Post insulator ice flashover risk assessment method and device based on ultraviolet imaging

Abstract

The present application provides a method and device for evaluating the risk of ice flashover of post insulators based on ultraviolet imaging, including: obtaining the ice condition of the post insulators of the substation to be evaluated and the meteorological data of the preset time period in the future, collecting the recent ultraviolet imaging spectrum and visible light image of the substation to be evaluated; determining the first photon number of stable corona and the second photon number of intermittent pulse discharge according to the ultraviolet imaging spectrum; and evaluating the ice flashover risk level of the post insulator; obtaining the shed parameters according to the visible light image, screening out the concentrated area of ​​corona discharge according to the ultraviolet imaging spectrum and determining its first width and first vertical spacing; evaluating the ice bridging risk of the post insulator. It provides a quantitative judgment basis for the risk assessment of ice flashover of post insulators based on ultraviolet imaging, with clear logic, conciseness and practicality, filling the gap in the risk assessment method of ice flashover of post insulators, and can effectively guide the maintenance decision of ice flashover defects of post insulators.

Description

Technical Field

[0001] The present application belongs to the technical field of risk assessment of ice flashover of post insulators, and in particular, relates to a method and device for risk assessment of ice flashover of post insulators based on ultraviolet imaging. Background Art

[0002] Local and large-scale ice disasters in power grids occur from time to time, causing serious damage to the safety of power grid equipment. Grid disconnection and large-scale power outages will cause immeasurable losses to economic and social operations. Due to the special terrain and climate characteristics, some areas are more likely to suffer from freezing disasters. Under extreme conditions, equipment damage, tripping, power outages and other accidents will occur. Among them, there are many cases where the primary equipment of the substation fails due to ice flashover on the pillar insulators, which leads to the tripping of the main transformer.

[0003] At present, in various live inspections for anti-icing and grid protection, the operation and maintenance personnel can often find the local discharge corona of 220 kV post insulators through ultraviolet imaging, and the number of photons is even as high as 50,000 or more. However, the existing ultraviolet imaging detection only puts forward clear requirements for the conditions and methods of ultraviolet detection, while the data analysis and judgment of ultraviolet imaging are still unclear. Since the operation and maintenance department cannot make an accurate assessment of the risk of ice flashover based on the spectrum and data of ultraviolet imaging, it is difficult to carry out ice control or defect elimination in an orderly and efficient manner. Summary of the invention

[0004] The main purpose of the embodiments of the present invention is to provide a method and device for evaluating the risk of ice flashover of post insulators based on ultraviolet imaging, which provides a quantitative judgment basis for the risk assessment of ice flashover of post insulators based on ultraviolet imaging. The method has clear logic, is concise and practical, fills the gap in the risk assessment method of ice flashover of post insulators, and can effectively guide the maintenance decision of ice flashover defects of post insulators.

[0005] In the first aspect, a method for evaluating the risk of ice flashover of post insulators based on ultraviolet imaging is provided, the method comprising: obtaining the ice condition of 220 kV post insulators of the substation to be evaluated and the meteorological data of a preset time period in the future, collecting ultraviolet imaging maps and visible light images of the post insulators of the substation to be evaluated in the near future; comprehensively considering the ice condition of the post insulators, the ultraviolet imaging maps and the meteorological data and establishing an insulator ledger with the risk of ice flashover; for any post insulator in the insulator ledger, performing data cleaning on the ultraviolet imaging maps, and determining the first photon number for the occurrence of stable corona and the second photon number for the occurrence of intermittent pulse discharge according to the ultraviolet imaging maps; evaluating the ice flashover risk level of the post insulator according to the first photon number and the second photon number, and if the first photon number is greater than the first reference threshold, determining that the post insulator is at risk of ice flashover. The post insulator is in an ice flashover crisis zone; if the first photon number is less than or equal to the first reference threshold and greater than or equal to the second reference threshold, and the second photon number is greater than or equal to the third reference threshold, it is determined that the post insulator is in an ice flashover warning zone; if the first photon number is less than the second reference threshold, or the first photon number is greater than the second reference threshold and the second photon number is less than the third reference threshold, it is determined that the post insulator is in an ice flashover safety zone; for the ice flashover warning zone and the ice flashover crisis zone, the shed parameters of the post insulator are obtained according to the visible light image, and the corona discharge concentrated area with the first photon number greater than the fourth reference threshold is screened out according to the ultraviolet imaging spectrum, and the first width and the first vertical spacing of the corona discharge concentrated area are determined; the ice bridging risk of the corona discharge concentrated area of ​​the post insulator is evaluated according to the first width, the first vertical spacing and the shed parameters.

[0006] In another possible implementation, the icing conditions of the post insulators, ultraviolet imaging maps and meteorological data are comprehensively considered and a ledger of insulators with the risk of icing flashover is established, including: comprehensively considering the icing conditions of the post insulators, ultraviolet imaging maps and meteorological data to determine at least one post insulator with the risk of icing flashover; all the post insulators with the risk of icing flashover are combined with the model of each post insulator to construct an insulator ledger.

[0007] In a possible implementation, performing data cleaning on the ultraviolet imaging spectrum includes: performing data cleaning on the ultraviolet imaging spectrum and eliminating data with low reliability.

[0008] In another possible implementation, the first photon number for the occurrence of a stable corona and the second photon number for the occurrence of an intermittent pulse discharge are determined based on an ultraviolet imaging spectrum, including: determining an average value of the number of photons for the occurrence of a stable corona based on the ultraviolet imaging spectrum to obtain a corresponding first photon number; identifying the ultraviolet imaging spectrum, extracting a spectrum with low image quality and identifying whether an intermittent pulse discharge phenomenon occurs in a post insulator; and determining an average value of the number of photons for the occurrence of an intermittent pulse discharge to obtain a second photon number.

