CN1054701C - Fuse assemblies - Google Patents

Abstract

A fuse sub-assembly has a hollow cylindrical support body 1 of an insulating material. A multiplicity of elongate conductors 2 extend helically around the outer surface of the support body 1 and merge at each end of the support body 1 into a conductive band 5,6 provided around the circumference of the support body 1. The conductors 2 are of a fusible material, with groups of adjacent conductors being merged together at at least one intermediate region along their lengths to form a bridge 8. The bridges 8 significantly improve the full-range performance of the sub-assembly.

Description

The protector subassembly

The protector subassembly that the present invention relates to comprises many group fuses, and specifically (although and nonessential), the present invention is particularly useful for the high voltage protector, and in this high voltage protector, fuse is on the insulated support of tubulose.

In the occasion of needs " gamut " protector, promptly must be able to cut off the protector of all electric currents that cause fuse fusing, if blowout current is required not really harsh, the protector described in the EP-0117582 just can be competent fully.These protectors generally are made up of many groups fuse that column quartz glass tube and helical form are wrapped in its surface.Under normal condition of work, the fuse electric current conducts in many group fuses fifty-fifty.The less notch of thickness is all arranged in each fuse, like this for low overload current, i.e. electric current in 1 to 10 times of scope of rated current, notch can fuse separately, and after having served as live stream and keeping the quite a while, when for example surpassing one second, whole fuse just fuses.In order to make protector protect hardware compatibility with other, and the requirement of satisfying high-voltage system, this contrary operating characteristic is fit to.

End cap described in the EP-0123331-A1 is suitable for protector type described in the EP-0117582-A1 to be provided and is electrically connected, and designed protector can reach desired overload current---the fusing time relation.

At title is the computer based model that the service behaviour of predicting protector discussed above is provided in " analog simulation of hot-fluid in the high pressure protector " literary composition, this article is write by J G J Sloot, be published in " the 3rd electric protector and application international conference collection of thesis (1987,5,11-5,13) " in.

Though above-mentioned computer simulation technique helps to optimize the design of multiple fuse protector, construct a time---protector that current work characteristic conforms Valuation Standard requires remains difficulty.When the malfunction in the low-pressure end zone of distribution transformer is eliminated when very fast, at this moment, the design of protector is difficulty particularly just.

Purpose of the present invention will overcome just or be the defective that reduces existing multiple fuse protector at least.Especially, the objective of the invention is to provide a kind of protector with gamut service behaviour, the prebreakdown characteristic that it had allows low removing situation of transshipping the voltage failure state to meet the requirement of Valuation Standard, such as VDE 0670/402 and ESI 12-8.

Further aim of the present invention provides a kind of breakdown phase in protector work, has the protector of measurable electric arc burn-back characteristic.

According to a first aspect of the invention, a kind of protector subassembly is provided, it comprises the straight shape supporter of the length of being made by insulating material and many groups fusible conductor of and stretched along supporter by support body supports, each fusible conductor has a plurality of notches on its length direction, each notch is width diminishes on the conductor one section, and the design of notch makes their fuse earlier before the major part fusing of fusible conductor; A plurality of conductors in each conductor group merge at least one zone line along its length direction, thereby form bridge circuit; The sectional area that it is characterized in that each bridge circuit is n a times of notch sectional area, and wherein n is the conductor number in the respective conductors group.

Described every group of conductor preferably can be merging along at least two middle somewheres of its length direction, if it is better to get two zone lines.

Described each group conductor preferably is made up of at least three fusible conductors, if it is better to get three fusible conductors.

The sectional area of each bridge circuit preferably the notch sectional area n doubly, n is the conductor radical in the respective conductors group herein.

More preferably way is, each fusible conductor along its length direction a plurality of notches are set, each notch is a cross section that has reduced width, these notches are designed to make its fusing earlier before integral body fusing of fusible conductor.

Even more preferably, adopt low-melting-point metal/metal alloy point on some bridge circuit, for example tin or tin-silver alloy are realized with the heat of bridge circuit and are electrically connected, better way is, at least one bridge circuit relevant with every group of fusible conductor such low-melting-point metal/alloy point is set.

