A kind of protection insulated conductor is with being with the external series gap metal oxide arrester
Technical field the utility model relates to the lightning arrester of power distribution network, at the lightning-caused breaking problem of power distribution network 10kV system suspended insulated guide wire, can prevent effectively that insulated conductor from damaging because of lightning overvoltage.
Background technology adopts insulated conductor to solve corridor that plain conductor can't resolve and safety problem in the middle of power distribution network, compares with cable, adopts the insulated conductor reduced investment, builds soon, and advantage is fairly obvious.Developed countries has gradually adopted suspended insulated guide wire from the later stage sixties 20th century.But insulated conductor also has the weakness of himself, i.e. lightning-caused breaking problem, and so-called thunderbolt must be broken.
Suffer the mechanism of lightning-caused breaking according to insulated conductor, the corresponding precautionary measures have " dredging formula " and " blocking type " dual mode.So-called " dredging formula " is exactly with near the local bare wireization of the insulated conductor the insulator, power frequency arc arc root is transferred on the special gold utensil burnt, thereby guardwire avoids scaling loss.The product that has occurred is peeled off insulating barrier as: Finland at insulator and wire coupling place arc protection molded lines folder is installed; The Sweden and the U.S. peel off one section insulating barrier with the insulated conductor of insulator both sides and install the preventing arc wire clamp additional; The wire insulation at insulator place is peeled off by Japan, and discharge clamp insulator etc. is installed.Simple to operate, the small investment of the mode of " dredging formula ", but lead is local exposed, has sealing and insulation defect.
So-called " blocking type " is exactly to stop the power frequency continued flow starting the arc behind the lightning stroke flashover, fundamentally got rid of the factor of lead scaling loss.Relative measures is set up lightning conducter, is reduced pole tower ground resistance, reinforced insulation, installation Transmission Line Arrestor etc.It is more satisfactory so far measure that Transmission Line Arrestor is installed, and the product that has occurred has the band of the Japan ring-like external series gap metal oxide arrester of connecting.In addition, Russia has also proposed long flashover gap mode, and promptly by increasing flashover path reaching the purpose that reduces the power frequency probability of sustained arc, but the realization means are still immature, and is with the insulated conductor phase spacing and reduces trend and contradict.Compare " dredging formula ", " blocking type " mode better protecting effect, shortcoming are the construction relative complex, and cost is higher.
China implements insulating since the eighties to city overhead distribution net and transforms pilot, has accelerated paces the nineties.In recent years, along with the increase of insulated conductor coverage rate in the power distribution network, the lightning-caused breaking problem is also day by day obviously got up.China also is in the stage of groping at present to the research starting evening of insulated conductor lightning-caused breaking problem.
Summary of the invention is in order to overcome above-mentioned defective and the deficiency that exists in the middle of the prior art, the purpose of this utility model provides structural metal, a kind of novel external series gap oxide lightning arrester that a kind of principle that adopts above-mentioned " blocking type " is developed, and can be used with the 10kV overhead transmission line of prior art needle type ceramic insulators, pillar porcelain insulator, post composite insulators commonly used.
The technical solution of the utility model is: a kind of novel protected insulated conductor is made up of the air gap of installing between gold utensil 4, lightning arrester body 5, top electrode 7, bottom electrode 6 and top electrode 7 and the bottom electrode 6 with band structural metal, external series gap oxide lightning arrester.Lightning arrester body 5 is arranged on to be installed on the gold utensil 4, and top electrode 7 is fixed on the insulated conductor 1, has bottom electrode 6 on the lightning arrester body 5, and top electrode 7 and bottom electrode 6 corresponding settings are the air gap between the two; Gold utensil 4 and line insulator 2 are installed all to be installed on the shaft tower cross-arm 3.
Top electrode 7 by fixture 9, lead arc pin 8 and insulation cover 10 3 parts constitute, fixture 9 and lead 1 fixed installation, lead arc pin 8 and be arranged on fixture 9 belows, a pair of clubfoot of leading arc pin 8 is respectively towards mains side and load side, fixture 9 and lead arc pin 8 and be coated with insulation cover 10.The installation of top electrode 7 can be adopted wire stripping formula and piercing dual mode.