[0009] In another possible implementation, before classifying the ice flashover risk level of the post insulator according to the first photon number and the second photon number, the method includes: determining a reference threshold for evaluating the ice flashover risk of the post insulator through a post insulator ice flashover simulation test.

[0010] In another possible implementation, a reference threshold for risk assessment of ice flashover on post insulators is determined through a simulation test of ice flashover on post insulators, including: in the simulation test of ice flashover on post insulators, a UV imager is used to monitor the number of UV imaging photons of corona discharge on the surface of the post insulator, and a quantitative relationship between leakage current and the number of UV imaging photons is determined; the risk of ice flashover on post insulators is divided into three levels: a critical zone, a warning zone and a safe zone according to the characteristics of the leakage current; and according to the quantitative relationship between the leakage current and the number of UV imaging photons, the number of stable corona photons entering the critical zone is determined as the first reference threshold, and the number of stable corona photons entering the safe zone and the number of pulse discharge photons are determined as the second reference threshold and the third reference threshold, respectively.

[0011] In another possible implementation, the shed parameters include: the number of shed pieces, the vertical spacing between adjacent sheds and the shed width of the post insulator; the ice bridging risk of the corona discharge concentrated area of ​​the post insulator is evaluated according to the first width, the first vertical spacing and the shed parameters, including: calculating the ratio of the first width to the shed width to obtain the ice width ratio, and calculating the ratio of the first vertical spacing to the vertical spacing between adjacent sheds to obtain the number of ice insulator pieces; if the corona discharge concentrated area is located in the shed part of the post insulator, if the number of ice insulator pieces is greater than the fifth reference threshold and the ice width ratio is greater than the sixth reference threshold, it is determined that the corona discharge concentrated area has an ice bridging risk; if the corona discharge concentrated area is located at the end of the post insulator, if the ice width ratio is greater than the seventh reference threshold, it is determined that the corona discharge concentrated area has an ice bridging risk; for the post insulator with the ice bridging risk, the icing morphology of the post insulator is determined according to the meteorological data, and the development speed of the ice bridging risk of the post insulator is evaluated according to the icing morphology and the altitude of the substation to be evaluated.

[0012] In the second aspect, a device for assessing the risk of ice flashover of post insulators based on ultraviolet imaging is provided, and the device includes: a data acquisition module, which is used to obtain the ice condition of 220 kV post insulators of the substation to be assessed and the meteorological data of a preset time period in the future, and collect ultraviolet imaging spectra and visible light images of the post insulators of the substation to be assessed in the near future; a ledger establishment module, which is used to comprehensively consider the ice condition of the post insulators, the ultraviolet imaging spectra and the meteorological data and establish an insulator ledger with the risk of ice flashover; a photon number acquisition module, which is used to clean the ultraviolet imaging spectra for any post insulator in the insulator ledger, and determine the first photon number for the occurrence of stable corona and the second photon number for the occurrence of intermittent pulse discharge according to the ultraviolet imaging spectra; a risk assessment module, which is used to assess the ice flashover risk level of the post insulator according to the first photon number and the second photon number, and if the first photon number is greater than the first reference threshold, It is determined that the post insulator is in an ice flashover emergency zone; if the first photon number is less than or equal to the first reference threshold and greater than or equal to the second reference threshold, and the second photon number is greater than or equal to the third reference threshold, it is determined that the post insulator is in an ice flashover warning zone; if the first photon number is less than the second reference threshold, or the first photon number is greater than the second reference threshold and the second photon number is less than the third reference threshold, it is determined that the post insulator is in an ice flashover safety zone; a concentrated area determination module is used to obtain the shed parameters of the post insulator according to the visible light image for the ice flashover warning zone and the ice flashover emergency zone, and screen out the corona discharge concentrated area with the first photon number greater than the fourth reference threshold according to the ultraviolet imaging spectrum, and determine the first width and the first vertical spacing of the corona discharge concentrated area; a bridging risk assessment module is used to assess the ice bridging risk of the corona discharge concentrated area of ​​the post insulator according to the first width, the first vertical spacing and the shed parameters.

[0013] In a third aspect, an electronic device is provided, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the program, a method for assessing the risk of ice flashover of a post insulator based on ultraviolet imaging as provided in the first aspect is implemented.

[0014] In a fourth aspect, a non-transitory computer-readable storage medium is provided, on which a computer program is stored. When the computer program is executed by a processor, a method for assessing the risk of ice flashover of a post insulator based on ultraviolet imaging as provided in the first aspect is implemented. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in describing the embodiments of the present application are briefly introduced below.

[0016] Figure 1A flow chart of a method for assessing the risk of ice flashover of a post insulator based on ultraviolet imaging provided by one embodiment of the present invention;

[0017] Figure 2 A schematic diagram of the logic for evaluating and judging the risk of ice flashover of a post insulator based on ultraviolet imaging provided in an embodiment of the present invention;

[0018] Figure 3 A structural diagram of a post insulator ice flashover risk assessment device based on ultraviolet imaging provided by one embodiment of the present invention;

[0019] Figure 4 A schematic diagram of the physical structure of an electronic device provided by the present invention. DETAILED DESCRIPTION

[0020] The embodiments of the present application are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar modules or modules with the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present application, and cannot be interpreted as limiting the present invention.

[0021] It will be understood by those skilled in the art that, unless expressly stated, the singular forms "a", "an", "said" and "the" used herein may also include plural forms. It should be further understood that the term "comprising" used in the specification of the present application refers to the presence of the features, integers, steps, operations, modules and / or components, but does not exclude the presence or addition of one or more other features, integers, steps, operations, modules, components and / or groups thereof. It should be understood that when we refer to a module as being "connected" or "coupled" to another module, it may be directly connected or coupled to the other modules, or there may be intermediate modules. In addition, the "connection" or "coupling" used herein may include wireless connection or wireless coupling. The term "and / or" used herein includes all or any modules and all combinations of one or more associated listed items.

