substation equipment with oily contamination.

[0012] Optionally, the target waveband is not less than 1000 nm.

[0013] Optionally, the femtosecond laser cleaning system comprises:

[0014] Femtosecond lasers, mirrors, half-wave plates, prisms, apertures, attenuators, axicons and beam steering heads.

[0015] Optionally, before the femtosecond laser cleaning system is used to irradiate the substation equipment with laser based on the processing parameters to clean the oil stains of the three-dimensional non-planar structure of the substation equipment with the femtosecond laser, the method further includes:

[0016] The laser beam is modulated using an axicon.

[0017] Optionally, the laser beam includes: a Bessel beam; the Bessel beam has a long focal depth and an adjustable focal spot shape.

[0018] Optionally, the central wavelength of the femtosecond laser is 1030 nm, the laser spot diameter is 20 μm, the pulse width is 10 ns, the single pulse energy is less than 0.1 mJ, and the laser repetition frequency is 10 kHz.

[0019] Optionally, the processing parameters of the femtosecond laser cleaning system include:

[0020] Processing power, processing speed, point spacing and number of processing times.

[0021] Optionally, the processing power is 150 mW, the processing speed is 10 mm / s, the point spacing is 0.01 mm, and the processing times are not less than 1 time.

[0022] Optionally, after the femtosecond laser cleaning system is used to irradiate the substation equipment with laser based on the processing parameters to clean the oil stains of the three-dimensional non-planar structure of the substation equipment with the femtosecond laser, the method further comprises:

[0023] An optical microscope is used to observe the cleaning effect of the power conversion equipment after the femtosecond laser cleaning system is used to irradiate the power conversion equipment with laser, and processing parameters are adjusted based on the cleaning effect.

[0024] Compared with the prior art, the present invention first uses an ultraviolet-visible-near-infrared spectrometer to measure the absorbance of materials on the surface of non-polluted substation equipment and substation equipment with oil stains in different bands, and selects the band with higher absorbance of the substation equipment with oil stains; then determines the processing parameters of the modulated femtosecond laser cleaning system; finally, based on the processing parameters, the femtosecond laser cleaning system is used to irradiate the substation equipment with laser, so as to realize the use of femtosecond laser to clean the oil stains of the three-dimensional non-flat structure of the substation equipment. It can avoid the damage of thermal ablation in the current laser cleaning method based on the advantage of the small thermal effect of femtosecond laser. This method can not only improve the laser cleaning effect, but also reduce the thermal damage and loss of the laser to the surface of the object. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 A schematic flow chart of a method for cleaning three-dimensional non-planar structure oil stains of power substation equipment using a femtosecond laser according to an embodiment of the present invention;

[0026] Figure 2 A line graph showing the absorbance of paint for power substation equipment in different wavebands provided by an embodiment of the present invention;

[0027] Figure 3 A schematic structural diagram of a femtosecond laser cleaning system provided by an embodiment of the present invention;

[0028] Figure 4 A schematic diagram of a process for cleaning a complex heat sink after laser modulation provided by an embodiment of the present invention;

[0029] Figure 5 A schematic diagram showing the cleaning effect using a femtosecond laser provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0030] The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, but should not be construed as limiting the present invention.

[0031] The cleaning of oil stains on substation equipment currently relies mainly on manual operation. Since cleaning requires power outage and stopping the equipment from running, it takes a lot of time to prepare for the power outage, and it may affect the operation of other equipment, causing serious economic losses. Therefore, most cleaning processes now do not shut down the equipment or disassemble it. When the equipment is energized and cleaned with a high-pressure cleaning gun through the spray of high-pressure water flow, there is a high risk of electric shock for the operator. In addition, high-pressure water gun cleaning will spray stains or pollutants onto surrounding objects or people, causing secondary pollution or threatening the safety of operators.

[0032] This high-pressure water cleaning method cannot completely remove stubborn oil stains, so chemical reagents are usually introduced in practical applications. This method requires manual use of acidic or alkaline reagents to clean the surface of the substation equipment, which can basically remove pollutants such as oil stains and oxide layers. However, the cleaning efficiency is low, which may cause the surface of the cleaned equipment to be rugged and uneven, causing potential concentration. In addition, many equipment will have parts such as rubber sealing rings that are easily corroded by chemical reagents, so the method of manual scrubbing with chemical reagents is not suitable for most substation equipment.