When electrical network normally moved, the gap isolated power-frequency voltage, and lightning arrester body bears voltage hardly; Under the lightning overvoltage effect of direct lightning strike or the generation of induction thunder, the air gap is breakdown, and lightning arrester body presents Low ESR, and lightning current is released into ground; After the lightning impulse, power-frequency voltage is added on the lightning arrester body, the resistance moment change of lightning arrester body is big, the electric current that passes through is that arc current is suppressed in low numerical value, increase falls in the air gap arc voltage, the insulation of air gap recovers rapidly, and electric arc extinguishes in the short time naturally at the utmost point, and power frequency continued flow is interdicted fully.
Owing to adopted above-mentioned technical scheme, the advantage that the utlity model has has:
(1) utilize " obstructions " mode principle to solve the lightning-caused breaking problem, comparatively ideal product is exactly the band developed of the Japan ring-like external series gap metal oxide arrester of connecting, and has been in the practical stage at present.Scheme of the present utility model and its relatively, under the intact situation of lightning arrester body, the protective value of the two is similar to; But the product of Japan is under the situation that lightning arrester body has damaged, if this moment, circuit suffered direct lightning strike or lightning induced voltage, after lightning impulse, power frequency continued flow can not get suppressing, with smooth combustion.The ring-like external series gap metal oxide arrester of band series connection does not have any protective effect at this moment, and insulated conductor still can scaling loss blow.And scheme of the present utility model because installed top electrode 7 additional on insulated conductor 1, has been equivalent to reinforce the metal part of insulated conductor 1 breakdown point, electric arc arc root is transferred on the electrode 7 by lead 1, thereby the scaling loss electrode has been avoided the damage of lead.On this layer meaning, scheme of the present utility model combines the thought of " blocking type " and " dredging formula " dual mode, to the protection better effects if of insulated conductor.
When (2) top electrode 7 of the present utility model was installed, at the wire stripping or the two kinds of mounting meanss that puncture, the former had increased special Seal Design, the structural advantages of The latter self, all fine local exposed airtight problem that causes of insulated conductor that solved.
(3) simultaneously, top electrode 7 outer surfaces have installed fire-retardant, a resistant to elevated temperatures insulation cover additional, and it is local exposed to have solved insulated conductor, have the problem of insulation defect.
Below in conjunction with accompanying drawing the utility model is described in detail.
Description of drawings
Fig. 1 is a kind of structure chart of protecting insulated conductor with band external series gap metal oxide arrester of the utility model.
Fig. 2 is a kind of structure chart of protecting insulated conductor with three kinds of typical bottom electrodes of band external series gap metal oxide arrester of the utility model, is respectively hemisphere electrode (a), plate electrode (b) and bar electrode (c).
Fig. 3 is a kind of front view and vertical view of protecting insulated conductor with the structure of the top electrode of band external series gap metal oxide arrester of the utility model.
Fig. 4 is a kind of typical scheme of installation (representing dome electrode from top to bottom successively, the installation of plate shape electrode and clavate electrode) of protecting insulated conductor with band external series gap metal oxide arrester of the utility model.
Fig. 5-Fig. 7 is that a kind of insulated conductor of protecting of the utility model is installed to lightning arrester body with hemisphere, plate shape and three kinds of typical electrode of clavate of band external series gap metal oxide arrester, cooperates the schematic diagram of assembling respectively with needle type ceramic insulators, pillar porcelain insulator and post composite insulators.
Embodiment
Referring to Fig. 1; a kind of protection insulated conductor is with being with structural metal, external series gap oxide lightning arrester; by gold utensil 4, lightning arrester body 5 being installed, being fixed on the top electrode 7 on the insulated conductor, the bottom electrode 6 on the lightning arrester body, and the air gap between top electrode 7 and the bottom electrode 6 is formed.Visible lightning arrester body 5 is arranged on and installs on the gold utensil 4 among Fig. 1, on the top electrode 7 stuck-at-0KV insulated conductors 1, has bottom electrode 6 on the lightning arrester body 5, and top electrode 7 and bottom electrode 6 corresponding settings are the air gap between the two; Gold utensil 4 and line insulator 2 are installed all to be installed on the shaft tower cross-arm 3.
Fig. 4 is the schematic diagram under the utility model typical case installs.Installation gold utensil 4 of the present utility model can pass through slotted hole up-down adjustment clearance distance, during on-the-spot the installation, adjusts in right amount according to actual conditions, to satisfy installation requirement.By a large amount of lightning impulse discharge tests; verified the top electrode axis to insulator 2 axial line distance in 150~400mm scope; series gap distance accounts for 40% of insulator dielectric distance H~90% o'clock; under different steepness lightning overvoltages; flashover path all occurs on the series gap; the lightning arrester reliable in action can effectively protect insulated conductor to avoid damaging.