[0022] In order to make the objectives, technical solutions and advantages of the present application clearer, the implementation method of the present application will be further described in detail below in conjunction with the accompanying drawings.

[0023] The technical solution of the present application and how to solve the above-mentioned technical problems are described in detail below with specific embodiments. The following specific embodiments can be combined with each other, and the same or similar concepts or processes may not be repeated in some embodiments. The embodiments of the present application will be described below in conjunction with the accompanying drawings.

[0024] like Figure 1The flowchart of a method for evaluating the risk of ice flashover of a post insulator based on ultraviolet imaging provided by an embodiment of the present invention is shown. The method comprises:

[0025] Step S11, obtaining the icing condition of the post insulators of the substation to be evaluated and the meteorological data of a preset time period in the future, and collecting the ultraviolet imaging spectrum and visible light image of the post insulators of the substation to be evaluated in the near future.

[0026] Specifically, investigate the current icing situation and icing equipment of the substation to be evaluated, as well as the meteorological information for the next 15 days, including temperature, humidity, climate, etc. At the same time, collect recent UV detection graphs and data. The icing equipment in this application is mainly post insulators, preferably 220 kV post insulators. Of course, in other embodiments of the present invention, it can also be other equipment in the substation to be evaluated, and this is not specifically limited. There will be patrol personnel in the substation, and the icing situation of the post insulators will be reported if the equipment is seriously iced.

[0027] Step S12, comprehensively consider the icing condition of the post insulators, ultraviolet imaging spectra and meteorological data and establish a record of insulators with the risk of icing flashover.

[0028] Step S13, for any post insulator in the insulator inventory, data cleaning is performed on the ultraviolet imaging spectrum, and the first photon number for the occurrence of stable corona and the second photon number for the occurrence of intermittent pulse discharge are determined according to the ultraviolet imaging spectrum.

[0029] Step S14, assessing the ice flashover risk level of the post insulator according to the first photon number and the second photon number. If the first photon number is greater than the first reference threshold, it is determined that the post insulator is in the ice flashover critical zone; if the first photon number is less than or equal to the first reference threshold and greater than or equal to the second reference threshold, and the second photon number is greater than or equal to the third reference threshold, it is determined that the post insulator is in the ice flashover warning zone; if the first photon number is less than the second reference threshold, or the first photon number is greater than the second reference threshold and the second photon number is less than the third reference threshold, it is determined that the post insulator is in the ice flashover safety zone.

[0030] Step S15, for the ice flashover warning area and the ice flashover critical area, the shed parameters of the post insulator are obtained according to the visible light image, and the corona discharge concentration area with a first photon number greater than a fourth reference threshold is screened out according to the ultraviolet imaging spectrum, and the first width and the first vertical spacing of the corona discharge concentration area are determined.

[0031] Step S16, evaluating the ice bridging risk of the corona discharge concentration area of ​​the post insulator according to the first width, the first vertical spacing and the shed parameters.

[0032] The embodiment of the present invention performs an assessment of the risk of ice flashover on post insulators based on ultraviolet imaging, can conduct a comprehensive analysis and diagnosis of the arc risk on the surface of the post insulator, and assess the risk of ice bridging damaging the insulation performance of the post insulator, filling the gap in the current ultraviolet detection defect diagnosis technology for post insulators. The logic is clear, concise and practical, filling the gap in the risk assessment method for ice flashover on post insulators, and can effectively guide the maintenance decision of ice flashover defects on post insulators.

[0033] In an embodiment of the present invention, in step S12, optionally, at least one post insulator with a risk of ice flashover is determined based on the ice condition of the post insulator, the ultraviolet imaging spectrum and the meteorological data; all the post insulators with a risk of ice flashover are combined with the model of each post insulator to construct an insulator ledger. The ice condition of the post insulator and the meteorological data are used to evaluate the possibility of subsequent icing to obtain the future icing trend. According to the ultraviolet imaging spectrum, if there is a local concentration of photons in the ultraviolet spectrum, there is a risk of flashover. The insulator ledger includes information such as the number and model of equipment with a risk of ice flashover.

[0034] In step S13, the ultraviolet imaging spectrum needs to be cleaned up first to remove data with low reliability. For any post insulator in the insulator ledger, the average number of photons that cause stable corona is determined based on the ultraviolet imaging spectrum to obtain the corresponding first photon number α; the ultraviolet imaging spectrum is identified to extract the spectrum with low image quality and identify whether the post insulator has intermittent pulse discharge; the average number of photons that cause intermittent pulse discharge is determined to obtain the second photon number β.

[0035] Before step S14, a reference threshold for risk assessment of ice flashover of post insulators is determined by a simulation test of ice flashover of post insulators. Optionally, in the simulation test of ice flashover of post insulators, a UV imaging device is used to monitor the number of UV imaging photons of corona discharge on the surface of post insulators, and the quantitative relationship between leakage current and UV imaging photons is determined; the risk of ice flashover of post insulators is divided into three levels: critical zone, warning zone and safe zone according to the characteristics of leakage current; the number of stable corona photons entering the critical zone is determined as the first reference threshold, the number of stable corona photons entering the safe zone and the number of pulse discharge photons are determined as the second reference threshold and the third reference threshold, respectively.

