249 results about "Flashover voltage" patented technology

The contamination level estimation method for high voltage insulators collects samples of naturally contaminated insulators and builds an image data set for the collected insulators. Flashover voltages of several insulators samples are measured. ESDD levels of the collected insulators are estimated. Images are input to image processing algorithms to extract representative features. The images are segmented. Transforming the image from RGB color space into grayscale model excludes the background from the image. Subsequently, the segmented images are transferred back to RGB color space model using matrix manipulation. Since contaminants on the insulator surface affect the color of the insulator, the segmented image is transformed from RGB to HSV color space which is used for extracting statistical and linear algebraic features from the hue image. A trained artificial neural network correlates the extracted features to the contamination levels enabling testing of other contaminated insulators.

The invention provides a multi-dimensional parameter assessment method of an aging degree of a running composite insulator. The method comprises the following steps: firstly measuring hardness, hydrophobicity, a surface defect area, an infrared absorption peak corresponding to a Si-O-Si group, a trap charge amount and a flashover voltage of a high-temperature vulcanized silicone rubber test sample of an umbrella skirt of a target composite insulator; then performing quantitative processing on the measured data, and scoring the aging degrees of the processed feature parameters; performing weighted summation on the scores of the feature parameters to obtain a comprehensive feature parameter characterizing the aging degree of the composite insulator; and finally determining the aging degree of the insulator according to a corresponding relation between the size of the comprehensive feature parameter and the grade of the aging degree. According to the multi-dimensional parameter assessment method provided by the invention, the microscopic electrical characteristics and microscopic physical and chemical characteristics of the umbrella skirt material of the composite insulator are combined with macroscopic characteristics to realize the comprehensive assessment of the aging degree of the composite insulator. By adoption of the method, the one-sidedness of the traditional assessment method is avoided, and thus the accuracy of an assessment result is guaranteed.

The invention relates to a lightning protection and especially relates to a 10-35kV overhead transmission line constraint space injection gas arc extinguishing lightning protection gap apparatus which is suitable for a 10-35kV overhead transmission line. The apparatus is installed in parallel on two ends of a line insulator string to protect a flash-over voltage between gaps to be less than the voltage of a protected insulator string so that the apparatus is punctured prior to the protected insulator string when the power transmission line is suffered from lightning stroke. During disruptive discharging, a signal acquisition device automatically senses a lightning current signal and triggers a high speed injection gas generation apparatus. A high speed injection air flow is instantly generated so as to carry out great impact on a follow current arc in a constraint space along a vertical direction, and carry out cooling till the arc is quenched. According to the invention, a structure is simple, installation and maintenance are convenient. Through using the apparatus of the invention, when the line is suffered from the lightning stroke, a lightning current can be rapidly led to the ground and simultaneously a high speed airflow quenching power frequency follow current is generated so that electric equipment can be effectively protected and power supply reliability is increased.

This invention relates to a vacuum isolation sub-coating and its process to improve the surface flashover voltage, wherein, the coating is composed of epoxide resin, aluminum hydroxide, modified synthesized amine firming agent, butyl epihydrin aether thinner. The process comprises the steps of materials, bacon, vacuum, mixture, heating and solidifying and cooling and demoulding Comparing with current material, the coating in this invention has higher surface flashover voltage and high flash burn endurance.

The invention discloses an intelligent detection method and a detection system device for a contaminated insulator and belongs to the technical field of contaminated insulator performance detection of a high-voltage transmission line. The method comprises the following steps of: hanging the detected contaminated insulator in an artificial fog room; adjusting a test power supply device so that a test program is adjusted to a working state; when an ultrasonic fog generator of the artificial fog room is started to fog to a saturated damping state, continuously increasing test voltage until the detected contaminated insulator is in a flashover state; acquiring the flashover voltage value by a data acquiring card; sending the flashover voltage value to an expert system, comparing the flashover voltage value with historical data in the expert system, and analyzing the data; and judging whether the detected contaminated insulator is safe or not. By the method and the device, the problems of poor accuracy of the test data and high investment of insulator string pollution flashover voltage test equipment in the prior art are solved, the external insulating level and the reliability of safe running of an insulator string are accurately judged, the probability of pollution flashover accidents is effectively reduced, and enormous indirect economic benefit is brought.

