Fuseless arcing device and fuseless arcing method

Abstract

To provide a non-fuse arc forming apparatus and a non-fuse arc forming method which do not use a fuse wire and require no large-scaled apparatus.SOLUTION: A non-fuse arc forming apparatus comprises an arc gap A (gap 4) for generating an arc, a control gap B for flashover control, a power supply 1 which is connected with the arc gap A and the control gap B at both ends to supply current, a high voltage pulse generator 3 which is connected in parallel with the arc gap A and the control gap B respectively, and a controller 6 for on / off control of the high voltage pulse generator 3, and sets properly a relation of sum total of the arc gap A, the control gap B, total flashover voltage, and power supply voltage.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to an arc-initiating device and an arc-initiating method, and more particularly to a fuseless arc-initiating device and a fuseless arc-initiating method suitable for use in arc resistance performance evaluation tests of power transmission and distribution equipment such as insulators and electric wires. [Background technology]

[0002] In arc resistance tests for electric power equipment, an arc generation method using fuse wire made of copper or the like is widely used (for example, Patent Document 1). By using fuse wire, an arc can be generated almost reliably at the desired position, and the procedures and items required for arc generation are relatively few. Therefore, this method is often used for research to verify accidents, or in arc resistance performance evaluation tests for power transmission and distribution equipment such as insulators and electric wires.

[0003] Arcing methods that do not use fuse wires include a method using an impulse generator and a method using a movable electrode. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2005-326244 Summary of the Invention [Problem to be solved by the invention]

[0005] However, the above-mentioned fuse blowing and arc-starting device has the drawback that, because the fuse wire is blown as a trigger for arcing, fuse components scattered around as the fuse blows and evaporates become mixed into the arc as impurities.

[0006] Furthermore, in the case of the arcing method using an impulse generator, there is a problem that the test circuit becomes large because a blocking circuit and a large impulse generator are required, and there is also a risk of failure or damage depending on the power supply.

[0007] Furthermore, in the case of the arc generation method using a movable electrode, the gap length changes over time, which causes the arc characteristics to change over time.

[0008] As described above, each arc-generating method has its advantages and disadvantages, and so they are used depending on the purpose. However, there is a demand for an arc-generating device and arc-generating method that can be used universally by solving the problems of each arc-generating method.

[0009] The present invention is made to meet such demands, and has as its object to provide a fuseless arcing device and a fuseless arcing method that do not use fuse wire and do not require large-scale equipment. [Means for solving the problem]

[0010] To achieve this object, the fuseless arc starting device described in claim 1 comprises an arc gap for generating an arc, a control gap for flashover control, a power supply connecting both ends of the arc gap and the control gap to supply current, a high-voltage pulse generator connected in parallel to each of the arc gap and the control gap, and a control device for controlling the on / off of the high-voltage pulse generator, wherein the control gap is made up of a plurality of gaps, the sum of the total flashover voltage of the plurality of gaps and the voltage of the power supply is higher than the flashover voltage of the arc gap, there is at least one gap which is shorter than the length at which the flashover voltage can be made to blow the arc with the voltage of the power supply alone, and the relationship between the sum of the total flashover voltage of the remaining gaps and the voltage of the power supply is higher than that of all gaps which are to flashover, and under the control of the control device a high voltage is applied to the arc gap and then each gap in the control gap in turn to cause a flashover, thereby connecting the arc up to the gap which can blow the arc with the voltage of the power supply alone and shorting the power supply.

[0011] In the fuseless arcing device according to the present invention, it is preferable that the gaps constituting the control gap have flashover voltages that gradually decrease with increasing distance from the arc gap.

[0012] In the fuseless arc starting device of the present invention, it is also preferable that the flashover voltage of the gap immediately before the last gap of the control gaps is lower than the sum of the flashover voltage of the last gap and the power supply voltage.

