CN219086459U - Enhanced lightning protection insulator - Google Patents

Abstract

The utility model provides an enhanced lightning protection insulator, which belongs to the technical field of lightning protection and arc extinguishing and comprises a recoil pipe, a plastic shell and a skirt, wherein the recoil pipe is arranged at the top end of the plastic shell, the skirt is arranged at the side edge of the plastic shell at intervals, a plurality of liquid valve plates and a plurality of zinc oxide valve plates are arranged in the plastic shell, the liquid valve plates and the zinc oxide valve plates are arranged in series from head to tail, the zinc oxide valve plates are connected in series between the liquid valve plates and the liquid valve plates, or the liquid valve plates are connected in series between the zinc oxide valve plates and the zinc oxide valve plates. The utility model improves the arc extinguishing capability of the insulator, is suitable for the full-scale large-current arc extinguishing requirement, has sensitivity to weak current extinguishing capability and acts rapidly and effectively. For high current, the self-energy conversion can effectively extinguish arc, thus forming a virtuous circle.

Description

Enhanced lightning protection insulator

Technical Field

The utility model relates to the technical field of lightning protection and arc extinction, in particular to an enhanced lightning protection insulator.

Background

The national standard AC gapless metal oxide insulator specifies that the standard heat dissipation time of the insulator is 60s, and the interval time of multiple lightning strokes is 30ms. The insulator is changed from a high-resistance state to a low-resistance state by means of the nonlinear resistance of the valve plate in the insulator, so that lightning current flows through the insulator to be led into the ground, and the potential difference between two ends of the insulator is reduced. However, the time lag effect exists in the resistance value transformation of the insulator, and the residual voltage is extremely easy to exceed the standard under the condition of multiple lightning strokes. The special structure of the insulator needs to have excellent sealing performance, so when huge lightning energy is accumulated in the insulator, the sealing structure influences the smoothness of heat release, and the addition of the skin effect leads to uneven current distribution in the valve plate and direct leads to thermal breakdown in the insulator. The insulator after thermal breakdown forms a short circuit point, which causes power transmission line faults, increases difficulty in line fault removal and greatly increases operation and maintenance costs.

Disclosure of Invention

The utility model aims to provide an enhanced lightning protection insulator, which solves the technical problems that the existing insulator is easy to break down, and damage or power frequency flashover occurs. The zinc oxide valve plate and the liquid valve plate are used in series. The electric arc is extinguished rapidly by the electrohydraulic effect generated by the electric arc in the liquid. Heat is prevented from accumulating on the solid valve plate, and finally, the internal thermal breakdown of the insulator is caused.

In order to achieve the above purpose, the technical scheme adopted by the utility model is as follows:

the utility model provides an enhancement mode lightning protection insulator, includes recoil pipe, plastics casing and shirt rim, and recoil pipe sets up on the top of plastics casing, and the shirt rim interval sets up in plastics casing side, and the inside a plurality of liquid valve block and a plurality of zinc oxide valve block that is provided with of plastics casing, and liquid valve block and zinc oxide valve block concatenate the setting end to end, has concatenated zinc oxide valve block or has concatenated liquid valve block between zinc oxide valve block and the zinc oxide valve block between liquid valve block and the liquid valve block.

Further, the backflushing pipe comprises an arc striking electrode, a communicating electrode and a backflushing pipe body, wherein the backflushing pipe body is of a pipe body structure with an opening at the upper end, the arc striking electrode is arranged at the top end of the backflushing pipe body, and the communicating electrode is arranged at the bottom end of the backflushing pipe body and is connected with the liquid valve plate or the zinc oxide valve plate.

Further, the liquid valve block comprises an insulating tube, a liquid medium, an insulating shell and a metal plate, wherein the metal plate is arranged at two ends of the insulating tube in a sealing mode, the liquid medium is arranged in the insulating tube, and the insulating shell is wrapped on the outer side of the insulating tube.

Further, an elastic layer is arranged on the inner side wall of the insulating tube, and the elastic layer is arranged between the inner side wall of the insulating tube and the liquid medium.

Further, the shell of the insulating tube is provided with a plurality of convex edges, the convex edges are arranged at intervals, and the convex edges and the insulating tube are integrally arranged.

Due to the adoption of the technical scheme, the utility model has the following beneficial effects:

(1) The utility model improves the arc extinguishing capability of the insulator, is suitable for the full-scale large-current arc extinguishing requirement, has sensitivity to weak current extinguishing capability and acts rapidly and effectively. For high current, the self-energy conversion can effectively extinguish arc, thus forming a virtuous circle. Especially, the protection effect on counterattack shielding failure accidents caused by multiple lightning strokes and induced overvoltage is good. The arc extinguishing requirements of the ultra-strong short-circuit current at the outlet of the transformer substation and the outlet of the generator can be met.

