Manufacturing method for heavy-load 10kv lightning arrester having large flowing current

Abstract

A manufacturing method for a heavy-load 10kV lightning arrester having a large flowing current, the method comprising: performing a direct-current reference voltage test on valve blocks to be selected, so as to obtain a target valve block, the target valve block meeting the following conditions: the large-current surge tolerance capacity is greater than or equal to 100kA, the flowing current capacity is greater than 600A, the residual voltage under a 10kA flowing current is less than or equal to 45kV, and the repeat transfer charge capacity is greater than or equal to 0.8C; and assembling a fiberglass epoxy resin layer and an electrode pair into a sealed housing, such that the target valve block is located in a chamber of the sealed housing, and the target valve block is separately and electrically connected to a first electrode of the electrode pair and a second electrode of the electrode pair so as to form a heavy-load 10kV lightning arrester having a large flowing current. The problems of frequent faults of lightning arresters in the prior art are solved.

Description

Preparation method of heavy-load 10kV large through-current arrester

[0001] This application claims priority to the Chinese patent application filed with the China Patent Office on June 12, 2023, with application number 202310693076.6 and invention name “Method for preparing heavy-load 10kV large-current lightning arrester”, the entire contents of which are incorporated by reference into this application. Technical Field

[0002] The present invention relates to the technical field of lightning arresters, and in particular to a method for preparing a heavy-load 10kV large-through-current lightning arrester. Background Art

[0003] The Southern Power Grid is located in tropical and subtropical regions with frequent lightning disasters. For a long time, it has been strongly affected by lightning activities. Based on the design of typical 10kV distribution lines and the parameters of D3, D4, and D5 series resistor-type lightning arresters, detailed calculations and analyses were conducted on the operating conditions of lightning arresters under conditions of lightning currents with different waveforms and amplitudes impacting conductors, towers, and induced lightning strikes. The residual voltage, through-current, discharge current, absorbed energy, and energy overload probability of various lightning arresters under different lightning faults were given. In particular, the main reason for the short life and high damage rate of the arrester caused by the severely insufficient through-current capacity of the D3 series resistor-type lightning arrester was pointed out. The energy absorbed by a single D3 series resistor-type lightning arrester is about 20kJ to 25kJ.

[0004] Currently, the 10kV rack transformers in the heavily loaded distribution network of the Southern Power Grid mostly use conventional YH5WS-17 / 50 type lightning arresters. When lightning current directly strikes the conductor, the arrester discharge current often exceeds 5kA, and the residual voltage can be as high as 60-80kV. This is low compared to the insulation coordination coefficient of the 10kV distribution transformer, and may even exceed the insulation level of the distribution transformer. This may exceed the 75kV (60kV) lightning impulse withstand voltage limit of 10kV distribution transformers specified in GB / T 50064-2014 "Design Specification for Overvoltage Protection and Insulation Coordination of AC Electrical Installations". Excessive residual voltage levels pose certain risks to the safe operation of the transformer. In addition, the current carrying capacity of conventional lightning arresters is only 150A, and the maximum high current impulse withstand capacity is 65kA.

[0005] Distribution network lightning arresters are used in huge numbers in power grids every year and are widely distributed. Conducting preventive tests to detect the operating conditions of lightning arresters requires a lot of manpower, material and financial resources. Currently, in most cases, lightning arresters are only handled when accidents occur, which is detrimental to the normal operation of the power grid system. Lightning arrester failures have a great impact on power supply reliability. From 2008 to 2018, distribution network lightning arresters frequently experienced defects and failures, and the number has reached 6.3 million. If all of these faulty distribution network lightning arresters are replaced, the cost will be huge.

[0006] Summary of the Invention

[0007] The main purpose of the present application is to provide a method for preparing a heavy-load 10kV large-current lightning arrester, so as to at least solve the problem of frequent lightning arrester failures in the prior art.

[0008] In order to achieve the above-mentioned purpose, according to one aspect of the present application, a preparation method of a heavy-load 10kV large-current arrester is provided, including: performing a DC reference voltage test on a selected valve plate to obtain a target valve plate, and the above-mentioned target valve plate meets the following conditions: large current impulse tolerance is greater than or equal to 100kA, current carrying capacity is greater than 600A, residual voltage under 10kA current is less than or equal to 45kV, and repeated charge transfer capability is greater than or equal to 0.8C; assembling a glass fiber epoxy resin layer and an electrode pair into a sealed shell, so that the target valve plate is located in the cavity of the sealed shell, and the target valve plate is electrically connected to the first electrode of the electrode pair and the second electrode of the electrode pair, respectively, to form a heavy-load 10kV large-current arrester.

[0009] Optionally, the glass fiber epoxy resin layer and the electrode pair are assembled into a sealed shell, so that the target valve plate is located in the cavity of the sealed shell, and the target valve plate is electrically connected to the first electrode of the electrode pair and the second electrode of the electrode pair respectively, to form a heavy-load 10kV large-current arrester, including: assembling the glass fiber epoxy resin layer, the electrode pair and the target valve plate to form a core group, so that the target valve plate is connected to the second electrode of the electrode pair and the first electrode respectively, and the glass fiber epoxy resin layer is connected to the target valve plate. contact setting; applying coupling agent to the core group and drying it; preheating the dried core group to obtain a preheated core group; vulcanizing the preheated core group on a machine to obtain a jacket mold, so that the test of the on-machine vulcanization process meets the temperature requirement of the mold; laying silicone rubber in the jacket mold, and using a molding process to stick the silicone rubber in the jacket mold to the preheated core group to obtain a jacket composed of silicone rubber; sealing the jacket and the preheated core group to form the heavy-load 10kV large-current arrester.