Above-mentioned first aspect according to the present invention, a kind of preferred embodiment of protector subassembly is that strutting piece is essentially tubulose (such as the cylinder of a hollow), preferably is made up of quartz glass.Preferably conductor can be wrapped in to spirality the outer surface of tubular supporting piece.Conductor also can wrap up in the outer surface that embeds tubular supporting piece.

According to a second aspect of the invention, provide a kind of protector, it comprises: a shell; An involved protector subassembly of being done according to first aspect of the present invention in the enclosure; A filler that is arranged in enclosure and surrounds subassembly; And a pair of electrical contact device, this links to each other to the respective end of contact device with a plurality of fusible leads, makes external electric power to be connected on the protector.

For the present invention there being one better understand, how to work to understand this fuse assemblies, now accompanying drawing is illustrated by example:

Fig. 1 has shown a perspective view that comprises the protector subassembly of multiple fuse.

Fig. 2 has shown the fuse of the subassembly of being showed among Fig. 1.

Fig. 3 has shown the relative size of one group of fuse of subassembly among Fig. 1.

Fig. 4 shown protector subassembly among Fig. 1 time-electric current operation characteristic and known protector subassembly with multiple fuse time-the electric current operation characteristic.

A part that has shown a protector subassembly among Fig. 1, this subassembly are used for incorporating into a gamut high pressure protector.This subassembly comprises the cylindric quartz glass tube 1 of a hollow, it the outer surface spirality twining fuse 2 (fuse that for clarity sake, has only shown protector subassembly the first half).Fuse extends between the relative terminal area 3 and 4 of quartz ampoule.In fact, can fuse be embedded the outer surface of quartz ampoule by processing as describing among the NL8801355.Also provide among the NL8801355 in order to increase voltage capacity, and by electroplating the method for the thickness that increases the conductor that is embedded into.Fuse 2 is integrated with in conductive materials 5,6 zones near pipe 1 each end, and this conductive materials and fuse are embedded in the pipe simultaneously. Zone 5,6 and fuse 2 all are the materials of fusible, such as silver.

In order to construct a protector that uses subassembly among Fig. 1, this subassembly is inserted into two ends all to be had in the cylinder blanket of end cap, and the conducting objects 5,6 of end cap (not shown) and subassembly electrically contacts.Outside electricity then arrives fuse by conductive region by end cap.

Fig. 2 shows is the fuse 2 of the subassembly that trails, and this makes their geometry to be seen clearlyer.

Just as shown in Figure 2, fuse 2 forms a plurality of groups, and every group has 3 adjacent fuses 2, and every group is merged into bridge circuit 8 at two places near the fuse corresponding terminal.In the particular arrangement that shows in Fig. 2, totally 15 fuses are lined up 5 groups.The current strength of each bridge circuit is by the decision of the cross-sectional area of the number of the fuse that is merged and bridge circuit, but it generally is three times of normal current intensity in the every fuse, and approximately is equal to the current strength at regular notch 9 places in the every fuse.The length of each bridge circuit is more much longer than the length of notch 9, and more much smaller than notch by the heat conduction of conductor from the bridge circuit center.

Fig. 3 shows one group of petiolarea that indicates the fuse 2 of size in greater detail, and size in the drawings is unit markings with the millimeter.The thickness of fuse (considering the radius of quartz ampoule) generally is 6 to 50 μ m, and the space between the adjacent fuse is the same wide with the width of fuse itself at least, for example, and 1.0mm or bigger.

Notch 9 is present in each fuse 2 of protector subassembly, is used for improving breakdown performance, and the electric current-time response that changes described subassembly.The width of notch 9 approximately is 1/2nd to 1/5th of relevant fuse 2 width, for example, is 0.25mm in Fig. 2.To between the 2.5mm, the notch number in each fuse 2 is between 2 to 12 at 0.5mm for the length of notch 9.

