171 results about "Ground resistance" patented technology

The invention relates to a traveling wave analysis and recognition method for distinguishing lightning shielding failure from lightning counterattack of direct current transmission line. The lightning shielding failure of line is that lightning avoids the lightning shield line and directly strokes on the transmission line, while lightning counterattack of line is that lightning directly strokes on the lightning shield line or the tower. Because the earth resistance of tower exists, the potential on tower top suddenly increases and causes insulation flashover. The electromagnetic transient component generation mechanism of the high voltage direct current transmission line and the propagation path of lightning electromagnetic transient of the line in the lightning shielding failure are different from those in the lightning counterattack, the size and polarity of the initial surge voltage and the second surge voltage of the voltage transient signal exist significant difference. The traveling wave analysis and recognition method of the invention analyzes zero mode voltage using wavelet and distinguishes the lightning shielding failure and lightning counterattack failure according to the size and polarity of the initial surge voltage and the second surge voltage of the zero mode voltage in the traveling wave analysis and high-speed acquisition system of the protection zone. A lot of simulation results show that the method is reliable and effect. The physical concept of the invention is visible and clear, the method is easy to achieve and wide to use in the direct current system protector, also provides accurate initial data for researching lightning characteristics, analyzing lightning accident, discussing lightning protection countermeasure of transmission line and designing insulation coordination in the power system.

The invention relates to a method for recognizing the shielding failure and the counterattack of a high-voltage DC transmission line. The shielding failure of the line means that the thunderbolt directly strikes on the transmission line by steering clear of a ground wire; the counterattack means that the thunderbolt directly strikes on the ground wire or a pole tower, the electric potential on the top of the tower increases instantaneously, which causes the insulation flashover due to the existence of a pole tower earth resistor. The different theories generated by the electromagnetic transient component of the shielding failure and the counterattack of the high-voltage DC transmission line and different paths of transmission of the thunderbolt electromagnetic transient component on the circuit cause that the energy distribution of different frequency bands of the generated voltage transient state signals are different greatly. In a travelling wave analysis and high-speed acquisition system at the protective installation position, the small wave analysis is adopted to extract the energy of the zero modulus voltage in different frequency bands. The shielding failure and the counterattack are differentiated according to the property of the energy distribution. A large amount of emulations show that the method is reliable and effective. The method has intuitive and clear physical concepts, is easy to implement, can be widely applied to a high-voltage DC system protective device, provides important data for the lightening protection design of the line and provides reference for the operation and maintenance of the line.

An earth clamp for testing contact voltage, comprising a measuring circuit formed of a voltage inducing transformer and a current measuring transformer, adapted to be mutually coupled by an earth conductor whose earth impedance is to be measured, a microcontroller to deliver an alternating voltage to the voltage inducing transformer and, in response, to receive a reference voltage generated in the earth conductor and an earth current iB+iF induced in the current measuring transformer, the microcontroller being configured to extract an amplitude E of the reference voltage, an amplitude IB and an amplitude IF of the earth current and a phase shift φ between the reference voltage and the loop current iB and to calculate the earth impedance Zb at a determined frequency, the microcontroller also computing the contact voltage Uc at said determined frequency by the product of the earth impedance times the amplitude IF.

Methods, devices, and systems for an image sensor device are disclosed. An image sensor device comprises an array of image pixels wherein each pixel is configured for sensing light incident on the pixel. An image sensor device may further comprise a ground contact shared between at least two image pixels of the plurality. The ground contacts may be provided in an even pattern, a random pattern, or a repeating random pattern across the array. The image sensor device may further include an array of shared pixel structures comprising a plurality of pixels, wherein a ground contact may be evenly or randomly placed within each pixel structure across the array of pixel structures.