[0010] Optionally, the fiberglass epoxy resin layer, the electrode pair and the target valve plate are assembled to form a core group, including: installing the target valve plate in the cavity of the fiberglass epoxy resin tube, the fiberglass epoxy resin tube being the cylindrical fiberglass epoxy resin layer; rotating the first electrode and the second electrode on the two opposite side walls of the fiberglass epoxy resin tube, respectively, so that the target valve plate is connected to the second electrode and the first electrode of the electrode pair, respectively, to form the core group.

[0011] Optionally, the outer sleeve and the preheated core group are sealed to form the heavy-load 10kV large-current arrester, including: respectively connecting the first electrode and the second electrode to the glass fiber epoxy resin tube through threads, applying room temperature curing glue at the connection of the threads, and providing a sealing ring on the contact surface between the electrode pair and the glass fiber epoxy resin layer to form the sealed shell, so that the sealed shell and the target valve plate constitute the heavy-load 10kV large-current arrester.

[0012] Optionally, after the outer jacket and the preheated core group are sealed to form the heavy-load 10kV high-current arrester, the method further includes: testing the DC reference voltage and leakage current of the heavy-load 10kV high-current arrester to obtain an initial DC reference voltage and an initial leakage current, wherein the initial leakage current is the leakage current of the heavy-load 10kV high-current arrester at 0.75 times the initial DC reference voltage; placing the heavy-load 10kV high-current arrester in salt water and boiling it for a predetermined time to obtain the heavy-load 10kV high-current arrester to be tested; testing the DC reference voltage, leakage current and discharge amount of partial discharge of the heavy-load 10kV high-current arrester to be tested to obtain the DC reference voltage to be verified, the leakage current to be verified and the discharge amount of partial discharge. The electrical measurement value is as follows: the leakage current to be verified is the leakage current of the heavy-load 10kV high-through-current arrester to be tested at 0.75 times the initial DC reference voltage, and the partial discharge measurement value is the discharge amount of the partial discharge at 1.05 times the initial DC reference voltage; when the three conditions of the first deviation being less than or equal to 5% of the initial DC reference voltage, the second deviation being less than or equal to 20μA, and the discharge amount of the partial discharge being less than or equal to 10pC are met, it is determined that the sealing of the heavy-load 10kV high-through-current arrester is qualified, the first deviation is the absolute value of the difference between the initial DC reference voltage and the DC reference voltage to be verified, and the second deviation is the absolute value of the difference between the leakage current to be verified and the initial leakage current.

[0013] Optionally, after installing the target valve disc in the cavity of the glass fiber epoxy resin tube, and before installing the first electrode and the second electrode on two opposite side walls of the glass fiber epoxy resin tube respectively, the method further includes: installing a pagoda-shaped spring between the target side wall and the target valve disc, so that the pagoda-shaped spring fixes the valve disc by elastic force, and the target side wall is the side wall on which the first electrode is installed.

[0014] Optionally, the pagoda-shaped spring is conductive.

[0015] Optionally, after installing the pagoda-shaped spring between the target side wall and the target valve plate, the method further comprises: winding a plurality of conductive tapes on the pagoda-shaped spring.

[0016] Optionally, after the first electrode and the second electrode are respectively connected to the glass fiber epoxy resin tube through threads, room temperature curing glue is applied at the connection of the threads, and a sealing ring is provided on the contact surface between the electrode pair and the glass fiber epoxy resin layer to form the sealed shell, the method further includes: providing a plurality of protrusions on the sealed shell.

[0017] Optionally, the target valve sheet includes at least one valve sheet, and the specification of the valve sheet is D52.

[0018] Applying the technical solution of the present application, in the preparation method of the above-mentioned large through-current arrester, first, a DC reference voltage test is performed on the valve plate to be selected to obtain a target valve plate, and the target valve plate meets the following conditions: large current impulse withstand capability is greater than or equal to 100kA, through-current capability is greater than 600A, residual voltage under 10kA current is less than or equal to 45kV, and repeated charge transfer capability is greater than or equal to 0.8C. The arrester valve plate is in accordance with the international standard IEC 60099-4:2014 conducted a combined current impulse test and successfully passed the combined current impulse test {(4 / 10μs large current impulse tolerance 100kA)+(8 / 20μs lightning impulse residual voltage 40kA)+(2ms square wave current carrying capacity 600A)+(8 / 20μs lightning impulse residual voltage 40kA)}, and selected the valve plate to be assembled; assembled the glass fiber epoxy resin layer and the electrode pair into a sealed shell, so that the valve plate is located in the cavity of the sealed shell, and the target valve plate is electrically connected to the first electrode of the electrode pair and the second electrode of the electrode pair, respectively, to form a heavy-load 10kV large current arrester. The preparation method has passed four 4 / 10μs high-current impulse withstand tests, an 8 / 20μs repeated charge transfer 0.8C (10 rounds / 20 times) test, and the arrester's lightning impulse residual voltage must not exceed ±5%, a 2ms square wave current capacity of 600A (18 times), and a bending load test of the entire arrester can reach 400N and be maintained for 18s without damage, in order to produce qualified heavy-load 10kV high-current arresters. The heavy-load 10kV high-current arrester dissipates heat absorbed by the target valve plate through the glass fiber epoxy resin layer. Due to the high thermal conductivity of the glass fiber epoxy resin, the arrester's tolerance to large lightning currents is improved, the failure rate is reduced, and the problem of frequent arrester failures in the prior art is solved. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] FIG1 shows a schematic flow chart of a method for preparing a heavy-load 10 kV high-through-current arrester according to an embodiment of the present application;

[0020] FIG2 shows a schematic structural diagram of a heavy-load 10 kV high-through-current arrester provided in an embodiment of the present application.