[0013] Furthermore, the fuseless arcing method of the present invention comprises an arcing circuit that includes, in addition to an arc gap for generating an arc, a plurality of gaps, at least one gap of a length equal to or shorter than the flashover voltage of the arc gap, where the sum of the total flashover voltage of the gaps and the voltage of the power supply is higher than the flashover voltage of the arc gap, and where the flashover voltage is such that the arc can be blown by the power supply voltage alone, and control gaps for flashover control are arranged at both ends of the power supply so that the sum of the total flashover voltage of the remaining gaps and the voltage of the power supply is higher than that of all gaps that are to be caused to flashover; and a high voltage is applied to the arc gap and then to each gap in the control gap in turn to cause a flashover, thereby connecting the arc up to the gap where the arc can be blown by the power supply voltage alone, thereby short-circuiting the power supply.

[0014] In the method for arcing without a fuse according to the present invention, the gaps constituting the control gap are preferably arranged so that the flashover voltage decreases with increasing distance from the arc gap.

[0015] In the non-fuse arcing method according to the present invention, it is preferable that the flashover voltage of the gap immediately before the last gap of the control gaps is lower than the sum of the flashover voltage of the last gap and the power supply voltage. [Effects of the Invention]

[0016] The fuseless arc starting device and fuseless arc starting method of the present invention can generate an arc without using a fuse wire or requiring a large-scale device. In other words, even without a fuse, an arc can be generated in an arc gap where it would normally be difficult to generate an arc. [Brief explanation of the drawings]

[0017] [Figure 1](a) shows a fuse-free circuit with one gap and a high-voltage single-pulse generator, and (b) shows a fuse-free circuit with two gaps and a high-voltage single-pulse generator. [Figure 2] FIG. 10 is an explanatory diagram showing an example of dividing a gap. [Figure 3] 1 is a circuit diagram showing an embodiment of a fuseless arcing device of the present invention. [Figure 4] 5A and 5B are graphs showing the results of verifying the arc phenomenon using the arc-generating device according to the present invention, where (a) is a voltage waveform diagram and (b) is a current waveform diagram. DETAILED DESCRIPTION OF THE INVENTION

[0018] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The configuration of the present invention will be described in detail below based on the embodiments shown in the drawings.

[0019] Figure 1 shows a circuit consisting of a high-voltage single-pulse generator, a gap, and a power source. In Figure 1(a), a pulse generator, such as high-voltage single-pulse generator 3, is connected in parallel to gap 4 (referred to as gap A) where an arc is desired to occur. If gap A is flashed over (also called a FO or spark discharge) by the high-voltage single-pulse generator, power source 1 is short-circuited, and an arc is expected to occur in gap A. However, even if high-voltage single-pulse generator 3 is connected in parallel to gap A, current flows through power source 1, and the voltage applied to gap A depends on the power source voltage. Therefore, a low-voltage power source 1 cannot generate an arc across a wide gap. In other words, a power source 1 with a voltage of several kV, e.g., 6 kV, can generate an arc when gap A is short, e.g., about 1 mm, but cannot generate an arc when gap A is long, e.g., about 15 mm, due to the lack of dielectric breakdown. Note that reference numeral 2 denotes wiring.

[0020] On the other hand, if a gap 5 (called gap B) with a higher flashover voltage than gap A is further provided in the circuit, as shown in Figure 1(b), the insulation provided by gap B prevents the high voltage of high-voltage pulse generator 3 applied to gap A from flowing to power supply 1, and it can be applied to gap A to cause a flashover. However, because gap B with a higher flashover voltage than arc gap A remains, a low-voltage power supply 1 that cannot cause dielectric breakdown in arc gap A, for example a power supply 1 of about 6 kV, cannot cause dielectric breakdown in gap B, and therefore the power supply and circuit cannot be short-circuited.