[0033] Therefore, there is currently no non-contact cleaning method for the three-dimensional non-flat structure of substation equipment.

[0034] See also Figure 1 , Figure 1 A schematic flow chart of a method for cleaning oil stains of three-dimensional non-planar structures of substation equipment using a femtosecond laser according to an embodiment of the present invention may include the following steps:

[0035] S101: Place substation equipment with oil stains.

[0036] Specifically, for a substation equipment with oil stains attached thereto, the method may further include:

[0037] 1. Use UV-visible near-infrared spectrometer to measure the absorbance of materials on the surface of substation equipment without oil pollution and substation equipment with oil pollution in different bands;

[0038] 2. Based on the absorbance, determine the target band of the femtosecond laser cleaning system; wherein the absorbance of the target band is lower in the non-polluted substation equipment, and higher in the substation equipment with oily dirt.

[0039] Specifically, the absorbance of the non-polluted substation equipment material itself and the substation equipment material with attached oil stains (such as paint) in different bands is measured using an ultraviolet visible near-infrared spectrometer. For example, the absorbance of the paint material of the substation equipment is measured in the band of 220nm-2500nm. It can be seen that the absorbance of the paint of the substation equipment decreases significantly after the 600nm band, and the absorbance is at the lowest state after the 1000nm band. Therefore, by selecting a laser with a band above 1000nm for processing, the energy absorbed by the substation equipment itself can be minimized.

[0040] That is, in an optional implementation, the target wavelength band may be set to be no less than 1000 nm.

[0041] In order not to affect the cleaning effect and reduce material damage at the same time, this application proposes to use a laser with a suitable wavelength, and select a more suitable laser wavelength and parameters for the oil stain itself. Therefore, this application compares the absorbance of unpolluted substation equipment and substation equipment with oil stains in different bands, so as to select a wavelength with a smaller absorbance of the substation equipment material. The absorbance of the paint on the surface of the substation equipment drops significantly after 600nm, and the absorbance is always at the lowest state after 1000nm. Therefore, according to the method of this application, the laser can be selected for processing at a wavelength above 1000nm, and the energy absorption of the substation equipment material itself can be reduced as much as possible, so that the energy of the laser acts on the surface of the oil stain, thereby obtaining a more accurate cleaning result and reducing damage. Based on the advantage of the small thermal effect of the femtosecond laser, the thermal ablation damage in the current laser cleaning method is avoided. This method can not only improve the laser cleaning effect, but also reduce the thermal damage and loss of the laser to the surface of the object.

[0042] See also Figure 2 , Figure 2 The absorbance line graph of the paint for substation equipment in different bands provided in the embodiment of the present invention shows that the absorbance of the paint on the surface of the power equipment decreases significantly after 600nm, and the absorbance is always at the lowest state after 1000nm. Therefore, according to the method of the present application, the target band can be set to a laser with a wavelength above 1000nm for processing.

[0043] S102: Determine processing parameters of the femtosecond laser cleaning system.

[0044] First, see Figure 3 , Figure 3 A schematic diagram of the structure of a femtosecond laser cleaning system provided by an embodiment of the present invention is shown in FIG. Figure 3 As shown, the femtosecond laser cleaning system may include: a femtosecond laser, a reflector, a half-wave plate, a prism, an aperture, an attenuation plate, a cone lens, and a beam guiding head.

[0045] Among them, for power devices with complex structures and many grooves such as heat sinks, this application proposes a method of first shaping the laser beam. By adding an aconic lens in the optical path, the beam can be modulated to different degrees. Figure 4 , Figure 4 A schematic diagram of a process for cleaning a complex heat sink after laser modulation provided in an embodiment of the present invention.

