63 results about "Arc resistance" patented technology

The invention provides an arc resistance characteristic-based segmented modeling method of a fuse for a direct current networking system, and relates to the technical field of common direct current bus system design, and the method comprises the steps: calculating the real-time arc resistance data of the fuse according to the continuously collected short-circuit voltage and short-circuit current at the two sides of the fuse in a short-circuit test process, and forming an arc resistance curve; intercepting an arc resistance curve from the peak moment of the short-circuit current to the slope descending moment of the arc resistance curve to obtain an arc starting stage arc resistance curve, and intercepting an arc resistance curve from the slope descending moment to the moment when the short-circuit current is zero to obtain an arc burning stage arc resistance curve; respectively carrying out data fitting according to the arc starting stage arc resistance curve and the arcing stage arc resistance curve to obtain a sectional arc resistance curve equation; and taking the arc resistance curve equation as a control signal to build and obtain a fuse simulation model based on the controlled resistor. The method has the advantages that the arc resistance curve is divided into two sections, the corresponding arc resistance curve equation is designed, the simulation precision is higher, and the method can be better suitable for different working conditions.

A converter station AC filter group circuit breaker abnormal arcing modeling analysis method comprises the following steps: firstly, carrying out time mark alignment, amplitude calibration and filtering de-noising on wave recording signals such as AC bus voltage and filter branch current to obtain high-quality input data; then, combining a primary wiring diagram, enabling an alternating current system to be equivalent to an ideal power supply and series impedance, enabling circuit breaker arcing to be equivalent to arc resistance changing along with time, and constructing an equivalent circuit model comprising the power supply, the impedance, a capacitor, an electric reactor and dynamic arc resistance; establishing a state space equation according to a voltage and current constraint relation, and performing time domain solution by adopting a two-step two-order or three-order diagonal implicit Runge-Kutta method to obtain voltage and current responses of the whole process of the fault; on this basis, the arc resistance change is inversed according to the ratio of arc voltage to current, the current zero passage is identified through the resistance symbol change at adjacent moments, and the zero passage section is smoothed; and finally, the inversion result is verified again by means of the simplified equivalent model.

The invention discloses a gas arc cooling performance detection method and a related device, and relates to the technical field of electrics. According to the method, the circuit breaker is controlled to be switched on and off at the arcing time point in the preset arcing interval corresponding to each to-be-detected gas medium, and the arcing information corresponding to each arcing time point is obtained; according to the voltage signal and the current signal between the fractures of the circuit breaker in the arcing information corresponding to each arcing time point, a target constant corresponding to each arcing time point is determined, and the target constant represents the rate at which the arc resistance value changes by the same multiple; determining a constant accumulated value according to a target constant corresponding to each arcing time point in a preset arcing interval corresponding to each to-be-detected gas medium; the constant accumulated value can reflect the accumulated strength of the cooling efficiency of the gas media to be detected on the electric arc in the arcing interval, and comparing the constant accumulated value corresponding to each gas medium to be detected to determine the electric arc cooling performance difference between the gas media to be detected.

The invention relates to the technical field of flat single-shaft tracking photovoltaic supports, and provides a flat single-shaft tracking photovoltaic power generation support and an installation method.The first-time cleaning is achieved through cooperative work of a cleaning mechanism and a reset mechanism, specifically, when a photovoltaic panel rotates from east to west, an arc-shaped abutting rod pushes a second insertion plate to compress a reset spring, a linkage gear releases a first insertion plate, and the first insertion plate is driven to rotate; the elastic pulling rope pulls the reciprocating sliding block to drive the rubber scraping strip to scrape the photovoltaic panel in one direction. And when the photovoltaic panel is reset to the east, a steering rod drives a second gear to drive a first gear, a rectangular pushing frame is pushed to slide along a T-shaped sliding way through a telescopic rod and a connecting rod, a reciprocating sliding block is forcibly reset to the starting point, and a rubber scraping strip scrapes the panel again in the reset process. The photovoltaic panel is completely utilized to track natural rotation of the sun to drive cleaning, extra energy or a control system is not needed, a comprehensive cleaning tracking process and a resetting process are automatically completed twice every day, the power generation efficiency is effectively improved, and manual maintenance is reduced.