Lightning arrester body adopts compound external insulation leakage conductor, and rated voltage is 13kV, selects the D35 valve block for use, and concrete parameter sees following table for details:
Parameter | Symbol | Unit | Relevant parameter | Numerical value |
The lightning arrester rated voltage | U
R | KV, effective value | | 13 |
The lightning arrester continuous operating voltage | U
C | KV, effective value | | 10.4 |
Nominal discharge current | I
n | KA, peak value | | 5 |
The heavy current impact withstand current | | KA, peak value | 4/10μs | 65 |
Square wave impacts withstand current | | A, peak value | 2ms | 150 |
The lightning impulse residual voltage | | KV, peak value | 8/20μs,5kA | ≤35 |
Direct current 1mA reference voltage | U
1mA | KV, peak value | DC,1mA | ≥20 |
0-75 times of U
1mALeakage current under the voltage
| | μ A, peak value | DC,0.75U
1mA | ≤30 |
Bottom electrode 6 of the present utility model plays the effect of uniform electric field, so bottom electrode 6 surfaces should be slick and sly as far as possible, and surperficial each point is consistent as far as possible to the distance of lead.Bottom electrode 6 shaped design can be become hemisphere, plate shape and clavate, three kinds of typical electrode structures are seen Fig. 2.Three kinds of typical electrode are installed to lightning arrester body and cooperate the assembling schematic diagram to see accompanying drawing 5-7 with line insulator (being followed successively by needle type ceramic insulators, pillar porcelain insulator, post composite insulators).
The structure of top electrode 7 is core design of technical solutions of the utility model.Referring to Fig. 3, top electrode 7 integral body by fixture 9, lead arc pin 8 and insulation cover 10 3 parts constitute, fixture 9 and lead 1 fixed installation, lead arc pin 8 and be arranged on fixture 9 belows, the a pair of clubfoot of leading arc pin 8 is respectively towards mains side and load side, fixture 9 and lead arc pin 8 and be coated with insulation cover 10.Top electrode 7 its installations are divided into wire stripping formula and piercing dual mode.
The wire stripping formula is installed the lead 1 that is about to the insulator load side and peeled off one section insulating barrier, at exposed 2~3 layers of aluminium armor tape of core surface parcel, then fixture 9 one dimidiations is embraced on core by former correspondence position earlier, and is fastening by clamp nut.Fixture 9 inner surfaces are smooth, closely contact with the aluminium armor tape layer, guarantee that contact resistance maintains very little value.All adopt Seal Design between the insulating barrier of fixture 9 and lead 1, fixture 9 two halves, the exposed core of strip off is hedged off from the outer world, guaranteed that core can be because of accelerated corrosions such as rainwater.
The realization principle that piercing is installed is: the pointed tooth of the some by fixture 9 inner surface projections punctures the insulating barrier of lead 1, slide certain distance after arriving the metal wire wicking surface, guarantee that core closely contacts with planar fashion with pointed tooth, thereby make contact resistance maintain very little numerical value (tens to μ Ω up to a hundred).During installation, two halves fixture pointed tooth zygodont to embracing on insulated conductor 1, is alternately tightened clamp nut with special-purpose torque spanner, when torque spanner no longer during stepping, installation is promptly finished.Because the two extruding of pointed tooth and insulating barrier closely, needn't additionally consider the seal problem of lead 1.
Practice shows that under comprehensive functions such as electromagnetic force and thermal stress, power frequency continued flow electric arc departs from the mains side burning, and for this reason, top electrode must be installed to the load side of insulator.Simultaneously, the utility model has designed and has independently led arc pin 8.After the installation, a pair of clubfoot of leading arc pin 8 is respectively towards mains side and load side.Like this, power supply just giving and anti-situation about sending under, power frequency continued flow electric arc arc root is transferred to all the time to lead on the arc pin and is burnt, the protection fixture avoids damaging, and also can freely change even lead arc pin 8 scaling loss, reaches purpose easy to maintenance.Fixture of the present utility model 9 and leading after arc pin 8 installs, the outside puts insulation cover 10, has solved wire stripping or puncture and has made insulated conductor 1 local exposed and have a problem of insulation defect.