42results about How to "Improve lightning resistance level" patented technology

The invention discloses a lightning arrester of an insulator for a power supply line, in particular relates to an outer-gap lightning arrester. The outer-gap lightning arrester is characterized in that an upper metal tool is provided with a pressure adjustment element, a conductive band, a zinc oxide resistance card, an inner discharge electrode, an insulating gasket and an outer discharge gap rod, wherein a thread upper part of an lower end metal tool is provided with an outer discharge gap sheath, and the shape of the outer discharge gap rod is drooping. The outer-gap lightning arrester disclosed by the invention has the advantages: a tiny residual voltage is introduced into the earth and the protection process of electric equipment is finished when the outer discharge gap rod generated by lightning discharges to the outer discharge gap sheath; therefore, the investment cost and the maintenance cost are reduced; the outer-gap lightning arrester is not influenced by the climatic environment, the atmospheric pollution and the geological conditions; the zinc oxide resistance card is not corroded, and the service life is long; the product made of a silicon rubber material has the advantages of lightness, portability, good insulation property, long creepage distance, convenience for construction, reduced labor intensity and safety, stability and reliability for operation. The lightning protection level of the power supply line is improved, and good effects of small investment, large yield, free-maintenance and over 98% of effective protection probability are achieved.

The invention discloses a grounding method for a composite insulating pole tower of a power transmission line and a pole tower thereof. The pole tower main body adopts a composite tube, a conductor cross arm adopts a composite insulator, a ground wire cross arm adopts a metal conductor, a grounding down-lead adopts a metal wire or a tube or a bar, the grounding down-lead is suspended from the middle of the tube and is led down to be grounded, the ground wire cross arm and the conductor cross arm are provided with metal electrodes, and the proper part of the pole tower is perforated for arranging the grounding down-lead to lead out the electrodes; and the air gap distance between the ground wire side electrode and the conductor side electrode and the air gap distance between the leading-out electrode of the grounding down-lead and the conductor can be determined according to the lightning protection requirement. The grounding mode of the composite pole tower effectively utilizes the insulating property of a composite pole, can improve the pollution flashover and ice flashover resistance, wind deflection prevention and lightning protection level of the line, can also compress the size of a tower head, and has the advantages of reducing the manufacturing cost and the transportation, assembly and maintenance expenses of the pole tower main body and reducing corridor width of the line at the same time.

The invention discloses a distribution network integrated lightning protection system comprising a transformer substation, and output lines led out of three phases of outlet ports of a transformer substation transformer. Each phase of line is connected in series with an overvoltage isolator. Overhead wires are formed through lead-out of the output ends of the voltage isolators to a pole tower. Pole tower insulating cross arms support the overhead wires, and power transmission wires are fixed via multifunctional wire clamps arranged on the insulating cross arms. A wave-resistant lightning rod is installed at the top end of the pole tower. A simple and rapid grounding device is embedded in the ground of the bottom part of the pole tower so that integrated lightning protection performed on the distribution network lines and the transformer substation is realized with pole tower protection acting as the center and prevention of distribution network lightning tripping and disconnection acting as the key points. Distribution network line dedicated lightning equipment like the wave-resistant lightning rod, the insulating cross arms, the multifunctional wire clamps and the simple grounding device are organically integrated by the system so that the multilayer and three-dimensional integrated lightning protection system is constructed and realized, lightning trip-out rate and disconnection rate can be substantially reduced, and maximum matching of distribution network lightning economical efficiency and effectiveness is realized.

The invention discloses an insulation tower head used for a distribution network overhead line, relating to the field of distribution network overhead line lightning overvoltage protection; wherein, the insulation tower head comprises an insulation pillar which is used for single-circuit or same-rod multi-circuit line. The insulation tower head also comprises a cross arm insulator or a cross arm and a pin-typed / pillar insulator; wherein, an overhead lead is fixed at one end of the cross arm insulator or on the pin-typed / pillar insulator at the end of the cross arm; the other end of the downmost cross arm or the middle part of the cross arm is fixed at the upper end of the insulation pillar; the lower end of the insulation pillar is fixed on the top of a power pole. According to the practical requirement of the system, the insulation pillar, the composite / ceramic cross arm insulator, the insulation / metal cross arm and the pin-typed / pillar insulator can be combined for usage to form the insulation tower head with a plurality of structure types, thus greatly improving the insulation level of the line and effectively preventing the accidents of line trip, insulator damage and insulation lead breakdown, etc. which are caused by lightning induction overvoltage of overhead line.