(2) The integral safety level of the insulator is improved, the attenuation effect of the liquid valve plate on the impact arc intensity is achieved through the transformation capability of current waveforms, the impact amplitude of natural lightning current is reduced, and the wave head steepness of discharge time is prolonged. Meanwhile, the zinc oxide valve block is replaced by the liquid valve block, so that the total resistance value of the valve block is reduced, the heating value of the zinc oxide valve block is reduced from two dimensions of current and resistance, and the occurrence probability of thermal breakdown hard short circuit of the lightning arrester is reduced.

(3) The characteristics of the voltage and the second are smooth, a uniform electric field is formed between the plate electrodes under the lightning strike condition, the characteristics of the voltage and the second are smooth, the steepness of current is reduced, and the voltage and the second can be in insulating fit with equipment such as cables and transformers. The air gap is not present, so that the reburning can be effectively blocked, and overheat explosion and breakdown of the current heat accumulated in the valve plate caused by continuous electric arc and repeated reburning can be prevented.

(4) The liquid insulating medium is in a short circuit state after being broken down, so that charges can be effectively released, lightning impulse current residual voltage is reduced, and potential safety hazards are reduced. Meanwhile, the pure zinc oxide valve plate is subjected to leakage current formed by high voltage application for a long time, and the liquid insulating medium can reduce equivalent voltage drop at two ends of the valve plate, so that the valve plate does not have leakage current to pass, heat aging caused by the leakage current is eliminated, the safety of the valve plate is ensured, and the service life of the device is greatly prolonged.

Drawings

FIG. 1 is a schematic view of an insulator structure according to the present utility model;

FIG. 2 is a schematic view of another insulator construction according to the present utility model;

fig. 3 is a schematic view of the structure of the liquid valve plate of the present utility model.

In the attached drawings, a 1-insulating tube, a 2-liquid medium, a 3-elastic layer, a 4-insulating shell, a 5-metal plate, a 6-liquid injection port, a 7-sealing bolt, an 8-liquid injection port sealing ring, a 9-sealing gasket, a 10-convex edge, a 11-recoil tube, a 12-arc striking electrode, a 13-communication electrode, a 14-grounding guide rod, a 15-liquid valve plate, a 16-zinc oxide valve plate, a 17-plastic shell, a 18-skirt edge and a 19-reinforcing layer are arranged.

Detailed Description

In order to make the objects, technical solutions and advantages of the present utility model more apparent, the present utility model will be further described in detail below by referring to the accompanying drawings and by illustrating preferred embodiments. It should be noted, however, that many of the details set forth in the description are merely provided to provide a thorough understanding of one or more aspects of the utility model, and that these aspects of the utility model may be practiced without these specific details.

As shown in fig. 1-3, an enhanced lightning protection insulator comprises a back flushing pipe 11, a plastic shell 17 and a skirt 18, wherein the back flushing pipe 11 is arranged at the top end of the plastic shell 17, the skirt 18 is arranged at the side edge of the plastic shell 17 at intervals, a plurality of liquid valve plates 15 and a plurality of zinc oxide valve plates 16 are arranged in the plastic shell 17, the liquid valve plates 15 and the zinc oxide valve plates 16 are arranged in series from head to tail, the zinc oxide valve plates 16 are connected between the liquid valve plates 15 and the liquid valve plates 15 in series, or the liquid valve plates 15 are connected between the zinc oxide valve plates 16 and the zinc oxide valve plates 16 in series.

Wherein, the plastic housing 17 can be set as an integral structure, also can be set as a detachable structure, and when being set as a detachable structure, the liquid valve plate 15 and the zinc oxide valve plate 16 inside can be replaced at any time, thereby having longer service life. The metal plate 5 of the liquid valve plate 15 is provided with a liquid injection port 6, the liquid injection port 6 is provided with a sealing bolt 7 for sealing, and the side edge of the sealing bolt 7 is provided with a liquid injection port sealing ring 8. The liquid injection port 6 is arranged to add liquid medium at random, so that the effect of repeated use is realized. The reuse of the liquid valve sheet 15 can be realized.

The insulating tube is made of inorganic nonmetallic materials with high hardness, high temperature resistance and high pressure resistance and is cylindrical; the inside of the insulating tube is filled with liquid (insulating oil, water-oil mixture, etc.); sealing gaskets are arranged at two ends of the insulating tube, and are sealed by adopting steel plates. Umbrella skirts are arranged around the insulating pipes and are integrally fixed by insulating plastic, so that a steel plate structure can be fixed, and lightning along-surface flashover can be avoided.

As shown in fig. 1 and 3, the liquid valve plate and the zinc oxide valve plate are connected in series through steel plate connection, and the valve plates are fixed by insulating materials at the periphery to form the mixed arc extinguishing lightning arrester. Under the action of normal line voltage, the current in the zinc oxide resistance valve plate is very small and is equivalent to an insulator. When the overvoltage wave caused by lightning strike approaches to the protected equipment, the mixed arc extinguishing arrester is broken down preferentially, the electric arc is introduced into the liquid valve plate and poured into the liquid to generate a liquid-electric effect, a strong shock wave is formed, and the electric arc is cut off by acting on the discharge channel in an impulse or impact pressure mode. Meanwhile, as the specific heat capacity of the liquid in the liquid valve block is higher, a large amount of arc heat can be absorbed, the heating value of the zinc oxide valve block of the valve block is reduced, and the zinc oxide valve block is prevented from thermal breakdown.

