JP4158953B2 - Special high-voltage and high-voltage discharge fuses - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to the improvement of special high voltage and high voltage discharge fuses that are mounted on discharge fuse cylinders, and in particular, suppresses the peak (crest value) of the passing current and discharges from the fuse cylinder when a large current is interrupted. The present invention relates to a configuration for limiting the arc length, the internal pressure rise, and the sound as much as possible.
[0002]
[Prior art]
In conventional discharge type extra high voltage and high voltage fuses, the wire diameter of the element used for the fuse element is a uniform thickness, so the element is heated and melted all at once when a large current is interrupted. Arcing over the entire length.
[0003]
[Problems to be solved by the invention]
For this reason, the arc emitted from the discharge end (discharge port) of the discharge type fuse cylinder to which the fuse is mounted has an extremely long arc length, and it may cause a burst of the fuse cylinder due to a sudden increase in internal pressure accompanied by a large sound. there were.
[0004]
[Means for Solving the Problems]
The present invention suppresses the passing current at the time of the above-mentioned large current interruption as much as possible, shortens the arc length emitted from the discharge end of the fuse cylinder, suppresses the generation of sound, and restricts an excessive rapid increase in internal pressure. Proposed is a discharge-type fuse , and the first invention is a discharge-type fuse to be mounted in an insulation cylinder (17) of a discharge-type fuse cylinder (16), and the insulation cylinder (17). The terminal part (7a) of the fuse terminal (7) in the discharge fuse (1) is locked to the upper electrode (18) fixed to the upper end of the terminal, the terminal screw (19) is tightened, and the lead wire (13) Is led out of the insulating tube (17) from the arc discharge end at the lower end of the insulating tube (17), and the lead wire (13) is folded and fixed to the lower outer periphery of the insulating tube (17). On the lower electrode (24) on the screw (20) A Rishimegi release Fusing connecting (1),
The discharge-type fuse (1) is formed by closing one end of the arc extinguishing tube (2) with the fuse terminal (7) and leading the lead wire (13) from the other end of the arc extinguishing tube (2). In the arc extinguishing tube (2), a fuse element (14) connected between the fuse terminal (7) and the lead wire (13) is disposed, and the fuse element (14) is an arc extending element ( 9) An arc extending element (10) having a diameter smaller than that of the arc extending element (9) and a main element (11) having a diameter smaller than that of the arc extending element (10) having a smaller diameter are connected in series in this order. is formed, further, the main element (11) and said leads (13) side is disposed, said fuse element (14) is a large current blocking region over the entire length (C) The intermediate current blocking region (B) and the overload current blocking region (A) are formed from the side close to the fuse terminal (7) in the large current blocking region toward the lead wire (13). further prior Symbol wire diameter of each element of the fuse element (14) are successively thinner toward the fuse terminal (7) side to leads (13), a narrow main element of the wire diameter at the large current interruption with (11) From the side, it is made to melt and vaporize sequentially toward the arc drawing element (9) side of the thick wire diameter,
Further, the outer periphery of the fuse element (14) is surrounded by the arc extinguishing tube (2), and the arc extinguishing agent (5), (6) is provided on the inner circumference of the tube over substantially the entire length. ,
Further, the arc extinguishing agents (5) and (6) arranged in the arc extinguishing tube (2) are an outer cylinder (3) made of kraft paper and an inner cylinder made of heat-resistant resin such as Teflon located inside the outer cylinder (3). (4) and an arc-extinguishing agent (5) of boric acid powder filled in a gap between the inner cylinder (4) and the outer cylinder (3) is appropriately provided in the outer peripheral portion of the element excluding the overload current interruption region (a ) And an arc extinguishing agent (6) in which boric acid powder is solidified in a cylindrical shape is further provided on the outer periphery of the overload current interruption region. The present invention proposes an extra high-voltage and high-voltage discharge fuse characterized by being arranged as described above.