The invention relates to a lightning protection performance analysis method for a graphite grounding device of a power transmission line tower, and the method comprises the following steps: (1), analyzing the structure of the tower grounding device according to the grounding data of the power transmission line, changing a round steel grounding material into a graphene material, and building a grounding grid model through an SESCAD module of CDEGS simulation software; (2) introducing the soil model, calculating the power frequency grounding resistance by using an MALZ module, comparing the power frequency grounding resistance with the grounding resistance of the original round steel grounding model, and judging whether the grounding resistance of the graphite grounding device meets the standard or not; (3) aiming at the tower top lightning stroke mode, adopting ATP-EMTP software simulation to establish a line and tower model, and analyzing the influence on the lightning resistance levelunder the graphite grounding condition; and (4) modifying the lightning current amplitude for multiple times as required, and performing simulation calculation for multiple times until the lightningresistance level is obtained. According to the method, the grounding resistance can be effectively reduced, the lightning resistance level is improved, and a basis is provided for design, popularization and application of the graphene grounding device.

The invention discloses an overhead distribution line, which comprises a strain pole, two composite cross arms and strain fixed parts, wherein the middle parts of the composite cross arms are horizontally fixed on the strain pole; the end parts of the composite cross arms are connected with the strain fixed parts; the two composite cross arms are connected into a whole through the strain fixed parts; and the strain fixed parts are used for fixing wires. Through the overhead distribution line, two composite cross arms are fixed on the same horizontal plane of the strain pole, so that the longitudinal tension required for tension can be met; the dry arcing distance can be further greatly increased by using compounding of composite cross arm bodies, the electrical lightning withstand level can be improved and the accidents, such as lightning stroke breakage flashover are avoided; the composite cross arms are free of maintenance and free of periodic inspection and maintenance, so that thehuman cost is greatly reduced; and a strain insulator can be omitted through use of the composite cross arms, so that the structure of the line is simplified.

The invention discloses a method for selecting the erection height of a lightning conductor of a 10kV overhead distribution line. The method comprises the following steps: (1) building and obtaining a mathematical model of the height of the lightning conductor; (2) obtaining a maximum of a lightning conductor height function; (3) calculating a phase conductor stress and a lightning conductor stress under a current meteorological condition; (4) calculating height maximum Hm of the lightning conductor under a different-span length 1; (5) calculating the coupling performance of the lightning conductor and the phase conductor at different heights of the lightning conductor; and (6) selecting the suitable height of the lightning conductor. According to the invention, the erection height of the lightning conductor can be analyzed and selected in the terms of mechanical stress and electrical coupling performance in a scientific and reasonable manner. The method provided by the invention is simple and feasible, and has good engineering use significance.

The invention discloses a device for reducing an impulse grounding impedance value. The device fro reducing the impulse grounding impedance value comprises a drainage conductor arranged on a tower horizontal grounding electrode. A plurality of shunt conductors are arranged on the periphery of the drainage conductor and are evenly distributed in sequence along the extending direction of an axis of the drainage conductor. During an operation process, the plurality of shunt conductors are welded on the drainage conductor, and therefore an 'end effect' of the grounding electrode is restrained, broken stream is enabled to be more even, middle broken stream capacity of the drainage conductor is fully used, a grounding conductor is used more fully, a whole assembling structure is simple and reliable, the operation process is convenient and easy to carry out, the impulse grounding impedance value can be greatly reduced, a lightning withstand level of a electric transmission and distribution circuit is obviously improved, trip phenomena caused by lightning stroke is reduced, and safe and stable operation of an electric system is endured. The invention further discloses a method which uses the device and used for reducing the impulse grounding impedance value.