The invention discloses a storage and calculation array structure and an operation method thereof. The array structure comprises a resistive unit crossing rod array M, first to fourth gate regions S1 to S4, n bit line voltage sources U1n to Unn, m word line voltage sources Um1 to Umm, n bit line grounding resistors R1n to Rnn and m word line grounding resistors Rm1 to Rmm, wherein the resistive unit crossing rod array is separated from the voltage sources and the grounding resistors through the gate regions; when the storage and calculation array structure is used for calculation, the gate regions are used for realizing the gating on the grounding resistors, the voltage sources and the resistive units participating in the calculation; a material implication (IMP) logic circuit is formed. The conventional IMP logic-based resistive array is expanded, so that the IMP calculation can be performed on the resistive unit in a certain row, and can also be performed on the resistive unit in a certain line; the utilization rate on the array is greatly improved; the calculation efficiency is improved, so that the functions of storage, calculation and the like of data in the array can become more flexible.

The invention discloses a comprehensive tester of programmable power supply insulation resistance and earthed resistance, which comprises an insulation resistance testing circuit, an earthed resistance testing circuit, an A / D (Analog / Digital) converter, a microcontroller, a keyboard and a display device; the signal output ends of the insulation resistance testing circuit and the earthed resistance testing circuit are connected with the A / D converter; the A / D converter is connected with the microcontroller through a signal transmission wire; and the keyboard and the display device are connected with the microcontroller through interfaces. The comprehensive tester can better realize the comprehensive testing of the power supply insulation resistance and earthed resistance of an electric device, and has the advantages of being small in volume, convenient to carrying and use, stable in operating process, large in measuring range, high in testing precision, reliable in performance, simple and convenient in operation; and the comprehensive tester can realize the unitization of measuring, controlling and displaying.

The combinational detecting device and detecting method of DC earth resistance switch-status is one of high degree of accuracy online detecting method for earth resistance of electric power system DC power plus-minus busbar and branch wire. The device includes first current-limiting resistance (R1), second current-limiting resistance (R2), sampling resistance (R3), and first controllable electronic switch (S1), (S2). The first current-limiting resistance connects to system positive pole (KM+) and first controllable electronic switch which connect to second current-limiting resistance and sampling resistance in the other end, as voltage sampling point (U). The other end of sampling resistance put to earth. The other end of the second controllable electronic switch connects to the second current-limiting resistance in one end and to system minus pole (KM-) in other end.

The invention belongs to the technical field of lightning-proof grounding of transformer station engineering, and particularly relates to a resistance reduction analysis and measurement system applied to a transformer station lightning-proof grounding system. The invention provides a resistance reduction analysis and measurement system applied to a transformer station lightning-proof grounding system, and the system can effectively solve the technical problem of grounding. The system includes a resistance reduction database, a resistance reduction problem application part and a ground resistance on-line monitoring part; the resistance reduction problem application part collects field soil environment data, extracts the resistance reduction database, determines a structure of the structure of layering arrangement and soil texture environmental data which are related with the ground resistance, and calculates the geological environment of the grounding system; a solution is selected in the database, calculation of the grounding system is completed, and the mode and the structure of grounding of a transformer station are determined; and the calculation flow of the grounding system is as follow: soil resistivity and grounding area data are collected, and thermostabilization examination of a grounding device is performed.

In the semiconductor device including a control input terminal, a GND terminal and an output terminal, and also having an IGBT and a control circuit driving the IGBT, a ground resistance and a temperature compensation resistance are connected in series to each other between the control input terminal and the GND terminal. A polysilicon resistance provided on an insulating film formed in a semiconductor substrate in which the IGBT is provided is employed as the ground resistance. A diffusion resistance obtained by injecting an impurity into said semiconductor substrate and performing a diffusion operation is employed as the temperature compensation resistance.