[0021] Based on the above phenomenon, the inventors have classified Gap B into a series of gaps in which the flashover voltage gradually decreases (for example, Gap 5 in which the gap length gradually decreases), as shown in FIG. -1 ~5 -5 ) and each gap is 5 -1 ~5 -5 and a high voltage pulse generator 3 is connected in parallel to each other, and a gap 5 -1 ~5 -5 They discovered that by turning on the high-voltage pulse generator 3 in order from the one with the highest flashover voltage and causing flashovers in the gaps one after another, it is possible to connect gaps that can generate an arc even with only a low-voltage power supply, ultimately leading to a short circuit. In other words, although a flashover is a discontinuous transient phenomenon that can only last for 1 ms or less, they came up with the idea that if the high-voltage pulse generators for each gap are operated sequentially with a time difference of several tens of μs, the gaps can be connected by flashover, thereby short-circuiting the circuit.

[0022] The fuseless arc starting device of the present invention is based on this finding and comprises an arc gap for generating an arc, a control gap for flashover control, a power supply connecting both ends of the arc gap and the control gap to supply current, a high-voltage pulse generator connected in parallel to each of the arc gap and the control gap, and a control device for controlling the on / off of the high-voltage pulse generator, wherein the control gap is made up of a plurality of gaps, the sum of the total flashover voltage of the plurality of gaps and the voltage of the power supply is higher than the flashover voltage of the arc gap, and there is at least one gap which is shorter than the length at which the flashover voltage can be made to blow an arc with the voltage of the power supply alone, and wherein the sum of the total flashover voltage of the remaining gaps and the voltage of the power supply is higher than that of all gaps which are to be flashed, and the control device controls the arc gap and then each gap in the control gap to cause a flashover, thereby connecting the arc up to the gap where the arc can be blown with the voltage of the power supply alone, thereby short-circuiting the power supply.

[0023] For example, as shown in one embodiment in FIG. 3, in addition to a gap 4 where an arc is desired to occur (referred to as arc gap A in this specification), a plurality of gaps 5 having a flashover voltage lower than that of arc gap A are provided. -1 ~5 -n A series of gaps for flashover control (referred to as control gap B in this specification) consisting of the above are connected to both ends of a power source 1 to form an arcing circuit, while a high-voltage pulse generator 3 for applying a flashover voltage is connected in parallel to each gap A, B, and the on / off of the high-voltage pulse generator 3 is controlled by a control device 6 to apply a flashover voltage to each gap 5 of the control gap B after the arc gap A. -1 ~5 -n By flashing over these in order of highest flashover voltage, the circuit is connected (i.e., the arc is connected to the gap where insulation breakdown occurs due to the power supply voltage alone), and the power supply 1 is short-circuited.

[0024] Here, for all gaps targeted for flashover, the control gap B is designed so that the flashover voltage of the gap targeted for flashover is lower than the sum of the total flashover voltage of the remaining gaps and the power supply voltage (i.e., the total flashover voltage of the remaining gaps + the power supply voltage). Furthermore, the minimum gap among the control gaps B is set to a length equal to or shorter than the flashover voltage that can cause an arc to jump using power supply 1 alone. In other words, the total flashover voltage of the remaining gaps is higher than that of the gap targeted for flashover, and the control gap B is configured to include at least one gap long enough to cause dielectric breakdown and cause an arc to jump using only the power supply voltage, thereby enabling a high voltage to be applied to the gap targeted for flashover. While it is sufficient to include at least one minimum gap, if the minimum gap is made sufficiently short, it is also possible to cause flashover using only the power supply voltage, including the minimum gap and the gap immediately preceding it. In other words, there may be a plurality of gaps having a length equal to or less than the flashover voltage at which an arc can be blown using only the voltage of the power supply.

[0025] On the other hand, for arc gap A, the pulsed high voltage generator for arc gap A is connected in reverse polarity, different from the pulsed high voltage generators 3 for each gap in control gap B, so the flashover voltage of gap A is lower than the sum of the total flashover voltage of control gap B and the power supply voltage (total flashover voltage of gap B - power supply voltage). However, in the early stage of flashover, the total flashover voltage of the remaining gaps is sufficiently high, so ignoring the power supply voltage is thought to have no significant effect.