The insulating tube is made of inorganic nonmetallic materials with high hardness, high temperature resistance and high pressure resistance and is cylindrical; the inside of the insulating tube is filled with liquid (insulating oil, water-oil mixture, etc.); the two ends of the insulating tube are sealed by steel plates. The periphery of the insulating tube is provided with insulating plastic, so that a steel plate structure can be fixed, and lightning surface flashover can be avoided.

And connecting a plurality of liquid valve plates in series through steel plate connection, and fixing the liquid valve plates with insulating materials at the periphery to form the liquid valve plate lightning arrester. When overvoltage waves caused by lightning strike approach to protected equipment, the liquid valve plate lightning arrester is broken down preferentially, electric arcs are introduced into the liquid valve plate and poured into liquid to generate a liquid-electricity effect, strong shock waves are formed, and the electric arcs are intercepted by acting on a discharge channel in an impulse or impact pressure mode.

Meanwhile, the serial liquid valve plates have the capability of multipoint synchronous arc extinction. The arc extinction suppression of the partial impact discharge arc is started at the initial stage of the impact arc, and the multipoint synchronous cut-off arc is implemented for the penetrating flashover. The accumulated arc break points have large arc break points and cannot be reburned.

The insulating tube is filled with liquid (insulating oil, water-oil mixture and the like), plate electrode seals are arranged at two ends of the insulating tube, and insulating materials are arranged at the periphery of the insulating tube to avoid lightning surface flashover. The size and shape of the cake-shaped liquid valve plate are consistent with those of the solid valve plate, so that the installation and replacement are convenient when the valve plate inside the existing lightning arrester is replaced, and the cost of the replacement device can be reduced.

When the device is used in the aspect of gap arc extinction, the liquid medium can be in a weak conductive state, and if the device is used in the aspect of a lightning arrester or a lightning rod, the liquid medium is in a state of near insulation, and the resistance must reach tens of megaohms. Among them, insulating oil is most preferable. Such as transformer oil, breaker oil, capacitor oil, cable oil, etc.

The hydro-electric effect insulating oil liquid electric effect arc extinguishing process under the insulating oil condition comprises the following steps: an insulating oil breakdown process, a hydro-electric effect process, an arc extinguishing process and a re-ignition suppressing process. The high viscosity, the high specific heat capacity and the high medium strength of the insulating oil affect the peak value and the peak value time of the hydro-electric effect pressure; the influence of the pressure peak value and the peak value time on the arc extinction threshold value and the arc extinction time; the effect of the sealing structure on the pressure peak and the peak time.

1. The reduction of the time of the pressure peak of the liquid-electricity effect reduces the time of the arc-extinguishing effect, forms early intervention of arc extinction and is beneficial to forming a strong arc-extinguishing situation.

2. And the extinction threshold can be improved by improving the pressure peak value of the hydro-electric effect. An asymmetric situation is formed in which the arc extinction pressure is far greater than the arc breaking resistance pressure, so that the arc extinction threshold is improved.

3. Compared with water, the insulating oil breakdown field intensity is high, which is favorable for improving the pressure peak value of the liquid electric effect and reducing the time of the pressure peak value: the insulating oil has much higher insulating strength and breakdown field strength than air and water, and under the same gap distance, the breakdown voltage and the bursting property of the breakdown process are improved, and the bursting property of the current can be increased by improving the breakdown voltage. The steady-state value of the current after breakdown is increased along with the increase of the breakdown voltage, so that the current change rate is increased, and the pressure peak value of the liquid-electric effect proportional to the current change rate is also increased. The improvement of the current change rate also correspondingly improves the climbing speed of the hydraulic-electric effect pressure intensity, thereby reducing the peak time of the hydraulic-electric effect pressure intensity.

4. The high viscosity of the insulating oil compared with water is beneficial to improving the time of the hydraulic effect pressure peak value and the male building pressure peak value. The viscosity of the insulating oil is high, the bonding force between molecules is inevitably increased, the space occupation difficulty of the electric arc is increased along with the increase of the space occupation difficulty of the electric arc in the arc breakdown process, the pressure required by the space occupation realization in the process of extruding the insulating oil by the electric arc is increased, the pressure applied to the insulating oil by the electric arc is increased, and the arc extinguishing pressure of the reaction of the insulating oil to the electric arc is also increased. Because the sensitivity of the insulating oil with high viscosity property for resisting the occupation of the breakdown arc volume is increased, under the condition of extremely small breakdown current, extremely high hydraulic effect pressure can be generated for resisting the occupation of the small arc volume, so that the time of the pressure peak of the hydraulic effect pressure is reduced, and the pressure peak is improved.

5. Compared with water, the insulating oil has higher stability: the insulating oil is an organic high polymer material, is not easy to decompose, gasify and age, has more stable physical and chemical properties, and meets the requirements of repeated arc extinction and maintenance-free arc extinction.

