JP6985742B2 - DC fuse and electrical equipment equipped with this DC fuse - Google Patents

Description

The present invention relates to a DC fuse that cuts off a DC high voltage current path by an overcurrent and an electric facility provided with the DC fuse.

Today's general power is mainly supplied as AC power of a specific frequency (50 Hz or 60 Hz). On the other hand, in general electric devices in recent years, AC power is converted into DC power by power converters installed inside and outside each device, such as AV devices, computers, information and communication devices, and inverter air conditioners. The number of devices used is increasing.
By the way, when AC power is transmitted, a loss peculiar to AC occurs, for example, an increase in AC resistance due to the skin effect. Further, when this AC power is used in the above-mentioned various devices, AC-DC conversion, DC-AC conversion, and the like are involved, so that the increase in conversion loss becomes a problem.
For this reason, in recent years, DC power converted from AC power or DC power from solar power generation equipment, storage batteries, etc. is used as a power source, and the DC power is transmitted and distributed at high voltage without being converted to AC power. The development of technology is underway.
In this way, when transmitting and distributing high-voltage DC power, it is necessary to consider cutting off the current assuming that an abnormal current has occurred due to a failure or accident of electrical equipment. Since there is no zero point in direct current, even if the electric power is partially disconnected, a high-voltage current is energized by the arc discharge generated in the space after the disconnection, making it difficult to cut off the current. There is.

Therefore, for example, in the invention described in Patent Document 1, when the first fuse and the second fuse are connected in series in the DC power path between the power conversion device and the storage battery, and an excessive abnormal current flows. In addition, these two fuses are thermally melted at almost the same time to cut off the abnormal current.

Japanese Unexamined Patent Publication No. 2008-29044

However, according to the above-mentioned prior art, there is a case where only one fuse is blown and the other fuse is not blown due to variations in melting temperature of the two fuses. In such a case. , An arc is generated in the space after melting of one of the fuses.
Then, the arc generated in this way may become a high voltage and be maintained for a relatively long time without being extinguished. Therefore, the path of the abnormal current cannot be cut off promptly, and there is a risk of damaging various devices in the electric circuit.

In view of such problems, one of the present inventions has the following configuration.
In a DC fuse that cuts off a DC high-voltage current path due to an overcurrent, a high-melting-melting conductor portion divided into three or more and arranged in series, and an adjacent high-melting-melting conductor portion among these three or more high-melting-melting conductor portions. Of the three or more high melting point conducting wires, the two high melting point conducting wires located on both ends are supported so as not to fall, and the twomost ends are supported. The high melting point conducting wire section located between the two high melting point conducting wire sections is a detachable lead wire section that separates from the two high melting point conducting wire sections on both ends thereof by its own weight when the low melting point conducting wire sections on both sides thereof are melted. The detachable conducting wire portion is extended along the non-vertical X-axis, and is provided so as to fall in the direction of gravity intersecting the X-axis due to melting of the low melting point conducting wire portions on both sides. The two refractory conductors located on both ends are supported by the two supports spaced in the X-axis direction so that they cannot fall, and the end of the detachable conductor and the end side. A DC fuse characterized in that the distance from the support portion that supports the high melting point conducting wire portion is set to be equal to or larger than the length of the detachable conducting wire portion.

Since the present invention is configured as described above, the DC high voltage current path can be quickly cut off by an overcurrent.

It is an electric circuit diagram which shows an example of the electric equipment provided with the DC fuse which concerns on this invention. It is a schematic diagram which shows an example of the DC fuse which concerns on this invention. It is a schematic diagram which shows the state which the detachable conductor part fell off about the DC fuse. It is a schematic diagram which shows the other example of the DC fuse which concerns on this invention. It is a schematic diagram which shows the other example of the DC fuse which concerns on this invention.

Next, an embodiment of the present invention will be described in detail with reference to the drawings. It should be noted that the embodiments of the present invention include, but are not limited to, the contents shown in the drawings. Further, in the following description of each figure, the parts common to the parts already described are designated by the same reference numerals, and some duplicate explanations will be omitted.

<First embodiment>
FIG. 1 shows an example of an electric facility provided with a DC fuse according to the present invention.
The electrical equipment A is configured to pass the direct current output from the first distribution unit 2 and the second distribution unit 3 to the direct current power system 1.

