74 results about "Flashover voltage" patented technology

The invention discloses a simple and efficient glass fiber fabric surface fluorination method, and belongs to the technical field of glass fiber fabric surface structure regulation and control. The fluorination method for the surface of the glass fiber fabric comprises the following steps: sequentially dipping glass fibers in a dopamine hydrochloride solution and a fluorine-containing silane coupling agent solution to obtain modified glass fibers. Firstly, polydopamine (PDA) is used for treating the surface of the fiber, then a fluorine-containing silane coupling agent is used for conducting structural design on the surface of the glass fiber, and comprehensive improvement of the interface bonding strength and the insulating property of the glass fiber epoxy resin composite material is achieved. The surface flashover voltage and the breakdown field strength of the composite material provided by the invention are remarkably improved, the treatment method is simple and convenient, and industrial batch preparation of the high-performance composite material can be realized.

The invention belongs to the technical field of electrical experiments, and particularly relates to an insulating material charge accumulation and flashover device and method under different tangent and normal electric fields, an insulating sample wafer of the device is arranged on a surface flashover assembly, and the surface flashover assembly is provided with an electrode assembly with an adjustable inclination angle; a lower plate electrode is arranged in the middle of an insulating support, a supporting rod assembly vertically penetrates through a middle through hole of the lower plate electrode to make contact with a polytetrafluoroethylene insulating plate, an insulating sample piece is arranged above the polytetrafluoroethylene insulating plate, the polytetrafluoroethylene insulating plate is hinged to the lower plate electrode, and the lower end of the supporting rod assembly is connected with a rotary driving mechanism. The rotary driving mechanism drives the supporting rod assembly to move to incline the insulating sample, and the lifting driving mechanism drives the supporting rod assembly to vertically move to enable the insulating sample to be in contact with the electrode assembly; the device has the capabilities of charge injection and charge measurement of the insulation sample wafer and measurement of flashover voltage and initial voltage along the surface of the insulation material under different tangential and normal electric fields.

The invention relates to an environment-friendly polypropylene composite material applied to a direct-current cable and a preparation method of the environment-friendly polypropylene composite material. The material comprises atactic polypropylene, a styrene-ethylene-butylene-styrene block copolymer (SEBS), a grafted nano inorganic oxide and an antioxidant. The preparation method comprises the following steps: grafting an elastomer styrene-butadiene-styrene copolymer (SBS) to a nano inorganic oxide through a ball-milling mechanochemical method, and blending the nano inorganic oxide with a polypropylene random copolymer and SEBS to prepare the PP composite material applied to the direct-current cable material. The PP composite material is characterized in that the PP composite material with better low-temperature toughness, higher direct-current breakdown strength and higher flashover voltage is prepared by using an environment-friendly and efficient modification method, and the requirements of direct-current cable application scenes are better met.

The invention relates to the technical field of high-voltage engineering and insulation, in particular to an artificial pollution test method in a high-voltage environment, which comprises the following steps of: firstly, constructing a target deposition distribution function and a target response set on a parameterized grid on the surface of an insulator, and combining environment boundary condition time sequence sets to form a target deposition and response data set; layered deposition of soluble pollutants and insoluble particles is carried out in a power-on state through an electrode system time-varying electric field and particle charge control, and a surface state field is collected to generate an in-situ deposition state data set. Electrical and surface responses are obtained according to segmented loading and stepped flashover tests, and a median flashover voltage is estimated, so that an electrical and physical response data set is formed; and finally, carrying out closed-loop optimization on the time-varying trajectory, the environment program and the deposition spectrum shape of the electrode system based on the dynamic model within the leakage current constraint. According to the method, configuration reproducibility, threshold estimation stability and test rapid convergence are realized.