6. Insulating oil has a higher specific heat capacity than water: the specific heat capacity of the insulating oil is high, so that a large amount of arc temperature can be absorbed, the arc is cooled, and the vulnerability and the easy-to-extinguish performance of the arc are improved;

7. compared with water, the insulating oil has better medium strength recovery property: after the liquid electric effect breaks the electric arc, the electric arc fracture is filled with insulating oil, and the breakdown field strength of the insulating oil is higher than that of water, so that the reburning resistance is improved.

8. Compared with water, the dielectric oil electric effect extinction threshold is larger: through the characteristics that insulating oil liquid electric effect pressure has higher sensitivity, the arc extinction start time is advanced, and the higher expected current can be extinguished in the initial arc establishing section, thereby meeting the 40kA full-scale power frequency short circuit current arc extinction requirement.

9. Compared with water, the electric effect arc extinguishing speed of the insulating oil is as high as possible: the arc extinction by the electric effect of the insulating oil liquid has higher arc extinction sensitivity, so that the arc extinction time is advanced. The time for extinguishing the 40kA full-scale short-circuit current is tens to hundreds of microseconds, which is less than the relay protection outlet response time of tens of milliseconds, and the requirement for extinguishing the 40kA full-scale power frequency short-circuit current before the relay protection response time is met.

10. The application range is wide: the electric effect of the insulating oil liquid reduces the time of the pressure peak value of the arc extinguishing shock wave, improves three dimensions of the pressure peak value of the arc extinguishing shock wave and the medium recovery strength, improves the arc extinguishing threshold value, reduces the arc extinguishing time and provides a new method for solving the lightning trip. Is suitable for arc extinction requirements of 10kV, 35kV, 110kV, 220kV, 500kV, 800kV and 1000kV voltage levels.

11. Insulation fit for each voltage class: the insulation fit requirement under any voltage level can be realized by controlling the length of the liquid electric effect arc extinguishing section and the length of the air gap.

12. Compared with water and valve plates, the insulating oil liquid electric effect arc extinction is quicker, the time lag effect existing in the valve plates is avoided, the pressure peak value is lower, the pressure peak value time lag and the medium recovery strength are low due to low viscosity and low breakdown field intensity in the process of the water medium liquid electric effect, the arc extinction time is long and the insulating oil liquid electric effect is easy to burn again to generate larger heating value, the result that the structure is damaged due to the gasification and decomposition of the water is triggered, and the safety and durability of the insulating oil liquid electric effect lightning protection are improved.

In the embodiment of the utility model, the backflushing tube 11 comprises an arc striking electrode 12, a communicating electrode 13 and a backflushing tube body, wherein the backflushing tube body is of a tube body structure with an opening at the upper end, the arc striking electrode 12 is arranged at the top end of the backflushing tube body, and the communicating electrode 13 is arranged at the bottom end of the backflushing tube body and is connected with the liquid valve plate 15 or the zinc oxide valve plate 16. The electric arc firstly carries out the recoil arc extinction of the first stage in the recoil tube 11, wherein, the liquid medium 2 is arranged in the recoil tube 11, and the hydro-electric effect also occurs in the recoil process, so that the recoil effect is better and the arc extinction speed is faster.

In the embodiment of the utility model, the liquid valve plate 15 comprises an insulating tube 1, a liquid medium 2, an insulating shell 4 and a metal plate 5, wherein the metal plate 5 is arranged at two ends of the insulating tube 1 in a sealing way, the liquid medium 2 is arranged in the insulating tube 1, and the insulating shell 4 is wrapped outside the insulating tube 1. As shown in fig. 1 or fig. 2, when there are one liquid valve sheet 15, there are two zinc oxide valve sheets 16, the liquid valve sheet 15 is disposed in the middle of the zinc oxide valve sheets 16, and when there are one zinc oxide valve sheet 16, there are two liquid valve sheets 15, the zinc oxide valve sheets 16 are disposed in the middle. The back flushing pipe 11, the plastic shell 17 and the insulating pipe 1 are insulating shells, and are made of rubber materials, epoxy resin, nylon glass fiber or elastic materials of PC materials, so that the plastic back flushing pipe has certain deformability and cannot be broken when the hydro-electric effect occurs.

In the embodiment of the utility model, the inner side wall of the insulating tube 1 is provided with the elastic layer 3, and the elastic layer 3 is arranged between the inner side wall of the insulating tube 1 and the liquid medium 2. The elastic layer 3 can be a rubber layer, reduces the pressure intensity in the pipe, and the elastic material of the elastic layer 3 arranged in the insulating pipe is provided with small pits on the surface of the elastic material, so that the stress area of the inner wall of the insulating pipe is increased, and meanwhile, the roughness of the surface is improved, and the pressure and the area satisfy the following relations: p=f/S, i.e. the force area is inversely proportional to the pressure.