Here, the DC voltage flowing through the DC power system 1 is 6.6 kV according to a preferred example of the present embodiment, but as another example, 500 kV or more, 275 kV, 220 kV, 187 kV, 154 kV, 110 kV, 77 kV. , 66 kV, 30 kV, 20 kV, 13.2 kV, 3.3 kV, 400 V, or intermediate voltages thereof and the like.

The first distribution unit 2 is, for example, a DC power generation facility 4 such as a photovoltaic power generation facility and a DC / DC converter 5 (power converter) electrically connected to the output side (load side) of the DC power generation facility 4. ) And.

On the output side of the DC / DC converter 5, a first DC current path 11 whose current direction is directed to the DC power system 1 and a second DC current path 11 which is along the first DC current path 11 and whose current direction is opposite to each other. The DC current path 12 is connected.
The first and second DC current paths 11 and 12 are composed of electric wires having a DC fuse 10 interposed therebetween, and the load side thereof is connected to the DC power system 1.

Further, the second distribution unit 3 includes, for example, an AC power generation facility 5 such as a thermal power generation facility, a transformer 6 electrically connected to the output side (load side) of the AC power generation facility 5, and the transformer 6. An AC / DC converter 7 (power converter) electrically connected to the output side of the power generator is provided.

The first DC current path 11 and the second DC current path 12 are connected to the output side of the AC / DC converter 7 in the same manner as the output side of the AC power generation facility 5. The first and second DC current paths 11 and 12 are composed of electric wires having a DC fuse 10 interposed therebetween and are connected to the DC power system 1.

As another example of the first power distribution unit 2, a storage battery or a DC power generation facility using a DC generator can be used. Further, in the illustrated example, the DC distribution unit (first distribution unit 2) and the AC distribution unit (second distribution unit 3) connected to the DC power system 1 are each singular, but both or one of them may be plural. It is also possible to do.

The DC fuse 10 is a high melting point conducting wire portion provided in the middle of a single first DC current path 11 (electric wire), divided into three or more (three according to the illustrated example), and arranged in series. The low melting point conductors 16 and 17 connecting between 13, 14 and 15 and the adjacent high melting point conducting wires among these three or more high melting point conducting wires, and the upper side of the high melting point conducting wires 13, 14 and 15. It is provided with an anti-power generation line portion 12a located at intervals.

Of the three or more melting point conducting points 13, 14 and 15, the two melting point conducting points 13 and 15 located on both ends are unable to fall due to the support portions 8 and 9, respectively, as shown in FIG. Supported by. These two melting point conducting wire portions 13 and 15 may be an electric wire integrated with an electric wire constituting the first DC current path 11 on the power supply side and the load side of the DC fuse 10, or may be a separate electric wire. good.

Further, the high melting point conductors 14 located between the two high melting point conductors 13 and 15 on both ends are supported only by the low melting point conductors 16 and 17 on both sides thereof, and the low melting point conductors 16 and 17 are supported by the low melting point conductors 16 and 17. It constitutes a detachable conducting wire portion that separates from the two melting point conducting wire portions 13 and 15 on both ends by melting by its own weight. Hereinafter, the description may be made with reference numeral 14 to the detachable conductor portion, if necessary.

That is, there is no member that supports the detachable conductor portion 14 around the detachable conductor portion 14.
The detachable lead wire portion 14 extends along a non-vertical X-axis (a substantially horizontal axis according to the illustrated example), and the Z-axis orthogonal to the X-axis is formed by melting the low melting point lead wire portions 16 and 17 on both sides. It falls in the direction of gravity along.

The high melting point conducting wire portions 13, 14 and 15 are formed of a conductive metal material having a high melting point as compared with the low melting point conducting wire portions 16 and 17 described later, such as copper (Cu) and aluminum (Al).
The thickness of these high melting point conducting wire portions 13, 14, and 15 is appropriately set according to the DC voltage and the amount of electric power flowing through them, and for example, a single wire having a diameter of 4 to 200 mm, a stranded wire, or a bus bar is used. It is composed.