Be provided with bridge circuit 8 in every group of fuse 2, this also can improve the time-current characteristics of subassembly.According to above-mentioned structure, in the prebreakdown stage, i.e. all required times of bridge circuit fusing, when being no more than 1 millisecond, in notch 9 and bridge circuit 8 initial breakdown can take place simultaneously.Initial breakdown will take place early than notch 9 in the bridge circuit 8 during at 1 millisecond to 1 second in the time that continues when the prebreakdown stage, and this is because be less than the notch place relatively at bridge circuit center heat dissipation.Along with the increase of pre arcing time, bridge circuit 8 also can increase (thermal loss increase in time and increase) with the time difference that initial breakdown take place notch 9, and this just can improve the time-current characteristics of subassembly significantly.

Used tin point 10 (being called tin point or M effect) in bridge circuit 8 centre, when pre arcing time surpasses 1 hour, can further improve the prebreakdown performance, this is because the fusing point of tin point will be lower than fine silver fuse 2, and the tin of fusing is lower than silver point with the fusing point of the alloy that silver forms.For the prebreakdown stage of minimum molten state, significantly increase along with passing to the terminal heat of fuse, thermal change rate pattern along fuse 2 can change, with the tin point be set in fuse central authorities compare, can obtain longer pre arcing time, this point is identical with traditional many conductors protector subassembly, can obtain bigger load current value.

Compare with alternate manner, the tin point is set, make slot-open-section before the fusing of tin point, can reach higher temperature, can reduce the required puncture energy of fusion silver like this, help electric arc burn-back process, so also just improved breakdown performance in fuse end.

As shown in Figure 2, between the two ends of protector subassembly, used the tin point on the bridge circuit of every group of conductor 2 in a different manner.

Use many conductors bridge circuit, bigger benefit is to improve the electric arc control ability, can accomplish this point when protector moves under low current running environment, promptly when 1 times of rated current is between 10 times.When using traditional many conductor arrangement, the tin point of all conductors or notch all must fuse before producing electric arc.Can produce electric arc at random between conductor, this situation lasts till that always final certain conductor obtains enough puncture voltages, to produce electric current.Adopted the configuration of many conductors bridge circuit, when bridge circuit fusing in all conductor groups, can puncture, electric arc can continue to result between the slot-open-section of same conductor group then, till arc transfer arrives another conductor group.This process lasts till till last conductor group outage always.

The process in these two steps has been strengthened the control to being electric arc production process at random in essence, and has reduced the puncture energy of the interrupt circuit that is accumulated in " last " conductor.

Fig. 4 has shown the transient response of the protector (B) of many conductors protector (A) described in EP-0117582-A2 and many conductors of use bridge circuit described above.Clearly,, be lower than in the zone of about 500amps, using the conductor bridge circuit can make the transient response curve be linear, and can reduce by an order of magnitude to pre arcing time at most for overload current.

Within the scope of the present invention, can do many changes for above-described device, for example, supporter can be plane and non-tubular shape, also has, and tin point also can change the sn-ag alloy point into.

Claims (6)

1. protector subassembly, it comprises the straight shape supporter of the length of being made by insulating material and many groups fusible conductor of and stretched along supporter by support body supports, each fusible conductor has a plurality of notches on its length direction, each notch is width diminishes on the conductor one section, and the design of notch makes their fusing earlier before the slot-open-section fusing that is not provided with at the fusible conductor; A plurality of conductors in each conductor group merge at least one zone line along its length direction, thereby form bridge circuit; The sectional area that it is characterized in that each bridge circuit is n a times of notch sectional area, and wherein n is the conductor number in the respective conductors group.

2. the protector subassembly described in claim 1 is characterized in that conductor in described each conductor group is along merging at least two zone line places on its length direction.

3. the protector subassembly described in claim 1 or 2 is characterized in that described each conductor group is made up of at least three fusible conductors.

4. protector subassembly as claimed in claim 1 is characterized in that, at least one relevant bridge circuit of every group of fusible conductor low-melting-point metal/alloy point is set, heat to be provided and to be electrically connected.

5. protector subassembly as claimed in claim 1 is characterized in that supporter is a tubulose, and conductor is spirally wrapped around the outer surface of pipe.

6. protector, it comprises a shell, be contained in the shell as any described protector subassembly in the top claim, the filler of described protector subassembly that has been contained in encirclement in the shell, a pair of each termination with each group fusible conductor forms the electric contactor that electrically contacts, so that fuse can be connected with external electric.

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