[0021] The above drawings include the following reference numerals: 10, first electrode; 20, second electrode; 30, valve plate; 40, glass fiber epoxy resin layer; 50, pagoda-shaped spring; 60, outer sleeve; 70, EPDM sealing ring; 80, aluminum spacer. DETAILED DESCRIPTION

[0022] It should be noted that, in the absence of conflict, the embodiments and features of the embodiments in this application can be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0023] In order to enable those skilled in the art to better understand the present invention, the following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts should fall within the scope of protection of this application.

[0024] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or sequential order. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present application described here. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0025] It should be understood that when an element (such as a layer, film, region, or substrate) is described as being "on" another element, the element may be directly on the other element or intervening elements may be present. Moreover, in the specification and claims, when it is described that an element is "connected to" another element, the element may be "directly connected to" the other element or "connected to" the other element through a third element.

[0026] As introduced in the background technology, in the prior art, lightning arresters frequently fail. To solve this technical problem, an embodiment of the present application provides a method for preparing a heavy-load 10kV high-current lightning arrester.

[0027] The technical solutions in the embodiments of the present invention will be described clearly and completely below with reference to the accompanying drawings in the embodiments of the present invention.

[0028] In this embodiment, a method for preparing a heavy-load 10kV high-through-current arrester is provided. As shown in FIG1 , the method comprises:

[0029] Step S101: Perform a DC reference voltage test on the valve slice to be selected to obtain a target valve slice. The target valve slice meets the following conditions: a large current impulse withstand capability greater than or equal to 100 kA, a flow capacity greater than 600 A, a residual voltage less than or equal to 45 kV at a current of 10 kA, and a repeated charge transfer capability greater than or equal to 0.8 C.

[0030] Specifically, through 4 times of 4 / 10 equal large current impulse withstand test, 8 / 20 impulse withstand repeated transfer charge 0.8C (10 rounds / 20 times) test and the lightning impulse residual voltage of the lightning arrester shall not exceed ±) test, and 2ms square wave current capacity 600A (18 times), the valve plate of the lightning arrester that meets the heavy load requirements is found, and the leakage current test under DC 1mA reference voltage and 0.75 times the reference voltage is used for grouping, and the target valve plate that meets the leakage current requirements is obtained to ensure that the produced heavy load 10kV large current lightning arrester is qualified.

[0031] Step S102, assemble the glass fiber epoxy resin layer and the electrode pair into a sealed shell, so that the above-mentioned target valve plate is located in the cavity of the sealed shell, and the above-mentioned target valve plate is electrically connected to the first electrode of the above-mentioned electrode pair and the second electrode of the above-mentioned electrode pair respectively, forming a heavy-load 10kV large-current lightning arrester.

[0032] Specifically, the glass fiber epoxy resin layer, the electrode pair and the target valve plate are assembled into a large-current lightning arrester. After the large-current lightning arrester is installed and grounded, it can be electrically connected to the first electrode of the electrode pair and the second electrode of the electrode pair through the target valve plate to form a circuit to withstand the large current of lightning strikes, thereby realizing the function of the lightning arrester.

[0033] In the preparation method of the above-mentioned large-current arrester, first, a DC reference voltage test is performed on the valve plate to be selected to obtain a target valve plate, which meets the following conditions: large current impulse tolerance greater than or equal to 100kA, current capacity greater than 600A, residual voltage under 10kA current less than or equal to 45kV, and repeated charge transfer capability greater than or equal to 0.8C. The arrester valve plate undergoes a combined current impulse test and successfully passes the combined current impulse test {(4 / 10μs large current impulse tolerance 100kA)+(8 / 20μs lightning impulse residual voltage 40kA)+(2ms square wave current capacity 600A)+(8 / 20 capacity lightning impulse residual voltage 40kA)}, and the valve plate to be assembled is selected; the glass fiber epoxy resin layer and the electrode pair are assembled into a sealed shell, so that the valve plate is located in the cavity of the sealed shell, and the target valve plate is electrically connected to the first electrode of the above-mentioned electrode pair and the second electrode of the above-mentioned electrode pair, respectively, to form a heavy-load 10kV large-current arrester. The preparation method passes 4 times of 4 / 10 method high current impulse withstand test, 8 / 20 impulse withstand repeated transfer charge 0.8C (10 rounds / 20 times) test and the lightning impulse residual voltage of the lightning arrester shall not exceed ± 100A (10 times), 2ms square wave current carrying capacity 600A (18 times), and the entire bending load test of the lightning arrester can reach 400N and maintain for 18s without damage, so as to produce qualified heavy-load 10kV high-current lightning arrester. The heavy-load 10kV high-current lightning arrester dissipates the heat absorbed by the target valve plate through the glass fiber epoxy resin layer. Due to the high thermal conductivity of the glass fiber epoxy resin, the lightning arrester's tolerance to high lightning current is improved, the failure rate is reduced, and the problem of frequent failure of the lightning arrester in the prior art is solved.