The invention relates to a method and a system for eliminating mutual inductance between leads in ground resistance measurement. By synchronously measuring measurement voltage and current waveform and analyzing the amplitude ratio of voltage to current and the phase angle difference between the voltage and the current, ground impedance under a given frequency and an impedance angle of the ground impedance can be obtained, the mutual inductance between the leads of a voltage electrode and a current electrode in measurement is obtained by calculation, and a true value of the ground impedance can be obtained by subtracting a part generated by the mutual inductance from the ground impedance on the basis. According to a testing method, the influence caused by various background interference signals is effectively avoided, and an accurate measurement result can be obtained even if the output current is very low. According to the method for eliminating the mutual inductance between the leads in the ground resistance measurement, the test pay-off workload is small, and a voltage lead and a current lead can be paved abreast. Test data can be acquired and analyzed under the automatic control of a portable system without manual intervention, and the characteristic of simplicity in operation is achieved. The data are directly analyzed on the scene by virtue of the portable system, the visualization is high, and industrial frequency ground resistance can be immediately given.

The present invention provides a single-phase earth fault location method and system applied to a power distribution network. The method comprises the steps of: determining whether single-phase earthfaults are generated or not according to change of zero sequence voltages of sectionalized busbars, when the zero sequence voltages are larger than a preset threshold value, connecting with a neutral-point earthing resistor of an earthing transformer, generating a large current by a fault loop, allowing electrical quantity feature information related to the fault lines to be changed, synchronouslycollecting electrical quantity feature information of each sectionalized busbar and each section of a transmission line and uploading the electrical quantity feature information to an intelligent protection control host by an intelligent collection control device, determining whether the electrical quantity feature information related to the fault line meets a differential protection motion condition or not by the intelligent protection control host so as to locate the fault lines. The single-phase earth fault location method can automatically, intelligently and rapidly locate the single-phase earth faults and can achieve rapid isolation for the fault lines so as to reduce the operation workload of a power distribution network and improve the power supply reliability of the power distribution network.

The invention provides a multilayer flexible printed circuit board and a manufacturing method thereof. The multilayer flexible printed circuit board comprises a circuit board and a grounded conductive reinforcement, wherein, the circuit board is formed by a plurality of single layer flexible printed circuit boards which bond together, each single layer flexible printed circuit board is provided with copper foil and a cover membrane which is positioned on the copper foil, wherein, a windows is welded on the cover membrane of the outer layer of the multilayer flexible printed circuit board and corresponds to the grounding position needing welding and conductive reinforcement; a copper-plating block is welded on the single layer of flexible printed circuit board and corresponds to the grounding position needing welding and conductive reinforcement, the copper-plating block protrudes out of the window of the cover membrane; and the conductive reinforcement is conducted with the copper-plating block through a conductive adhesive. The multilayer flexible printed circuit board can decrease the height difference between the conductive reinforcement grounding position and the cover membrane, reduces the height of the circuit board and the conductive reinforcement which are attached with each other through a conductive adhesive, reduces the grounding resistance of the conductive reinforcement, and improves the yields of the product.

The invention belongs to the field of grounding systems, and particularly relates to conducting concrete, a manufacturing method thereof and an application. The concrete comprises, by weight, 6-9 parts of carbon fibers, 43-50 parts of steel fibers, 68-78 parts of graphite, 1.38-1.58 parts of dispersing agents, 10-15 parts of preservative and 5.2-6 parts of water reducing agents. The concrete solves the problems that grounding resistance value requirements are difficultly met by a common grounding method in partial areas, a common grounding system is high in construction difficulty due to topographical restrictions, construction difficulty is effectively reduced, grounding efficiency is improved, and operability is good.

The invention discloses a medium-voltage power grid neutral point arc suppression coil and resistor combined grounding method. On the basis of a mode that a neutral point is grounded in a resonance way through an arc suppression coil, a median resistor and a small resistor with different resistance values are connected in parallel to the arc suppression coil, and the connection and disconnection of the median resistor and the small resistor are controlled by a switch connected with a controller, so that the mutual switching among different neutral point grounding modes is achieved in the following mode. According to the invention, a neutral point grounding mode of automatically tracking the combination of the arc suppression coil system and the grounding resistor is adopted, so that transient faults and permanent faults are distinguished while overvoltage is limited, and the grounding line selection of the permanent faults is achieved, namely the advantages of suppressing overvoltage by the middle resistor, reducing the grounding current of the fault point and extinguishing arc of the arc suppression coil are fully exerted, the grounding mode of the small resistor having the good relay protection selectivity is adopted to rapidly cut off the permanent earth fault so as to improve the power supply reliability, safety and economical efficiency.