The invention designs a numerical weather prediction-based early warning method for windage yaw flashover of a power transmission line. The method comprises the steps of firstly, performing grid point forecast wind velocity mapping processing by adopting an inverse distance weighted interpolation algorithm, and finishing a wind velocity component perpendicular to the line according to an included angle between a wind direction and a line route; secondly, calculating a minimum air gap between the line and a pole tower by applying a rigid straight bar method by taking a typical cup tower as an example; and finally, performing air density, humidity and precipitation correction on a gap breakdown voltage to obtain a flashover voltage value under a forecast weather condition, and comparing the flashover voltage with a system running voltage to finish graded early warning of the windage yaw flashover. The method has an important practical significance for wind prevention and disaster reduction work of a power grid.

The invention discloses an evaluation method for an insulator icing flashover risk of an ultrahigh voltage alternating-current transmission line. The method comprises: S1, carrying out meteorological and line basic data collection; S2, carrying out determination of an insulator icing flashover initial condition; S3, carrying out insulator icing flashover voltage calculation; and S4, carrying out insulator icing flashover risk evaluation. According to the invention, on the basis of the real-time meteorological data, an insulator icing flashover risk is evaluated by combining basic data of the ultrahigh voltage alternating-current transmission line and the powerful guidance can be provided for disaster prevention and reduction of the power grid operation management department. The method can be realized simply with high feasibility; and the prediction result has the high reference value.

The invention belongs to the technical field of electrical insulating materials, and relates to an extremely effective method for inhibiting the accumulation of surface charge of epoxy resin and composite materials thereof. The method comprises the following step that the epoxy resin and the composite materials thereof are subject to gas phase fluorination treatment in a closed reaction chamber. The method disclosed by the invention is applied to the inhibition of the accumulation of the surface charge of electrical insulating pieces of the epoxy resin and the composite materials thereof, so as to improve the flashover voltages and the electrical insulating performance of the electrical insulating pieces, such as epoxy insulating supports and epoxy insulators of the epoxy resin and the composite materials thereof, and static electricity resistance of the epoxy resin and the composite materials thereof when the epoxy resin and the composite materials thereof are used in other aspects.

A test method for a spark plug ceramic insulator includes placing a first electrode in an inner hole of the ceramic insulator and placing a second electrode on an outer peripheral side of the ceramic insulator, developing a defect in the ceramic insulator by the application of a first voltage onto the ceramic insulator between the first and second electrodes and detecting the defect in the ceramic insulator by the application of a second voltage, which is lower than a flashover voltage that causes a flashover of the ceramic insulator, onto the ceramic insulator between the first and second electrodes.

The invention discloses a method for predicting a flashover voltage by using a surface conductivity and a leakage current. A surface conductivity of an insulator is measured; by using the surface conductivity of the insulator as an input parameter and combining a form factor parameter of the insulator, a dynamic arc model is established, a leakage current development trend is calculated to obtain a minimum flashover voltage of an insulator string, and the insulation margin and the external insulation level of the insulator are judged on the basis of the minimum flashover voltage. According to the invention, the whole conductivity of the insulator string is measured actually, the leakage current development trend is calculated by using the dynamic arc model, the change rule of the leakage current and the arc length with the time is described by using the arc dynamic model through a mathematical equation and more accords with the actual condition, and the purpose of insulation state judging and pollution flashover pre-warning is realized.

The invention provides a method for improving surface hydrophobicity of a contaminated silicon sulfide rubber product. The method includes steps of providing the silicon sulfide rubber product contaminated by dirt; and injecting atmospheric-pressure low-temperature plasma jet on the dirt on the surface of the product for conducting surface treatment. The atmospheric-pressure low-temperature plasma jet acts on the dirt on the surface of the silicon sulfide rubber product and enables hydrophobicity of the surface of the silicon sulfide rubber product to be transferred to the surface of the dirt, so that flashover voltage on the surface of the contaminated silicon sulfide rubber product is kept. The processing efficiency is high. Surface hydrophobicity of contaminated composite insulators, post insulators, insulating bushes and the like can be improved ideally. Therefore, the method for improving surface hydrophobicity of the contaminated silicon sulfide rubber product is suitable for popularization and application.