The invention relates to the field of semiconductor ceramic preparation, in particular to tin-antimony gradient doped insulating semiconductor glaze and a low-temperature sintering process thereof. The gradient change of the element doping amount per unit volume from the inner layer to the surface layer of the glaze layer is formed through different treatment processes of the tin-antimony solid solution, and compared with traditional uniform doping, the surface electric field distortion rate can be effectively reduced, and the surface pollution flashover voltage can be improved. According to the invention, a composite fluxing agent system is adopted, the sintering temperature is reduced, segmented differential atmosphere sintering is adopted to ensure the structural compactness of the glaze layer, excessive loss of doped elements at high temperature is avoided, and the overall performance of the glaze layer is improved. According to the invention, the surface photocatalytic material is doped and forms a heterojunction structure with the internal doped material after sintering, so that relatively strong surface light cleaning performance is formed, and the probability of pollution flashover is reduced.

The present invention provides a nonlinear material gradient coating method for improving surface flashover of insulators, belonging to the technical field of high-voltage insulation materials. For pot-type insulators, a nonlinear material SiC is used as a coating material. SiC is added to epoxy resin at different mass fractions as a coating layer and coated on the pot-type insulator surface. The electric field distribution on the insulator surface is simulated using Comsol software. Subsequently, by varying the number, thickness, and height of the coating layer, the electric field distribution patterns of the number, thickness, and height of the coating layer on the insulator surface are summarized. Finally, a coating layer with three layers, a thickness of 0.5 mm, and a non-uniform height distribution (1.1 mm, 2.8 mm, and 11.1 mm) is selected, thus determining the nonlinear material gradient coating method for improving surface flashover of insulators. The present invention uses the above-mentioned nonlinear material gradient coating method for improving surface flashover of insulators to improve the DC surface flashover voltage of pot-type insulators in SF6 atmosphere. The coating method is low in difficulty and highly operable.

The embodiment of the invention discloses an insulator pollution flashover test method considering the property of a pollution source, and the method comprises the steps: carrying out the pollution treatment of a sample insulator according to the property of the pollution source, and obtaining a test insulator; arranging the test object insulator and a test environment thereof; applying low voltage and steam mist to the test object insulator to enable the test object insulator to reach a saturated wet state; according to the method, a pollution test is carried out on the test object insulator by adopting a gradually-decreasing constant voltage method to obtain the flashover voltage of the test object insulator, the test object insulator can be smeared in a targeted manner according to the pollution source property of a certain area, and then the flashover voltage is obtained through the test, so that the representativeness and typicality of the test are improved, and more accurate test data are obtained; and guidance is provided for insulation configuration and operation maintenance of the power transmission line in the region.

The invention discloses a GIS insulator charge accumulation and surface flashover prevention composite structure based on surface microstructure regulation and control. The structure is characterized in that a honeycomb microstructure is arranged on the surface of an insulator; the microstructure is a submicron order periodic array; the microstructure is coated with a functional insulating coating, and the coating comprises an insulating matrix and a nano filler; the preparation of the composite structure comprises the steps of surface pretreatment, microstructure preparation, coating spraying and thermocuring. Through the synergistic effect of the submicron honeycomb microstructure and the functional insulating coating, charge accumulation is inhibited in an environment-friendly gas environment, and the flashover voltage is increased.

The application discloses an air insulation structure verification method and device based on surface flashover voltage calculation, a terminal equipment and a storage medium, and belongs to the technical field of voltage testing. The method comprises the following steps: obtaining an original structure parameter set; establishing a three-dimensional model according to the original structure parameter set; performing steady-state simulation on the three-dimensional model to obtain an initial electric field distribution; correcting the initial electric field distribution according to surface roughness to obtain a first corrected electric field distribution; performing transient simulation on the three-dimensional model to obtain a surface charge density distribution; correcting the first corrected electric field distribution according to the surface charge density distribution to obtain a second corrected electric field distribution; accumulating the volume with a second corrected electric field value not less than a preset gas critical ionization field strength to obtain a critical volume; and calculating the surface flashover voltage based on the critical volume, and verifying the original insulation structure according to the surface flashover voltage. Therefore, by implementing the application, the problem of inaccurate surface flashover voltage calculation in the prior art can be solved.