The invention discloses a fault detection method and system based on lightning protection device performance data, and relates to the technical field of fault detection, and the method comprises the steps: capturing the airflow velocity and airflow pressure deviation of a multi-crack outlet of a lightning protection device under the impact of a high lightning current in real time, and collecting the arc length data of an outlet point of the lightning protection device, and the temperature and instantaneous arc resistance of the thermocouple induction arc column are calculated. According to the method, the normalized airflow energy density and arc energy density features are combined into the joint feature sequence, so that the coupling relationship between the airflow performance and the arc discharge behavior of the lightning protection device can be captured, and the global detection state of slow evolution and instantaneous mutation of the equipment fault is realized; the lightning stroke threat intensity can be independently reflected by defining the dynamic risk index, lightning stroke threat propagation and topological network characteristics are combined in combination with lightning protection device performance detection data, and therefore transmission effect modeling of the lightning stroke dynamic risk is achieved.

The invention relates to the technical field of powder coatings, and provides an insulating powder coating and a preparation method thereof. The insulating powder coating comprises the following raw materials in parts by weight: 82-96 parts of epoxy resin, 5-8 parts of phenolic resin, 12-18 parts of silica powder, 10-15 parts of modified nano aluminum oxide, 3-9 parts of a flame retardant and 0.5-1 part of a flatting agent. Wherein the modified nano aluminum oxide and the silica powder can remarkably improve the breakdown voltage, the arc resistance and the insulativity of the coating; the flame retardant can improve the flame retardance and chemical resistance of the coating, is a halogen-free flame-retardant system, avoids the toxicity problem of the traditional brominated flame retardant, and improves the environmental protection property; in conclusion, the flame-retardant insulating powder coating overcomes the defects of the traditional insulating powder coating in flame retardance, chemical resistance and environmental protection, and has important application value in high-end power electronic equipment.

The utility model belongs to the technical field of furnace roller thermal spraying, and particularly relates to a furnace roller thermal spraying clamping tool which comprises a working table, a mounting plate is mounted at the top of the working table, a supporting column is fixedly mounted at the top of the mounting plate, a lower arc plate is fixedly mounted at the top of the supporting column, an upper arc plate is hinged to the top of the lower arc plate, and the upper arc plate is hinged to the top of the upper arc plate. According to the furnace roller cleaning device, the upper arc plate which is opened and closed is closed to the top of the lower arc plate, then a threaded column is rotated, so that an arc-shaped abutting plate is attached to the outer surface of the furnace roller, the heating wire on the inner wall of the lower arc plate is powered on, the friction assembly is installed in the upper arc plate, and the friction assembly is used for conducting friction cleaning on the outer surface of the furnace roller. The outer surface of the furnace tube is preheated, and the arc-shaped abutting plates rub and clean the outer surface of the furnace roller, so that the effect of preheating and cleaning the outer surface of the furnace roller is achieved.

The invention discloses a molded case circuit breaker on-off process dynamic simulation method based on a heterogeneous simulation system, and relates to the technical field of low-voltage electric appliance design and simulation. Loop current calculated by the first simulation subsystem is transmitted to the second simulation subsystem in real time and used for calculating electromagnetic force for driving a mechanism to move, and contact displacement generated by mechanism movement is immediately fed back to the first subsystem and used for dynamically updating resistance characteristics of an arc model, so that calculation of arc voltage is affected, and the simulation effect is achieved. The arc voltage is directly fed back to the circuit model to determine the current value at the next moment, so that a simulation chain for complete dynamic interaction of the circuit current, the electromagnetic force, the mechanical displacement, the arc resistance, the arc voltage and the circuit current is formed; therefore, the simulation model can reflect the dynamic evolution process of each physical quantity in the real on-off process in a self-consistent manner.