The invention relates to a new use of addition silicofluoric rubber, specially an application of room temperature sulfureted addition silicofluoric rubber (PRTV) to an insulator, and its advantages are as follows: (1) excellent hydrophobic property and fast, balanced, and durable hydrophobic-migration property, heightened by twice above; (2) dielectric strength up to 30MV/m, antipollution flashover voltage reaching TMA 4.5 grade, flame retardancy reaching FV-0 grade, resisting arc and on an abnormal condition, effectively protecting electrotechnical porcelain devices from being damaged; (3) high mechanical strength, good adhesion, corrosion resistance to acids, alkalis, salts and chemical reagents, and good oil resistance; (4) ultraviolet and ozone resistance, environmental corrosion resistance, non-skinning, non-cracking, and service life reaching above 20 years; (5) small friction coefficient, and good anti-adhesion and self-cleaning property; (6) room temperature vulcanization, local moulding, convenient use, and meeting the needs of filed antipollution technical measures.

The invention discloses an anti-icing coating for an insulator. The anti-icing coating consists of a high-resistivity coating and a low-resistivity coating. The high-resistivity coating consists of silicon rubber and carbon black, wherein the weight percentage content of the carbon black is lower than 1 percent; and the high-resistivity coating is coated at the outermost edge of the skirt of the insulator. The low-resistivity coating consists of silicon rubber and carbon black, wherein the weight percentage content of the carbon black is between 10 percent and 30 percent; and the low-resistivity coating is coated on the surface of the insulator except the outermost edge. Two coatings with high resistivity and low resistivity are prepared respectively by adding carbon black into the silicon rubber according to different proportions; the upper surface and the lower surface of the skirt of the insulator are coated with the low-resistivity coating; and the outermost edge of the skirt of the insulator is coated with the high-resistivity coating. By adopting the high-resistivity coating, ice is prevented from growing at the skirt edge by adopting the high-resistivity coating, the flashover voltage is prevented from being lowered by ice bridging, the working stability of the insulator is enhanced, and safe and reliable power transmission is ensured.

A lightning arrester for protecting elements of electrical facilities or a power transmission line comprises an insulating body which is made of a solid dielectric, preferably in the form of a bar, a strip or a cylinder, two main electrodes that are mechanically coupled to the insulating body and two or more intermediate electrodes. The intermediate electrodes, preferably made in the form of bars or cylinders, are arranged between the main electrodes so that said intermediate electrodes are mutually shifted along the longitudinal axis of the insulating body or along a spiral line. Such design makes it possible to form a discharge channel between the adjacent electrodes. Furthermore, said electrodes are located inside the insulating body and are separated from the surface of the body by an insulation layer. Discharge chambers formed as cavities or through bores opened to the surface of the insulating body are arranged between the pairs of the adjacent electrodes. Dimensions of the chambers are selected such that a discharge is easily blown out from the chambers to the surface of the insulating body, thereby increasing the efficiency of the discharge current quenching. In the preferred embodiments, the arrester is provided with an additional electrode for reducing a flashover voltage. Various embodiments of a power transmission line using the arrester of the invention are also disclosed.

The invention discloses a fault probability online evaluation method of power transmission line faults caused by freezing rain, and belongs to the technical field of electric power systems and automation. The method includes the steps that according to space-time evolution of freezing rain disasters, loads borne by lines and towers and flashover voltages borne by insulators are evaluated dynamically, the fault probability of the power transmission lines coated with ice is calculated, and expected risk equipment sets are provided for blackout defense systems. In the method, consideration is given to various fault ways when the power transmission lines are damaged by coated ice, and the method conforms to the mechanism that the coated ice triggers the line faults and is good in practicability and adaptability.

