CN215816827U - Gas discharge tube capable of generating distortion electric field - Google Patents

Abstract

The utility model discloses a gas discharge tube capable of generating a distorted electric field, which comprises an insulating tube body and end electrodes sealed at two ends of the insulating tube body, wherein a discharge gap positioned between the two end electrodes is formed in the insulating tube body; the terminal electrode comprises an electron emission surface which is positioned at one side in the insulating tube body and coated with an electron emission coating; the electron emission surface is provided with a groove and a plurality of grooves, the groove is positioned at the central part of the electron emission surface, and the grooves extend outwards from the groove; the gas discharge tube with the structure can be enriched at the groove and the groove when the gas discharge tube works in transient overvoltage of a power supply system, so that a distortion electric field which is distorted is formed in a discharge gap, the distortion electric field enables an electron emission point on an electron emission surface to rapidly drift, long-time partial discharge of the electron emission surface is avoided, the problem that an end electrode of the electron emission surface is melted or an insulating tube body is damaged due to long-time partial discharge is solved, and the service life of the gas discharge tube is effectively prolonged.

Description

Gas discharge tube capable of generating distortion electric field

Technical Field

The utility model relates to the technical field of gas discharge tubes, in particular to a gas discharge tube capable of generating a distortion electric field.

Background

The gas discharge tube commonly used in the lightning overvoltage protection scheme of the current low-voltage alternating current and direct current power distribution system is a cylindrical parallel gap discharge tube, as shown in fig. 9 and fig. 10, the gas discharge tube comprises a metal electrode 5 and a ceramic tube 6, a closed space is formed in the ceramic tube 6, inert gas is filled in the space, an auxiliary trigger graphite electrode 8 is drawn on the inner wall of the ceramic tube 6, an electron emission surface 50 is arranged on the metal electrode 5, and a cylindrical parallel discharge gap 7 is formed by the electron emission surfaces 50 on the two metal electrodes 5.

When lightning overvoltage is applied to the two metal electrodes 5, the spatial electric field of the cylindrical discharge gap 7 is a uniform parallel electric field. At this time, because the voltage rising rate formed by lightning overvoltage is very large, and the electric field intensity at two ends of the auxiliary trigger graphite electrode 8 is maximum, the nearby inert gas is firstly ionized and broken down to form a plasma arc, the lightning voltage with very large rising rate causes the rising rate of the discharge current in the discharge tube to be also very large, the plasma arc formed at two ends of the graphite electrode 8 rapidly expands towards the cylindrical discharge gap 7, the discharge plasma is formed in the cylindrical discharge gap 7 to participate in the current discharge, and the uniform parallel electric field is beneficial to the service life of the emitting surface on the metal electrode 5.

However, when the gas discharge tube is connected to a low-voltage alternating current power distribution system or a low-voltage direct current power distribution system, not only the overvoltage condition caused by lightning stroke is avoided, but also transient overvoltage possibly generated by the power distribution system must be borne.

Compared with lightning strike voltage, the transient overvoltage voltage generated by a power distribution system has lower voltage rising rate, inert gas is firstly ionized and punctured at a certain point in a cylindrical discharge gap area, the voltage rising rate is low, so that the current rising rate formed by discharge plasma in the discharge gap after ionization and puncture is low, the electron emission on the electron emission surface 50 on the metal electrode 5 is changed from surface emission of the lightning strike overvoltage to point emission, the emission point continuously drifts in the area of the electron emission surface 50, and a uniform parallel electric field has no effect on the drift of the emission point. At this time, if the over-current drift rate of the transient over-voltage is too slow, partial discharge is formed, which may cause the metal at the position of the emission point to be locally overheated and melted, and the melted metal is raised in the direction of the electric field under the action of the parallel electric field in the discharge gap, causing short circuit in the discharge gap, causing damage to the gas discharge tube, and possibly causing other damages to the power supply system. If the local hot spot is close to the inner wall of the ceramic tube 6, the ceramic tube 6 may burst and the gas discharge tube may fail to open.

SUMMERY OF THE UTILITY MODEL

The present invention is directed to solving the above-mentioned problems and to providing a gas discharge tube capable of generating a distorted electric field which can effectively prevent partial discharge.