The application provides a simulation method, system and device considering the closing pre-breakdown characteristics of a circuit breaker, and belongs to the technical field of SF6 circuit breaker simulation. The method comprises the following steps: S1, establishing an SF6 circuit breaker controlled element model in simulation software, wherein the controlled element model comprises the relationship between the closing state in the closing process of the circuit breaker and the SF6 gas parameters, and the relationship between the SF6 circuit breaker gap voltage; and the relationship between the arc resistance value in the closing process of the circuit breaker and the arc parameters, the SF6 circuit breaker gap voltage, and the passing current of the SF6 circuit breaker; S2, building an SF6 circuit breaker test circuit simulating a power system and connecting the SF6 circuit breaker controlled element model to the SF6 circuit breaker test circuit; and S3, loading the SF6 gas parameters and the arc parameters, adjusting the real-time gap voltage and the real-time passing current, and performing the system electromagnetic transient process simulation of the SF6 circuit breaker closing pre-breakdown in the SF6 circuit breaker test circuit.

The invention discloses an electric contact material for a high-resistance circuit breaker and a preparation method of the electric contact material, and relates to the technical field of electric contact materials for circuit breakers, the material comprises the following components based on 100 parts by weight of the total weight of a finished product: 92.0-96.8 parts by weight of a pre-alloyed matrix phase which is Ag-30Ni pre-alloyed powder prepared by a gas atomization method; an in-situ carbon reinforcing phase: 1.0 to 2.0 parts by weight of a novolac resin powder as a carbon precursor; the three-phase functional layer phase is 0.1-5.0 parts by weight and is one of tungsten carbide and titanium carbide or a compound of tungsten carbide and titanium carbide according to the weight ratio of 1: 1; the copper infiltration filling phase is electrolytic copper powder or oxygen-free copper liquid; a multi-phase synergistic material system is constructed, all components are complementary, core performance such as arc resistance is balanced and optimized, and the problem that a traditional contact material is short in service life is solved; a precise preparation process chain is integrated, the structure and performance are directionally regulated and controlled, defects are reduced, the anti-loss capacity is improved, the strict requirements of a high-resistance circuit breaker are met, and the service cycle is prolonged.

The utility model belongs to the technical field of gasoline desulfurization, and discloses a device for desulfurization in gasoline preparation, which comprises a reaction box, a gas pipe is fixedly connected to one end of the reaction box close to the top in a penetrating manner, a one-way valve is fixedly connected to a pipe body of the gas pipe, and an oil outlet valve pipe is fixedly connected to the other end of the reaction box close to the bottom in a penetrating manner. A desulfurization part is arranged on the reaction box; t-shaped long plates are stressed and can slide in an arc abutting groove in a limiting mode, then a rotating disc is driven to rotate in a positioning mode in a charging barrel, rotation of the rotating disc can drive two T-shaped blocks to slide in the arc sliding grooves in the opposite directions, and therefore partition plates installed on the two T-shaped blocks can be driven to synchronously conduct limiting translation in the opposite directions in a disc groove; therefore, gasoline or a catalyst in the charging barrels can be discharged without tight separation of the two partition plates, and the two charging barrels can alternately discharge materials intermittently due to back-and-forth swinging of the swing plates, so that the mixing effect and efficiency can be improved subsequently.

The application provides a segmented modeling method of a fuse for a direct current networking system based on arc resistance characteristics, relates to the technical field of common direct current bus system design, and comprises the following steps: calculating real-time arc resistance data of the fuse according to short-circuit voltages and short-circuit currents of two sides of the fuse in a continuously collected short-circuit test process to form an arc resistance curve; intercepting the arc resistance curve between a peak value moment of the short-circuit current and a slope drop moment of the arc resistance curve to obtain an arc resistance curve in an arc striking stage, and intercepting the arc resistance curve between the slope drop moment and a moment when the short-circuit current is zero to obtain an arc resistance curve in an arc burning stage; respectively performing data fitting according to the arc resistance curve in the arc striking stage and the arc resistance curve in the arc burning stage to obtain a segmented arc resistance curve equation; and building a fuse simulation model based on a controlled resistance by taking the arc resistance curve equation as a control signal. The beneficial effect is that the arc resistance curve is divided into two segments and corresponding arc resistance curve equations are designed, the simulation precision is higher, and the method can be better applied to different working conditions.