In the embodiment of the utility model, the shell of the insulating tube 1 is provided with a plurality of convex edges 10, the convex edges 10 are arranged at intervals, and the convex edges 10 and the insulating tube 1 are integrally arranged. The rim 10 is most preferably formed as a unitary structure to prevent arcing from between layers. Without the collar 10, the metal plate needs to be made smaller than the outer diameter of the insulating tube 1.

When lightning strikes the transmission line, the internal channel of the enhanced lightning protection insulator arranged on the tower pole is broken down preferentially, flashover electric arcs enter from the backflushing pipe 11, backflushing and arc extinguishing are performed firstly, then residual electric arcs enter into the liquid valve plate 15 and the zinc oxide valve plate 16, when the electric arcs conduct the internal liquid medium 2 of the liquid valve plate 15, a liquid electric effect is generated, a reflection shock wave superposition effect and a Pascal effect are generated, shock waves are formed, the shock waves act on the discharge channel in a manner of impulse or impact pressure, the electric arcs are intercepted, meanwhile, because the specific heat capacity of liquid in the liquid valve plate 15 is high, a large amount of electric arc heat can be absorbed, the heating value of the zinc oxide valve plate is reduced, the thermal breakdown of the zinc oxide valve plate is avoided, the intermittent discharge is reduced, the current intensity and the rising rate are reduced, the reburning time is delayed, and the internal arc extinguishing of the arc protection insulator is realized.

The backflushing pipe 11 may or may not be provided with a liquid medium, backflushing is performed to realize backflushing arc extinguishing at the ground stage, and then the residual arc is extinguished if the residual arc is continuously conducted to the liquid valve plate 15 at the back.

After the electric arc breaks down the spark gap, the arc is quickly extinguished by the hydro-electric effect: when the arc is poured into the insulating tube, and discharges in the tube containing liquid, part of the liquid in the discharge channel is instantaneously vaporized, decomposed and ionized into high-temperature plasma to be suddenly expanded, so that a mechanical pressure wave which rapidly propagates outwards is formed. However, since the liquid is regarded as a shock wave transmission medium which is not compressed by itself, when the discharge channel performs liquid phase discharge, a mechanical effect of ultra-high power is exhibited to the outside, and an impact force is formed in the insulating tube, and acts on the discharge channel in the form of impulse or impact pressure to impact and cut off the arc.

The liquid valve plate is connected with the zinc oxide valve plate in series, so that the intermittent discharge is reduced, and the current intensity and the rising rate are reduced: under the action of normal line voltage, the resistance value of the pure zinc oxide resistance valve plate is very large and is equivalent to an insulator. Therefore, the zinc oxide arrester can effectively inhibit the power frequency follow current after the lightning impulse voltage through the high resistance of the valve plate under the normal voltage of the circuit.

After the liquid valve plates are connected in series, the liquid electric effect starts to act at the initial stage of the impact arc, and arc extinction suppression is carried out on the arc of the local impact discharge. And because the specific heat capacity of the liquid in the liquid valve block is higher, a large amount of arc heat can be absorbed, the heating value of the zinc oxide valve block of the valve block is reduced, and the zinc oxide valve block is prevented from thermal breakdown.

After the liquid valve plate is connected with the zinc oxide valve plate in series, the zinc oxide valve plate inhibits the intensity of the liquid-electricity effect, and the pressure exceeding is avoided. The reduction of the current intensity can avoid damage to the valve plate due to too high pressure of the hydraulic effect.

The ability of the liquid valve plate to extinguish arc and the ability of the zinc oxide valve plate to delay the re-burning time are mutually matched: the breakdown ignition voltage is determined by volt-second characteristics, and the residual voltage is determined by negative resistance volt-ampere characteristics. When lightning strike occurs, but before the liquid valve plate breaks down, a capacitor chain formed by the liquid valve plate has a large capacitance and can play a role in guiding high-frequency lightning pulse, so lightning energy is released into the ground through an arc extinguishing path of the liquid valve plate, lightning current is easier to pass through, the ignition voltage under the lightning pulse is reduced, the volt-second characteristic and breakdown voltage are reduced, the lightning current waveform is more gentle, and the lightning current waveform is in insulating fit with high-capacity electrical equipment such as a transformer substation. The arc extinguishing capability of the liquid valve plate in the pre-breakdown stage and the re-ignition time delaying capability of the zinc oxide valve plate are mutually matched, so that the arc extinguishing capability is improved, and meanwhile, the heating value is reduced, and the arc extinguishing voltage threshold is improved.

When lightning breaks down the liquid valve plate, the plate is in a short circuit state after breakdown, and residual voltage is reduced to a low level by arc voltage. The reduced residual voltage is beneficial to protecting power electronic equipment. Meanwhile, under the normal working condition, the liquid valve plate is in an open state, and the main pressure drop of the valve plate can be shared. And the leakage current of the valve block is eliminated, and the thermal aging of the valve block under the normal working condition is avoided, so that the aging loss of the valve block under the standby condition is eliminated. The lightning-proof level of the device is more reliable and effective, and reasonable insulation fit is formed with the liquid valve plate insulator.