[0036] The magnitude of leakage current is the most effective and direct physical parameter for evaluating the severity of partial discharge. During the development and evolution of ice flashover on post insulators, a stable and weak corona first appears on the surface of the post insulators. As the ice coverage intensifies, the ice gradually grows and further shorts the sheds of the post insulators. The corona gradually develops into intermittent pulse discharge. When the ice covering the post insulators initially melts and forms a layer of ice-melting water film on the surface of the equipment, the water film on the surface of the ice body quickly dissolves during the ice melting process based on the crystal release effect. The electrolyte in the dirt is precipitated on the surface and the conductivity of the ice surface water film is increased, which reduces the flashover voltage of the ice-covered post insulators. At this time, under the combined action of stable corona and intermittent pulse discharge, arcs appear on the surface of the post insulators and discharge. Based on the development and evolution of ice flashover on post insulators, the risk of ice flashover is divided into three levels. The first is the critical zone, that is, the stable arc discharge phenomenon has appeared on the surface of the post insulator, which will cause the short circuit grounding of the post insulator after ice flashover at any time, thereby causing equipment failure or damage. The second is the early warning zone, that is, intermittent pulse discharge occurs on the surface of the post insulator on the basis of stable corona. At this time, the risk of arc discharge on the surface of the post insulator is relatively high. The third is the safe zone, that is, there is only local weak corona discharge on the surface of the post insulator, but no intermittent pulse discharge occurs. The corona does not have the conditions to develop into arc, and does not pose a threat to the safe and stable operation of the equipment.

[0037] According to the simulation test of ice flashover on 220 kV post insulators, the quantitative relationship between the three stages of ice flashover and the leakage current was obtained. In the critical area, obvious arc discharge occurs on the surface of the post insulator, and the leakage current is at least 50 mA. In the warning area, intermittent pulse discharge occurs on the surface of the post insulator, and the leakage current is between 20 mA and 50 mA. In the safe area, only local weak corona appears on the surface of the post insulator, and the leakage current is less than 20 mA.

[0038] In the simulation test, the number of photons of corona discharge on the surface of the post insulator was monitored synchronously using an ultraviolet imager, and the quantitative relationship between the leakage current characteristics and the number of ultraviolet imaging photons was obtained. When the leakage current is greater than 50mA, the number of photons on the surface of the post insulator is at least 40,000, and a large area of ​​discharge area can be clearly observed in the ultraviolet imaging spectrum. When the leakage current is between 20mA and 50mA, the surface of the post insulator is accompanied by intermittent pulse discharge on the basis of stable corona, and its stable photon number is at least 20,000, and intermittent pulses with a photon number of 50,000 appear at the same time. When the leakage current is less than 20mA, the number of photons on the surface of the post insulator is less than 20,000. So far, a quantitative relationship between the ice flashover risk level-leakage current characteristics-ultraviolet imaging photon number has been established.

[0039] Thus, in the embodiment of the present invention, the first reference threshold is greater than the second reference threshold, the first reference threshold is preferably 40000, the second reference threshold is preferably 20000, and the third reference threshold is preferably 50000. Of course, in other implementations of the present invention, the first reference threshold, the second reference threshold and the third reference threshold may also be set to other values, which are not specifically limited herein.

[0040] The embodiment of the present invention firstly explores the quantitative relationship between the number of ultraviolet imaging photons and the leakage current during ice flashover of the post insulator by means of simulation experiments, and then divides the risk of ice flashover of the post insulator into three categories: critical, warning and safe according to the characteristics of the leakage current. It provides a quantitative judgment basis for the risk assessment of ice flashover of the post insulator based on ultraviolet imaging, with clear logic, concise and practical, which fills the gap in the risk assessment method of ice flashover of the post insulator, and can effectively guide the maintenance decision of ice flashover defects of the post insulator.

[0041] In step S14, optionally, if the first photon number is greater than the first reference threshold, it is determined that the post insulator is in an ice flashover crisis zone. If the first photon number is less than or equal to the first reference threshold and greater than or equal to the second reference threshold, and the second photon number is greater than or equal to the third reference threshold, it is determined that the post insulator is in an ice flashover warning zone. If the first photon number is less than the second reference threshold, or the first photon number is greater than the second reference threshold and the second photon number is less than the third reference threshold, it is determined that the post insulator is in an ice flashover safety zone. That is, the stable corona photon number α is first determined, and when it is greater than 40,000, it is determined to be an ice flashover crisis zone. When the stable corona photon number α is between 20,000 and 40,000, and the pulse discharge photon number β exceeds 50,000, it is determined to be a warning zone. When the stable corona photon number α is less than 20,000 or greater than 20,000, but the pulse discharge photon number β does not exceed 50,000, it is determined to be a safe zone.

[0042] For the post insulators whose ice flashover risk is judged to be in the critical zone and the warning zone, the corona discharge phenomenon on the surface of the post insulator is obvious, and ice ridges may already exist on the ends or sheds of the post insulators. Ice on the ends of the post insulators will cause more serious local discharge, causing insulation damage to the sheds and reducing their insulation level. The continuous development of ice on the sheds will cause several sheds to be bridged by ice and lose their insulation function, and even cause a short-circuit grounding fault of the post insulator, thereby causing a main transformer tripping accident. The embodiment of the present invention further evaluates the severity of the loss of insulation function of the post insulator due to ice bridging, and the possibility of further growth and development of ice. It is necessary to clarify that the evaluation object is the post insulator that has been judged to be in the ice flashover critical zone and the ice flashover warning zone. In step S15, for the ice flashover warning zone and the ice flashover critical zone, the shed parameters of the post insulator are obtained according to the visible light image, and the corona discharge concentrated area with a first photon number greater than the fourth reference threshold is screened out according to the ultraviolet imaging spectrum, and the first width and the first vertical spacing of the corona discharge concentrated area are determined. The fourth reference threshold is preferably 5000. Specifically, the following feature data are obtained through image preprocessing. The visible light image is preprocessed to obtain the shed parameters of the post insulator. The shed parameters include the number of shed sheets n, the vertical spacing between adjacent sheds h, and the shed width w. The ultraviolet spectrum is preprocessed to screen out the corona discharge concentration area with a photon number greater than 5000, that is, the weaker corona discharge parts with a photon number less than 5000 are ignored. The local corona discharge concentration area is estimated with a rectangular area to obtain the first width w of the area l The first vertical distance h l .