The invention belongs to the technical field of insulators, and discloses an anti-pollution flashover umbrella skirt structure optimized composite insulator which comprises an insulating core rod and a plurality of umbrella skirt units arranged on the insulating core rod in a sleeving mode, each umbrella skirt unit comprises a main umbrella skirt body and an auxiliary umbrella skirt body, and an annular pollution dredging and flow guiding inclined face is arranged on the upper umbrella face of each main umbrella skirt body. The radial inclination angle of the sewage draining and flow guiding slope is gradually increased in a gradient manner outwards along the radial direction of the umbrella body; the edge of the lower umbrella surface of the main umbrella skirt body is provided with an annular arc-resisting rib; the arc cutting fracture structures cut off the circumferential development path of an electric arc, the annular arc blocking ribs lengthen the creepage path of the electric arc, meanwhile, the arc cutting fractures of the upper and lower adjacent main umbrella skirt bodies are distributed in a staggered mode, axial through of the electric arc is eradicated, the arc extinguishing probability is remarkably improved, and the arc extinguishing effect is improved. And pollution flashover is thoroughly inhibited, and the device is suitable for severe working conditions such as counter-weight pollution and rainstorm.

The invention discloses an AgSnO2 contact material and a preparation method thereof, relates to the technical field of electric contact materials for electric appliances, and solves the problems of high resistivity, poor welding resistance, short arc resistance life, high production cost and the like of contact materials in the prior art. The raw materials of the contact material comprise raw material powder and a dispersing agent, wherein the raw material powder comprises the following components in percentage by mass: 79-90% of Ag powder, 4-10% of Sn powder and 4-10% of alkali metal M powder; the dispersing agent accounts for 0.2-1% of the mass of the raw material powder. According to the preparation method, the AgSnO2 contact material with low resistivity, high welding resistance and long arc-resistant life is obtained through the synergistic effect of methods such as alkali metal doping, freeze drying and oxidation after sintering, the arc-resistant life and other properties of the obtained contact material are improved by 15% or above compared with those of a conventional AgSnO2 material, the process is simple, and the production cost is low.

The invention discloses an arc resistance simulation verification method for a field suppression switch structure and operating characteristics, an arc resistance simulation verification device for the field suppression switch structure and operating characteristics, arc resistance simulation verification equipment and a computer readable storage medium. The method comprises the following steps: firstly, establishing a three-dimensional geometric model comprising an arc extinguish chamber, a contact system and an operating mechanism; then, constructing a mechanical structure dynamic simulation model to obtain the motion characteristics of the moving contact, and finally, establishing a multi-physical field coupling mathematical model based on a fluid dynamic equation, an electromagnetic field equation and a heat transfer equation to realize numerical simulation of the arc breaking process of the field suppression switch. According to the method, the flowing, electromagnetic and heat transfer characteristics of the arc are comprehensively considered, the whole process from generation to extinguishing of the arc can be completely simulated, and an effective simulation analysis means is provided for design optimization, performance evaluation and breaking capacity verification of the field suppression switch.

The application relates to a judgment method and device for DC arc resistance of an arc extinguishing chamber and a computer device. The method comprises the following steps: building an arc burning working condition simulation environment of the arc extinguishing chamber in a pre-constructed high-speed switch geometric model, calculating a gas flow field in the arc extinguishing chamber based on a real gas model of an arc magnetic fluid model, calculating distribution structures of multiple physical fields of the arc extinguishing chamber in a preset time under the arc burning working condition based on a gas flow field control equation group, a turbulence model and the gas flow field in the arc magnetic fluid model, calculating an ablation mass of the arc extinguishing chamber in the preset time under the arc burning working condition based on a radiation model and an ablation model in the arc magnetic fluid model, and evaluating the resistance characteristics of the arc extinguishing chamber based on the distribution structures of the multiple physical fields and the ablation mass of the arc extinguishing chamber in the preset time in the arc burning process. The evaluation of the long-time DC arc resistance performance of the arc extinguishing chamber can be realized based on the distribution structures of the multiple physical fields and the ablation mass of the arc extinguishing chamber in the preset time.