The specific process for reducing the intermittent discharge and reducing the current intensity is as follows: after the zinc oxide valve block is connected with the liquid valve block in series, the liquid electric effect starts to act at the initial stage of the impact arc, arc extinction inhibition is carried out on the arc of the partial impact discharge, the zinc oxide valve block inhibits the strength of the liquid electric effect, the exceeding of pressure is avoided, the damage caused by the overlarge pressure of the liquid electric effect valve block can be avoided by reducing the current strength,

the specific processes of the rising speed and the delayed reburning time are as follows: the breakdown ignition voltage is determined by volt-second characteristics, residual voltage is determined by negative resistance volt-ampere characteristics, when lightning strike occurs, but before the liquid valve plate breaks down, a capacitor chain formed by the liquid valve plate has a large capacitor, the effect of guiding high-frequency lightning pulse can be achieved, lightning energy is released into the ground through an arc extinguishing path of the liquid valve plate, so that lightning current can pass more easily, the ignition voltage under the lightning pulse is reduced, the volt-second characteristics and the breakdown voltage are reduced, insulation fit is facilitated, the arc extinguishing capacity of the liquid valve plate in a pre-breakdown stage and the zinc oxide valve plate delay reignition time capability are mutually matched, the heating value is reduced while the arc extinguishing capacity is improved, the arc extinguishing voltage threshold is improved, after the liquid valve plate is broken down by lightning strike, the residual voltage is reduced to a low level by the arc voltage, the residual voltage reduction is beneficial to protecting power electronic equipment, and the lightning resisting level of the equipment and a liquid valve plate arrester after the residual voltage attenuation form reasonable insulation fit.

The liquid medium 2 adopts emulsion mixed liquid of oil and water or insulating oil, the oil is wrapped by water and then is connected into a piece through water, a complete water medium discharge channel is formed, the breakdown characteristic of single pure water medium is reserved, in the process of discharging an electric arc along the water medium, electric arc plasma is subjected to incompressibility restriction generated by wrapping of the insulating oil, pressure intensity and damping shock wave conduction pressure intensity are generated, the liquid cannot be deformed and displaced instantaneously due to short lightning arc impact time, at the moment, the mixed liquid can be regarded as shock wave transmission medium which cannot be compressed by itself, and compared with a medium which is harder to compress by common single liquid, the mixed liquid is higher in viscosity and higher in surface tension, so that the force of the emulsion mixed liquid in the original state can be increased, under the pressure effect generated by the electric arc space occupation breakdown mixed liquid, the pressure intensity of hundreds of megapascals is synchronously generated on the contact surface of the electric arc and the emulsion mixed liquid, the pressure intensity of the hundreds of megapascals is synchronously counteracted and the electric arc is eliminated, the incompressibility of the high-viscosity mixed liquid is ensured, meanwhile, the high-viscosity liquid can absorb more shock wave transmission medium can be regarded as the shock wave, the pressure intensity is reduced, and the damping shock wave is durable to the structure is improved.

In the process of dielectric oil breakdown by the hydraulic electric effect impact arc under the condition of dielectric oil, the volume occupation requirement is set for the dielectric oil in a very short time, because the viscosity of the dielectric oil is high, the displacement is not enough to yield the space occupied by the arc in a very short time, the strong countermeasure of the space position is formed between the occupation of the arc and the displacement of the dielectric oil, thereby the mechanical pressure peak shock wave of hundred megapascals is generated, the shock wave is reacted to the power frequency arc body, and the factors for improving the pressure peak value of the hydraulic electric effect shock wave and reducing the time of the pressure peak value of the hydraulic electric effect comprise: the insulation strength can improve the breakdown field strength, and meanwhile, a high field strength extremely fast electron collapse process is formed, so that the arc breakdown speed is improved, the sudden performance of the space occupation of an arc is increased, the space abdication speed is reduced due to the high viscosity of the insulating oil, a large amount of arc heat can be absorbed by the high specific heat capacity, and the arc temperature is reduced.

The shock wave and the reflected shock wave meet and overlap, the interference phenomenon occurs, the energy of vibration enhanced vibration is increased, when the electric arc enters an arc extinguishing channel containing emulsion mixed liquid, the temperature of plasma generated by liquid phase discharge is up to 1500-3000K, high temperature and high pressure generated in the channel cannot leak outwards in time, the shock wave is reflected back and forth on the inner wall surface of the arc extinguishing channel, and the reflected waves of the inner wall surface overlap each other, so that the overpressure peak value is increased.

If the emulsifier is an ionic surfactant, on the interface, the emulsion droplets are charged due to ionization and adsorption, and the charge size depends on ionization intensity; the non-ionic surfactant has friction effect to make the liquid drop have charge, and its charge size is related to the concentration of external phase ion, dielectric constant and friction constant, when the charged liquid drop is close to it, it produces repulsive force to make it difficult to coalesce, so that it can raise emulsion stability, and the charged liquid drop of emulsion can form electric double layer structure on two sides of interface, and the repulsive effect of electric double layer can produce great mechanical effect, and can produce reflective impact pressure in the interior of insulating tube to act on electric arc.