[0034] In order to ensure the safety of the lightning arrester, in an optional implementation manner, the above step S101 further includes:

[0035] Step S1011, connecting the target valve plate to the third electrode and the fourth electrode respectively, and grounding the fourth electrode;

[0036] Step S1012, inputting a DC voltage to the third electrode and measuring the leakage current to obtain a first leakage current;

[0037] Step S1013, adjusting the DC voltage until the leakage current reaches 1 mA, thereby obtaining a DC reference voltage, wherein the DC reference voltage is the DC reference voltage when the first leakage current reaches 1 mA;

[0038] Step S1014, inputting 0.75 times the DC reference voltage to the first electrode, and measuring the leakage current to obtain a second leakage current;

[0039] Step S1015 : When the second leakage current is less than 50 μA, it is determined that the target valve plate is qualified.

[0040] Specifically, use lint-free paper dipped in a small amount of anhydrous ethanol to wipe the dust on the surface of the core group, carefully move the entire core group with adjusted voltage to the test fixture, and place the test high-voltage conductive electrode on the top of the core group. The group is matched according to the DC reference voltage and the leakage current at 0.75 times the reference voltage to ensure that the DC voltage is within the required range. For example, the DC voltage is less than 1.15 times the DC reference voltage. The target valve piece with a leakage current of less than 50μA at 0.75 times the reference voltage is a qualified valve piece. Otherwise, the target valve piece is unqualified and needs to be eliminated and selected.

[0041] In order to ensure that the arrester forms a compact structure, in an optional implementation manner, the above step S102 includes:

[0042] Step S1021, assembling the fiberglass epoxy resin layer, the electrode pair, and the target valve disc to form a core assembly, such that the target valve disc is electrically connected to the first electrode of the electrode pair and the second electrode of the electrode pair, respectively, and the fiberglass epoxy resin layer is in contact with the target valve disc;

[0043] Step S1022, applying a coupling agent to the core group and letting it dry;

[0044] Step S1023, preheating the dried core group to obtain a preheated core group;

[0045] Step S1024, vulcanizing the preheated core assembly on a machine to obtain a jacket mold, so that the test of the vulcanization process on the machine meets the temperature requirements of the mold;

[0046] Step S1025, placing the silicone rubber in the outer shell mold, and using a molding process to attach the silicone rubber in the outer shell mold to the preheated core group to obtain an outer shell made of the silicone rubber;

[0047] Step S1026: sealing the outer jacket and the preheated core group to form the heavy-load 10kV high-current arrester.

[0048] Specifically, place the core group in a special coupling agent container and roll it to ensure uniform coating. After coating, let it dry, then place the core group in an oven for preheating, and finally put it on the machine for vulcanization. First, use a thermometer to test whether the mold cavity temperature is within the specified value. The lower mold test points are the center point of the mold surface on both sides of the mold and the edge position in the ejection direction. When testing the mold temperature, the center point temperature of the mold surface is required to be 150±5℃, and the edge position in the ejection direction is not lower than the middle point temperature by 10℃. The temperature of the corresponding point on the mold is ±10℃ different from the actual measured temperature of the lower mold. For mold vulcanization, first spread the rubber material in the lower mold cavity, center it, press the rubber material downwards by hand to make it "U" shaped in the mold cavity, place the core group in the mold cavity where the rubber material has been laid, and ensure that the core group positioning tooling and the mold positioning baffle are well matched, then place another piece of rubber material on the core group, press it down by hand to make the rubber material stick tightly to the core group, start the switch, vulcanize and form, place the product in the lower mold, place it on the tooling to cool, use a putty shovel to clean up the excess waste on both sides of the upper and lower molds to form a tightly structured arrester to avoid device dislocation. In addition, the arrester composite jacket is vulcanized using The high-strength glass fiber epoxy resin cylinder suitable for the vulcanization process is processed and formed with molded high-temperature vulcanized silicone rubber. The molded mixed silicone rubber must be suitable for the vulcanization process and have good electrical and mechanical properties. By adjusting the structure control agent and reinforcing filler used in the mixed rubber and adjusting the mixing process, the rubber compound has excellent high-temperature fluidity and heat-resistant aging activity, as well as excellent mechanical and electrical properties. Silane coupling agent is used to bond the epoxy cylinder and the silicone rubber outer sheath, so that the sheath and the epoxy cylinder become a complete whole, forming a heavy-load 10kV large-current arrester.

[0049] In addition, the above-mentioned jacket can protect the internal structure of the lightning arrester from damage. If the bending load test of the entire lightning arrester can reach 400N and be maintained for 18 seconds without damage, it can be determined that the quality of the jacket is qualified.

[0050] In order to achieve the lightning protection function, in an optional implementation, the above step S1021 includes:

[0051] Step S10211, installing the target valve disc in the cavity of the glass fiber epoxy resin cylinder, wherein the glass fiber epoxy resin cylinder is a cylindrical glass fiber epoxy resin layer;

[0052] Step S10212, respectively installing the first electrode and the second electrode on two opposite side walls of the glass fiber epoxy resin tube, so that the target valve plate is respectively connected to the second electrode and the first electrode of the electrode pair to form the core group.

[0053] Specifically, the cylindrical glass fiber epoxy resin layer forms the skeleton of the core group, and due to its high strength, it is suitable for the molding process. The first electrode and the second electrode are respectively installed on the two opposite side walls of the glass fiber epoxy resin cylinder, and the target valve plate is respectively connected to the second electrode and the first electrode of the electrode pair to enhance the contact preload force. The electrodes at both ends are tightened to form a core group, and the core group can realize the lightning protection function.