[0043] In step S16, optionally, the ratio of the first width to the shed width is calculated to obtain the ice width ratio, and the ratio of the first vertical spacing to the vertical spacing of adjacent sheds is calculated to obtain the number of ice insulators; if the corona discharge concentration area is located at the shed part of the post insulator, if the number of ice insulators is greater than the fifth reference threshold and the ice width ratio is greater than the sixth reference threshold, it is determined that the corona discharge concentration area has an ice bridging risk; if the corona discharge concentration area is located at the end of the post insulator, if the ice width ratio is greater than the seventh reference threshold, it is determined that the corona discharge concentration area has an ice bridging risk; for the post insulator with an ice bridging risk, the icing morphology of the post insulator is determined according to the meteorological data, and the development speed of the ice bridging risk of the post insulator is evaluated according to the icing morphology and the altitude of the substation to be evaluated. Among them, the fifth reference threshold is preferably 5, the sixth reference threshold is preferably 50%, and the seventh reference threshold is preferably 80%. For example, the ultraviolet spectrum is compared and identified with the visible light image, and the location of the corona discharge concentration area is first determined. If it is located at the skirt of the post insulator, calculate the number of ice insulator pieces N covered by the corona discharge concentration area. l , N l=h l / h, and the ratio of the ice width covered by the corona discharge concentration area γ, γ = w l / w. If the number of ice insulators is greater than 5, and the ice width is greater than 50%, then the risk of ice bridging of the post insulator is judged to be relatively large, that is, the shed of the post insulator has ice with a length that runs through five or more sheds and a width that covers 50% or more of the shed width, and the local insulation of the post insulator is lost due to ice bridging, otherwise the risk of ice bridging is general. If the corona discharge concentration area is located at the end of the post insulator, if the ice width ratio γ is greater than or equal to 80%, then the risk of ice bridging of the post insulator is judged to be relatively large, otherwise it is general. Furthermore, for the post insulators judged to have a relatively large risk of ice bridging, the altitude H of the substation to be evaluated is obtained, and the icing form is obtained according to the meteorological data, including rime, rime and mixed rime. Considering that the higher the altitude, the easier it is to be covered with ice, and the rime form is more likely to form ice bridging. A joint assessment can be made based on the altitude and ice cover form. If the altitude H of the substation to be assessed exceeds 1,300 meters and the ice cover form is rime, then the ice bridging development speed is judged to be relatively fast, otherwise it is normal.

[0044] The embodiment of the present invention establishes a quantitative relationship among the ice flashover risk level, leakage current characteristics and ultraviolet imaging photon number, provides a quantitative criterion for the ice flashover risk assessment of post insulators based on ultraviolet imaging, and simultaneously evaluates the ice bridging risk and ice development speed of the end and shed parts of the post insulator, filling the gap in the current ultraviolet detection defect diagnosis technology for 220 kV post insulators; comprehensively analyzes the data characteristics of the stable corona photon number and the intermittent pulse photon number, conducts a comprehensive analysis and diagnosis of the arc risk on the surface of the post insulator, intuitively and clearly judges the risk of ice bridging to damage the insulation performance of the insulator, and predicts the development speed of ice bridging. The judgment method is comprehensive, logically clear and direct, and has technical advancement, which can provide a technical basis for the equipment operation and maintenance unit to organize the de-icing work of the post insulator in an orderly manner.

[0045] Figure 2 A logic diagram of a post insulator ice flashover risk assessment based on ultraviolet imaging is provided in accordance with an embodiment of the present invention. Figure 2 As shown, including:

[0046] Step 101: Start;

[0047] Step 102: Acquire real-time meteorological data and ultraviolet detection data;

[0048] Step 103: Determine whether there is a flashover risk. If yes, execute step 104; otherwise, jump to execute step 107;

[0049] Step 104: Determine whether the number of stable corona photons α is greater than 40000. If so, determine that the post insulator is a critical area, and then jump to step 107, otherwise, execute step 105;

[0050] Step 105: Determine whether the number of stable corona photons α is greater than 20000. If not, execute step 106. If yes, determine that the post insulator is a safe zone, and then jump to execute step 107;

[0051] Step 106: Determine whether the pulse discharge photon number β is greater than 50000. If so, determine that the post insulator is a warning area, and then execute step 107. Otherwise, determine that the post insulator is a safe area, and then execute step 107;

[0052] Step 107: End.

[0053] In summary, the embodiment of the present invention obtains the icing condition of the post insulators of the substation to be evaluated and the meteorological data of a preset time period in the future, collects the ultraviolet imaging spectrum and visible light image of the post insulators of the substation to be evaluated in the near future; comprehensively considers the icing condition of the post insulators, the ultraviolet imaging spectrum and the meteorological data, and establishes an insulator ledger with the risk of icing flashover; for any post insulator in the insulator ledger, performs data cleaning on the ultraviolet imaging spectrum, and determines the first photon number for the occurrence of stable corona and the second photon number for the occurrence of intermittent pulse discharge according to the ultraviolet imaging spectrum; evaluates the icing flashover risk level of the post insulator according to the first photon number and the second photon number, and if the first photon number is greater than the first reference threshold, it is determined that the post insulator is in the icing flashover critical zone; if the first photon number is less than or equal to the first reference threshold and greater than or equal to the second reference threshold, If the second photon number is greater than or equal to the third reference threshold, the post insulator is determined to be in the ice flashover warning zone; if the first photon number is less than the second reference threshold, or the first photon number is greater than the second reference threshold and the second photon number is less than the third reference threshold, the post insulator is determined to be in the ice flashover safety zone; for the ice flashover warning zone and the ice flashover emergency zone, the shed parameters of the post insulator are obtained according to the visible light image, and the corona discharge concentration area with the first photon number greater than the fourth reference threshold is screened out according to the ultraviolet imaging spectrum, and the first width and the first vertical spacing of the corona discharge concentration area are determined; the ice bridging risk of the corona discharge concentration area of ​​the post insulator is evaluated according to the first width, the first vertical spacing and the shed parameters; the arc risk on the surface of the post insulator can be comprehensively analyzed and diagnosed, filling the gap in the current ultraviolet detection defect diagnosis technology for post insulators. Figure 3 The figure shows a structural diagram of a post insulator ice flashover risk assessment device based on ultraviolet imaging provided by an embodiment of the present invention, the device comprising:

[0054] The data acquisition module 301 is used to obtain the icing condition of the post insulators of the substation to be evaluated and the meteorological data of a preset time period in the future, and collect the ultraviolet imaging spectrum and visible light image of the post insulators of the substation to be evaluated in the near future;

[0055] A ledger establishment module 302 is used to comprehensively consider the icing conditions of the pillar insulators, ultraviolet imaging spectra and meteorological data and establish a ledger of insulators with icing flashover risks;

[0056] The photon number acquisition module 303 is used to perform data cleaning on the ultraviolet imaging spectrum for any post insulator in the insulator ledger, and determine the first photon number for the occurrence of stable corona and the second photon number for the occurrence of intermittent pulse discharge according to the ultraviolet imaging spectrum;

[0057] The risk assessment module 304 is used to assess the ice flashover risk level of the post insulator according to the first photon number and the second photon number. If the first photon number is greater than the first reference threshold, it is determined that the post insulator is in the ice flashover emergency zone; if the first photon number is less than or equal to the first reference threshold and greater than or equal to the second reference threshold, and the second photon number is greater than or equal to the third reference threshold, it is determined that the post insulator is in the ice flashover warning zone; if the first photon number is less than the second reference threshold, or the first photon number is greater than the second reference threshold and the second photon number is less than the third reference threshold, it is determined that the post insulator is in the ice flashover safety zone;

[0058] The concentrated area determination module 305 is used to obtain the shed parameters of the post insulator according to the visible light image for the ice flashover warning area and the ice flashover critical area, screen out the corona discharge concentrated area with the first photon number greater than the fourth reference threshold according to the ultraviolet imaging spectrum, and determine the first width and the first vertical spacing of the corona discharge concentrated area;

[0059] The bridging risk assessment module 306 is used to assess the ice bridging risk of the corona discharge concentration area of ​​the post insulator according to the first width, the first vertical spacing and the shed parameters.

[0060] The device of the above embodiment is applied to the corresponding method in the above embodiment, and has the beneficial effects of the corresponding method embodiment, which will not be described in detail here.

[0061] Figure 4 An example of a physical structure diagram of an electronic device is shown in FIG. Figure 4As shown, the electronic device may include: a processor (processor) 401, a communication interface (Communications Interface) 402, a memory (memory) 403 and a communication bus 404, wherein the processor, the communication interface and the memory communicate with each other through the communication bus. The processor may call the logic instructions in the memory to execute a method for evaluating the risk of ice flashover of post insulators based on ultraviolet imaging, the method comprising: obtaining the ice condition of the post insulators of the substation to be evaluated and the meteorological data of a preset time period in the future, collecting ultraviolet imaging spectra and visible light images of the post insulators of the substation to be evaluated in the near future; comprehensively considering the ice condition of the post insulators, the ultraviolet imaging spectra and the meteorological data and establishing an insulator ledger with the risk of ice flashover; for any post insulator in the insulator ledger, cleaning the ultraviolet imaging spectra, and determining the first photon number of stable corona and the second photon number of intermittent pulse discharge according to the ultraviolet imaging spectra; evaluating the ice flashover risk level of the post insulator according to the first photon number and the second photon number, and if the first photon number is greater than the first reference threshold, determining the post insulator. The post insulator is in an ice flashover emergency zone; if the first photon number is less than or equal to the first reference threshold and greater than or equal to the second reference threshold, and the second photon number is greater than or equal to the third reference threshold, it is determined that the post insulator is in an ice flashover warning zone; if the first photon number is less than the second reference threshold, or the first photon number is greater than the second reference threshold and the second photon number is less than the third reference threshold, it is determined that the post insulator is in an ice flashover safety zone; for the ice flashover warning zone and the ice flashover emergency zone, the shed parameters of the post insulator are obtained according to the visible light image, and the corona discharge concentration area with the first photon number greater than the fourth reference threshold is screened out according to the ultraviolet imaging spectrum, and the first width and the first vertical spacing of the corona discharge concentration area are determined; the ice bridging risk of the corona discharge concentration area of ​​the post insulator is evaluated according to the first width, the first vertical spacing and the shed parameters.

[0062] In addition, the logic instructions in the above-mentioned memory can be implemented in the form of software functional units and can be stored in a computer-readable storage medium when sold or used as an independent product. Based on this understanding, the technical solution of the present invention is essentially or the part that contributes to the prior art or the part of the technical solution can be embodied in the form of a software product, and the computer software product is stored in a storage medium, including several instructions to enable a computer device (which can be a personal computer, server, or network device, etc.) to perform all or part of the steps of the methods of each embodiment of the present invention. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk and other media that can store program codes.