The invention relates to a corrosion prevention technology for grounding net metal materials, in particular to a method and a device for protecting a power facility grounding net. Focused on an electrochemical corrosion principle, the invention meets the requirement on grounding net protection in different soil environments by reducing the potential of a grounding body for inhibiting grounding net corrosion and by selecting different materials, technologies and methods, including surface treatment of grounding net materials, the material, the weight, the quantity, cladding materials of sacrificial anodes, and connecting and installation mode. By reducing the potential of the grounding body for inhibiting grounding net corrosion, a grounding net is protected and the problems of short service life and large resistance of the grounding net and high equipment replacement cost can be solved. The corrosion prevention technology is simple and practicable, reduces the grounded resistance of the grounding net to below 0.3 ohm averagely after being implemented, needs low investment, can prolong the service life of the grounding net and can achieve very remarkable economic benefits.

A wind turbine thunder expelling protective device comprises a thunder expelling metal piece installed at the end of a wind turbine blade. A plasma generator connected with the thunder expelling metal piece is installed at the end, far away from the thunder expelling metal piece, in the blade and is connected with the ground through a grounding wire arranged in the blade and through the inside of a tower truss. The thunder expelling metal piece and the passive plasma generator are designed at the end of the blade, so that passive active thunder resistance is achieved. A metal outer cover, an insulator and an electrode are designed, so that under the action of a thundercloud electric field, plasma is generated through high-voltage air ionization, ions opposite to cloud charges are transferred to the outside world through the thunder expelling metal piece to eliminate the cloud charges, and thus the purpose of passive thunder resistance is achieved without the influence of grounding resistance.

The invention relates to a device and method for diagnosing the corrosion state of a grounding electrode based on relative grounding resistance, and belongs to the technical field of operation and management of power transmission and transformation equipment. The method comprises the following steps of S1, designing the grounding electrode and calculating the relative grounding resistance of the grounding electrode; S2, selecting a method for diagnosing the corrosion state of the grounding electrode according to different soil resistivities; S3, selecting a corrosion diagnosing criterion basedon the relative grounding resistance according to the soil resistivities; S4, designing and measuring the grounding resistance of the grounding electrode; S5, designing and measuring the soil resistivity of soil where the grounding electrode is located. The design method eliminates the influence of the soil resistivities on a diagnosis result of the corrosion state of the grounding electrode, achieves the classification of the corrosion state of the grounding electrode and further improves the accuracy of the diagnosis result of the corrosion state of the grounding electrode.

The invention relates to a resistance-type winter bamboo shoot detector, which consists of a storage battery direct-current power supply circuit (8), a ground resistance detection circuit (9), a single-chip microcomputer control circuit (10), a nixie tube display circuit (11), a sound-light prompt circuit (12) and a shell (6), and also comprises a nixie tube display screen (1), a sound generator or a light emitter (2), a storage button (3), a display mode control button (4) and a power supply main switch (5) which are arranged on the shell (6). Positive and negative probes (7) are installed on the bottom surface of the shell. The detection method of the resistance-type winter bamboo shoot detector is realized through four steps: selection of time, climate, forestland and detection and digging points, pretreatment before detection and digging, detection, and digging. The detector has functions of automatic relevant digital processing and sound / light display, and is suitable for dark places and bamboo shoot growers who start work early, knock off late and suffer from unsound eyesight; the detection reliability is high, the problems that a great quantity of holes are dig in the forestland, underground stems are broken during digging, the bamboo shoot bodies are crushed during digging and the yield of bamboo shoots and bamboos is influenced as a result of untargeted digging are prevented from occurring, the bamboo shoot digging efficiency is high, the detector is simple to operate and the manufacturing cost is low.