The specific process of generating the pascal effect is: the pressure change of a certain part of static fluid in the sealed tube structure is transmitted to all directions unchanged, and then the liquid medium around is impacted by larger acting force from a discharge channel in the insulated tube, the acting force bounces after striking against the wall of the insulated tube, the acting force with the direction pointing to the center of the insulated tube is formed, the impact pressure and the occupied pressure peak value are generated in the hydro-electric effect, the dual pressure sources are amplified together, the electric arc is intercepted, the longer the electric arc in the insulated tube is, the larger the acting force on the wall of the insulated tube is, and the larger the impact pressure for intercepting the electric arc is, so that the secondary reburning of the electric arc is prevented.

The insulating body 1 of sealed tube structure is provided with elastic layer 2 in, and elastic layer 2 increases the atress area, reduces intraductal pressure, and the elastic material of elastic layer 2 that sets up in insulating tube has little pit at its surface, increases the atress area of insulating tube inner wall, also improves the roughness on surface simultaneously, because satisfy the relation between pressure and the area and be: p=f/S, namely the inverse proportion between the stress area and the pressure, after the elastic layer 2 is added in the insulating tube body 1 of the sealing tube structure, the maximum pressure in the insulating tube body 1 of the sealing tube structure is lower than before the elastic material is not added under the action of arc impact, so that the condition of explosion of the insulating tube caused by the overlarge pressure in the tube is avoided;

the elastic layer 2 also reflects fundamental waves of the hydro-electric effect, so that the fundamental waves act on an electric arc channel, the electric arc is more easy to extinguish, the instant pressure born by the pipe wall is reduced, and the explosion of the insulating pipe is avoided.

Meanwhile, the impact force generated by Pascal effect is avoided to directly impact the insulating tube, impact force is firstly formed on the elastic insulating material by the impact wave in the tube, the reaction force acting on the inner surface of the insulating tube is reduced, and the insulating tube with smaller hardness is prevented from being broken due to the impact of the reaction force.

When lightning breaks down the liquid valve plate, the plate is in a short circuit state after breakdown, and residual voltage is reduced to a low level by arc voltage. The residual voltage is reduced, which is favorable for protecting power electronic equipment, so that the lightning-proof level of the equipment and the lightning arrester of the liquid valve plate after the residual voltage is attenuated form reasonable insulation fit.

(1) Under the combined action of liquid-electric effect arc extinction and zinc oxide nonlinear arc damping, the liquid valve plate reburning recovery voltage is reduced, the arc reburning time is prolonged, the lightning current enters an intermittent discharge mode, the increase of a current value is restrained, the increase rate of the lightning current is restrained, the wave head time of the lightning current is increased, the lightning current amplitude is attenuated, the liquid valve plate is inserted, meanwhile, the lightning current intensity and the steepness are attenuated, and the lightning current amplitude flowing through a lightning arrester is greatly reduced by prolonging the discharge time of ultra-low-intensity current (tens of ampere levels). Because the heat generated when the current flows through the zinc oxide valve plate is in direct proportion to the square of the current and in direct proportion to the first power of the through-flow time, the effects of reducing the current amplitude and prolonging the through-flow time are superimposed comprehensively, and the heat of the zinc oxide valve plate is linearly attenuated, the through-flow capacity and the current tolerance threshold of the valve plate are improved, and the safety problem of thermal breakdown and hard short circuit of the zinc oxide valve plate is solved. When the lightning current passes through the lightning arrester instantaneously, the electric arc flowing through the liquid valve plate generates liquid electric arc discharge and generates liquid-electric effect in the pre-breakdown stage, and the pressure of hundreds of megapascals is generated to the whole section of the electric arc through the Pascal pressure amplification principle, the electric arc volume occupation and the liquid evaporation expansion principle caused by incompressible opposition of a liquid medium and the high temperature of the electric arc, so that the electric arc is blocked integrally and simultaneously. Because the lightning voltage is very high, the liquid can reburn and break down, under the partial pressure effect of the zinc oxide arrester valve block, the voltage born by the liquid valve block is reduced, meanwhile, the liquid thermal expansion pressure generated by the liquid in the previous breakdown is very huge, the high pressure reduces the free travel among molecules of the liquid medium, the breakdown field intensity is increased, the breakdown voltage is improved, and the time of reburning the liquid valve block is delayed by considering the partial pressure and time constant damping effect of the nonlinear resistor of the zinc oxide valve block. The extension of the period of the gap discharge is beneficial to damping the lightning current amplitude and reducing the heating value, and is also beneficial to the heat dissipation of the valve plate.