[0063] On the other hand, an embodiment of the present invention further provides a computer program product, which includes a computer program stored on a non-transitory computer-readable storage medium, and the computer program includes program instructions. When the program instructions are executed by a computer, the computer can execute a post insulator icing flashover risk assessment method based on ultraviolet imaging provided by the above-mentioned method embodiments, the method including: obtaining the icing condition of the post insulators of the substation to be evaluated and the meteorological data of a preset time period in the future, collecting ultraviolet imaging maps and visible light images of the post insulators of the substation to be evaluated in the near future; comprehensively considering the icing condition of the post insulators, the ultraviolet imaging maps and the meteorological data, and establishing an insulator ledger with the risk of icing flashover; for any post insulator in the insulator ledger, cleaning the ultraviolet imaging map, and determining the first photon number for the occurrence of stable corona and the second photon number for the occurrence of intermittent pulse discharge according to the ultraviolet imaging map; and determining the first photon number for the occurrence of stable corona and the second photon number for the occurrence of intermittent pulse discharge according to the first photon number and the second photon number. The ice flashover risk level of the post insulator is evaluated according to the number of first photons. If the first photon number is greater than the first reference threshold, it is determined that the post insulator is in the ice flashover crisis zone; if the first photon number is less than or equal to the first reference threshold and greater than or equal to the second reference threshold, and the second photon number is greater than or equal to the third reference threshold, it is determined that the post insulator is in the ice flashover warning zone; if the first photon number is less than the second reference threshold, or the first photon number is greater than the second reference threshold and the second photon number is less than the third reference threshold, it is determined that the post insulator is in the ice flashover safety zone; for the ice flashover warning zone and the ice flashover crisis zone, the shed parameters of the post insulator are obtained according to the visible light image, and the corona discharge concentrated area with the first photon number greater than the fourth reference threshold is screened out according to the ultraviolet imaging spectrum, and the first width and the first vertical spacing of the corona discharge concentrated area are determined; the ice bridging risk of the corona discharge concentrated area of ​​the post insulator is evaluated according to the first width, the first vertical spacing and the shed parameters.

[0064] On the other hand, an embodiment of the present invention further provides a non-transitory computer-readable storage medium having a computer program stored thereon, which is implemented when the processor executes a method for assessing the risk of icing and flashover of post insulators based on ultraviolet imaging provided in the above-mentioned embodiments, the method comprising: obtaining the icing condition of the post insulators of the substation to be assessed and the meteorological data of a preset time period in the future, collecting ultraviolet imaging maps and visible light images of the post insulators of the substation to be assessed in the near future; comprehensively considering the icing condition of the post insulators, the ultraviolet imaging maps and the meteorological data and establishing an insulator ledger with the risk of icing and flashover; for any post insulator in the insulator ledger, performing data cleaning on the ultraviolet imaging map, and determining the first photon number for the occurrence of stable corona and the second photon number for the occurrence of intermittent pulse discharge according to the ultraviolet imaging map; and conducting icing and flashover risk assessment on the post insulators according to the first photon number and the second photon number. Level assessment, if the first photon number is greater than the first reference threshold, it is determined that the post insulator is in the ice flashover crisis zone; if the first photon number is less than or equal to the first reference threshold and greater than or equal to the second reference threshold, and the second photon number is greater than or equal to the third reference threshold, it is determined that the post insulator is in the ice flashover warning zone; if the first photon number is less than the second reference threshold, or the first photon number is greater than the second reference threshold and the second photon number is less than the third reference threshold, it is determined that the post insulator is in the ice flashover safety zone; for the ice flashover warning zone and the ice flashover crisis zone, the shed parameters of the post insulator are obtained according to the visible light image, and the corona discharge concentration area with the first photon number greater than the fourth reference threshold is screened out according to the ultraviolet imaging spectrum, and the first width and the first vertical spacing of the corona discharge concentration area are determined; the ice bridging risk of the corona discharge concentration area of ​​the post insulator is evaluated according to the first width, the first vertical spacing and the shed parameters.

[0065] It should be understood that, although the steps in the flowchart of the accompanying drawings are displayed in sequence as indicated by the arrows, these steps are not necessarily executed in sequence in the order indicated by the arrows. Unless otherwise specified herein, there is no strict order restriction on the execution of these steps, and they can be executed in other orders. Moreover, at least a part of the steps in the flowchart of the accompanying drawings may include multiple sub-steps or multiple stages, and these sub-steps or stages are not necessarily executed at the same time, but can be executed at different times, and their execution order is not necessarily sequential, but can be executed in turn or alternately with other steps or at least a part of the sub-steps or stages of other steps.

[0066] The above is only a partial implementation of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for assessing the risk of ice flashover of post insulators based on ultraviolet imaging, characterized in that: The method comprises: Obtaining the icing conditions of the 220 kV post insulators of the substation to be evaluated and the meteorological data for a preset time period in the future, and collecting the recent ultraviolet imaging spectra and visible light images of the post insulators of the substation to be evaluated; Comprehensively consider the icing condition of the post insulators, the ultraviolet imaging spectrum and the meteorological data and establish a record of insulators with icing flashover risks; For any post insulator in the insulator inventory, data cleaning is performed on the ultraviolet imaging spectrum, and the first photon number for the occurrence of stable corona and the second photon number for the occurrence of intermittent pulse discharge are determined according to the ultraviolet imaging spectrum; An ice flashover risk level assessment is performed on the post insulator according to the first photon number and the second photon number. If the first photon number is greater than a first reference threshold, it is determined that the post insulator is in an ice flashover critical zone; if the first photon number is less than or equal to the first reference threshold and greater than or equal to a second reference threshold, and the second photon number is greater than or equal to a third reference threshold, it is determined that the post insulator is in an ice flashover warning zone; if the first photon number is less than the second reference threshold, or the first photon number is greater than the second reference threshold and the second photon number is less than the third reference threshold, it is determined that the post insulator is in an ice flashover safety zone; For the ice-covered flashover warning area and the ice-covered flashover critical area, the shed parameters of the post insulator are obtained according to the visible light image, and the corona discharge concentration area where the first photon number is greater than the fourth reference threshold is screened out according to the ultraviolet imaging spectrum, and the first width and the first vertical spacing of the corona discharge concentration area are determined; The ice bridging risk of the corona discharge concentration area of ​​the post insulator is evaluated according to the first width, the first vertical spacing, and the shed parameters.