The invention discloses a three-loop iron tower of a power transmission line. The three-loop iron tower comprises a tower body as well as three layers of horizontal trusses, wherein two tower columns are arranged at the top of the tower body at intervals in parallel; the tower columns are arranged in the length direction of the tower body; the horizontal trusses comprise two large trapezoids as well as a small trapezoid, wherein the two large trapezoids take the tower columns as a center; the bottom sides of the two large trapezoids are connected between the two tower columns; the small trapezoid takes the bottom sides of the two large trapezoids between the two tower columns as the bottom; the upper bottom of the small trapezoid is supported on the waists of the two large trapezoid; lead suspending points are arranged on the lower bottom angles on the lower bottom corners, outside the two tower columns, of the two large trapezoids; another lead suspending point is also arranged at a public lower bottom corner where the two large trapezoids join each other. According to the three-loop iron tower, the three layers of the horizontal trusses are arranged on the head of the tower to bear the load of a lead, and the load of the horizontal trusses is conducted to truss columns on two sides of the tower head in symmetry and is further conducted to the tower body through the reasonably arranged truss structure, so that the rigidity mutation of the tower body is avoided; the three-loop iron tower is simple and definite in mechanical structure and simple in structure.

The invention relates to a differential lightning-proof reconstruction method of a 35kV power transmission line, belongs to the technical field of lightning protection for power facilities and solves the technical problems by providing the reconstruction method of the 35kV power transmission line, whereby lightning damage is effectively avoided for the power transmission line. According to the technical scheme, the method includes the steps of collecting the pole type, insulation configuration, topographic conditions and historical lightning fault information of existing 35kV power transmission line pole / tower equipment, and subjecting the pole / tower equipment, not satisfactory to lightning protection, to data statistics; subjecting a power transmission line pole / tower ground network, not satisfactory to lightning protection, to reconstruction and to differential insulation reconstruction, and mounting lighting arrestors; recording the state of the reconstructed 35kV power transmission line pole / tower equipment in a power production management system, and combining the state with GIS (geographic information system) information to form a GIS map of the power transmission line pole / tower equipment. The method is suitable for power systems.

The invention provides an insulation pole of a 10 kV high voltage line. The insulation pole comprises an insulation cross arm and an insulation pole body; the insulation cross arm has a lengthwise direction, the insulation rod body has a height direction, and the lengthwise direction is perpendicular to the height direction; the insulation rod body is fixedly connected with the midpoint of the insulation cross arm.

The invention relates to a grading ring used on an electric transmission line tower, and belongs to the technical field of high-voltage electrical equipment. The grading ring is a hollow flat round shape, an installation hole is formed in the center of the grading ring, the height H of the grading ring ranges from 20 cm to 30 cm, the thickness d of a shell of the grading ring ranges form 0.1 cm to 1 cm, the radius R of the grading ring ranges form 15 cm to 25 cm, and the arc radius r of the shell of the grading ring is equal to H / 2. Tests and simulated analysis of the compact electric transmission line tower with the grading ring prove that compared with a common grading ring 37 cm in diameter at present, the grading ring used on an electric transmission line tower has the advantages that 50% of discharged voltage of shielding failure and counter attracts of positive thunders and negative thunders simulated in a thunder impact test can be improved, and the thunder withstand level of the electric transmission line tower on the shielding failure and the counter attracts of the positive thunders and the negative thunders can be further improved. The grading ring is simple in structure and convenient to install and manufacture, and bringing convenience to large-scale production and application.

The invention discloses a neutral point disperse grounding type two-terminal direct current bipolar transmission system which comprises first pole leads and second pole leads which are symmetrically arranged according to transmission and form a loop. A current converter is respectively arranged between one end of each first pole lead and one end of an adjacent second pole lead and between the other end of the first pole lead and the other end of the adjacent second pole lead, and the current converters are symmetrically arranged. First grounding pole leads and second grounding pole leads which are mutually connected are respectively symmetrically arranged on two sides in the loop formed by the first pole leads and the second pole leads. The neutral point disperse grounding type two-terminal direct current bipolar transmission system further comprises two-terminal direct current systems which are respectively connected between the first grounding pole leads and the second grounding pole leads and are symmetrically arranged. The neutral point disperse grounding type two-terminal direct current bipolar transmission system reduces electric energy loss, has good diversion and transfer effects, is improved in line lightning protection capability, is large in coupling ground wire diversion effect, and greatly improves line lightning protection level; reduces direct current single electrode locking failure occurrence rate, greatly reduces line construction investment, and improves influence on ecological environment; and more importantly, greatly protects ecology in initially planned grounding pole address areas due to removal of grounding-pole pole addresses.