Bare wires or insulating coated wires can be used for these high melting point conducting wire portions 13, 14 and 15, but in particular, when an insulating coated wire is used, the detachable conducting wire portions 14 may fall off due to the insulating coating. For example, it is preferable to omit the insulating coating only in the vicinity of each low melting point conducting wire portion 16 (or 17) so as not to cause any trouble.

Of these high melting point conductors 13, 14 and 15, the high melting point conductor (detachable lead portion 14) on the center side thereof is an arc generated when the high melting point conductors 13 and 15 are separated from the high melting point conductors 13 and 15 on both sides in an energized state. Is formed to have a length L that can be extinguished.
More specifically, the length L of the detachable conductor portion 14 is set to 1 cm or more per 1 kV of the voltage of the first and second DC current paths 11 and 12, preferably in anticipation of a safety factor. It is set to 4 to 10 times that, and more preferably 10 cm or more / 1 kv.
For example, in the present embodiment, since the voltages of the first and second DC current paths 11 and 12 are 6.6 kV, the length L is set to about 66 cm or more, preferably 4 to 10 times that of 264 to 264. It is 660 cm, more preferably 660 cm or more.

The low melting point conducting wire portions 16 and 17 are made of a metal material having a melting point lower than that of the high melting point conducting wire portions 13, 14 and 15, respectively, and being overheated by a preset overcurrent to melt off.
Examples of the metal material include lead (Pb), zinc (Zn), tin (Sn), bismuth (Bi), antimony (Sb), indium (In), cadmium (Cd) and the like, or alloys thereof. It is possible to use alloys of these with other metals.

The support portions 8 and 9 are fixed to the ground or the upper surface of the structure and are formed vertically upward. As a specific example of the support portions 8 and 9, a steel tower, a pole-shaped member, or the like may be used.
On the upper end side of the support portions 8 and 9, the melting point conducting wire portions 13 and 15 and the anti-power generation wire portion 12a are supported so as not to fall.

The distance W1 or W2 between the end of the detachable conductor 14 and the support 8 or 9 supporting the high melting point conductor 13 or 15 on the end side is preferably the length L or more of the detachable conductor 14. According to the illustrated example, the length L, the interval W1, and the interval W2 are set to substantially the same length.

The anti-power generation line portion 12a is composed of a part of the second DC current path 12 or an electric wire connected in the middle of the second DC current path 12.
The anti-power generation line portion 12a of the illustrated example is located so as to be substantially parallel to the high melting point conducting wire portions 13, 14 and 15 with a space above them. Then, the anti-power generation line portion 12a generates a repulsive force by the magnetic fields M1 and M2 between the anti-power generation line portion 12a and the detachable conductor portion 14.
The anti-power generation wire portion 12a is insulated from the high melting point conductor portions 13, 14, 15, the low melting point conductor portions 16, 17, the support portions 8, 9, and the like. The insulating means includes, for example, a configuration in which a part or the whole of the second DC current path 12 including the anti-power generation line portion 12a is an insulated coated electric wire, a configuration in which insulation is secured by an insulating plate, and a detachable conductor of the anti-power generation line portion 12a. The configuration may be such that a sufficient insulating space is secured on the portion 14 side, or a configuration in which these are appropriately combined.

Next, the characteristic operation and effect of the DC fuse 10 having the above configuration will be described in detail.
In the first and second direct current paths 11 and 12, in a normal energized state, a right-handed magnetic field M1 is generated around the first direct current path 11 toward the load side, and the second direct current is applied. Since a magnetic field M2 that rotates in the opposite direction (counterclockwise) toward the load side is generated around the current path 12, the action of the magnetic fields M1 and M2 in the opposite directions causes the two DC current paths 11 and 12 to have the magnetic field M2. A force that tends to separate along the orthogonal direction (Z-axis direction in the figure) acts.

When an overcurrent flows through the DC current paths 11 and 12 due to a failure or accident of the equipment constituting the electrical equipment A, and the low melting point conducting wires 16 and 17 are thermally melted by this overcurrent, these two The detachable conducting wire portion 14 located between the two low melting point conducting wire portions 16 and 17 separates from the high melting point conducting wire portions 13 and 15 on both sides thereof, and falls due to its own weight. At this time, since the detachable conductor portion 14 receives the repulsive force from the anti-power generation wire portion 12a, the detachable conductor portion 14 is quickly detached from between the two high melting point conductor portions 13 and 15.