According to the circuit breaker breaking arc simulation system and method, a near-zone circuit simulation module is used for constructing and operating a circuit breaker external near-zone fault circuit model, outputting an arc current value and receiving an arc resistance value; the breaking arc simulation module is used for constructing and operating an arc magnetofluid model, outputting a gas chamber counterforce and receiving a contact movement speed; the spring operating mechanism simulation module is used for constructing and operating a circuit breaker operating mechanism multi-body dynamic model, outputting contact movement speed and receiving air chamber counterforce; the data relay and processing node module is used for receiving data information from the near-zone circuit simulation module, the breaking arc simulation module and the spring operating mechanism simulation module, analyzing and classifying the data information and then sending the data information to the corresponding simulation modules; the UDP communication module is used for realizing data transmission between each simulation module and the data relay and processing node; and the automatic running script module is used for controlling initialization, running, parameter updating and iterative loop of each simulation module.

The application provides an insulating tube for high-voltage cable protection and a preparation method thereof. The insulating tube is composed of an outer tube, an inner tube and a transition layer. The raw material for preparing the outer tube comprises a base resin, a carrier resin, a flame retardant and a slip agent, wherein the flame retardant comprises low-melting-point glass fiber, a phosphorus-nitrogen intumescent flame retardant and a silane coupling agent; the raw material for the inner tube comprises a main body resin and a solubilizing agent; and the raw material for the transition layer comprises soluble fiber raw material, nano-clay and a dispersing agent. Through a composite flame-retardant system and a multi-layer structure design, the application significantly improves the arc resistance, the flame retardant grade and the interlayer bonding force of the insulating tube, solves the technical problems that the traditional insulating tube is prone to breakdown and peeling in a high-voltage environment, and is suitable for long-term safe protection of high-voltage cables.

The invention discloses a material composition for a high-pressure-resistant product and a preparation method of the material composition. The composite material comprises the following raw materials in percentage by mass: 40-55% of PPS; 25% to 35% of PPA; 10 to 20% of reinforcing fiber; 5-8% of a flame retardant synergist; 0.5-2% of a coupling agent; 0.3 to 1% of an antioxidant; and 3-5% of an inorganic filler. In the preparation process, a gradient temperature control melt extrusion process is adopted, and a fiber directional distribution and interface chemical bonding technology is combined, so that the material has high rigidity, low shrinkage rate and excellent arc resistance. The obtained material can still keep stable mechanical properties and insulation characteristics in a high-humidity and high-pressure environment, is suitable for the fields of high-voltage connectors of new energy automobiles, electronic and electric appliance parts and the like with strict requirements on dimensional accuracy and voltage resistance grade, and solves the technical contradiction that high CTI value of PPA is difficult to cooperate with high rigidity and dimensional stability of PPS.

The invention discloses a method for detecting the cooling performance of gas to an axial arc and a related device, and relates to the technical field of electrics. Under the action of each to-be-detected gas medium, the circuit breakers with the same operation parameters are controlled to be switched on and off in the preset arcing interval corresponding to the to-be-detected gas medium, and arcing information corresponding to switching on and switching off is obtained; taking an intersection of the actual arcing durations corresponding to all the gas media to be detected as a common arcing interval; determining a characteristic time constant corresponding to each to-be-detected gas medium according to arc resistance characteristics reflected by the voltage signal and the current signal between the fractures of the circuit breaker in the common arcing interval corresponding to each to-be-detected gas medium; and comparing the characteristic time constants corresponding to the to-be-tested gas media to determine the cooling performance difference of the axial arc between the to-be-tested gas media, thereby providing a reference basis for circuit breaker design and gas type selection.