The application discloses a high-speed rail roof insulator surface flashover voltage prediction method, medium and system, comprising the following steps: obtaining a first simulation value of airflow parameters on the surface of an insulator based on a preset value of airflow parameters in front of the high-speed rail roof insulator through a simulation experiment; obtaining an experimental value of the surface flashover voltage of the insulator under an airflow environment based on the preset value and the first simulation value of the airflow parameters through a wind tunnel experiment; training a prediction neural network by using the preset value of the airflow parameters, the first simulation value of the airflow parameters and the experimental value of the flashover voltage; obtaining a second simulation value of the airflow parameters on the surface of the insulator based on a measured value of the airflow parameters in front of the insulator through a simulation experiment; and inputting the measured value of the airflow parameters in front of the insulator and the second simulation value of the airflow parameters on the surface into the trained prediction neural network to output a prediction value of the surface flashover voltage of the high-speed rail roof insulator. The application can realize the prediction of the surface flashover voltage of the high-speed rail roof insulator under strong airflow.

An anti-pollution flashover type sleeve belongs to the technical field of sleeves for transformer substations and comprises an upper-end metal accessory, an upper-end cement adhesive layer, a porcelain piece and a semiconductor glaze layer. A plurality of first umbrellas are integrally arranged above the outer side of the porcelain piece, and a plurality of second umbrellas are integrally arranged below the outer side of The surface of the first umbrella is provided with a semiconductor glaze layer. The surface of the second umbrella is provided with an electric porcelain glaze layer. The first umbrella with a large diameter is arranged to be an umbrella with a larger diameter, so that the rain-proof and icing-proof capabilities of the sleeve can be improved; and meanwhile, the creepage distance and the large umbrella surface area are increased, and the specific capacitance of the first umbrella porcelain surface is reduced, so that the gliding lightning voltage of the sleeve is improved. The semiconductor glaze is applied to improve the electric field distribution around the high-voltage metal accessory at the upper end, so that the discharge is not easy to develop, and the flashover voltage and the corona initial voltage are improved. The surface temperature of the porcelain is increased by 1-5 DEG C higher than the ambient temperature, so that a dirt layer absorbing moisture and dust can be dried, ice melting is promoted, ice flashover is prevented, and the purpose of pollution flashover prevention is achieved.

The invention provides a branched chain polycarboxylic acid mixture and a preparation method and application thereof, and belongs to the field of electrolyte for aluminum electrolytic capacitors. The electrolyte consisting of the ammonium salt of the branched chain polycarboxylic acid mixture has the characteristics of excellent low-temperature conductivity and high sparking voltage, and has a relatively good application prospect in the field of aluminum electrolytic capacitors.

The application relates to the technical field of electrolyte, and discloses an electrolyte for high-conductivity high-water-content wide-temperature-range aluminum electrolytic capacitors and a preparation method thereof, which comprises main solutes 5-20%, auxiliary solutes 0.5-5%, solvents 50-90% and additives 0.5-10% in percentage by mass. The electrolyte prepared by the application has a conductivity of 38 ms / cm, a water content of not less than 40%, and a flashover voltage of 210 V. The electrolyte of the application can effectively reduce the vapor pressure of the electrolyte, inhibit gas generation, reduce the internal pressure of the capacitor and improve the high-temperature performance of the electrolyte through the cooperation between raw materials. The electrolyte of the application has stable high-temperature performance, a wide use temperature range and high oxidation efficiency, and the aluminum electrolytic capacitor assembled by using the electrolyte can be reliably and continuously operated for more than 3000 hours under the environment of-40 DEG C to +105 DEG C.