[0054] In order to further reduce the failure rate, in an optional implementation, the above step S1026 includes:

[0055] Step S10261, respectively connect the above-mentioned first electrode and the above-mentioned second electrode to the above-mentioned glass fiber epoxy resin tube through threads, apply room temperature curing glue on the connection of the above-mentioned threads, and set a sealing ring on the contact surface between the above-mentioned electrode pair and the above-mentioned glass fiber epoxy resin layer to form the above-mentioned sealed shell, so that the above-mentioned sealed shell and the above-mentioned target valve plate constitute the above-mentioned large-flow arrester.

[0056] Specifically, considering that the south belongs to a relatively humid area, according to incomplete statistics, 70% of the accidents of lightning arresters are caused by poor sealing. Therefore, the YH10W-17 / 45 model lightning arrester adopts a double sealing structure, the target valve plate is loaded into a high-strength glass fiber epoxy resin cylinder, the upper and lower electrodes of the core group are connected by threads, the threaded connection is coated with room temperature curing glue, and EPDM sealing rings are added to the contact surface of the upper and lower electrodes and the insulating cylinder to form a double seal, which prevents moisture, air and other substances from entering the large-flow lightning arrester, causing internal pollution and rust, etc., leading to failures, improving the service life of heavy-load 10kV large-flow lightning arresters and reducing the failure rate.

[0057] In order to further reduce the failure rate, in an optional implementation, after step S1026, the method further includes:

[0058] Step S201, testing the DC reference voltage and leakage current of the heavy-load 10 kV high-through-current arrester to obtain an initial DC reference voltage and an initial leakage current, wherein the initial leakage current is the leakage current of the heavy-load 10 kV high-through-current arrester at 0.75 times the initial DC reference voltage;

[0059] Step S202: placing the heavy-load 10 kV high-current arrester into salt water and boiling it for a predetermined time to obtain a heavy-load 10 kV high-current arrester to be tested;

[0060] Step S203, testing the DC reference voltage, leakage current, and discharge amount of partial discharge of the heavy-load 10 kV high-through-current arrester to be tested, and obtaining a DC reference voltage to be verified, a leakage current to be verified, and a partial discharge measurement value, wherein the leakage current to be verified is the leakage current of the heavy-load 10 kV high-through-current arrester to be tested at 0.75 times the initial DC reference voltage, and the partial discharge measurement value is the discharge amount of partial discharge at 1.05 times the initial DC reference voltage;

[0061] Step S204, when the three conditions of the first deviation being less than or equal to 5% of the above-mentioned initial DC reference voltage, the second deviation being less than or equal to 20μA, and the discharge amount of the above-mentioned partial discharge being less than or equal to 10pC are all met, it is determined that the sealing of the above-mentioned heavy-load 10kV large-current lightning arrester is qualified, the above-mentioned first deviation is the absolute value of the difference between the above-mentioned initial DC reference voltage and the above-mentioned DC reference voltage to be verified, and the above-mentioned second deviation is the absolute value of the difference between the above-mentioned leakage current to be verified and the above-mentioned initial leakage current.

[0062] Specifically, a heavy-load 10kV high-current arrester undergoes a sealing water boiling test. The arrester is placed in water containing 0.1% NaCl and boiled for 42 hours. After the boiling is completed, the following judgments are made: 1) The deviation of the DC reference voltage compared with the initial measurement does not exceed 5%; 2) The leakage current at 0.75 times the DC reference voltage does not change by more than 20μA compared with the initial measurement; 3) For partial discharge measurement, the measured value under Uc at 1.05 times the continuous operating voltage does not exceed 10pC.

[0063] In addition, in order to avoid the aging problem of the silicone rubber of the arrester composite jacket, the thickness of the silicone rubber composite jacket during one-piece vulcanization molding was increased from the original 3.5mm to 5.0mm.

[0064] In order to further reduce the failure rate, in an optional implementation, after step S10211 and before step S10212, the method further includes:

[0065] Step S201 , installing a pagoda-shaped spring between a target side wall and the target valve plate, so that the pagoda-shaped spring fixes the valve plate through elastic force, and the target side wall is the side wall on which the first electrode is installed.

[0066] Specifically, a pagoda-shaped spring, referred to as a tower spring, is placed between the first electrode and the target valve plate to enhance the contact preload force, press the target valve plate to prevent the target valve plate from shaking and dislocating, thereby further avoiding structural failure. In addition, an aluminum pad can be set between the tower spring and the target valve plate to prevent the preload force from causing deformation and damage to the target valve plate.

[0067] In order to further reduce the failure rate, in an optional embodiment, the pagoda-shaped spring is conductive.

[0068] Specifically, the pagoda-shaped spring is conductive and can conduct the current of the first electrode to the target valve plate, thereby improving the conductivity and preventing the pagoda-shaped spring from being damaged by lightning.

[0069] In order to further improve the performance of the large through-current arrester, in an optional implementation manner, after step S201, the method further includes:

[0070] Step S301: Winding a plurality of conductive tapes on the pagoda-shaped spring.

[0071] Specifically, the conductive performance of the pagoda-shaped spring may not meet the current flow requirements of lightning current. Four conductive tapes are wrapped around the pagoda-shaped spring to increase the current flow capacity and prevent the pagoda-shaped spring from being damaged by lightning current. The 2ms square wave current flow capacity is large and can reach 600A.

[0072] In order to further improve the heat dissipation capacity of the large through-current arrester, in an optional implementation manner, after step S10261, the method further includes:

[0073] Step S401: providing a plurality of protrusions on the sealed housing.