The utility model provides a high-precision multidimensional welding robot, which relates to the technical field of welding robots and comprises a main mounting rack, the main body of the main mounting rack is an L-shaped rack body, the top of the main mounting rack is slidably provided with a movable arm seat matched with a guide rail, and the outer side of the top of the movable arm seat is rotatably provided with a swing arm; a lifting arm is slidably arranged at the outer end of the swing arm, an elevation arm is hinged to the bottom of the lifting arm, a support is fixedly arranged at the bottom of the elevation arm, and a middle sliding block is fixedly arranged at the bottom of the support. An arc-shaped resistor is arranged, the swinging angle can be monitored, a second servo motor drives a swinging arm to rotate, swinging can be conducted, and an electric cylinder is used for pushing a positioning friction block to press the swinging arm to conduct fixing; and during rotation of the swing arm, the trigger block slides in a manner of being attached to the arc-shaped resistor, the resistance of the arc-shaped resistor is adjusted, the swing angle can be calculated and monitored through resistance change feedback, and the problem that an existing welding robot is inconvenient to monitor dimensional movement is solved.

A recyclable epoxy resin system for electrical insulation is provided The recyclable epoxy resin system comprises a resin component, at least recyclable curing agent and at least one filler. Said recyclable epoxy resin has a dielectric strength (t=2 mm) of more than 22 kV / mm as measured by IEC 60243 and a dry arc resistance of more than 400 seconds as measured by ASTM D 495.

The utility model discloses a steel tube tower holding pole fixing device, which relates to the technical field of electric power engineering and comprises a holding hoop main body, a first semi-arc sleeve and a second semi-arc sleeve of the holding hoop main body are in butt joint to form an annular holding hoop, arc cavities are arranged in the first semi-arc sleeve and the second semi-arc sleeve, inner arc plates are arranged in the arc cavities in a sliding manner, and the inner arc plates are arranged in the arc cavities. And notches are formed in the positions, close to the ends, of the upper end and the lower end of the inner arc plate, gradually-high arc strips are fixed in the notches, and driven ladder blocks are arranged on the inclined upper surfaces of the gradually-high arc strips in a sliding mode. The two sets of semi-arc sleeves which are in butt joint in a staggered mode can be conveniently connected to the outer wall arm of the holding pole in a sleeved mode, meanwhile, the bolts for locking the two sets of semi-arc sleeves are used for enabling the inner arc plates to stretch into the opposite semi-arc sleeves, locking of the two sets of semi-arc sleeves is convenient, meanwhile, the arc-shaped abutting pieces on the inner walls can be driven to get close to the hoop in the radial direction, and therefore locking is convenient. In this way, the holding power between the hoop and the holding pole can be increased, and the device is firmly connected to the outside of the holding pole.

This disclosure provides a method, apparatus, equipment, and storage medium for controlling a welding torch, belonging to the field of welding construction equipment for long-distance oil and gas pipelines. The method includes detecting a first welding arc resistance of the welding torch at a first position; determining a target welding arc resistance of the welding torch at the first position; and controlling the welding torch to oscillate in a direction perpendicular to the extension direction based on the first welding arc resistance and the target welding arc resistance. This disclosure can reduce costs and improve the reliability of pipeline welding.

The utility model relates to battery formation technical field, concretely is a kind of battery formation contact quick-change device, including support plate and contact, the surface of support plate is connected with slider and passes through, the lower surface of support plate is equipped with screw hole, the both sides of slider are connected with screw rod and pass through, slider is inserted with support plate by screw rod and screw hole, the surface of slider is connected with support cylinder and passes through, the outer surface of support cylinder is sleeved with sleeve, the outer surface of sleeve is sleeved with connecting cylinder.The utility model adopts modularization quick-change design and standardization interface, makes replacement time shorten to 1 minute;Built-in adaptive contact structure to compensate the deformation or deviation of battery pole, ensure contact stability;Key components adopt wear-resistant high-temperature material to enhance conductivity and arc resistance;Integrated safety interlock function prevents energization when not locked;With strong compatibility, can be adapted to a variety of battery specifications, meet the flexible production line demand.

