JP3349288B2 - Surge suppressor for high-voltage large-capacity power supply - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surge suppressor used together with a high-voltage large-capacity power supply, and more particularly, to a surge suppressor used for exhaust gas treatment between a high-voltage large-capacity DC power supply and an electron gun. And a surge suppressor for protecting the DC power supply.

[0002]

2. Description of the Related Art An electrostatic electron accelerator is basically composed of an electron gun for generating electrons in a vacuum, an acceleration tube for accelerating the generated electrons, and applying acceleration energy to the electrons. And a surge suppressor for protecting the DC power supply from unexpected discharge in the accelerating tube section, between the DC power supply and the accelerating section. Have been placed. FIG. 3 shows the configuration of such a conventional electrostatic electron accelerator. In FIG. 3, reference numeral 1 denotes an electron gun, and 2 denotes an accelerating tube including a voltage dividing resistor 21. Reference numeral 3 denotes a thyristor switch circuit which is turned on at a predetermined conduction angle and passes an alternating current from a primary power supply such as a commercial power supply.
Is a high-voltage, large-capacity DC power supply that converts AC from the thyristor switch circuit 3 to DC and outputs a DC voltage of about 150 to 5000 KV at its output terminal. Reference numeral 5 denotes a thyristor switch for controlling the insulation of the insulating transformer in the DC power supply 4, that is, controlling the AC power on the primary side of the filament transformer 6 via the insulating transformer. Reference numeral 6 denotes a filament transformer. A deflecting coil for deflecting and scanning electrons, 8 is a scanning tube, 9 is a vacuum pump for bringing the scanning tube 8 into a vacuum state, and 10 is a control unit.

The control unit 10 controls the conduction angle of the thyristor switch circuit 3 and thereby controls the acceleration voltage control circuit 10 ₁ and the thyristor switch 5 for controlling the level of the output voltage from the high voltage DC power supply 4. An electron flow control circuit 10 ₂ for controlling and thereby controlling the supply of the electron flow;
It includes a scanning control circuit 10 ₃ for controlling the scanning coil 7 and a vacuum control circuit 10 ₄ for controlling the vacuum state of the vacuum pump 9. 11 is a window cooling blower, 12 is a window cooling air duct, and 13 is an irradiation window. Reference numeral 14 denotes a surge suppression device including _two surge suppression resistors 14 ₁ and 14 ₂ inserted in a reciprocating current path from the DC power supply 4.
As shown in FIG. 4, it is arranged at the center of the inside of the grounded conductive pipe 15 insulated from the pipe.

[0004]

In the conventional surge suppressor 14 shown in FIGS. 3 and 4, surge suppressors 141, 1 for suppressing a surge caused by an accidental discharge.
Since 42 has to share most of the surge voltage, it is necessary to use a resistor having a large resistance value such as 20 KΩ. Further, as shown in FIG. 4, since it is necessary to sufficiently insulate from the grounded pipe 15 and attach it to the high-voltage current path, a pipe 15 having a large diameter is required, and a large installation space is required. There was a problem of doing. Further, for example, the surge suppression resistors 141 and 14
2 is assumed to be 20 KΩ, and it is assumed that a DC current of 1 A is required to flow in the normal electron acceleration operation, and the power loss consumed by the surge suppression resistors 141 and 142 during the normal operation is 20 KW, respectively. There is a problem that a very large power loss occurs. Accordingly, an object of the present invention is to solve such a problem and to provide a surge suppression device which has a small power loss and does not require a large installation space.

[0005]

In order to achieve the above object, according to the present invention, there is provided a surge suppression device including first and second surge suppression circuits respectively inserted at the output terminals of a high-voltage large-capacity power supply. , First and second insulating cylinders arranged coaxially, first and second coils wound around the first and second insulating cylinders, and diameters of the first and second insulating cylinders The first built in the smaller insulating cylinder
And a second resistor, wherein the first surge suppression circuit is constituted by a parallel connection circuit of the first resistor and a first coil, and wherein the second surge suppression circuit is It is characterized by comprising a parallel connection circuit of a resistor and a second coil.

That is, in the present invention, focusing on the fact that the direct current impedance of the inductance element is small and the alternating current impedance is large, each of the two surge suppression circuits is constituted by a parallel circuit of a coil and a resistor, and is used during normal operation. Reduces the power loss by flowing current mainly to the coil side, and furthermore, the two coils are wound around two coaxially arranged insulating cylinders, and two resistors are arranged at the center of the insulating cylinder. When the surge suppressor is incorporated in a grounded conductive conduit, the electric field strength of the surge suppressor can be reduced, and the diameter of the conduit can be reduced, so that the installation space can be reduced. I have.

[0007]

1A and 1B show a cylindrical surge suppressor according to an embodiment of the present invention. FIG. 1A is a cross-sectional view of the surge suppressor cut parallel to its circular surface, and FIG. () Shows a cross-sectional view along line LL in (A). In FIG. 1, reference numerals 20 and 21 denote a large-diameter insulating cylinder and a small-diameter insulating cylinder which are coaxially arranged.
_1, 22 ₂ is wound around. Further, inside the small-diameter insulating cylinder 21, resistors 23 ₁ and 23 ₂ are included. Coil 2
As shown in FIG. 1 (C), 2 ₁ , _{2 2} and resistors 23 ₁ , _{2 3} are connected in parallel to form two sets of parallel circuits, and are connected to a pair of output terminals of a high-voltage large-capacity DC power supply. Connected and inserted into the reciprocating current path between the power supply and the load.