The present application belongs to the field of direct current transmission, and particularly relates to a support insulator, an insulating support structure and a direct current GIL. In order to solve the technical problem that the electric field lines pass through the support insulator in the prior art, resulting in that the normal field intensity of the side surface of the support insulator is too large, the present application provides a support insulator, which comprises a high-potential support surface for supporting a conductive rod, a low-potential support surface for supporting an insulating cylinder and a side surface, the high-potential support surface and the low-potential support surface are both arc surfaces, the axis of the high-potential support surface and the low-potential support surface corresponds to the axis of the matched conductive rod, and the extension line of the projection of the side surface of the support insulator in the direction of the axis of the corresponding conductive rod intersects with the axis of the conductive rod. The present application further provides an insulating support structure and a direct current GIL using the support insulator. By making the electric field lines parallel to the side surface of the support insulator, the normal field intensity of the side surface of the support insulator can be reduced, and the surface flashover voltage and the insulating strength of the support insulator can be improved.

The present invention relates to the technical field of power equipment monitoring and diagnosis, and specifically to a method for calculating the flashover voltage of a composite insulator under heavy pollution conditions. The method comprises inputting initial parameters into a target pollution flash circuit model to calculate the arc root radius; calculating the target residual pollution layer resistance based on the arc root radius, and calculating the initial arc current based on the Newton secant method; calculating the pollution layer voltage gradient and arc voltage gradient based on the initial arc current; determining whether flashover has occurred based on the initial local arc length and the insulator creepage length; and, if flashover has not occurred, correspondingly increasing the initial local arc length or the initial applied voltage based on the magnitude of the pollution layer voltage gradient and the arc voltage gradient until the pollution flashover voltage is calculated when flashover occurs. The present invention implements the calculation of the flashover voltage of a composite insulator under heavy pollution conditions and has excellent application prospects.

According to the power distribution network risk assessment method under the lightning and rainstorm composite disaster based on the blind number theory, the influence of rainfall intensity on the insulation flashover voltage of the power distribution line is considered to construct the power distribution line fault probability model, and the influence of rainfall intensity on the insulation margin of the fan blade is considered to construct the fan fault probability model; constructing a transformer fault probability model; selecting a typical fault scene of the power distribution network under the lightning and rainstorm composite disaster by adopting an information entropy method; respectively representing the load loss rate, the distribution line heavy load proportion, the transformer heavy load proportion and the node voltage out-of-limit proportion as different blind numbers, calculating the risk measurement of each risk assessment index through the expectation operation of the blind numbers, and then synthesizing the weights of different risk assessment indexes to calculate the fusion value of the power distribution network risk assessment indexes. And determining the risk level of the power distribution network. According to the invention, the accuracy and comprehensiveness of power distribution network risk assessment under lightning and rainstorm composite disasters can be improved.

The invention belongs to the technical field of ceramic materials, and particularly relates to a large-size special-shaped silicon nitride-based ceramic support column and a preparation method and application thereof. The large-size special-shaped silicon nitride-based ceramic pillar is prepared from the following basic raw materials in percentage by mass: 70-85% of industrial alumina powder, 2-3.5% of a sintering aid, 2-5% of washed clay, 5-20% of micron silicon nitride powder, 3-5% of a nano filler, an additional dopant accounting for 0.1-0.6% of the mass of the basic raw materials, a water reducing agent accounting for 0.2-0.3% of the mass of the basic raw materials and 31-35% of the mass of the basic raw materials, the washed clay is clay which is dried after washing treatment. The silicon nitride-based ceramic pillar prepared by the invention is high in surface flashover voltage, low in dielectric loss and dielectric constant and high in electric breakdown resistance, and can be used as an internal insulation pillar of power equipment.