[0074] Specifically, the surface of the jacket includes a plurality of protrusions, which increase the contact area with the air, that is, increase the heat dissipation area and improve the heat dissipation efficiency.

[0075] In order to further improve the performance of the large through-current arrester, in an optional embodiment, the target valve piece includes at least one valve piece, and the specification of the valve piece is D52.

[0076] Specifically, based on the proposed arrester current carrying capacity requirements and to meet the requirements for multiple lightning current surges and strong lightning impulses, we developed a φ52*28 resistor with strong high-current surge tolerance (100kA), high current carrying capacity (600A), low residual voltage (10kA 8 / 20μs residual voltage no more than 45kV), and high repetitive charge transfer capability (Qrs = 0.8C). Furthermore, the developed arrester resistor was tested in accordance with the international standard IEC 60099-4:2014 for combined current surges and successfully passed the combined current surge test ((4 / 10μs high-current surge tolerance 100kA) + (8 / 20μs lightning surge residual voltage 40kA) + (2ms square wave current carrying capacity 600A) + (8 / 20μs lightning surge residual voltage 40kA)}, further improving the performance of the heavy-duty 10kV high-current arrester and reducing the failure rate.

[0077] According to an embodiment of the present invention, a large through-current arrester is further provided. FIG2 is a structural schematic diagram of a large through-current arrester according to an embodiment of the present application. As shown in FIG2 , the large through-current arrester includes:

[0078] An electrode pair, comprising a first electrode 10 and a second electrode 20;

[0079] The valve plate 30 is connected to the second electrode 20 and the pagoda-shaped spring 50 respectively. The valve plate 30 is used to convert the energy of the lightning current into heat;

[0080] The glass fiber epoxy resin layer 40 is disposed in contact with the valve plate 30 , and is used to conduct the heat for heat dissipation.

[0081] The heavy-load, high-through-current arrester includes an electrode pair, a valve plate, and a glass fiber epoxy resin layer. The electrode pair includes a first electrode and a second electrode. The valve plate is connected to the second electrode and the aluminum spacer, respectively, and is used to convert the energy of the lightning current into heat. The glass fiber epoxy resin layer is arranged in contact with the valve plate and is used to conduct the heat to dissipate the heat. The high-through-current arrester dissipates the heat generated by the valve plate through the glass fiber epoxy resin layer. Due to the high thermal conductivity of glass fiber epoxy resin, the arrester's ability to withstand high lightning currents is improved, the failure rate is reduced, and the frequent failure problem of arresters in the prior art is solved.

[0082] In order to further reduce the failure rate, in an optional embodiment, the glass fiber epoxy resin layer is cylindrical, and the glass fiber epoxy resin layer wraps the valve plate.

[0083] Specifically, the cylindrical glass fiber epoxy resin layer, i.e. the glass fiber epoxy resin cylinder, and the high-strength glass fiber epoxy resin cylinder serve as the pressure release port of the arrester, which can normally release pressure when the arrester fails, thereby avoiding the arrester from shattering and bursting. The use of the high-strength glass fiber epoxy resin cylinder increases the tensile and bending strength of the arrester.

[0084] In order to further reduce the failure rate, in an optional embodiment, as shown in FIG2 , the large through-current arrester further includes:

[0085] The pagoda-shaped spring 50 is located between the first electrode 10 and the aluminum pad 80 . The pagoda-shaped spring 50 is used to fix the valve plate 30 through elastic force and is conductive.

[0086] Specifically, a pagoda-shaped spring, referred to as a tower spring, as shown in Figure 2, is placed between the first electrode 10 and the aluminum pad 80 to enhance the contact preload force, press the valve plate to prevent the valve plate from shaking and dislocating, thereby further avoiding structural failure. In addition, the pagoda-shaped spring 50 is conductive and can conduct the current of the first electrode to the valve plate 30.

[0087] In order to further improve the performance of the high-through-current arrester, in an optional embodiment, the high-through-current arrester further includes:

[0088] A plurality of conductive strips are wound around the pagoda-shaped spring.

[0089] Specifically, the conductive performance of the pagoda-shaped spring may not meet the current flow requirements of lightning current. Four conductive tapes are wrapped around the pagoda-shaped spring to increase the current flow capacity and prevent the pagoda-shaped spring from being damaged by lightning current. The 2ms square wave current flow capacity is large and can reach 600A.

[0090] In order to improve the safety of the large through-current arrester, in an optional embodiment, as shown in FIG2 , the large through-current arrester further includes:

[0091] The outer shell 60 is used to wrap the glass fiber epoxy resin layer 40 and the electrode pair.

[0092] Specifically, the outer jacket and the glass fiber epoxy resin tube constitute a composite outer jacket of the arrester, which can protect the large-current arrester from being damaged by external forces and ensure the safety of the large-current arrester.

[0093] In order to further improve the heat dissipation capability of the large through-current arrester, in an optional embodiment, the surface of the outer sleeve includes a plurality of protrusions.

[0094] Specifically, the surface of the jacket includes a plurality of protrusions, which increase the contact area with the air, that is, increase the heat dissipation area and improve the heat dissipation efficiency.

[0095] In order to further improve the heat dissipation capability of the large through-current arrester, in an optional embodiment, the material of the outer jacket is silicone rubber, and the outer jacket is formed by a molding process.

[0096] Specifically, the outer jacket is formed by processing with flat plate high temperature vulcanized silicone rubber. The mixed silicone rubber for flat plate vulcanization is suitable for molding process and meets electrical and mechanical properties. The molding process is simple.