2. The method according to claim 1, characterized in that The method of comprehensively considering the icing condition of the post insulators, the ultraviolet imaging spectrum and the meteorological data and establishing a record of insulators with icing flashover risks includes: Comprehensively considering the icing condition of the post insulator, the ultraviolet imaging spectrum and the meteorological data, determining at least one post insulator with an ice flashover risk; An insulator inventory is constructed by including the models of all the post insulator combinations that have the risk of ice flashover.

3. The method according to claim 1, characterized in that The data cleaning of the ultraviolet imaging spectrum includes: The ultraviolet imaging spectrum is cleaned up to remove data with low reliability.

4. The method according to claim 1, characterized in that The method of determining the first photon number for generating a stable corona and the second photon number for generating an intermittent pulse discharge according to the ultraviolet imaging spectrum comprises: Determine the average value of the number of photons that generate a stable corona according to the ultraviolet imaging spectrum to obtain a corresponding first photon number; Identify the ultraviolet imaging spectrum, extract the spectrum with low image quality and identify whether the post insulator has intermittent pulse discharge phenomenon; An average value of the number of photons occurring in the intermittent pulse discharge is determined to obtain a second photon number.

5. The method according to claim 1, characterized in that Before classifying the ice flashover risk level of the post insulator according to the first photon number and the second photon number, the method includes: The reference threshold for risk assessment of post insulator ice flashover was determined through a simulation test of post insulator ice flashover.

6. The method according to claim 5, characterized in that The reference threshold for risk assessment of post insulator ice flashover is determined by the post insulator ice flashover simulation test, including: In the post insulator ice flashover simulation test, a UV imager is used to monitor the number of UV imaging photons of corona discharge on the surface of the post insulator, and a quantitative relationship between the leakage current and the number of UV imaging photons is determined; According to the characteristics of the leakage current, the flashover risk of the post insulator ice coating is divided into three levels: critical zone, warning zone and safe zone; According to the quantitative relationship between the leakage current and the ultraviolet imaging photon number, the number of stable corona photons entering the critical area is determined as the first reference threshold, and the number of stable corona photons and pulse discharge photons entering the safe area are determined as the second reference threshold and the third reference threshold, respectively.

7. The method according to claim 1, characterized in that The shed parameters include: the number of sheds of the post insulator, the vertical spacing between adjacent sheds, and the shed width; and the step of evaluating the ice bridging risk of the corona discharge concentration area of ​​the post insulator according to the first width, the first vertical spacing, and the shed parameters includes: The ratio of the first width to the shed width is calculated to obtain the ice width ratio, and the ratio of the first vertical spacing to the vertical spacing of adjacent sheds is calculated to obtain the number of ice insulator pieces; If the corona discharge concentration area is located at the shed part of the post insulator, if the number of ice insulators is greater than the fifth reference threshold and the ice width ratio is greater than the sixth reference threshold, it is determined that there is an ice bridging risk in the corona discharge concentration area; If the corona discharge concentration area is located at the end of the post insulator, and if the ice width ratio is greater than a seventh reference threshold, it is determined that there is an ice bridging risk in the corona discharge concentration area; For the post insulators with ice bridging risks, the ice coating forms of the post insulators are determined based on the meteorological data, and the development speed of the ice bridging risks of the post insulators is evaluated based on the ice coating forms and the altitude of the substation to be evaluated.

8. A post insulator ice flashover risk assessment device based on ultraviolet imaging, characterized in that: The device comprises: A data acquisition module is used to obtain the icing conditions of the 220 kV post insulators of the substation to be evaluated and the meteorological data of a preset time period in the future, and to collect ultraviolet imaging spectra and visible light images of the post insulators of the substation to be evaluated in the near future; A ledger establishment module, used to comprehensively consider the icing condition of the post insulators, the ultraviolet imaging spectrum and the meteorological data and establish a ledger of insulators with icing flashover risks; A photon number acquisition module, for cleaning the data of the ultraviolet imaging spectrum for any post insulator in the insulator ledger, and determining the first photon number for the occurrence of stable corona and the second photon number for the occurrence of intermittent pulse discharge according to the ultraviolet imaging spectrum; a risk assessment module, configured to assess the ice flashover risk level of the post insulator according to the first photon number and the second photon number, and if the first photon number is greater than a first reference threshold, determine that the post insulator is in an ice flashover emergency zone; if the first photon number is less than or equal to the first reference threshold and greater than or equal to a second reference threshold, and the second photon number is greater than or equal to a third reference threshold, determine that the post insulator is in an ice flashover warning zone; if the first photon number is less than the second reference threshold, or the first photon number is greater than the second reference threshold and the second photon number is less than the third reference threshold, determine that the post insulator is in an ice flashover safety zone; a concentrated area determination module, for obtaining the shed parameters of the post insulator according to the visible light image for the ice flashover warning area and the ice flashover emergency area, screening out the corona discharge concentrated area where the first photon number is greater than a fourth reference threshold according to the ultraviolet imaging spectrum, and determining the first width and the first vertical spacing of the corona discharge concentrated area; The bridging risk assessment module is used to assess the ice bridging risk of the corona discharge concentration area of ​​the post insulator according to the first width, the first vertical spacing and the shed parameters.

9. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that: When the processor executes the program, the method according to any one of claims 1 to 7 is implemented.

10. A non-transitory computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the method according to any one of claims 1 to 7 is implemented.

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