[0046] It should be noted that the laser beam may include: a Bessel beam; the Bessel beam has a long focal depth and an adjustable focal spot shape. Since the Bessel beam is a light field whose spatial electromagnetic field intensity distribution is a first-order Bessel function, the distribution on the propagation cross section presents a light field with a center point and a series of concentric rings, and the energy gradually decreases from the inside to the outside. The longer focal depth and adjustable focal spot shape of the Bessel beam make it have a very large processing dynamic range in the application of laser cleaning, which has great advantages for cleaning power devices with rugged surfaces and complex structures, and finally realizes the use of Bessel beams to clean heat sinks of different heights and narrow structural gaps. At the same time, this method can also be applied to power devices with complex structures such as transformers and circuit breakers.

[0047] In an optional embodiment, a laser with a wavelength band where the material of the transformer substation has a low absorbance and the oil stain has a high absorbance is selected for processing, for example, a femtosecond laser with a central wavelength of 1030nm, a laser spot diameter of 20μm, a pulse width of 10ns, a single pulse energy of less than 0.1mJ, and a laser repetition frequency of 10kHz can be used for processing.

[0048] S103: Based on the processing parameters, the femtosecond laser cleaning system is used to irradiate the substation equipment with laser, so as to clean the oil stains on the three-dimensional non-planar structure of the substation equipment with the femtosecond laser.

[0049] Specifically, the substation equipment with attached oil stains is placed. The modulated laser is used to select appropriate parameters to process the substation equipment with oil stains, and the processing effect is explored. Laser cleaning begins, and a laser with a certain power is irradiated onto the contaminants on the surface of the substation equipment. Due to the large difference in light absorption between the contaminants and the base material, the contaminants absorb more laser energy than the base material. Therefore, the contaminants will be heated more, resulting in evaporation and decomposition, while the material itself will not be significantly heated, reducing thermal damage to the material itself.

[0050] Exemplarily, different laser parameters are tried for laser cleaning, and finally the processing parameters of processing power of 150 mW, processing speed of 10 mm / s, processing times of 1 time, and point spacing of 0.01 mm can be selected for cleaning.

[0051] See also Figure 5 , Figure 5 A schematic diagram showing the cleaning effect of a femtosecond laser provided in an embodiment of the present invention shows that the oil stains at the processing position are removed while the surface paint of the substation equipment components is not damaged.

[0052] In an optional embodiment, after the femtosecond laser cleaning system is used to irradiate the substation equipment with laser based on the processing parameters to achieve the cleaning of oil stains on the three-dimensional non-flat structure of the substation equipment by femtosecond laser, the method may further include:

[0053] An optical microscope is used to observe the cleaning effect of the power conversion equipment after the femtosecond laser cleaning system is used to irradiate the power conversion equipment with laser, and processing parameters are adjusted based on the cleaning effect.

[0054] Specifically, an optical microscope is used to observe the processing effects of substation equipment with attached oil stains with different processing parameters, and the optimal processing parameters are determined to obtain processing parameters with high processing efficiency and good cleaning effect. Then, laser cleaning is started with the optimal laser cleaning parameters and wavelength, and the laser is focused on the pollutants on the surface of the substation equipment with attached oil stains. Since the material itself will not be heated much, the pollutants will be heated more, resulting in evaporation and decomposition. This achieves the purpose of more energy acting on the pollutants and protecting the material. Finally, an optical microscope is used to observe the removal effect before and after laser cleaning. Since the surface damage of the material is small, it can be repeatedly processed to improve the cleaning effect without excessively damaging the surface.

[0055] Compared with the prior art, the present invention first places the substation equipment contaminated by oil pollution; then determines the processing parameters of the modulated femtosecond laser cleaning system; finally, based on the processing parameters, the femtosecond laser cleaning system is used to irradiate the substation equipment with laser, so as to realize the use of femtosecond laser to clean the oil pollution of the three-dimensional non-flat structure of the substation equipment. It can avoid the damage of thermal ablation in the current laser cleaning method based on the advantage of the small thermal effect of femtosecond laser. This method can not only improve the laser cleaning effect, but also reduce the thermal damage and loss of the laser to the surface of the object.