The embodiment of the invention relates to a structural data determination method and device for an umbrella skirt damage insulator, equipment and a medium. The method comprises the steps that umbrella skirt damage data of a current insulator and insulation attribute data of a complete insulator corresponding to the current insulator are acquired; determining a first relation function, a second relation function and a third relation function corresponding to the umbrella skirt damage data; wherein the first relation function represents the relation between the pollution flashover voltage and the creepage distance, the second relation function represents the relation between the grading ring field intensity and the grading ring pipe diameter, and the third relation function represents the relation between the umbrella skirt field intensity and the cover depth; and determining improved structure data corresponding to the current insulator according to the insulation attribute data, the first relation function, the second relation function and the third relation function. Therefore, the insulation characteristic of the insulator still meets the required insulation effect after the umbrella skirt is damaged.

The invention provides a gas-phase fluorination regulation and control method for synchronously improving internal and external insulating properties of an extra-high-voltage direct-current wall bushing, and relates to the technical field of power transmission and transformation equipment of a power system. According to the method, the electric-thermal-mechanical coupled multi-physical field simulation model is established, iteration with experimental data is carried out, the fluorination reaction rate of the surface of the epoxy resin core rod and the fluorination layer thickness of the silicone rubber outer insulation layer are synchronously regulated and controlled by adopting a collaborative fluorination process, and the gas-solid interface breakdown voltage and the outer insulation surface flashover gradient of the sleeve are respectively improved by about 20% and 25%. Experiment and simulation results show that the method can effectively regulate and control gas-solid interface charge distribution, inhibit electric field distortion and improve surface flashover voltage; the direct fluorination treatment obviously enhances the breakdown strength and surface flashover tolerance of the high polymer material, obviously improves the overall insulation performance of the bushing under the extra-high voltage direct current working condition, and solves the technical problem of synchronous improvement of the internal and external insulation performance of the extra-high voltage wall bushing.

The invention provides an alternating current flashover voltage prediction method and a terminal, and the method comprises the steps: calculating an initial value of each circuit parameter according to a simulation parameter and an equivalent circuit, and recalculating a new leakage current under the initial value of the circuit parameter through employing an obtained result; the development of the local electric arc is distinguished by utilizing the electric arc development criterion; if the electric arc development criterion is met, the electric arc development speed is calculated, the electric arc length is updated, the circuit parameters and the leakage current value are updated, and then the alternating-current electric arc reignition condition is judged; and the steps are continuously and circularly repeated until the arc penetrating condition is met, and the corresponding first voltage is the predicted value of the flashover voltage. The method can consider the influence of the environment temperature, the water band resistance and other factors on each parameter in the dynamic development process of the alternating-current arc, and can predict the alternating-current flashover voltage in the wet and dirty scene more simply, efficiently and accurately.

The invention discloses a ceramic vacuum insulator with a three-dimensional microstructure on the surface and a preparation method of the ceramic vacuum insulator, and solves the technical problems that an existing modified ceramic insulator cannot be used in a high-temperature environment, and an existing vacuum surface flashover voltage boosting method is limited in application range, high in equipment requirement, complex in operation and the like. The ceramic vacuum insulator comprises a ceramic vacuum insulator base body and a three-dimensional microstructure coating the surface of the ceramic vacuum insulator base body, the three-dimensional microstructure is formed by interweaving micron wires in a three-dimensional space on the surface of the ceramic vacuum insulator substrate; and the micro-wire adopts a polymethylsiloxane micro-wire of which the surface is subjected to high-temperature ceramic treatment. The three-dimensional micro-structure can improve the vacuum surface voltage withstanding level of the insulator, and after high-temperature ceramization, the insulator with the three-dimensional micro-wire structure on the surface can be applied to the high-temperature environment of 800 DEG C or below and has the high-temperature insulation characteristic, so that the application range of the ceramic vacuum insulator is widened.