The invention discloses a method for measuring the power frequency grounding resistance of a single ground wire iron pipe tower, which can greatly improve the test efficiency and the test accuracy, discover bad grounding in time and improve the lightning withstand level of equipment. The method comprises the following steps: (a) checking a ground electrode of the iron pipe tower, recording and timely processing abnormalities that a ground wire is damaged or a bolt is stolen and the like; (b) measuring the grounding resistance of the iron pipe tower using a clamp meter method without detaching the ground wire, checking whether ironware connecting bolts are loosed or in bad contact if the grounding resistance of the iron pipe tower is obviously increased relative to the grounding resistance of other surrounding tower and the conventional value of the iron pipe tower or exceeds the provision of the corresponding standard or regulation on the grounding resistance, re-measuring the grounding resistance after excluding, and executing step (c) if the grounding resistance is still increased or exceeds the standard; and (c) measuring the grounding resistance of the iron pipe tower using a three-pole method under the condition that the ground wire is disconnected from tower metal, checking whether the ground electrode is unqualified or the ground wire at the upper part of the tower is in bad contact and the like, judging the reason and making corresponding reformation.

The invention discloses a method for measuring the power frequency grounding resistance of an iron pipe tower with double ground wires, which can greatly improve the test efficiency and the test accuracy, discover bad grounding in time and improve the lightning withstand level of equipment. The method comprises the following steps: (a) checking a ground electrode of the iron pipe tower, recording and timely processing abnormalities that a ground wire is damaged or a bolt is stolen and the like; (b) measuring the grounding resistance of the iron pipe tower using a clamp meter method under the condition that one ground wire is opened, checking whether ironware connecting bolts are loosed or in bad contact if the grounding resistance of the iron pipe tower is obviously increased relative to the grounding resistance of other surrounding tower and the conventional value of the iron pipe tower or exceeds the provision of the corresponding standard or regulation on the grounding resistance, re-measuring the grounding resistance after excluding, and executing step (c) if the grounding resistance is still increased or exceeds the standard; and (c) measuring the grounding resistance of the iron pipe tower using a three-pole method under the condition that the two ground wires are disconnected from tower metal.

The invention discloses an alternating current transmission line iron tower which comprises a tower body and a cross arm at the top end of the tower body. The middle and the two ends of the lower side of the cross arm are each connected with a lightning-proof insulator. The lower ends of the lightning-proof insulators at the two ends are each connected with a side phase conductor. The lower end of the lightning-proof insulator in the middle is connected with a middle phase conductor. A compound fiber overhead ground wire is arranged on the waist of the tower body. The conductors are suspended on the lightning-proof insulators, so that the alternating current transmission line iron tower has the functions of suspension, insulation and lightning prevention at the same time. When ground lightning directly strikes the tower or the conductors, the lightning overvoltage will make the lightning-proof insulators move, impact energy is absorbed, the overvoltage is suppressed so as to protect the insulators against flashover, tripping of a transmission line is avoided, and power supply reliability is improved; the compound fiber overhead ground wire is located below the three phase conductors, so that the normal power communication function is achieved, the lightning overvoltage on the lightning-proof insulators can be decreased due to the coupling effect, the lightning-proof level is further improved, the lightning tripping frequency of the transmission line is effectively decreased, and the power supply reliability is improved.

The invention relates to a grounding disc device used for a concrete telegraph pole. The grounding disc device is constituted by a bottom plate, supporting columns disposed on the bottom plate, and fixed hoop connected with the top ends of the supporting columns. The grounding disc device is characterized in that the supporting columns are disposed on the periphery of the bottom plate, and the adjacent supporting columns are parallely arranged; the size of the bottom plate is cooperated with the size of the fixed hoop, and the fixed hoop is connected with a grounding disc lead. By adopting the grounding disc device, the damage on the road surface can be reduced, and the compensation costs can be greatly reduced. Under the same topographical and geological condition, the grounding resistance value of the grounding disc is lower than that of the grounding tube, and the low lightning current back flashover voltage can be reduced, and then the lightning resistant level of the line can be improved, and the power failure accident can be reduced. The construction operation intensity of the workers can be greatly reduced, and the construction quality can be guaranteed, and therefore the object of improving the working efficiency can be achieved.