[0007]
Further, the second invention is the above first invention, wherein the powder arc extinguishing agent 5 filled in the gap g formed by the inner cylinder 4 and the outer cylinder 3 of the arc extinguishing tube 2 is prevented from falling off from the gap. In particular, an inorganic embolus 15 is provided at the end of the air gap, and a fuse element 14 is further passed through the central through hole 15a of the plug. This is a proposal.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described based on the examples of FIGS. Reference numeral 1 denotes an extra high-voltage and high-voltage discharge fuse. Reference numeral 2 denotes an arc extinguishing tube, an outer cylinder 3 made of kraft paper, an inner cylinder 4 having heat resistance, arc extinguishing properties, etc., such as Teflon resin inserted into the outer cylinder 3, and an outer cylinder 3 and an inner cylinder 4 An arc extinguishing agent 5 made of powder of boric acid or the like filled in, for example, vibration injection in the gap g between them, and the arc extinguishing tube 2 particularly located in the overload current interruption region A is made of kraft paper. An arc-extinguishing agent 6 made of solid boric acid formed into a cylindrical shape is provided inside the outer cylinder 3. This solid arc-extinguishing agent 6 is prepared by blending a binder made of methyl cellulose and boric acid powder in a weight ratio of 1: 1, mixing, and then forming into a cylindrical shape.
[0009]
7 is a conductive member such as copper which is fitted so as to close one open end 2a of the tube by inserting the connecting portion 7b into the arc extinguishing tube 2 with the disk-like terminal portion 7a at one end being the outside. An arc extending element 9 made of copper or the like having a slightly smaller diameter than the connecting portion is connected to the connecting portion 7b in the tube of the terminal, and an arc extending element having a smaller diameter is connected to the arc extending element 9. An element 10 is connected, and a main element 11 having a smaller diameter than that of the element 10 is connected to a lead wire 13 made of a stranded wire via a connection fitting 12.
[0010]
That is, the fuse element 14 is composed of the arc extension element 9, the arc extension element 10, and the main element 11 connected in series as described above, and the wire diameter gradually decreases as the distance from the fuse terminal 7 increases. At the time of current interruption, the element is controlled in time so that the element is sequentially melted and vaporized from the main element 11 side toward the arc extending portion 9 side, in which arc resistance is increased and overvoltage after operation is suppressed. Incidentally, in the fuse having a rated current of 20A, the connecting portion 7b of the terminal 7 from the fuse terminal 7 side has a diameter of 4 mm, whereas the arc extending element 9 uses a copper wire having a diameter of 2 mm, and the arc extending element 10 is A copper wire having a diameter of 1 mm is used, and a 0.4 mm to 0.6 mm copper-nickel wire, stainless steel wire, brass wire or the like is appropriately used for the main element 11 at the end of the element.
[0011]
In the above description, a single line (single line) is used as the main element in the present embodiment, but the present invention can also be implemented in the case of a composite line. In addition, the element 14 is a large current interruption region C from the arc extension element 9 to the main element 11, and is an intermediate current interruption region B from the arc extension element 10 to the main element 11, and the main element 11 is overloaded. 5 and FIG. 6, the element 14 has an arc extinguishing agent 5, 6 as opposed to the arc extinguishing agent 5, 6 in the relationship between the main element 11 corresponding to the overload current interrupting region and the arc extinguishing agent 6. While the space b between the two is relatively large so that the main element 11 does not inadvertently contact the arc extinguishing agent 6, the arc extending element 9 mainly for dealing with a large current interruption region, the arc extending The relationship between the element 10 and the arc-extinguishing agent 5 is that the space a is closer to the space b than the above-mentioned space b, The arc-extinguishing gas from the arc agent 5 is likely to occur.
[0012]
Reference numeral 15 denotes an inorganic member, for example, ceramic, which is inserted into the outer cylinder 3 so as to be positioned in the vicinity of the boundary between the arc extending element 10 and the main element 11 and through which the element 10 passes through a through hole 15a provided in the center thereof. A stopper made of paper, which prevents the arc-extinguishing agent 5 filled in the gap g between the outer cylinder 3 and the inner cylinder 4 by the stopper 15 and allows the element 10 to pass through the central through hole 15a. Thus, inadvertent contact with the inner wall (arc-extinguishing agent) of the inner cylinder of the element 14 is prevented.
[0013]
FIGS. 3 to 4 show a state in which the discharge fuse 1 of the present invention is mounted on the discharge fuse cylinder 16 for extra high voltage cutout, and a detachable terminal of the upper electrode 18 fixed to the upper end of the insulating cylinder 17. After the screw 19 is once removed, the terminal screw 19 is fastened with the terminal portion 7a of the fuse terminal 7 engaged with the inner step portion 18a of the upper electrode 18 with the lead wire 13 side first, and then screwed again. Further, the lead wire 13 is once led out of the cylinder from the discharge end 17a at the lower end of the insulating cylinder 17, and the lead wire 13 thus led back is fastened to the lower electrode 24 fixed to the lower outer periphery of the insulating cylinder 17 with screws 20. It is a configuration to connect. Reference numeral 21 denotes a supplementary tension for separating the fuse element 14 when the fuse is mounted, and at the same time, the display cylinder 22 colored, for example, in red or affixed with a night reflective tape is attached to the lower end of the insulating cylinder, that is, the lower part. This is a coil spring that protrudes rearward from the insulating cover 23 that is fixed to the screw portion 24a of the electrode 24 to notify the fusing state, and is in a compressed state when normally attached (normally energized), and is restrained. Thus, the display tube 22 is urged so that it can jump out of the insulating cover 23 at any time.