[0097] In order to further improve the structural stability of the large through-current arrester, in an optional embodiment, the electrode pair is connected to the outer sleeve via threads, and a curing glue is provided at the threaded connection.

[0098] Specifically, the first electrode and the second electrode are connected by threads, and room temperature curing glue is applied to the threaded connection to fix the first electrode and the second electrode to prevent them from falling off, thereby improving the structural stability of the large-current lightning arrester. In addition, the curing glue fills the gaps between the threads, greatly improving the sealing, and preventing water vapor and dust in the air from entering the interior of the large-current lightning arrester and affecting the performance of the lightning arrester.

[0099] In order to further improve the sealing performance of the large through-current arrester, in an optional embodiment, as shown in FIG2 , the large through-current arrester further includes:

[0100] The EPDM sealing ring 70 is disposed on the contact surface between the electrode pair and the glass fiber epoxy resin layer 40 .

[0101] Specifically, an EPDM sealing ring is added to the contact surface between the electrode pair and the glass fiber epoxy resin tube to form a double seal with the curing glue, further improving the sealing performance and ensuring that water vapor and dust in the air will not enter the heavy-load and large-current arrester, thereby not affecting the performance of the arrester.

[0102] It should be noted that the above-mentioned heavy-load, large-current lightning arrester can fully meet the requirements of 4 times of 100kA large current impulse tolerance and 20 times of repeated charge transfer of 0.8C; the 2ms square wave current-carrying capacity is large, which can reach 600A. In addition, the developed lightning arrester resistor is subjected to a combined current impulse test in accordance with the international standard IEC60099-4:2014, and has successfully passed the combined current impulse test {(4 / 10μs large current impulse tolerance 100kA)+(8 / 20μs lightning impulse residual voltage 40kA)+(2ms square wave current-carrying capacity 600A)+(8 / 20μs lightning impulse residual voltage 40kA)}, with good heat dissipation; compared with the previous price of lightning arresters, it has a simple structure, low assembly labor cost, higher cost performance, compact design, high mechanical properties, strong anti-fouling ability, easy installation, and maintenance-free, which effectively improves the protection characteristics and operating characteristics of the lightning arrester, enabling the distribution network system to operate effectively.

[0103] It should also be noted that the terms "comprises," "includes," or any other variations thereof are intended to encompass non-exclusive inclusion, such that a process, method, commodity, or apparatus that includes a series of elements includes not only those elements but also other elements not explicitly listed, or includes elements inherent to such process, method, commodity, or apparatus. In the absence of further limitations, an element defined by the phrase "comprises a ..." does not exclude the presence of other identical elements in the process, method, commodity, or apparatus that includes the element.

[0104] From the above description, it can be seen that the above embodiments of the present application achieve the following technical effects:

[0105] 1) In the preparation method of the large through-current arrester of the present application, first, a DC reference voltage test is performed on the valve plate to be selected to obtain a target valve plate, which meets the following conditions: large current impulse tolerance greater than or equal to 100kA, current capacity greater than 600A, residual voltage under 10kA current less than or equal to 45kV, and repeated charge transfer capability greater than or equal to 0.8C. The arrester valve plate undergoes a combined current impulse test and successfully passes the combined current impulse test {(4 / 10μs large current impulse tolerance 100kA) + (8 / 20μs lightning impulse residual voltage 40kA) + (2ms square wave current capacity 600A) + (8 / 20 capacity lightning impulse residual voltage 40kA)}, and the valve plate to be assembled is selected; the glass fiber epoxy resin layer and the electrode pair are assembled into a sealed shell so that the valve plate is located in the cavity of the sealed shell, And the target valve plate is electrically connected to the first electrode of the electrode pair and the second electrode of the electrode pair respectively, forming a heavy-load 10kV large-current arrester. The preparation method passes 4 times of 4 / 10 method large-current impulse withstand test, 8 / 20 impact withstand repeated transfer charge 0.8C (10 rounds / 20 times) test and the lightning impulse residual voltage of the arrester shall not exceed ±) test, 2ms square wave current capacity 600A (18 times), and the entire bending load test of the arrester can reach 400N and maintain 18s without damage to produce qualified heavy-load 10kV large-current arrester. The heavy-load 10kV large-current arrester dissipates the heat absorbed by the target valve plate through the glass fiber epoxy resin layer. Due to the high thermal conductivity of glass fiber epoxy resin, the arrester's tolerance to large lightning current is improved, the failure rate is reduced, and the problem of frequent failure of arresters in the prior art is solved.

[0106] 2) The heavy-load, high-through-current arrester comprises an electrode pair, a valve plate, and a glass fiber epoxy resin layer. The electrode pair comprises a first electrode and a second electrode. The valve plate is connected to the second electrode and the aluminum spacer, respectively, and is used to convert the energy of the lightning current into heat. The glass fiber epoxy resin layer is disposed in contact with the valve plate and is used to conduct the heat for dissipation. The high-through-current arrester dissipates heat generated by the valve plate through the glass fiber epoxy resin layer. Due to the high thermal conductivity of glass fiber epoxy resin, the arrester's ability to withstand high lightning currents is improved, the failure rate is reduced, and the problem of frequent arrester failures in the prior art is resolved.

[0107] The above description is merely a preferred embodiment of the present application and is not intended to limit the present application. Various modifications and variations are possible for those skilled in the art. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present application shall be included within the scope of protection of the present application.