Therefore, a gap c having a width slightly larger than the length L of the detachable conductor portion 14 is formed between the two refractory conductor portions 13 and 15 left on the support portions 8 and 9. Therefore, it is possible to prevent an arc from being generated between the ends of the two high melting point conducting wire portions 13 and 15 and conducting the conduction between these ends, and by extension, the first DC current path 11 can be quickly routed. It can be blocked.

In the above process, at first, of the two low melting point lead wire portions 16 and 17, one of the low melting point lead wire portions 16 (or 17) may melt first and fall off. In such a case. In As described above, the detachable lead wire portion 14 will fall off.

<Second embodiment>
Next, another embodiment of the DC fuse according to the present invention will be described. In addition, since the embodiment shown below is a partially modified version of the above-described embodiment, the modified portion will be mainly described in detail, and duplicate detailed description will be omitted.

The DC fuse 20 shown in FIG. 4 is provided with a parallel wiring portion 21 having a constant voltage element 21a with respect to the DC fuse 10.
More specifically, the DC fuse 20 has one end side and the other end side connected to the two high melting point conducting wire portions 13 and 15 on both sides of the detachable conducting wire portion, respectively, and is electrically parallel to the detachable conducting wire portion 14. A parallel wiring unit 21 is provided, and a constant voltage element 21a is provided in the parallel wiring unit 21.

The constant voltage element 21a is an element in which a current suddenly flows when a voltage rises above a certain value (sometimes referred to as a breakdown voltage or a Zener voltage). For example, a Zener diode is used. It may be configured.

According to the DC fuse 20 having the above configuration, after the detachable conductor portion 14 has fallen off, an arc is generated in the gap c between the two high melting point conductor portions 13 and 15, and the voltage suddenly rises. However, it is possible to pass a current through the parallel wiring portion 21 due to the sudden rise in the voltage, suppress the increase in the voltage, make the generation of the arc temporary, and quickly extinguish the arc.
According to the above embodiment, the Zener diode is exemplified as the constant voltage element 21a, but the constant voltage element 21a may have a configuration in which a current starts to flow when a predetermined voltage rises, and is generally a Zener diode. The arrester is more preferred because it can process more energy.

Further, as a more preferable example, a series of a capacitor and a resistor may be connected in parallel to the arrester or the like.
That is, when the current is flowing, magnetic energy is stored in the parasitic inductance of the distribution line or the like. Therefore, when the current is cut off due to the detachable conducting wire portion 14 falling off, an overvoltage occurs due to the discharge of magnetic energy. Then, the magnetic energy is processed so that the arrester or the like does not become overvoltage. However, when the magnetic energy is larger than the processing capacity of the arrester, if a series of capacitor and resistor is provided as described above, the discharged energy is taken in as electrostatic energy, the burden on the arrester etc. is reduced, and the overvoltage is reduced. It can be suppressed. Here, the resistor is for preventing an overcurrent to the capacitor.
When the energy to be processed is relatively small, it is possible to omit the arrester and use only a series of a capacitor and a resistor.

<Third embodiment>
The DC fuse 30 shown in FIG. 5 is obtained by adding a magnetic field generating unit 31 to the DC fuse 10 in the vicinity of the drop path of one end of the detachable conducting wire unit 14.
According to the illustrated example, the magnetic field generation unit 31 is a coil that generates a magnetic field by the current of the first direct current path 11.

According to the DC fuse 30, when the detachable conductors 14 fall off due to the melting of the two low melting point conductors 16 and 17, one end of the detachable conductors 14 in the middle of falling and the end facing the ends. When an arc a is generated between the arc a and the end of the high melting point conducting wire portion 15, the arc a can be quickly extinguished by shifting the direction of the arc a by the magnetic field of the magnetic field generating portion 31. can.

According to an example shown in FIG. 5, the magnetic field generation unit 31 is provided at one place on the power supply side of the detachable conductor unit 14, but as another example, the magnetic field generation unit 31 is provided on the power supply side of the detachable conductor unit 14. It is also possible to provide a mode in which each is provided on the load side, a mode in which a plurality of magnetic field generating portions 31 on the power supply side and / or the load side are provided in the vertical direction, and the like.
Further, as another example, the power supply of the magnetic field generating unit 31 may be a power supply circuit other than the first and second DC current paths 11 and 12, or a permanent magnet may be used for the magnetic field generating unit 31. Is also possible.