[0026] Specifically, in this embodiment, the control gap B is a plurality of gaps whose gap length is successively shortened (i.e., a plurality of gaps 5 whose flashover voltage is successively reduced). -1 ~5 -7), for example, the first gap (second gap 5) is the second gap in flashover voltage height (i.e., gap length) after arc gap A (i.e., first gap 4). -1 ) are the remaining gap groups (i.e., the third to eighth gaps in the example of FIG. 3). -2 ~5 -7 The relationship is set so that the flashover voltage is lower (i.e., the gap length is shorter) than the sum of the total flashover voltage of the power supply 1 and the voltage of the power supply 2. -2 is the remaining gap group (i.e., the 4th to 8th gaps 5 -3 ~5 -7 ) and the sum of the power supply voltage, and the fourth gap 5 -3 is the remaining gap group (i.e., the 5th to 8th gaps 5 -4 ~5 -7 ) and the sum of the power supply voltage, and the flashover voltage of the fifth gap 5 -4 is the remaining gap group (i.e., the 6th to 8th gaps 5 -5 ~5 -7 ) and the sum of the power supply voltage, and the flashover voltage of the sixth gap 5 -5 is the remaining gap group (i.e., the 7th to 8th gaps 5 -6 ~5 -7 The flashover voltage of the seventh gap 5 is set lower than the sum of the total flashover voltage of the seventh gap 5 and the power supply voltage. -6 The 8th gap is 5 -7 The flashover voltage is higher than the sum of the flashover voltage of the eighth gap 5 -7 The seventh gap 5 is configured to be the gap with the minimum flashover voltage. -6 and 8th Gap 5 -7 The total flashover voltage of the two gaps is the gap length that is short enough to generate a flashover voltage that can cause an arc to fly using only the power supply voltage. -6 The flashover voltage (i.e., gap length) of the 7th gap is 5 -6and 8th Gap 5 -7 This is set to be lower than the total flashover voltage of the first two gaps. -5 From the 8th gap 5 -7 The voltage of the power supply alone cannot generate an arc for the first three gaps, but the operation of the high voltage pulse generator 3 generates an arc for the sixth gap 5 -5 A flashover can occur in the sixth gap. -5 At the same time as a flashover occurs, the seventh gap 5 remains with only the voltage of power supply 1. -6 and 8th Gap 5 -7 In other words, this embodiment is configured to include two gaps of such a length that even the voltage of the power supply alone can cause a dielectric breakdown and generate an arc.

[0027] The high-voltage pulse generator 3 functions as a high-voltage, high-impedance power source that can apply a voltage high enough to cause a flashover between the gaps (i.e., a voltage exceeding the flashover voltage), and in this embodiment, it is configured as a high-voltage single-shot pulse generator that applies the voltage stored in a capacitor to the ignition coil of a motorcycle in one go. In other words, it is configured as a battery-powered, compact high-voltage single-shot pulse generator. In this embodiment, the high-voltage single-shot pulse generator 3 applies a voltage high enough to cause a flashover between the gaps 4 and 5. -1 ~5 -7 Every 4,5 gaps -1 ~5 -7 and connected in parallel, all gaps 4, 5 -1 ~5 -7 The gaps 4 and 5 are provided so that a flashover voltage can be applied to cause a flashover. -1 ~5 -7 The high voltage single pulse generators 3 are each connected to the control device 6 by, for example, an optical fiber 7, and the application of the flashover voltage is controlled by an optical signal (pulse) sent from the control device 6 through the optical fiber 7. The control device 6 controls the gaps 4 and 5 with an extremely short time difference, for example, several tens of μs, during which the flashover continues. -1 ~5-7 Turn on the high voltage single pulse generator in order from the larger one, and then turn on the gap 4, 5 -1 ~5 -7 This causes the gaps to flash over, ultimately resulting in a short circuit. In this way, the greater the number of divisions of the control gap B, i.e., the greater the number of constituent gaps, the lower the voltage power supply can be used. Of course, the high-voltage pulse generator 3 does not need to be capable of generating only a single high-voltage pulse, nor does it need to be battery-powered. It is sufficient that it can cause multiple gaps to flash over in a predetermined order.