The application provides a lightning storm composite disaster-based distribution network risk assessment method based on blind number theory, considers the influence of rainfall intensity on the insulation flashover voltage of the distribution line to construct a distribution line fault probability model, considers the influence of rainfall intensity on the insulation margin of the fan blade to construct a fan fault probability model, and constructs a transformer fault probability model; the information entropy method is used to select a typical fault scene of the distribution network under the lightning storm composite disaster; the loss of load rate, the heavy load proportion of the distribution line, the heavy load proportion of the transformer and the node voltage out-of-limit proportion are respectively expressed as different blind numbers, the risk measurement of each risk assessment index is calculated through the expectation operation of the blind numbers, the weight of different risk assessment indexes is comprehensively considered, the fusion value of the distribution network risk assessment index is calculated, and the risk grade of the distribution network is determined. The application can improve the accuracy and comprehensiveness of the distribution network risk assessment under the lightning storm composite disaster.

According to the insulation protection device of the antenna feed tube current inductor, the upper small corrugated section, the middle smooth section and the lower large corrugated section are arranged on the insulation sleeve, the smooth surface of the upper corrugated section and the smooth surface of the lower large corrugated section are changed into the surfaces of the wave structures, the surface flashover length of the insulation sleeve is increased, and when the discharge distances are the same, the flashover length of the insulation sleeve is increased; the surface flashover voltage is lower than the breakdown voltage of a pure air gap, air breakdown does not occur firstly between the inner walls of the wave surfaces, surface flashover occurs on the inner edges of the wave surfaces, and the surface flashover voltage of the insulation sleeve can be remarkably increased by increasing the surface discharge length of the surface of the insulation sleeve; and the lower large corrugated section can also overcome the electric field distortion and point discharge danger caused by the electric field intensity generated after the electric part at the bottom of the base is electrified. And the middle smooth section and the current inductor are arranged at intervals, so that the voltage monitoring performance is improved, the surface of the insulating sleeve is convenient to clean, and the problem of pollution discharge caused by long-time use is solved.

The application discloses a method for preparing a composite material by loading nanometer particles on a fiber and filling an epoxy resin and application thereof. The method is characterized by the following steps: a semiconductor nanometer particle SiC is loaded on a filler network structure of a glass fiber fabric surface; and a plasma treatment technology is combined to activate the fiber surface, so that a stable and efficient fiber loading nanometer particle structure preparation is realized. Based on the structure, an epoxy resin is infiltrated to obtain a composite material. In the composite material, the nanometer SiC particles can be used as a connecting point to form a charge dissipation path, so that the surface charge dissipation rate of the material is obviously improved, and thus the surface flashover voltage of the material is improved.

This invention discloses a rapid prediction method for insulator surface flashover voltage considering microscopic surface collisions, achieving a balance between computational efficiency and microscopic physical accuracy. The method innovatively maps the macroscopic roughness of the insulator to the collision restitution coefficient (characterizing kinetic energy dissipation), local electric field enhancement factor (characterizing microscopic distortion), and diffuse reflection distribution model of microscopic particles. Under electric field driving, particle trajectories are iteratively calculated, and velocity reduction and local field strength correction are performed based on the aforementioned dual competition mechanism when particles collide with the interface. Finally, the effective ionization coefficient is integrated in the time domain with velocity weight along the microscopic trajectory, and the flashover voltage is iteratively output by comparing it with the streamer critical criterion. This method, by introducing a particle tracking mechanism, maps macroscopic surface roughness to microscopic collision restitution coefficients and diffuse reflection distribution, and proposes a time-domain integration model, achieving efficient and accurate prediction of flashover voltage.

The electrolyte of the aluminum electrolytic capacitor comprises 50-80 parts by weight of a solvent, 10-40 parts by weight of a solute, 5-20 parts by weight of a sparking voltage boosting agent and 1-10 parts by weight of an additive, and the additive comprises ammonium dihydrogen phosphate or a mixture of ammonium dihydrogen phosphate and 24-carbon multi-branched chain ammonium tetracarboxylate. After the ammonium dihydrogen phosphate and the 24-carbon multi-branch chain ammonium tetracarboxylate are added into the electrolyte, the ammonium dihydrogen phosphate and the 24-carbon multi-branch chain ammonium tetracarboxylate can form an organic matter-inorganic matter composite adsorption layer; ammonium dihydrogen phosphate can prevent a large number of holes from being formed in a generated oxidation film; the 24-carbon multi-branched chain ammonium tetrapolycarboxylate can be further adsorbed to positions with relatively high energy, such as micro cracks and hole edges on the surface of the oxidation film; therefore, a layer of compact protective film is formed, and a stable interface environment is created for repairing the oxidation film; the oxide film repaired by the electrolyte is continuous and compact; therefore, the leakage current performance of the aluminum electrolytic capacitor is improved.