In order to achieve the purpose, the utility model discloses a gas discharge tube capable of generating a distorted electric field, which comprises an insulating tube body and end electrodes sealed at two ends of the insulating tube body, wherein a discharge gap between the two end electrodes is formed in the insulating tube body; the terminal electrode comprises an electron emission surface which is positioned on one side in the insulating tube body and coated with an electron emission coating; the electron emission surface is provided with a groove and a plurality of grooves, the groove is located at the center of the electron emission surface, and the grooves extend outwards from the groove.

Preferably, the insulating tube body is a metalized ceramic tube.

Preferably, a graphite electrode for assisting in triggering gas ionization is arranged on the inner wall of the insulating tube body.

Preferably, a plurality of the grooves are uniformly spaced around the groove.

Preferably, one end of the groove is communicated with the groove, and the other end of the groove extends outwards from the groove.

Preferably, the groove is in a linear structure or a curved structure.

Preferably, the grooves have three or four grooves.

Preferably, the groove comprises a plurality of rings of annular grooves arranged around the recess.

Preferably, the groove has two.

Compared with the prior art, the gas discharge tube capable of generating the distorted electric field comprises an insulating tube body and end electrodes sealed at two ends of the insulating tube body, wherein the end electrodes are provided with electron emission surfaces, the electron emission surfaces are provided with grooves and a plurality of grooves distributed around the grooves, when the gas discharge tube works in transient overvoltage of a power supply system, charges can be enriched at the grooves and the grooves after inert gas in the insulating tube body is ionized due to the existence of the grooves and the grooves, and the charge enrichment density is gradually reduced outwards from the grooves, so that distorted electric fields are formed in discharge gaps, electron emission points on the electron emission surfaces are rapidly drifted by the distorted electric fields, the long-time partial discharge of the electron emission surfaces is avoided, and the problem that the end electrodes are melted or the insulating tube body is damaged due to the long-time partial discharge of the electron emission surfaces is solved, effectively prolonging the service life of the gas discharge tube.

Drawings

FIG. 1 is a schematic longitudinal sectional view of a gas discharge tube in an embodiment of the present invention.

Fig. 2 is an enlarged schematic view of a portion D in fig. 1.

Fig. 3 is a schematic perspective view of a terminal electrode according to an embodiment of the utility model.

Fig. 4 is a top view of fig. 3.

Fig. 5 is a schematic perspective view of a terminal electrode according to another embodiment of the present invention.

Fig. 6 is a top view of fig. 5.

Fig. 7 is a schematic perspective view of a terminal electrode according to another embodiment of the present invention.

Fig. 8 is a top view of fig. 7.

FIG. 9 is a schematic longitudinal cross-sectional view of a prior art gas discharge tube.

Fig. 10 is a schematic cross-sectional view of fig. 9.

Detailed Description

In order to explain technical contents, structural features, and objects and effects of the present invention in detail, the following detailed description is given with reference to the accompanying drawings in conjunction with the embodiments.

Referring to fig. 1 to 4, the present embodiment discloses a gas discharge tube capable of generating a distorted electric field, which includes an insulating tube 1 and terminal electrodes 2 sealed at two ends of the insulating tube 1, wherein a discharge gap 3 is formed in the insulating tube 1 and located between the terminal electrodes 2. The terminal electrode 2 includes an electron emission surface 20 located at one side of the insulating tube 1 and coated with an electron emission coating, the electron emission surface 20 is provided with a groove 200 and a plurality of grooves 201, the groove 200 is located at the center of the electron emission surface 20, and the grooves 201 extend outwards from the groove 200.

Preferably, the insulating tube 1 is a metalized ceramic tube, and a graphite electrode 4 for assisting the trigger of gas ionization is further disposed on the inner wall of the insulating tube 1.

The working principle of the gas discharge tube in the above embodiment is:

referring to fig. 1 to 4 again, the insulating tube 1 is filled with inert gas, and a cylindrical discharge gap 3 is formed between the electron emission surfaces 20 of the two end electrodes 2. When an overvoltage (a lightning voltage or a transient overvoltage of a power distribution system) is applied to the electrodes 2 at both ends, the inert gas is ionized, and the electron emission surfaces 20 of the electrodes 2 at both ends emit electrons, thereby forming a discharge current connected to the ground terminal through the discharge gap 3. At this time, since the charges on the electron emission surface 20 are concentrated near the edges of the grooves 200 and the trenches 201 (see fig. 4), and the charges on the electron emission surface 20 are concentrated from the far end of the grooves 200 to the near end, that is, the charge density at the edges of the grooves 200 and the trenches 201 on the electron emission surface 20 is greater than that in other regions, the charge density at the near end of the grooves 200 is greater than that at the far end of the grooves 200, as shown in fig. 4, the charge density at points a and B is greater than that at point C, and since point a is closer to the grooves 200, the charge density at point a is greater than that at point B, so that the electric field intensity in the discharge gap 3 is in a varied abnormal distribution rather than the conventional uniform electric field, as shown in fig. 1 and 2, the density of the electric field lines E is varied in a non-uniform state with different sizes. Under the action of the electric field force, the ions in the plasma formed by the ionized inert gas move along the direction of the electric field force, the electrons emitted from the electron emission surface 20 move along the opposite direction of the electric field force to form plasma current, at this time, because the electric field is in a deformed distribution, so the electric field force is also in a deformed distribution, and simultaneously, because the movement of electrons and ions has inertia, the current path formed by the plasma is in a drift state, the ions bombard the electron emission surface 20 to obtain electrons and restore to gas molecules, and the electron emission surface 20 emits electrons again in the bombardment, resulting in that the electron emission points on the electron emission surface 20 also drift, thereby preventing partial long-time discharge on the electron emission surface 20, thereby effectively preventing the terminal electrode 2 from melting or the insulating tube body 1 from cracking due to partial long-time discharge and prolonging the service life of the gas discharge tube.

Preferably, as shown in fig. 3 to 8, the plurality of grooves 201 are uniformly spaced around the groove 200, so that the charge intensity variation on the electron emission surface 20 is uniformly distributed, and the damage to the insulating tube 1 caused by the discharge arc approaching the wall of the insulating tube 1 due to the excessive deviation of the electric field is avoided.

Further, as shown in fig. 3 to 6, one end of the groove 201 communicates with the groove 200, and the other end of the groove 201 extends outward from the groove 200. Specifically, in the present embodiment, the trench 201 has a linear structure or a curved structure. When the grooves 201 having a straight line structure are used, as shown in fig. 3 and 4, four grooves 201 are provided, and the four grooves 201 are uniformly spaced around the circumference of the groove 200. When a curved structure is adopted, as shown in fig. 5 and 6, three grooves 201 are provided, the three grooves 201 are uniformly spaced at the periphery of the groove 200, and the curved grooves 201 in the embodiment are in a fan-blade structure.

In addition, as shown in fig. 7 and 8, the groove 201 may also be an annular groove with several rings surrounding the groove 200. In this embodiment, two annular grooves 201 having a common center with the groove 200 are used.

The above disclosure is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the scope of the present invention, therefore, the present invention is not limited by the appended claims.

Claims (9)

1. A gas discharge tube capable of generating a distorted electric field is characterized by comprising an insulating tube body and end electrodes sealed at two ends of the insulating tube body, wherein a discharge gap between the two end electrodes is formed in the insulating tube body; the terminal electrode comprises an electron emission surface which is positioned on one side in the insulating tube body and coated with an electron emission coating; the electron emission surface is provided with a groove and a plurality of grooves, the groove is located at the center of the electron emission surface, and the grooves extend outwards from the groove.

2. A gas discharge tube as claimed in claim 1 in which the insulating tube body is a metallised ceramic tube.

3. A gas discharge tube capable of generating a distorted electric field according to claim 1, wherein the inner wall of the insulating tube body is provided with a graphite electrode for assisting the triggering of the ionization of the gas.

4. The distorted electric field generating gas discharge tube of claim 1, wherein several of the grooves are evenly spaced around the groove.

5. The gas discharge tube capable of generating a distorted electric field according to claim 1, wherein one end of the groove communicates with the recess, and the other end of the groove extends outward from the recess.

6. The gas discharge tube capable of generating distorted electric fields of claim 5, wherein the grooves have a linear or curved configuration.

7. The gas discharge tube capable of generating a distorted electric field according to claim 6, wherein the number of the grooves is three or four.

8. A gas discharge tube as claimed in claim 1 in which the groove comprises a plurality of annular grooves disposed around the recess.

9. The gas discharge tube capable of generating a distorted electric field according to claim 8, wherein the grooves have two.

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