The invention relates to a compound material pole tower. A main body of the pole tower adopts a compound material; a main connecting part adopts compound material or galvanized steel; a lead cross arm adopts a compound insulator; a ground lead cross arm adopts galvanized steel; a downlead cross arm adopts galvanized steel adopts galvanized steel; a grounding downlead adopts wires and bars; the upper end of the grounding downlead is fixed on the grounding wire cross arm, is led from leads at the outside of one side or two sides of the pole tower, is fixed on the downlead cross arm to lead the grounding downlead and the lead to keep fixed distance, and is grounded from the downlead cross arm along the tower body. Compared with the conventional 110kV iron tower, the compound material pole tower greatly increases phase-earth and interphase air gaps and insulating creepage distance of a tower head, greatly improves pollution flashover resistance, ice flashover resistance, windage yaw prevention and lightning-resistant level, also can compress the size of the tower head, and has the advantages of reducing the cost as well as expenses for transportation, installation and maintenance of the pole tower body and simultaneously reducing the width of a line corridor.

The invention discloses a 10kV overhead line lightning protection method using a coupling ground wire and a lightning arrester cooperatively. The method comprises the steps of firstly considering the impact on the bearing of a line tower and other mechanical aspects after the coupling ground wire is additionally installed, calculating the applicability, and obtaining the installation number of the coupling ground wires, secondly, under various extreme conditions (icing and windage yaw), ensuring that no discharge occurs between the coupling ground wire and the wire at the center of the span, so as to determine the installation position of the coupling ground wire, and further provide the method for testing the lightning resistance level of the 10kV overhead line containing the coupling ground wire. Aiming at the problem that the lightning resistance level is reduced after a coupling ground wire is erected in a segmented manner, the invention provides a lightning protection method matched with a lightning arrester for use at the segment of the coupling ground wire, and a 10kV overhead line lightning overvoltage simulation calculation model is established by utilizing simulation software, with the condition that a distribution line is not subjected to two-phase short circuit, the lightning protection effect of the segmented part of the coupling ground wire matched with the MOA is tested. On the basis of the existing lightning protection design, the lightning resistance level of the 10kV distribution line is further improved, and the operation reliability of the distribution network is improved.

The invention discloses an insulation tower head used for a distribution network overhead line, relating to the field of distribution network overhead line lightning overvoltage protection; wherein, the insulation tower head comprises an insulation pillar which is used for single-circuit or same-rod multi-circuit line. The insulation tower head also comprises a cross arm insulator or a cross arm and a pin-typed / pillar insulator; wherein, an overhead lead is fixed at one end of the cross arm insulator or on the pin-typed / pillar insulator at the end of the cross arm; the other end of the downmost cross arm or the middle part of the cross arm is fixed at the upper end of the insulation pillar; the lower end of the insulation pillar is fixed on the top of a power pole. According to the practical requirement of the system, the insulation pillar, the composite / ceramic cross arm insulator, the insulation / metal cross arm and the pin-typed / pillar insulator can be combined for usage to form theinsulation tower head with a plurality of structure types, thus greatly improving the insulation level of the line and effectively preventing the accidents of line trip, insulator damage and insulation lead breakdown, etc. which are caused by lightning induction overvoltage of overhead line.

The invention discloses a steel pipe pole for preventing indirect lightning strike. The steel pipe pole comprises a pole body (1) and cross arms (2), wherein the plurality of cross arms (2) are symmetrically mounted on the pole body (1) at intervals; the steel pipe pole is characterized in that a lightning arrester (4) is mounted on the pole body (1) through an insulator (3); one end of a lower lead (5) is connected with the lightning arrester (4), and the other end of the lower lead (5) is connected with a ground electrode. The steel pipe pole disclosed by the invention is simple in structure and convenient to operate, can reduce the lightning trip-out rate of an electric transmission line, and reduces the power failure influence.