This application provides a short-circuit protection device for a power generation system, relating to the field of low-voltage electrical appliances. It includes a frame containing a cavity through which the power supply arc passes; and a first arc-extinguishing grid, spaced apart within the cavity of the frame, forming a channel with the same path as the cavity. This application achieves progressive energy dissipation of the arc by setting up an alternately distributed three-stage arc-extinguishing grid system and a composite path control structure: the third arc-extinguishing grid and the front form a dense cutting layer to force initial arc splitting; the inclined connecting middle section and the second arc-extinguishing grid construct a twisted and elongated channel; the reverse bending section constructs a three-dimensional cable network to rapidly increase the arc resistance; the grooved and protruding sections guide the arc to bifurcate and ascend, ultimately forcing the arc to zero through the synergistic effect of multi-stage segmentation, path reconstruction, and heat dissipation area.

The invention discloses porcelain sand for extra-high voltage insulator production and a preparation method, the porcelain sand comprises the following components: 30-50 parts of formula mud, 13-18 parts of alumina powder, 10-15 parts of glaze powder, 4-9 parts of talc, 3-8 parts of first-class clay, 5-10 parts of second-class clay, and 4-9 parts of albite, the formula mud is prepared from the following components in parts by weight: 45 to 60 parts of kaolin, 25 to 30 parts of quartz sand, 10 to 15 parts of potassium feldspar, 8 to 10 parts of bentonite and 0.8 to 1.2 parts of carboxymethyl cellulose; the preparation method of the porcelain sand comprises the steps of ingredient grinding, magnetic separation for iron removal, filter pressing for dehydration, vacuum pugging, drying for sand making and high-temperature sintering. The porcelain sand has extremely high high temperature resistance, arc resistance and aging resistance, can be adhered to the root of an insulator blank through glue and is sintered and molded together with the blank, so that the root of the insulator can be better connected with a fitting through cement, and the overall mechanical strength and electrical performance of the insulator are improved.

According to the piezoresistor for the surge protection device and the surge protection device, the encapsulating layer is arranged outside the square piezoresistor disc, and aluminum nitride and aluminum oxide are added into the encapsulating layer in proportion, so that a compact heat conduction network is formed, the heat conduction efficiency and the heat stability of the prepared encapsulating layer are greatly improved, and the service life of the encapsulating layer is prolonged. And the service life of the piezoresistor is prolonged. The superfine mica powder is arranged to form an insulating barrier, and the gas-phase silicon dioxide is used for filling the micropores, so that current is effectively prevented from passing through, a good insulating effect is achieved, electrical contact between the square piezoresistor disc and the external environment is effectively isolated, the arc resistance during use is improved, the piezoresistor can respond to surge more quickly, and the service life of the piezoresistor is prolonged. And the surge energy is effectively dispersed and dissipated. The phosphorus-nitrogen flame retardant plays a flame retardant role through a gas phase and condensed phase dual mechanism, and is matched with the addition of the ceramic fiber and the mica powder, so that the flame retardant property of the encapsulation layer can be greatly improved, and the safe operation of an electrical system is ensured.

The invention discloses a broadband conducted electromagnetic interference modeling method for very fast transient overcurrent on a secondary side of an electronic transformer, and belongs to the technical field of electromagnetic compatibility test simulation, and the method comprises the following steps: constructing a multi-arcing model of a GIS isolation switch, which is used for simulating and generating very fast transient overcurrent VFTC; the multi-arcing model is constructed by introducing fracture dynamic capacitance, establishing a segmented arc resistance model and setting arcing and quenching criteria; according to the method, fracture dynamic capacitance is introduced at the fracture of the disconnecting switch, segmented arc resistance models of three stages of pre-breakdown, steady-state combustion and arc quenching are fused, and meanwhile, accurate arcing and arc quenching criteria based on dynamic breakdown voltage and current zero-cross detection are set; the constructed multi-arcing model can highly vividly reproduce the VFTC waveform generated during the operation of the GIS disconnecting switch.

The invention relates to a process for producing low-nitrogen crude steel. This process includes melting directly reduced iron and / or scrap in a melting furnace with arc resistance heating to give a metallic melt and a slag. The metallic melt is removed from the melting furnace and used to charge a converter. The metallic melt is refined in the converter to give liquid crude steel. The liquid crude steel is tapped having a nitrogen content [N] of not more than 50 ppm, especially of not more than 30 ppm.