The invention provides a pole and tower impact grounding resistance measurement method considering soil space moisture distribution. The method comprises the following steps of 1) investigating measured pole and tower information; 2) according to a site condition, constructing a soil space moisture distribution test system; 3) selecting points and detecting a surrounding soil moisture distributioncondition of a measured grounding network; 4) calculating and acquiring an influence weight of data of each measurement point on an integral impact grounding resistance; and 5) according to test point soil water content data, calculating and acquiring the impact grounding resistance of a pole and tower ground in different soil space moisture distribution. In the invention, based on an actual workcondition, the impact grounding resistance when soil space moisture distribution is unbalanced can be accurately calculated and acquired; through calculating the impact grounding resistance, a line operation state when a pole and tower is hit by lightning strike can be effectively determined; and a test platform is easy to arrange, is simple and effective, and is suitable for various conditions.

The invention is a numerical simulation method for a cathode-protection shallow-buried type anode ground bed grounding resistance, and relates to the technical fields of general corrosion prevention and pipeline system of metal materials. The numerical simulation method comprises the following steps: carrying out preliminary design of a ground bed; measuring on-site parameters; setting a plurality of preliminary ground bed design schemes; aimed at each of the preliminary design schemes, building a corresponding three-dimensional geometric model; dividing gridding and setting boundaries; solving a calculation model, and utilizing the Ohm's law to obtain the anode ground bed grounding resistance; finally, continuing to create a ground bed grounding resistance variable Rgrounding for storing a ground bed grounding resistance value with an expression formula of Rgrounding=delta U / I-total, wherein delta U represents a difference between a set anode ground bed boundary potential and a spherical crown potential; and thus obtaining corresponding grounding resistance values of the ground bed design schemes in specific soil conditions. The method is based on a finite element discretization algorithm, has wide application range, is simple and feasible to implement, and has high accuracy.

The invention discloses a ground resistance calculation method of a double-layer soil containing a massive medium. A double-layer soil model containing the massive medium comprises a ground, upper layer soil, lower layer soil and the massive medium which are arranged under the ground and at least one cylindrical ground body. The massive medium is evenly distributed in the upper layer soil and the lower layer soil, and the ground body is vertically inserted into the ground surface and is completely wrapped by the massive medium. A moment method is adopted to disperse an integral equation to be calculated by building the model, a matrix equation is calculated, and finally the ground resistance is obtained. The method is smaller in error and accurate in calculation result.

A semiconductor memory device and a method for manufacturing the same are provided. The semiconductor memory device includes an oxide layer for isolating individual devices which define device areas so that a cell area and a peripheral circuit area are separated from each other on a semiconductor substrate, a plurality of MOS transistors, which are comprised of source areas, drain areas, and gates that are formed in the cell area and the peripheral circuit area, a bit line, which is formed on the plurality of MOS transistors and is electrically connected to the MOS transistor, a stack-shaped capacitor, which is comprised of a first electrode, a dielectric layer, and a second electrode between which the MOS transistors and the bit line in the cell area is interposed, a guard-ring pattern, which are interposed between the cell area and the peripheral circuit area, surrounds the cell area and is apart from the peripheral circuit area, and a contact fill for plate electrode, which is formed in the guard-ring pattern and is in contact with the second electrode that is formed on the internal sidewall and the bottom of the guard-ring pattern. The guard-ring pattern is formed in a boundary between the cell area and the peripheral circuit area while surrounding the cell area, and thereby step caused by manufacture of the stack-shaped capacitor are removed during a manufacturing process, and the contact fill for plate electrode is formed in the guard-ring pattern, and thereby the ground resistance of the capacitor is reduced, and the electrical characteristics of the memory device are improved.