[0056] It should be noted that, for the above-mentioned method embodiments, for the sake of simplicity, they are all described as a series of action combinations, but those skilled in the art should know that the present invention is not limited by the described action sequence, because according to the present invention, certain steps can be performed in other sequences or simultaneously. Secondly, those skilled in the art should also know that the embodiments described in the specification are all preferred embodiments, and the actions and modules involved are not necessarily required by the present invention.

[0057] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0058] In the several embodiments provided by the present invention, it should be understood that the disclosed devices can be implemented in other ways. For example, the device embodiments described above are only schematic, such as the division of the above units, which is only a logical function division. There may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, and the indirect coupling or communication connection of devices or units can be electrical or other forms.

[0059] The units described above as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0060] In addition, each functional unit in each embodiment of the present invention may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit. The above-mentioned integrated unit may be implemented in the form of hardware or in the form of software functional units.

[0061] If the above-mentioned integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable memory. Based on this understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art, or all or part of the technical solution can be embodied in the form of a software product, and the computer software product is stored in a memory, including a number of instructions for a computer device (which can be a personal computer, a server or a network device, etc.) to perform all or part of the steps of the above-mentioned methods of each embodiment of the present invention. The aforementioned memory includes: U disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), mobile hard disk, magnetic disk or optical disk and other media that can store program codes.

[0062] The embodiments of the present invention are described in detail above. Specific examples are used herein to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core idea. At the same time, for those skilled in the art, according to the idea of ​​the present invention, 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 the present invention.

Claims

1. A femtosecond laser cleaning method for three-dimensional non-planar structure oil stains in power substation equipment, characterized in that: The method comprises: Placement of substation equipment with oil stains; Determine the processing parameters of the femtosecond laser cleaning system; Based on the processing parameters, the femtosecond laser cleaning system is used to irradiate the substation equipment with laser, so as to clean the oil stains on the three-dimensional non-planar structure of the substation equipment with the femtosecond laser.

2. The method according to claim 1, characterized in that Before placing the substation equipment with oil stains attached, the method further comprises: The UV-visible near-infrared spectrometer is used to measure the absorbance of materials on the surface of non-polluted substation equipment and substation equipment with oil stains in different bands. Based on the absorbance, a target band of the femtosecond laser cleaning system is determined; wherein the absorbance of the target band is lower in the non-polluted substation equipment and higher in the substation equipment with oily contamination.

3. The method according to claim 2, characterized in that The target waveband is not less than 1000 nm.

4. The method according to claim 3, characterized in that The femtosecond laser cleaning system comprises: Femtosecond lasers, mirrors, half-wave plates, prisms, apertures, attenuators, axicons and beam steering heads.

5. The method according to claim 4, characterized in that Before the femtosecond laser cleaning system is used to irradiate the transformer equipment with laser based on the processing parameters to clean the oil stains of the three-dimensional non-flat structure of the transformer equipment with the femtosecond laser, the method further comprises: The laser beam is modulated using an axicon.

6. The method according to claim 5, characterized in that The laser beam comprises: a Bessel beam; the Bessel beam has a long focal depth and an adjustable focal spot shape.

7. The method according to claim 6, characterized in that The central wavelength of the femtosecond laser is 1030nm, the laser spot diameter is 20μm, the pulse width is 10ns, the single pulse energy is less than 0.1mJ, and the laser repetition frequency is 10kHz.

8. The method according to claim 7, characterized in that The processing parameters of the femtosecond laser cleaning system include: Processing power, processing speed, point spacing and number of processing times.

9. The method according to claim 8, characterized in that The processing power is 150 mW, the processing speed is 10 mm / s, the point spacing is 0.01 mm, and the processing times are not less than 1 time.

10. The method according to any one of claims 1 to 9, characterized in that: After the femtosecond laser cleaning system is used to irradiate the substation equipment with laser based on the processing parameters to achieve the cleaning of oil stains on the three-dimensional non-planar structure of the substation equipment by femtosecond laser, the method further comprises: An optical microscope is used to observe the cleaning effect of the power conversion equipment after the femtosecond laser cleaning system is used to irradiate the power conversion equipment with laser, and processing parameters are adjusted based on the cleaning effect.

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