Reference numeral 23a denotes a locking portion of the insulating cover 23, and the locking portion 22a of the display tube 22 is locked to this during the display operation, and excessive protrusion restricts the protrusion.
[0014]
Next, the blocking operation will be described.
(At high current interruption)
When a large current passes through the fuse due to a short circuit accident or the like, the element is melted and vaporized while arcing with the main element 11 having a small diameter on the lead wire 13 side, the arc extension element 10 and the arc extension element 9 by the passing current, and the arc is maintained. While being generated, the arc is elongated for a long time, and the arc resistance is increased, thereby suppressing the peak value (crest value) of the current passing therethrough.
[0015]
In the current-limited (suppressed) state, the insulation finally recovers and shuts off when the zero value passes. In this case, as described above, arcing is prolonged while continuing, but in such a case, a large amount of arc extinguishing gas (such as carbon dioxide or water vapor in the case of boric acid) is generated from the arc extinguishing agent provided over the entire length. It is generated and becomes a turbulent state with the arc, released from the discharge end at the lower end, recovered from insulation, and extinguished.
[0016]
At this time, as described above, since each element sequentially fires without firing at once, the generated sound is also suppressed. Furthermore, a rapid increase in internal pressure of the fuse cylinder is suppressed by the sequential firing, and no mechanical reinforcement of the fuse cylinder is particularly required.
[0017]
In addition, if it is attached to a 20 KV cut-out discharge fuse cylinder and the test results conducted under the rated voltage 20 KV, rated current 20 A, breaking current 12.5 KA, single-phase breaking test conditions are described for reference, the conventional type Compared with the discharge type fuse of the present invention, the discharge type fuse of the present invention has a peak value (crest value) of the passing current suppressed to about 1/2, an arc length of 2.5 m is reduced to 0.7 m, It has been observed that the sound became softer as the size of the sound became about 1/5.
[0018]
(When overload is cut off)
In the case of an overload current interruption where the passing current is several times the rated current, the element 14 in the overload interruption region melts and arcs, and in this case, the overload current interruption A is close to the discharge end 17a. The arc generated from the arc extinguishing agent 6 by the arc is immediately discharged from the discharge end together with the arc extinguishing gas and extinguished. The display cylinder 22 which has been restrained by the fuse due to the interruption is released from the restraint, and the coil spring 21 projects rearward from the insulating cover 23 to indicate that the fuse has been blown. This display operation is the same whether the interruption is performed at the time of large current or the interruption at the time of medium current described later.
[0019]
(When medium current is cut off)
The interruption operation other than the large current and the overload current is an intermediate interruption operation between the large current interruption and the overload interruption.
[0020]
【The invention's effect】
The extra high voltage and high voltage discharge type fuse according to the present invention is characterized in that, in the invention of claim 1 , particularly when the large current interrupting region is interrupted, the fusing arc of the fuse element is changed from the small diameter element on the lead wire side to the fuse terminal. As a result of controlling the firing time of the elements so that they are sequentially performed toward the large-diameter element on the side, the arc resistance is increased and the peak value (crest value) of the passing current is suppressed to a low level. Elongation of the arc emitted from the discharge end of the lower end of the steel tube is suppressed as much as possible, the generation of sound is restricted, and the sudden increase in internal pressure of the fuse tube is also suppressed to a small level. The safety can be further improved.
[0021]
As a result of the inner cylinder of the arc extinguishing tube overload current blocking region is disposed slightly to separate the and elements using heat-resistant member such as Teflon from extinguishing agent, during the always energized, extinguishing the contact elements It is possible to prevent the tube from being burnt, burned out, or the arc extinguishing tube from being deprived of heat and greatly changing the fusing characteristics of the fuse. Further, in the large current interruption region and the medium current interruption region, the arc extinguishing agent is placed close to the element and arranged over the entire length, so that the arc and the arc extinguishing agent are generated at the time of arcing at the time of the large current interruption and the intermediate current interruption. This increases the chance of contact with the arc and facilitates the generation of arc-extinguishing gas, which can further improve the breaking performance of the fuse.