[0028] With the fuseless arc-starting device configured as described above, because control gap B exists, which has a higher flashover voltage than arc gap A, a high-impedance, high-voltage pulse generator 3 can be used to cause a flashover in arc gap A, which cannot be triggered by a low-impedance power supply 1. Then, starting from arc gap A, each gap in control gap B is triggered to flashover in order of highest flashover voltage, ultimately resulting in a short circuit (short-circuiting the power supply). The arc is then maintained by the current power supply. In other words, without using fuse wire or requiring large-scale equipment, an arc can be generated and maintained for the time required for testing and experiments, even in gaps where the flashover voltage cannot be obtained with the power supply voltage (i.e., gaps of a length that cannot generate an arc) and the gaps are too long to generate an arc.

[0029] While the above-described embodiment is one example of a preferred embodiment of the present invention, it is not limited thereto and various modifications are possible without departing from the spirit and scope of the present invention. For example, in the above-described embodiment, the control gap B is configured with a group of gaps arranged so that the flashover voltage decreases in stages (in other words, so that the gap length decreases in stages). However, this is not particularly limited, and in some cases, all or some of the gaps in the control gap B may be configured with gaps having the same flashover voltage (in other words, the same length). That is, if the flashover voltage of all or some of the gaps that make up the control gap B is lower than the power supply voltage, and the gaps are short enough in length to provide a flashover voltage that can cause an arc to jump using only the voltage of power supply 1, and the total flashover voltage is higher than the flashover voltage of arc gap A, then after the high-voltage pulse generator causes flashover in the gaps sequentially, the last gap will experience dielectric breakdown due to the voltage of power supply 1 alone, resulting in a short circuit of the power supply. In this case, the flashover voltage of the gap immediately preceding the final gap is set lower than the sum of the flashover voltage of the final gap and the power supply voltage.

[0030] In the above embodiment, the two gaps 5 are designed to allow arcing only with the voltage of the power supply 1. -6 , 5 -7 By providing the gap 5, which is to be flashed over by the high voltage single pulse generator 3 immediately before it, -5However, the present invention is not limited to this. In some cases, the final gap may be a gap of a length equal to or shorter than the flashover voltage at which the voltage of power supply 1 alone is sufficient to produce a flashover voltage that can cause an arc to fly, and even if the flashover voltage of the gap immediately preceding this final gap is set lower than the sum of the flashover voltage of the final gap and the power supply voltage, this will still result in a short circuit of the power supply.

[0031] Furthermore, in the above-described embodiment, control gap B is configured by connecting in series a plurality of gaps whose flashover voltages are gradually lower than arc gap A so that the flashover voltage decreases in stages, but this is not particularly limited to this, and does not exclude, for example, the case where control gap B includes a gap whose flashover voltage is higher than arc gap A. In other words, it is sufficient that the sum of the total flashover voltage of control gap B and the power supply voltage is set higher than the flashover voltage of arc gap A, and that the gaps constituting control gap B are also set in a relationship such that the sum of the flashover voltages and power supply voltages of the remaining gaps is higher than the gap to be flashed, so that the arc is ultimately connected to a gap where the arc can be blown using only the voltage of power supply 1, and the power supply is short-circuited. [Example]