Claims

1. A method for preparing a heavy-load 10kV high-current arrester, characterized in that: include: A DC reference voltage test is performed on the selected valve slice to obtain a target valve slice, which satisfies the following conditions: a large current impact tolerance greater than or equal to 100kA, a flow capacity greater than 600A, a residual voltage less than or equal to 45kV at a current of 10kA, and a repeated charge transfer capability greater than or equal to 0.8C; The glass fiber epoxy resin layer and the electrode pair are assembled into a sealed shell, so that the target valve plate is located in the cavity of the sealed shell, and the target valve plate is electrically connected to the first electrode of the electrode pair and the second electrode of the electrode pair respectively, forming a heavy-load 10kV large-current arrester.

2. The method according to claim 1, characterized in that The glass fiber epoxy resin layer and the electrode pair are assembled into a sealed shell, so that the target valve plate is located in the cavity of the sealed shell, and the target valve plate is electrically connected to the first electrode of the electrode pair and the second electrode of the electrode pair respectively, forming a heavy-load 10kV large through-current arrester, including: Assembling the glass fiber epoxy resin layer, the electrode pair and the target valve sheet to form a core group, so that the target valve sheet is connected to the second electrode and the first electrode of the electrode pair respectively, and the glass fiber epoxy resin layer is arranged in contact with the target valve sheet; Applying a coupling agent to the core group and drying it; preheating the dried core group to obtain a preheated core group; The preheated core group is vulcanized on a machine to obtain a jacket mold, so that the test of the vulcanization process on the machine meets the temperature requirement of the mold; Laying the silicone rubber in the outer shell mold, and using a molding process to stick the silicone rubber in the outer shell mold onto the preheated core group to obtain the outer shell composed of the silicone rubber; The outer jacket and the preheated core group are sealed to form the heavy-load 10kV large-current arrester.

3. The method according to claim 2, characterized in that Assembling the glass fiber epoxy resin layer, the electrode pair and the target valve sheet to form a core group includes: Installing the target valve plate in the cavity of the glass fiber epoxy resin cylinder, wherein the glass fiber epoxy resin cylinder is a cylindrical glass fiber epoxy resin layer; The first electrode and the second electrode are respectively rotatably mounted on the glass fiber epoxy resin. On two opposite side walls of the grease cylinder, the target valve sheet is respectively connected to the second electrode and the first electrode to form the core group.

4. The method according to claim 2, characterized in that: The outer jacket and the preheated core group are sealed to form the heavy-load 10kV large through-current arrester, including: The first electrode and the second electrode are respectively connected to the glass fiber epoxy resin tube through threads, and room temperature curing glue is applied at the connection of the threads, and a sealing ring is arranged on the contact surface between the electrode pair and the glass fiber epoxy resin layer to form the sealed shell, so that the sealed shell and the target valve plate constitute the heavy-load 10kV large-current arrester.

5. The method according to claim 2, characterized in that: After the outer jacket and the preheated core group are sealed to form the heavy-load 10kV large through-current arrester, the method further comprises: Testing the DC reference voltage and leakage current of the heavy-load 10 kV high-through-current arrester to obtain an initial DC reference voltage and an initial leakage current, wherein the initial leakage current is the leakage current of the heavy-load 10 kV high-through-current arrester at 0.75 times the initial DC reference voltage; The heavy-load 10 kV high-through-current arrester is placed in salt water and boiled for a predetermined time to obtain a heavy-load 10 kV high-through-current arrester to be tested; Test the DC reference voltage, leakage current and discharge amount of partial discharge of the heavy-load 10kV large through-current arrester to be tested, and obtain the DC reference voltage to be verified, the leakage current to be verified and the partial discharge measurement value, wherein the leakage current to be verified is the leakage current of the heavy-load 10kV large through-current arrester to be tested at 0.75 times the initial DC reference voltage, and the partial discharge measurement value is the discharge amount of partial discharge at 1.05 times the initial DC reference voltage; When the three conditions that the first deviation is less than or equal to 5% of the initial DC reference voltage, the second deviation is less than or equal to 20μA, and the discharge amount of the local discharge is less than or equal to 10pC are met, it is determined that the sealing of the heavy-load 10kV high-current arrester is qualified, the first deviation is the absolute value of the difference between the initial DC reference voltage and the DC reference voltage to be verified, and the second deviation is the absolute value of the difference between the leakage current to be verified and the initial leakage current.

6. The method according to claim 3, characterized in that After installing the target valve plate in the cavity of the glass fiber epoxy resin cylinder and before installing the first electrode and the second electrode on two opposite side walls of the glass fiber epoxy resin cylinder, the method further includes: The pagoda-shaped spring is installed between the target side wall and the target valve plate, so that the pagoda-shaped spring fixes the valve plate through elastic force, and the target side wall is the side wall on which the first electrode is installed.

7. The method according to claim 6, characterized in that The pagoda-shaped spring is electrically conductive.

8. The method according to claim 6, characterized in that After installing the pagoda-shaped spring between the target side wall and the target valve plate, the method further includes: A plurality of conductive tapes are wound around the pagoda-shaped springs.

9. The method according to claim 5, characterized in that After the first electrode and the second electrode are respectively connected to the glass fiber epoxy resin tube through threads, room temperature curing glue is applied at the connection of the threads, and a sealing ring is provided on the contact surface between the electrode pair and the glass fiber epoxy resin layer to form the sealed housing, the method further includes: A plurality of protrusions are arranged on the sealing housing.

10. The method according to any one of claims 1 to 9, characterized in that: The target valve sheet includes at least one valve sheet, and the specification of the valve sheet is D52.

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