(2) The number of zinc oxide valve plates is reduced, and the through-flow capacity of the whole lightning arrester can be directly reduced. If the impact current tolerance value of the single valve plate is i ₁ The impact current tolerance value of the M valve plates is i _M The relationship between them is scaled as follows:

the tolerance energy of a valve plate is set as follows:

wherein i is ₁ Is 1 valve plate limit withstand current, W ₁ Energy absorbed by M valve plates is 1 valve plate limit tolerance energy:

wherein i is _M Is the withstand current under the condition of M valve plates, W _M For the tolerance energy of M valve plates, the heat insulation process stripUnder-piece (arrester valve plate sealed) W _M ＝W ₁ When the tolerance limit energy of the whole lightning arrester is constant and equal to the tolerance limit energy of 1 valve block, the increase of the resistance of the valve block of the whole lightning arrester inevitably leads to the reduction of the amplitude of the through current, and according to the serial relation of a plurality of valve blocks and the equality of the current flowing through each valve block, the method can be used for solving:

the through-flow relation between the through-flow capacity of the whole lightning arrester and the through-flow relation under the test condition of one valve plate meets the following conditions:

the larger the number M of the valve plates is, the smaller the through-flow capacity of the whole lightning arrester is. After the zinc oxide valve plate is replaced by the liquid valve plate, the M value is reduced, and the total resistance value of the lightning arrester is reduced, thereby improving the i _M The value improves the current capacity of the whole lightning arrester.

(3) The residual pressure of the liquid valve plate is almost zero, so that the residual pressure of the lightning arrester can be reduced. After the liquid valve plate breaks down, the electric arc short-circuits the liquid valve plate to form residual voltage close to zero, so that the total residual voltage of the lightning arrester is reduced, and the dual lightning protection effects of residual voltage reduction and arc extinguishing capability improvement are realized.

(4) The open circuit of the liquid valve block under the power frequency condition can not only block the leakage current of the zinc oxide valve block, but also eliminate the permanent fault caused by the hard short circuit of the zinc oxide valve block, avoid the secondary damage to the power grid caused by the short circuit of the lightning arrester, and improve the operation safety of the lightning arrester.

(5) The combined arc extinguishing capability can cut off the re-burning arc and improve the arc extinguishing voltage. Under the action of the power frequency voltage, the liquid valve plate is in an open circuit state, so that the power frequency breakdown voltage of the liquid valve plate is higher than that of the zinc oxide valve plate, the liquid valve plate is compared with the zinc oxide valve plate, the liquid valve plate needs higher breakdown voltage, and the power frequency arc extinguishing voltage threshold value can be improved by replacing the zinc oxide valve plate with the liquid valve plate.

(6) Because the liquid valve plate adopts liquid medium, the dielectric coefficient is far greater than 1, the equivalent capacitance is very large, under the action of lightning voltage, the liquid valve plate presents large capacitance, lightning current can pass through before the liquid medium breaks down, so that the lightning arrester can be opened under the condition of lower lightning voltage, the volt-second characteristic of the wave head time period is reduced, the breakdown ignition voltage is reduced, and the matching of the clamping lightning voltage and the volt-second characteristic is facilitated.

The foregoing is merely a preferred embodiment of the present utility model and it should be noted that modifications and adaptations to those skilled in the art may be made without departing from the principles of the present utility model, which are intended to be comprehended within the scope of the present utility model.

Claims (5)

1. An enhanced lightning protection insulator is characterized in that: including recoil pipe (11), plastic casing (17) and shirt rim (18), recoil pipe (11) set up the top at plastic casing (17), and shirt rim (18) interval sets up in plastic casing (17) side, and plastic casing (17) inside is provided with a plurality of liquid valve block (15) and a plurality of zinc oxide valve block (16), and liquid valve block (15) concatenate with zinc oxide valve block (16) head and the tail setting, has concatenated zinc oxide valve block (16) between liquid valve block (15) and liquid valve block (15) or has concatenated liquid valve block (15) between zinc oxide valve block (16) and zinc oxide valve block (16).

2. An enhanced lightning protection insulator according to claim 1 wherein: the backflushing pipe (11) comprises an arc striking electrode (12), a communicating electrode (13) and a backflushing pipe body, wherein the backflushing pipe body is hollow, the upper end of the backflushing pipe body is of a pipe body structure with an opening, the arc striking electrode (12) is arranged at the top end of the backflushing pipe body, and the communicating electrode (13) is arranged at the bottom end of the backflushing pipe body and is connected with the liquid valve plate (15) or the zinc oxide valve plate (16).

3. An enhanced lightning protection insulator according to claim 1 wherein: the liquid valve block (15) comprises an insulating tube (1), a liquid medium (2), an insulating shell (4) and a metal plate (5), wherein the metal plate (5) is arranged at two ends of the insulating tube (1) in a sealing mode, the liquid medium (2) is arranged in the insulating tube (1), and the insulating shell (4) is wrapped on the outer side of the insulating tube (1).

4. An enhanced lightning protection insulator according to claim 3 wherein: an elastic layer (3) is arranged on the inner side wall of the insulating tube (1), and the elastic layer (3) is arranged between the inner side wall of the insulating tube (1) and the liquid medium (2).

5. An enhanced lightning protection insulator according to claim 3 wherein: the shell of the insulating tube (1) is provided with a plurality of convex edges (10), the convex edges (10) are arranged at intervals, and the convex edges (10) and the insulating tube (1) are integrally arranged.

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