[0022]
According to the second aspect of the present invention, the arc-extinguishing powder can be prevented from falling off from the gap between the inner cylinder and the outer cylinder by the embolization. Since it is difficult to contact the arc extinguishing agent, it is possible to expect a stable fusing characteristic without taking heat away from the arc extinguishing tube.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of an extra high-voltage and high-voltage discharge fuse according to the present invention.
FIG. 2 is an enlarged cross-sectional view showing a part of FIG. 1 in a separated state.
FIG. 3 is a cross-sectional view showing a state where the discharge fuse of the present invention is mounted on a discharge fuse cylinder.
4 is an enlarged sectional view showing a part of FIG. 3 in a separated state.
FIG. 5 is a sectional view taken along line XX in FIG.
6 is a YY cross-sectional view in FIG. 1. FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Discharge-type fuse 2 Arc-extinguishing tube 3 Outer cylinder 4 Inner cylinder 5 Arc-extinguishing agent 6 Arc-extinguishing agent 7 Fuse terminal 13 Lead wire 14 Element 16 Release-type fuse cylinder a Space b Space g Air gap A Overload current interruption area B Medium current Breaking area C Large current breaking area

Claims (2)

A discharge-type fuse (1) is connected to an upper electrode (18) which is a discharge-type fuse to be mounted in the insulation tube (17) of the discharge-type fuse tube (16) and fixed to the upper end of the insulation tube (17). The terminal portion (7a) of the fuse terminal (7) is locked and the terminal screw (19) is tightened, and the lead wire (13) is further insulated from the arc discharge end at the lower end of the insulating cylinder (17). A discharge type fuse which is led out of the cylinder (17), the lead wire (13) which is led out is folded back, and the lower electrode (24) fixed to the lower outer periphery of the insulating cylinder (17) is fastened with screws (20). (1)
The discharge-type fuse (1) is formed by closing one end of the arc extinguishing tube (2) with the fuse terminal (7) and leading the lead wire (13) from the other end of the arc extinguishing tube (2). In the arc extinguishing tube (2), a fuse element (14) connected between the fuse terminal (7) and the lead wire (13) is disposed, and the fuse element (14) is an arc extending element ( 9) An arc extending element (10) having a diameter smaller than that of the arc extending element (9) and a main element (11) having a diameter smaller than that of the arc extending element (10) having a smaller diameter are connected in series in this order. is formed, further, the main element (11) and said leads (13) side is disposed, said fuse element (14) is a large current blocking region over the entire length (C) The intermediate current blocking region (B) and the overload current blocking region (A) are formed from the side close to the fuse terminal (7) in the large current blocking region toward the lead wire (13). further prior Symbol wire diameter of each element of the fuse element (14) are successively thinner toward the fuse terminal (7) side to leads (13), a narrow main element of the wire diameter at the large current interruption with (11) From the side, it is made to melt and evaporate sequentially toward the arc drawing element (9) side of the thick wire diameter,
Further, the outer periphery of the fuse element (14) is surrounded by the arc extinguishing tube (2), and the arc extinguishing agent (5), (6) is provided on the inner circumference of the tube over substantially the entire length. ,
Further, the arc extinguishing agents (5) and (6) arranged in the arc extinguishing tube (2) are an outer cylinder (3) made of kraft paper and an inner cylinder made of heat-resistant resin such as Teflon located inside the outer cylinder (3). (4) and an arc-extinguishing agent (5) of boric acid powder filled in a gap between the inner cylinder (4) and the outer cylinder (3) is appropriately provided in the outer peripheral portion of the element excluding the overload current interruption region (a ) And an arc extinguishing agent (6) in which boric acid powder is solidified in a cylindrical shape is further provided on the outer periphery of the overload current interruption region. special high-pressure and high-pressure discharge Fusing characterized by being arranged. The end of the gap to prevent the powder arc extinguishing agent (5) filled in the gap (g) formed by the inner cylinder (4) and the outer cylinder (3) of the arc extinguishing tube (2) from falling out of the gap. 2. An extra-high voltage device according to claim 1, wherein an inorganic embolus (15) is provided at a position of the fuse element and a fuse element (14) is further passed through a central through hole (15a) of the plug. And high-voltage discharge fuses.

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