The invention belongs to the technical field of high voltage and insulation, and specifically relates to a method for fluorinating an insulator through use of a CF4 plasma. According to the method, an insulator is put in a reaction cavity, a mixture of CF4 and an inert gas is fed into the reaction cavity, the insulator is processed by a discharge plasma for 2-30min at room temperature and at low pressure of 0.01-0.1atm, so CF4 and the surface of the insulator are reacted with each other to generate a fluorinated layer. The method has the characteristic that the surface of a insulator is fluorinated through plasma processing in CF4, the surface flashover characteristic of insulators is improved, the electric strength of insulators is improved, the flashover voltage can be improved by about 50% to the maximum, the hydrophobic and oleophobic properties of the surfaces of insulators are improved, and the capability of insulators to prevent wet flashover and pollution flashover is improved.

The invention discloses a transmission line suspension insulator string external insulation state assessment method. By measuring the conductivity of the surface of a monolithic insulator, the external insulation state of a suspension insulator string of a transmission line in actual operation is assessed. According to the detection method provided by the invention, the needs of pollution level data collection and law observation of the transmission line suspension insulator are met, and the flashover voltage is predicted.

The invention discloses a device and a method for processing surfaces of a basin-type insulator by means of glow discharge fluorination. The method comprises the steps of: cleaning and drying the basin-type insulator, placing the basin-type insulator in a sealed cavity body, and connecting upper and lower parts of the basin-type insulator with two electrodes; vacuumizing the sealed cavity body by utilizing a vacuum pump, and filling the cavity body with low-pressure SF6 gas; and adjusting power-frequency voltage amplitude applied on the electrodes so as to produce glow discharge of the SF6 gas, utilizing a current meter for recording a current value of a loop, and utilizing plasma generated by the glow discharge for carrying out fluorination processing on the surface of the basin-type insulator for a period of time. The device and the method adopt the SF6 glow discharge plasma for carrying out fluorination processing on the surface of the basin-type insulator, the discharging current is small, the voltage amplitude is low, the basin-type insulator cannot be damaged, and the surface flashover voltage of the basin-type insulator can be greatly increased in a short time; and the device and the method have the advantages of being simple in operation, safe and efficient, low in cost and the like.

The invention relates to a test method for analyzing influences imposed on external insulation of power transmission and transformation equipment by haze, which is technically characterized by comprising the steps of 1, carrying out a test on haze components and physiochemical properties; 2, carrying out a test on haze for external insulation contamination accumulation characteristics; 3, carrying out a test for simulating a haze environment, simulating the haze components and establishing a test platform; and 4, carrying out a test on influences imposed on flashover voltage and leakage current by the haze. The test method provided by the invention analyzes the influences imposed on the external insulation of the power transmission and transformation equipment by the haze from the aspects of the test content and the analysis process. The test method is a group of complete analysis methods and test systems, and carries out quantitative analysis and quantitative calculation on the influences imposed on the power transmission and transformation equipment by the haze.

The invention discloses a voltage integral method based segmentation fitting method for calculating a volt-time characteristic curve. The method comprises: by adopting a voltage integral method as an insulator flashover criterion, segmentally calculating the volt-time characteristic curve of an insulator string in a non-standard waveform in combination with a numerical analysis method, and performing continuous correction. The obtained lightning impulse volt-time characteristic theoretical calculation curve of the insulator string is most relevant to a volt-time characteristic curve fitted by lightning impulse test data of an actual test. The flashover characteristic of the insulator string determines lightning withstand level of a power transmission line, and the situation that actual line flashover rate is not consistent with theoretical calculation data is caused if the influence of lightning waveform change on 50% discharge voltage of an insulator gap is not considered. Therefore, the flashover voltage of the insulator string under the action of an actual lightning waveform can be obtained in combination with the numerical analysis method by selecting the voltage integral method as the flashover criterion, and a theoretical reference is provided for an electric power department to accurately evaluate the lightning withstand level of the line.

The invention relates to an optimal configuration method for preventing icing flashover of a transmission line composite insulator, and is mainly used for preventing icing flashover of a transmission line composite insulator in the North. The method comprises the following steps of performing a pollution flashover test and a flashover test, obtaining a pollution flashover voltage and a flashover voltage, and then calculating the optimal length of an insulator chain through a formula. With the adoption of the method provided by the invention, the problem that the insulator icing flashover accident happens is solved, guarantee is provided for the safe operation of the transmission line and substation equipment, the safe operation of a power grid is ensured, the stable development of society and economy is promoted, thus the method has extremely strong promotion and application values.