The invention discloses a semiconductor package with a cooling fin, and the semiconductor package comprises a lead frame. The lead frame comprises a chip carrier and a plurality of bent pins, wherein the plurality of bent pins are electrically connected with the chip carrier, and each pin comprises a pin surface, is parallel to the chip carrier and continuously extends between the chip carrier and the pin surface. The semiconductor package also comprises a chip installed on the chip table; a source electrode metal piece and a grid electrode metal piece, which are arranged in an insulated and isolated manner, wherein one plane of the source electrode metal piece and one plane of the grid electrode metal piece are respectively connected with a source electrode metal layer and a grid electrode metal layer of the chip in an all-surface manner, and the opposite planes of the source electrode metal piece and the grid electrode metal piece share one plane with the pin surface; and a package body which enables the lead frame, the chip, the source electrode metal piece and the grid electrode metal piece to be packaged. The semiconductor package can increase the effective connection area of the source electrode, so as to reduce the conducting resistance and grounding resistance. The semiconductor package reduces the power loss, is low in cost, and is small in package size.

The invention discloses a method for obtaining the impulse impedance of a grounding device through low lightning current impulse test, comprising the steps as follows: (1) using a low-current lightning impulse current generator to carry out impulse test of a grounding device, measuring the grounding resistance of the grounding device when the output current peak is 1KA and the lightning impulse waveform is 8 / 20muS, and taking the grounding resistance as the power-frequency grounding resistance R3 containing an inductive effect; (2) acquiring the spark correction coefficient K1; and (3) calculating the impulse impedance R1 of the grounding device based on the formula R1=K1*R3. According to the invention, an impulse coefficient is decomposed into a spark effect correction coefficient and an inductive effect correction coefficient through spark effect and inductive effect decoupling, the spark effect correction coefficient is obtained by related standard querying or field testing, the inductive effect correction coefficient is obtained by field low lightning current impulse test, and therefore, the impulse impedance of the grounding device under the action of actual high lightning current impulse is obtained.

The invention discloses a back segment technology for improving the reliability performance of a compound semiconductor device. After a wafer finishes a front side manufacture procedure and steps including back hole, back metal layer and barrier layer manufacture and the like, the surface of the barrier layer is infiltrated by isopropyl alcohol, then, photoresist is coated and is subjected to general exposure, exposure time is controlled until photoresist out of the back hole is completely exposed and at least parts of photoresist in the back hole are not completely exposed, and development iscarried out to remove the completely exposed photoresist. After the exposed barrier layer is removed by etching, residual photoresist in the back hole is removed, and therefore, the barrier layer inthe back hole is left. By use of a method for infiltrating the barrier layer by IPA (isopropyl alcohol), the photoresist can be evenly coated in the hole, a photomask plate is not required, exposure adhesive thickness is controlled by the general exposure time, and the barrier layer guarantees to be only positioned in the back hole after etching. Compared with a traditional technological structure, the technology disclosed by the invention reduces device ground resistance, meanwhile, sintering porosity is reduced, and the reliable performance of the device is improved.

The invention discloses a transformer core multi-point earthing fault testing device. The device mainly comprises a transformer, a fault simulation module, a communication conversion module, a computer and a box. A transformer core is a wound core, an excitation winding is wound on the core, 12 earthing wires are led out from different positions in the core and connected with the fault simulation module, instructions are sent out through the computer, and the on-off state of a relay on the fault simulation module is controlled through the communication conversion module so as to be connected or disconnected with the ground. Multi-point earthing fault testing of the core at different positions can be conducted, the amplitude of faulty current is monitored, and influences of ground resistance on fault conditions are researched. The testing device is simple in structure, accurate and reliable in detection, convenient to operate and very suitable for on-site application.

The invention relates to a radio frequency high-power heat pipe radiator. The radiator comprises a radiating base (1), a radiating fan (2), a heat pipe and a mask (4), wherein the lower surface of the radiating base (1) is provided with a fin (11); the radiating fan (2) is fixed on the lower surface of the radiating base (1); the heat pipe (3) is embedded in the upper surface of the radiating base (1); and the mask (4) is covered on the heat pipe (3). The heat pipe is arranged in the radiating base, and the mask in close contact with a PCB board which is provided with a radio frequency high-power amplifier chip is arranged on the heat pipe, so thermal resistance and grounding resistance between the radio frequency high-power amplifier chip and the radiating base is reduced, radiating area is saved, and radiating efficiency is enhanced.