The invention relates to a composite insulator resistant to lightning strike. The composite insulator comprises a core rod, a first sheath, an umbrella skirt arranged on the sheath, a high voltage end armor clamp and a grounding end armor clamp. The composite insulator is characterized by also comprising at least one first stress cone (group), the first stress cone (group) is arranged at the position(s) where the high voltage end armor clamp and / or the grounding end armor clamp and / is connected with the core rod, the first stress cone group is composed of two first stress cones whose bottoms are fit, and the first stress cone is an externally insulated stress cone. The composite insulator has the advantages that the structural safety of the armor clamps in the end portions is effectively protected, the lightning-resistant level of the insulator is improved, and the service life of the insulator is prolonged; the force, of lightning strike voltage, borne by the armor clamps in the end portions is reduced, it is ensured that temperature rise of the insulator is no 20K more than the ambient temperature; and the flashover voltage and the corona voltage of the insulator are improved; and the structure is simple and reasonable, and installation is convenient.

The invention discloses a grounding method for a composite insulating pole tower of a power transmission line and a pole tower thereof. The pole tower main body adopts a composite tube, a conductor cross arm adopts a composite insulator, a ground wire cross arm adopts a metal conductor, a grounding down-lead adopts a metal wire or a tube or a bar, the grounding down-lead is suspended from the middle of the tube and is led down to be grounded, the ground wire cross arm and the conductor cross arm are provided with metal electrodes, and the proper part of the pole tower is perforated for arranging the grounding down-lead to lead out the electrodes; and the air gap distance between the ground wire side electrode and the conductor side electrode and the air gap distance between the leading-out electrode of the grounding down-lead and the conductor can be determined according to the lightning protection requirement. The grounding mode of the composite pole tower effectively utilizes the insulating property of a composite pole, can improve the pollution flashover and ice flashover resistance, wind deflection prevention and lightning protection level of the line, can also compress the size of a tower head, and has the advantages of reducing the manufacturing cost and the transportation, assembly and maintenance expenses of the pole tower main body and reducing corridor width of the line at the same time.

The invention discloses a differential lightning protection modification method for 35kV transmission lines, which belongs to the technical field of electric facility lightning protection; the technical problem to be solved is: to provide a 35kV transmission line modification method that can effectively avoid the lightning hazard of transmission lines; the adopted technical scheme is as follows: : A 35kV transmission line differential lightning protection transformation method, comprising the following steps: first, collecting the tower type, insulation configuration, terrain conditions and historical lightning strike fault information of the existing 35kV transmission line tower equipment, and those that do not meet the lightning protection requirements The data statistics of the tower equipment of the transmission line are carried out; secondly, the grounding network of the transmission line tower that does not meet the lightning protection requirements is transformed, the poor insulation is transformed, and the lightning arrester is installed; thirdly, the status of the transformed 35kV transmission line tower equipment is entered into the power production management system, And combined with GIS information to form a GIS map of transmission line tower equipment; suitable for power systems.

According to the method for calculating the power frequency follow current interrupting capacity of the multi-cavity arc extinguishing device, an arc model is used for representing a plurality of short arcs based on the arc chain type idea, the number of cavities is changed by changing the dissipated power value, and the arc model is built in ATP-EMTP. Modeling of the multi-cavity arc-extinguishing device is achieved by combining an insulation flashover model, the multi-cavity arc-extinguishing device is applied to a lightning stroke model of the power transmission line, a lightning stroke model of the power transmission line of the multi-cavity arc-extinguishing device is obtained, and the power frequency follow current interruption capacity of the multi-cavity arc-extinguishing device under different cavity numbers is calculated in a simulating mode. Compared with a multi-chamber arc extinguishing device, an arc model is realized by connecting arc models of single chambers in series, and due to the fact that the number of chambers of a multi-chamber structure is too large when the voltage grade of a power transmission line is high, the multi-chamber structure is difficult to realize in simulation. Therefore, the number of the cavities is changed by changing the dissipated power value, and safe and reliable operation of the power transmission line can be effectively guaranteed by selecting the proper number of the cavities in the lightning stroke transient model of the power transmission line.

A lightning impact resistant composite insulator of the present invention comprises a mandrel, a first sheath, an umbrella shed provided on the sheath, a high-voltage end fitting and a grounding end fitting, and is characterized in that it also includes at least one first stress cone or second stress cone A stress cone group, the first stress cone or the first stress cone group is arranged at the connection between the high-voltage end fittings and / or the grounding end fittings and the mandrel, and the first stress cone group is composed of two cone bottoms bonded by the second A stress cone is combined, and the first stress cone is an external insulation stress cone. The invention has the following beneficial effects: effectively protecting the structural safety of the end fittings, improving the lightning resistance level and service life of the insulator; reducing the intensity of the lightning impulse voltage received by the end fittings; ensuring that the temperature rise of the insulator does not exceed the ambient temperature 20K, which improves the flashover voltage and corona inception voltage of the insulator; the structure is simple and reasonable, and the installation is convenient.