This invention provides a method for predicting surface flashover voltage in a perfluoroisobutyronitrile (PFOS) mixed gas based on plasma dynamics. It comprehensively considers the effects of gas molecule desorption and collisional ionization, surface charge accumulation at the gas-solid interface, and carrier traps in the solid medium on the solid side. A surface flashover model is constructed, and by solving the continuity governing equations, Poisson's equation, and local field approximation equations for charged particles, the spatiotemporal distribution of the electric field intensity and the transport of charged particles in space are obtained, serving as a means to predict the surface flashover voltage. This invention not only predicts surface flashover voltage but also holds promise as a data reference for the development of environmentally friendly insulating gas equipment, saving experimental costs and improving R&D efficiency.

The invention discloses a composite insulator silicone rubber material service life evaluation method based on alkaline hydrolysis simulation aging, and belongs to the technical field of insulator aging detection.The method comprises the steps that a sample test is conducted on an artificial simulation aging sample to obtain test data, and aging indexes are extracted from the test data; the aging indexes comprise the infrared spectrum peak area, the high oxygen state Si atom content, the ATH proportion, the crosslinking density, the elongation at break, the flashover voltage, the trap density and the dielectric relaxation intensity; according to the aging indexes, the life of the natural aging sample and the life of the artificial simulation aging sample are comprehensively evaluated by using an HTV-SR life evaluation method, the predicted life of the natural aging sample and the predicted life of the artificial simulation aging sample are respectively obtained, an efficient and reliable solution is provided for life evaluation of the HTV-SR material, and the HTV-SR life evaluation method has both scientific preciseness and engineering practicability.

The invention provides a method for predicting lower surface flashover voltage of perfluoroisobutyronitrile mixed gas based on plasma dynamics, which comprises the following steps of: constructing a surface flashover model by comprehensively considering the influence of desorption and collision ionization of gas molecules related to a gas side, charge accumulation on the surface of a gas-solid interface and a carrier trap existing in a solid medium on a solid side; by solving a continuity control equation, a Poisson equation and a local field approximation equation of the charged particles, the spatial and temporal distribution condition of the electric field intensity and the transport condition of the charged particles in the space are obtained as a means for predicting the surface flashover voltage. The method not only can predict the surface flashover voltage, but also is expected to serve as data reference for research and development of environment-friendly insulating gas equipment, test cost is saved, and research and development efficiency is improved.

The invention provides an insulating oil-based composite material, a preparation method and application thereof, and an oil-paper composite insulating product, and belongs to the technical field of insulating materials. The insulating oil-based composite material comprises a base solution and an alpha-linolenic acid grafted and modified nano inorganic material, the base solution comprises ester insulating oil, and the ester insulating oil comprises triglyceride. The alpha-linolenic acid grafted and modified nano inorganic material is prepared by modifying the nano inorganic material with the alpha-linolenic acid, and long-chain alkyl of the alpha-linolenic acid on the surface of the nano inorganic material is combined with ester insulating oil molecules through Van der Waals' force, so that agglomeration of the nano inorganic material is reduced; the dispersity and compatibility of nanoparticles in the insulating oil-based composite material are improved, and the interface charge accumulation is reduced, so that the flashover voltage is increased, and the insulating property of an insulating material system is improved. The oil-paper composite insulation product is prepared by combining the insulation oil-based composite material and an insulation paperboard, so that the surface flashover performance of the oil-paper composite insulation product is further improved.