In the above embodiment, as a particularly preferable embodiment, the anti-power generation line portion 12a is provided on the upper side of the detachable conductor portion 14, but as another example, the anti-power generation line portion 12a is provided at a position other than above the detachable conductor portion 14 (for example,). , It is also possible to install it in a position where it is lined up horizontally).
Further, as another example, if the detachable conductor portion 14 can be quickly dropped off only by its own weight, the second DC current path 12 including the anti-power generation wire portion 12a does not affect the magnetic field of the first DC current path 11. It can also be installed at a position.

Further, in the above embodiment, three high melting point conductors 13, 14 and 15 are provided, but as another example, four or more high melting point conductors are provided in series and a plurality of adjacent high melting point conductors are provided. The parts may be connected by a low melting point conducting wire part, respectively.

Further, in the above embodiment, the two melting point conducting wire portions 13 and 15 located on both ends are fixed so as not to fall by the supporting portions 8 and 9, respectively, but as another example, the two melting point conducting wire portions 13 and It is also possible to suspend the 15 by a member provided on the upper side thereof to make it impossible to drop.

Further, in the above embodiment, as a particularly preferable embodiment, the detachable conductor portion 14 is supported only by the low melting point conductor portions 16 and 17 on both sides, but as another example, the detachable conductor portion 14 is a member that moves by its own weight (a member that moves by its own weight. For example, it may be supported by an elastic member or the like, and when the detachable conducting wire portion 14 falls off from the low melting point conducting wire portions 16 and 17 on both sides, the member may be elastically deformed or moved.

Further, according to the illustrated example, as a particularly preferable embodiment, the high melting point conductor portion, the detachable lead wire portion and the low melting point conductor portion are arranged substantially horizontally, but as another example, these the high melting point conductor portion and the low melting point conductor portion are arranged. It is also possible to provide the portions in an inclined shape, and further, if the detachable conductor portions fall off from the two melting point conductor portions on both sides, these can be provided vertically. be.

Further, the electrical equipment according to the present invention is not limited to the illustrated example as long as it has a configuration in which the DC fuse 10 is provided in the DC high voltage current path.
That is, the concept of electrical equipment according to the present invention includes, for example, a DC / DC converter connected to a DC distribution line or a DC system via a DC fuse 10, and a DC distribution line or a DC system connected to the DC system via a DC fuse 10. DC power generation system, AC / DC power conversion system connected to DC distribution line or DC system via DC fuse 10, AC / DC power conversion system connected to DC distribution line or DC system via DC fuse 10, DC fuse A DC load system connected to a DC distribution wire or a DC system via a DC fuse 10, an AC load system connected to a DC distribution wire or a DC system via a DC fuse 10, a DC system system equipped with a DC fuse 10, or these. Includes electrical equipment, power equipment, load equipment, systems, etc., which are made by appropriately combining devices and systems.

Although the embodiments of the present invention have been described in detail with reference to the drawings, the specific configuration is not limited to these embodiments, and there are design changes and the like within a range that does not deviate from the gist of the present invention. Even included in the present invention.
Further, the embodiments shown in the above figures can be combined with each other as long as there is no particular contradiction or problem in the purpose and configuration thereof.
Further, the description content of each figure can be an independent embodiment, and the embodiment of the present invention is not limited to one embodiment in which each figure is combined.

5: DC / DC converter (power converter)
7: AC / DC converter (power converter)
8, 9: Support 11: First DC current path 12: Second DC current path 10, 20, 30: DC fuse 13, 15: High melting point lead wire section 14: High melting point lead wire section (removable lead wire section)
16, 17: Low melting point conductor 21a: Constant voltage element 31: Magnetic field generator A: Electrical equipment

Claims (8)