[0032] The arcing phenomenon was verified using the arcing device of this embodiment shown in Figure 3. This experimental device used a capacitor (6 kV, 0.4 μF) as the power source 1, and arc gap A and multiple gaps 5 -1 ~5 -7 A control gap B consisting of -1 ~5 -7A battery-powered, compact, high-voltage, single-shot pulse generator 3 that applies a flashover voltage to the capacitor 1 was connected in parallel, and an attempt was made to short-circuit the capacitor 1 by flashing over each gap in turn, starting with arc gap A and ending with control gap B. This made it possible to generate an arc even with a low-voltage power supply of around 6 kV, even in a relatively wide gap of around 15 mm, where an arc would not normally occur, and experimentally confirmed that this could be maintained for a sufficiently long time, for example, several tens of ms to 100 ms.

[0033] In this experiment, a battery-powered high-voltage single-shot pulse generator was used as the high-voltage pulse generator 3. This generator applies the voltage stored in a capacitor to the ignition coil of a motorcycle in one go. The peak voltage value when the terminals are open is approximately 58 kV, and the peak current value when the terminals are shorted is 1.4 A. This high-voltage single-shot pulse generator 3 was used for each gap 4, 5 -1 ~5 -7 Each of the high-voltage single-shot pulse generators 3 is connected in parallel and connected to the control device 6 via an optical fiber 7, and the application of voltage is controlled by an optical signal from the control circuit 6. That is, the high-voltage single-shot pulse generator 3 outputs a high voltage when an optical signal is received from the control device 6. Because this high-voltage single-shot pulse generator 3 is composed of an ignition coil and a capacitor, it is small and lightweight, and has a high response speed on the order of microseconds (see Nakano Tomoyuki, "Study on a Low-Cost High-Voltage Single-Shot Pulse Generator," Institute of Electrical Engineers of Japan 2020 Electric Power and Energy Division Conference, 310, (2020)).

[0034] (About the gap) In the case of the arc generating device of this embodiment, the gaps are an arc gap A (called the first gap 4) where an arc is to be generated, and second to eighth gaps 5 for flashover control. -1 ~5 -7 (collectively referred to as control gap B). Here, since the level of flashover voltage correlates with the length of the gap, arc gap A (first gap 4) was set to 15 mm, and control gap B (second to eighth gaps 5 -1 ~5-7 ) is 29.2 mm, and control gap B is made up of seven gaps with successively shorter gap lengths: second gap 10 mm, third gap 7 mm, fourth gap 5 mm, fifth gap 3 mm, sixth gap 2 mm, seventh gap 1.5 mm, and eighth gap 0.7 mm. In other words, the flashover voltage of control gap B is higher than the flashover voltage of arc gap A, and the flashover voltages of the gaps that make up control gap B are all lower than the flashover voltage of arc plasma A, and the flashover voltages of all gaps that are to undergo flashover are arranged so that they decrease in succession.

[0035] (Experimental methods and conditions) The experimental conditions are shown in Table 1. The power supply voltage was 6 kV, the arc gap length was 15.0 mm, and each gap of the control gap B was 5 -1 ~5 -7 A time lag of several tens of microseconds was set for the flashover.

[0036] [Table 1]

[0037] (Experimental results) The measured voltage waveform is shown in Figure 4(a), and the current waveform is shown in Figure 4(b). The vertical axis of Figure 4(a) is the voltage between the terminals of the capacitor, and the vertical axis of Figure 4(b) is the output current of the capacitor, and the horizontal axis of each represents the time when the capacitor is shorted, with 0 μs as the time.