In the present invention, as described above, the surge suppressor is formed by the coil and the resistor connected in parallel. The principle of the surge suppressor will be described below. It is well known that a coil does not theoretically cause any power loss with respect to direct current.If it is forcible, since the coil has a resistance component of about several Ω, only a power loss due to the resistance component occurs It is. Therefore, for example, even if a current of 1 A flows through the coil, only a power loss of about several W is generated, and the coil is an element having a small DC impedance. On the other hand, the coil exhibits a high impedance characteristic with respect to alternating current, and exhibits an impedance of several tens of kilohms with a surge of 1 msec when the inductance is about several mH. Therefore, the coil can exert a surge suppression effect.

Therefore, in the surge suppressor according to the present invention, since the DC current mainly flows through the coil side having a small DC impedance, the power loss is small in the normal operation, and the surge can be suppressed when the surge occurs. In addition, when a surge suppression device is configured with only a coil, an excessive voltage is excessively applied to both ends of the coil when a surge occurs. However, in the present invention, since a resistor is connected in parallel to the coil, the surge is not generated. Sometimes, an excessive voltage is prevented from being applied to the coil. Thereby, the same surge suppression effect as in the case where only the resistor is used can be obtained, and the power loss can be reduced.

Furthermore, the surge suppressor of the present invention has a structure in which two insulating cylinders, that is, a large-diameter and a small-diameter insulation resistance are arranged coaxially and a coil is wound around their outer circumferences, so that they can be formed compact. Therefore, it is easy to insert the surge suppressor between the DC high-voltage power supply and the acceleration tube, and when included in a grounded conductive conduit, as described below, the surge suppressor which is a conductor is used. The surface electric field intensity of the device can be reduced. That is, FIG.
As shown in (A), generally, when a conductor having a radius R and a radius r is disposed at the center of a grounded conductive conduit, the applied voltage applied to the conductor is V and Then, the maximum electric field intensity E _MAX on the conductor surface can be approximately expressed as follows.

E _MAX = V / {r · 2.3 log (R / r)} (1)

Considering the electric field strength of the present invention, the present invention can be schematically represented as shown in FIG. 2B. For example, the outer coil, that is, the large-diameter insulating cylinder 20
If the radius of the coil 22 ₁ wound around is 100 mm, the radius of the conduit is 300 mm, and the applied voltage is 1000 KV,

## EQU2 ## r = 100 mm, R = 300 mm, V = 10
The _{00KV ∴ E MAX = 9.1KV / mm} . On the other hand, when two resistors are arranged at the center of the pipeline as in the conventional surge suppressor, the cross section of the two resistors arranged in parallel is not circular, so the above equation (1) is corrected. However, since the radius r of the conductor is the diameter of the resistor, and the diameter of the resistor is about 35 mm, assuming that r = 35 mm, E _MAX ≒ 14 KV / mm approximately. Therefore, in order to reduce the electric field intensity on the surface of the surge suppressor, in the conventional example, it is necessary to take measures such as increasing the diameter of the resistor or further increasing the diameter of the pipeline. According to this, even if a conduit having the same diameter as the conventional example is used, the electric field intensity is reduced, so that the installation space can be reduced.

[0012]

As described above, the surge suppressor according to the present invention comprises the surge suppressor using two parallel circuits of a coil and a resistor. Power loss during operation can be reduced. In particular, when an electrostatic electron accelerator is used in a field where improvement in power supply conversion efficiency is required, such as for exhaust gas treatment, for example, the generation of 1 MV voltage and 1 A current, that is, 1 MW power is required. In the required DC power supply, the power loss of 20 kW can be reduced by 20 kW / 1 MW = 2%
This means that it contributes to the improvement of the efficiency of the method, and the practical effect is extremely large. Further, since a resistor is connected in parallel to the coil, an excessive voltage is not applied to both ends of the coil when a surge occurs. Furthermore, in the surge suppressor according to the present invention, the coils are wound around two coaxially arranged insulating cylinders, respectively, and two resistors are arranged therein. In the case where is included in a conductive conduit grounded, even if the diameter of the conduit is reduced, the electric field intensity generated in the surge suppressor does not increase so much, the diameter of the conduit can be reduced. Space can be reduced.

[Brief description of the drawings]

FIG. 1 is a view showing a configuration of a surge suppressor formed in a cylindrical shape according to an embodiment of the present invention, wherein (A) and (B) are cross-sectional views of the surge suppressor, and (C) is a circuit diagram thereof. It is.

FIG. 2 is an explanatory diagram for explaining that the electric field intensity on the surface of the surge suppressor can be reduced by the present invention.

FIG. 3 is a schematic diagram showing a configuration of an electrostatic electron accelerator using a conventional surge suppressor.

FIG. 4 is a schematic cross-sectional view showing a state in which a conventional surge suppressor is incorporated in a grounded conductive conduit.

[Explanation of symbols]

20 Large-diameter insulating cylinder 21 Small-diameter insulating cylinder 22 ₁ , 22 ₂ Coil 23 ₁ , 23 ₂ Resistance

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H02H 9/00-9/06

Claims (3)

(57) [Claims] 1. A surge suppression device comprising first and second surge suppression circuits inserted into a reciprocating current path from an output terminal of a high-voltage large-capacity power supply, wherein the first and second coaxially arranged first and second surge suppression circuits are coaxially arranged. An insulating cylinder; first and second windings wound around the first and second insulating cylinders;
And a first and a second resistor incorporated in the insulating cylinder having a smaller diameter of the first and second insulating cylinders, wherein the first surge suppressing circuit is provided with the first resistor. Wherein the second surge suppression circuit is constituted by a parallel connection circuit of the second resistor and the second coil. apparatus. 2. The surge suppression device according to claim 1, wherein said surge suppression pressure device is built in substantially the center of a grounded conductive conduit. 3. The surge suppressor according to claim 1, wherein the high-voltage large-capacity power supply is a DC power supply for electron acceleration of an electrostatic electron accelerator.