The invention discloses a device for reducing an impulse grounding impedance value. The device fro reducing the impulse grounding impedance value comprises a drainage conductor arranged on a tower horizontal grounding electrode. A plurality of shunt conductors are arranged on the periphery of the drainage conductor and are evenly distributed in sequence along the extending direction of an axis of the drainage conductor. During an operation process, the plurality of shunt conductors are welded on the drainage conductor, and therefore an 'end effect' of the grounding electrode is restrained, broken stream is enabled to be more even, middle broken stream capacity of the drainage conductor is fully used, a grounding conductor is used more fully, a whole assembling structure is simple and reliable, the operation process is convenient and easy to carry out, the impulse grounding impedance value can be greatly reduced, a lightning withstand level of a electric transmission and distribution circuit is obviously improved, trip phenomena caused by lightning stroke is reduced, and safe and stable operation of an electric system is endured. The invention further discloses a method which uses the device and used for reducing the impulse grounding impedance value.

The invention relates to a compact high-attitude electric transmission line tower window allowing wires to be specially arranged, and belongs to the technical field of high-voltage electrical equipment. A grading ring, an insulator, a divided conductor and the electric transmission wires are arranged inside the tower window, wherein the electric transmission wires are evenly distributed around the divided conductor, the distance Lda between each lower-phase electric transmission wire and the side surface of the tower window is 4.3 m, the horizontal distance Lbc between every two upper-phase electric transmission wires is 7.0 m, and the distance Lba between the upper-phase electric transmission wires and the distance Lca between the lower-phase electric transmission wires are respectively 7.3 m. According to the compact high-attitude electric transmission line tower window, by means of the inner wire arrangement mode, the positive polarity shielding-failure lightning withstand level is higher than that of an original arrangement mode of the compact high-attitude electric transmission line tower window by 6.9%, the negative polarity shielding-failure lightning withstand level is higher than that of the original arrangement mode by 2.8%, and circuit safety operation capacity can be improved under the circumstance that cost is saved as much as possible.

The invention discloses a method for measuring the power frequency grounding resistance of a single ground wire iron pipe tower, which can greatly improve the test efficiency and the test accuracy, discover bad grounding in time and improve the lightning withstand level of equipment. The method comprises the following steps: (a) checking a ground electrode of the iron pipe tower, recording and timely processing abnormalities that a ground wire is damaged or a bolt is stolen and the like; (b) measuring the grounding resistance of the iron pipe tower using a clamp meter method without detaching the ground wire, checking whether ironware connecting bolts are loosed or in bad contact if the grounding resistance of the iron pipe tower is obviously increased relative to the grounding resistance of other surrounding tower and the conventional value of the iron pipe tower or exceeds the provision of the corresponding standard or regulation on the grounding resistance, re-measuring the grounding resistance after excluding, and executing step (c) if the grounding resistance is still increased or exceeds the standard; and (c) measuring the grounding resistance of the iron pipe tower using a three-pole method under the condition that the ground wire is disconnected from tower metal, checking whether the ground electrode is unqualified or the ground wire at the upper part of the tower is in bad contact and the like, judging the reason and making corresponding reformation.

The invention discloses a device for lowering the lightning stroke trip-out rate of an electric transmission line by utilizing a coupling ground wire. The device comprises the coupling ground wire (1), wherein the coupling ground wire (1) is arranged below a cross arm of a lower lead wire (5), the coupling ground wire (1) is provided with a wire clamp (2), and the coupling ground wire (1) is connected with a principle material (3) through the wire clamp (2); anti-vibration whips (4) are sleeved on both ends of the coupling ground wire (1), and the installation distance of the anti-vibration whips (4) is a pre-twisted wire with a tail end outward of the wire clamp (2). By utilizing the current division and coupling action of the coupling ground wire, the lightning stroke overvoltage is reduced, and the lightning stroke trip-out rate of the electric transmission line is lowered.