[0038] From Fig. 4(a) and (b), at time 0 μs, the first to sixth gaps 5 -1 ~5 -7It was found that the flashover of gap A was the trigger (starting point) and shorted the capacitor (power supply), causing the voltage between the terminals to drop and a current of several tens of amperes to flow. At this time, arcs occurred in all gaps, arc gap A and control gap B. Because noise generated by the flashover of arc gap A (first gap) was measured approximately 170 μs before the capacitor was shorted, it is presumed that the capacitor was shorted at the same time as the flashover of gap 6, which occurred 170 μs after the flashover of arc gap A. Therefore, it is believed that gaps 7 and 8 flashed over due to the capacitor's charging voltage of 6 kV before the operation of high-voltage single-shot pulse generator 3, leading to short circuits. In other words, the voltage of power supply 1, which was about 6 kV, alone would not be enough to cause an arc to jump to the three gaps from the sixth gap to the eighth gap, but because the flashover voltage of the sixth gap, which was to be caused to flashover, was lower than the sum of the power supply voltage and the total flashover voltage of the remaining gaps, namely the seventh and eighth gaps, it was possible to cause a flashover in the sixth gap by the operation of high-voltage single-pulse generator 3. And, at the same time that a flashover occurred in the sixth gap, it is estimated that the voltage of power supply 1, 6 kV alone, was able to cause dielectric breakdown in both the remaining seventh and eighth gaps.

[0039] This revealed that with a 6 kV power supply, it is possible to cause an arc to jump across a gap of, say, 15 mm, which would not normally cause breakdown. In other words, it was verified that even with a low-voltage power supply of around 6 kV, it is possible to cause an arc to jump across arc gap A, which is a length (for example, 15 mm) that would not normally cause breakdown. [Explanation of symbols]

[0040] 1 Power source 2 Wiring 3. High-voltage single-pulse generator 4 Arc Gap 5. Control Gap 6. Control device 7. Optical Fiber

Claims

1. an arc gap for generating an arc; a control gap for flashover control; a power supply connected to both ends of the arc gap and the control gap to supply current; a high-voltage pulse generator connected in parallel to each of the arc gap and the control gap; a control device for controlling on / off of the high-voltage pulse generator; the control gap is made up of a plurality of gaps, the sum of the total flashover voltage of the plurality of gaps and the voltage of the power supply is higher than the flashover voltage of the arc gap, and the control gap has at least one gap having a length equal to or shorter than the flashover voltage at which the power supply voltage alone can blow an arc, and the total flashover voltage of the remaining gaps and the voltage of the power supply are higher than those of all gaps to be flashed, A fuseless arcing device characterized in that a high voltage is applied to the arc gap and then to each gap of the control gap in sequence under the control of the control device to cause flashover, thereby connecting the arc to the gap where the arc can be blown using only the voltage of the power supply, thereby short-circuiting the power supply.

2. 2. The fuseless arcing device according to claim 1, wherein the gaps constituting the control gap have flashover voltages that decrease progressively with increasing distance from the arc gap.

3. 3. A fuseless arcing device according to claim 1, wherein the flashover voltage of the gap immediately preceding the last gap of said control gaps is lower than the sum of the flashover voltage of the last gap and the power supply voltage.

4. a fuseless arc starting method comprising: an arcing circuit including, in addition to an arc gap for generating an arc, a plurality of gaps each having a length equal to or shorter than that at which the sum of their total flashover voltage and the voltage of the power supply is higher than the flashover voltage of the arc gap; at least one gap having a length equal to or shorter than that at which the flashover voltage can be made to jump an arc using only the voltage of the power supply; and control gaps for flashover control located at both ends of the power supply, the control gaps being arranged so that the sum of the total flashover voltage of the remaining gaps and the voltage of the power supply is higher than that of all gaps to be caused to flashover; and applying a high voltage to the arc gap and then to each gap in the control gap in turn to cause a flashover, thereby connecting the arc to the gap that can be caused to jump an arc using only the voltage of the power supply, thereby short-circuiting the power supply.

5. 5. A method for arcing without a fuse according to claim 4, wherein said gaps constituting said control gap are arranged so that the flashover voltage decreases with increasing distance from said arc gap.

6. 6. A fuseless arcing method according to claim 4, wherein the flashover voltage of the gap immediately preceding the final gap of said control gaps is set lower than the sum of the flashover voltage of the final gap and the power supply voltage.

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