In a DC fuse that cuts off the DC high voltage current path due to overcurrent
It is provided with a high melting point conducting wire portion divided into three or more and arranged in series, and a low melting point conducting wire portion connecting between adjacent high melting point conducting point portions among these three or more high melting point conducting wire portions.
Of the three or more melting point conducting points, the two melting point conducting points located on both ends are supported so as not to fall.
The high melting point conductor portion located between the two high melting point conductors on both ends is separated from the two high melting point conductors on both ends by its own weight when the low melting point conductors on both sides are melted. constitute a detachable conductor portions,
The detachable conductor portion is extended along a non-vertical X-axis, and is provided so as to fall in the direction of gravity intersecting the X-axis due to melting of the low melting point conductor portions on both sides.
The two melting point conducting wire portions located on both ends are supported by the two supporting portions spaced in the X-axis direction so as not to fall.
The distance between the end portion of the detachable conductor portion and the support portion that supports the melting point conductor portion on the end portion side is set to be equal to or longer than the length of the detachable conductor portion. DC fuse. In a DC fuse that cuts off the DC high voltage current path due to overcurrent
It is provided with a high melting point conducting wire portion divided into three or more and arranged in series, and a low melting point conducting wire portion connecting between adjacent high melting point conducting point portions among these three or more high melting point conducting wire portions.
Of the three or more melting point conducting points, the two melting point conducting points located on both ends are supported so as not to fall.
The high melting point conductor portion located between the two high melting point conductors on both ends is separated from the two high melting point conductors on both ends by its own weight when the low melting point conductors on both sides are melted. Consists of a detachable conductor
A DC fuse characterized in that the length of the detachable conductor portion is set to 1 cm or more per 1 kV of voltage of the DC high voltage current path. In a DC fuse that cuts off the DC high voltage current path due to overcurrent
It is provided with a high melting point conducting wire portion divided into three or more and arranged in series, and a low melting point conducting wire portion connecting between adjacent high melting point conducting point portions among these three or more high melting point conducting wire portions.
Of the three or more melting point conducting points, the two melting point conducting points located on both ends are supported so as not to fall.
The high melting point conductor portion located between the two high melting point conductors on both ends is separated from the two high melting point conductors on both ends by its own weight when the low melting point conductors on both sides are melted. constitute a detachable conductor portions,
The DC current path is used as the first DC current path, and a second DC current path along the first DC current path and in the opposite direction is provided.
The second direct current path is a direct current fuse characterized in that an anti-power generation line portion that generates a repulsive force due to a magnetic field is formed between the second direct current path and the detachable conductor portion. In a DC fuse that cuts off the DC high voltage current path due to overcurrent
It is provided with a high melting point conducting wire portion divided into three or more and arranged in series, and a low melting point conducting wire portion connecting between adjacent high melting point conducting point portions among these three or more high melting point conducting wire portions.
Of the three or more melting point conducting points, the two melting point conducting points located on both ends are supported so as not to fall.
The high melting point conductor portion located between the two high melting point conductors on both ends is separated from the two high melting point conductors on both ends by its own weight when the low melting point conductors on both sides are melted. Consists of a detachable conductor
A DC fuse characterized in that a parallel wiring section electrically parallel to the detachable conductor section is provided, and a constant voltage element that starts to flow a current due to a predetermined voltage rise is provided in the parallel wiring section. In a DC fuse that cuts off the DC high voltage current path due to overcurrent
It is provided with a high melting point conducting wire portion divided into three or more and arranged in series, and a low melting point conducting wire portion connecting between adjacent high melting point conducting point portions among these three or more high melting point conducting wire portions.
Of the three or more melting point conducting points, the two melting point conducting points located on both ends are supported so as not to fall.
The high melting point conductor portion located between the two high melting point conductors on both ends is separated from the two high melting point conductors on both ends by its own weight when the low melting point conductors on both sides are melted. Consists of a detachable conductor
A DC fuse characterized in that a magnetic field generating portion for generating a magnetic field is provided in the vicinity of the drop path of the detachable conducting wire portion. The DC fuse according to any one of claims 1 to 5, wherein the detachable conductor portion is supported only by the low melting point conductor portions on both sides. Claim 1 to any one of claims 1 to 6, wherein the detachable conductor portion is formed to have a length capable of extinguishing an arc generated when the arc is detached from the melting point conductor portions on both sides in an energized state. The DC fuse described. An electric facility comprising the DC fuse according to any one of claims 1 to 7 in the DC high voltage current path .

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