The invention provides a method for calculating a protective gap distance based on Weibull distribution, and relates to a method for calculating the protective gap distance. When the normal distribution is used for calculating, multiple previous procedures are performed, and the calculating is complicated. The method comprises the following steps of testing an insulator string, and recording the lightning impulse flashover voltage; enabling a parallel adjustable protecting device to measure the breakdown voltage, and recording the lightning breakdown voltage; using a Weibull probability method to treat the lightning impulse flashover voltage of the insulator string; selecting a plurality of gap distances; selecting the protective gap distance according to the insulation matching principle that Ui0.1% is greater than Ug99.9%. By adopting the technical scheme, the method has the advantages that the distance between the parallel gaps is determined on the basis of the Weibull method, the optimum lightning impulse insulation matching is guaranteed, the operation is convenient, and the rapidity and reliability are realized.

The invention relates to a high thermal conductivity insulation structure of a stator bar of an excess epoxy mould pressing insulation system. The stator bar is suitable for the excess epoxy mould pressing insulation system. High thermal conductivity ceramic fiber is contained in the insulation layer on the outer surface of an electromagnetic wire; and reinforcement material in position-changing pit insulation, bar insulation, a restricted area filler strip, major insulation and anti-corona material contains the high thermal conductivity ceramic fiber. The stator bar manufactured by the invention has major technical performance figures that firstly, the temperature conductivity reaches 0.5 W/mK; secondly, tg delta is smaller than 1% under normal 0.2 UN (nominal voltage); thirdly, the stator bar has no visible corona trace for 60 seconds under 1.5 UN; fourthly, the flashover voltage of the finished bar reaches 5.5 UN; and fifthly, the service life of the bar is longer than 10 h under the 3.0 UN and is longer than 1100 h under the 2.0 UN during the electric resistance aging test.

The invention discloses a GIL insulator flashover voltage increasing method based on gas-solid interface electric field optimization. A surface of an epoxy insulator is partitioned, different parts ofthe epoxy insulator are respectively subjected to fluorination treatment at different degrees, and the surface conductivity of the insulator is high at three junction points where an electric field distorts, so that electric field distribution is improved, flashover voltage of the insulator along the surface is improved, and the insulating property of the insulator is improved.

The invention discloses a method for increasing a vacuum surface flash-over voltage of an insulating material. The method includes cleaning the surfaces of the insulating material by absolute ethyl alcohol and naturally air-drying the insulating material; placing the air-dried insulating material into an ultrasonic cleaning machine and cleaning the insulating material by deionized water; placing the cleaned insulating material into an oven, heating and drying the insulating material and naturally cooling the insulating material; judging whether the surface length of the insulating material is smaller than a threshold value or not, uniformly stirring liquid with the specific resistance ranging from 108 omega to 109 omega for standby application as a high-specific-resistance material at a room temperature if the surface length of the insulating material is smaller than the threshold value, uniformly coating the high-specific-resistance material on the insulating material and naturally air-drying the insulating material at the room temperature. The method has the advantage that technical problems of constraints of existing methods on selection of metal electrode materials with high escape power, difficulty in technically implementing methods for sputtering metal films on insulators under the condition of small surface distances and constraints of processing and performance of materials on selection of insulating materials can be solved.

The invention relates to a gap distance determination method for a lightning arrester with a series gap. The method comprises the steps of 1, processing the data of multiple flashover tests on an insulator chain in the normal probability distribution manner to obtain a discharge voltage value at any breakdown probability; 2, calculating the 50% discharge voltage ULS50% of the series gap of the lightning arrester according to the formula of ULS50%=(ULG50%+U1mA)*m, wherein ULG50% represents the 50% impulse discharge voltage of the series gap, U1mA represents the 1mA DC type reference voltage of the lightning arrester and m represents a matching coefficient; 3, processing multiple flashover voltage values for different series gaps still in the normal probability distribution manner to obtain discharge voltage values corresponding to the series gaps under the condition of 50% discharge probability, and selecting one series gaps out of the series gaps within the scope of normal distribution with the ULG50% as a reference. According to the technical scheme of the invention, a most appropriate range of series gaps can be obtained based on normal distribution models.