Surge arrester with pressure relief device

Abstract

The application discloses a lightning arrester with a pressure relief device. The lightning arrester comprises an insulating outer cover, a zinc oxide resistor, an upper terminal electrode and a lower terminal electrode, the upper terminal electrode is connected with a power grid cable, and the lower terminal electrode is connected with a grounding wire. An annular chamber is arranged in a lower end cover of the insulating outer cover, the chamber is provided with elastic filler and a plastic clamp with an opening and an inclined surface, and the lower end cover is provided with a pressure relief ring opening which is directly connected with the outside. In normal times, the plastic clamp is kept above the pressure relief ring opening by the elastic filler to be closed; when pressure relief is needed, high-pressure gas makes the plastic clamp compress the elastic filler and be opened by the inclined surface, and the gas is discharged from the pressure relief ring opening. The design effectively avoids high-speed fragments, reduces safety hazards, guarantees the safety of personnel and equipment, and has a reasonable and compact structure without affecting the overall performance of the lightning arrester.

Description

Technical Field

[0001] The present invention relates to the field of lightning arresters, in particular to a lightning arrester with a pressure relief device. Background Art

[0002] A lightning arrester, also known as an overvoltage protector or overvoltage limiter, is typically connected between the power grid cable and the ground, usually in parallel with the protected equipment. A lightning arrester effectively protects the equipment by triggering protection if abnormal voltage levels occur. When the equipment is operating at normal operating voltage, the arrester is inactive, acting as a short circuit to the ground. However, if high voltage levels occur and threaten the insulation of the protected equipment, the arrester immediately activates, directing the high-voltage surge current to the ground, thereby limiting the voltage amplitude and protecting the equipment. Once the overvoltage subsides, the arrester quickly returns to its original state, allowing the equipment and lines to function normally.

[0003] The zinc oxide resistors in commonly used zinc oxide arresters have excellent nonlinear volt-ampere characteristics. When the arrester is operating at normal operating voltage, only a small leakage current flows through the resistors, effectively creating an open circuit. However, when an overvoltage occurs, a large current flows through the arrester, but the voltage is limited to a certain range, nearly causing a short circuit.

[0004] The zinc oxide arrester is made up of multiple zinc oxide resistors stacked together, surrounded by an insulating jacket. Terminal electrodes are connected to both ends of the zinc oxide resistors: the upper terminal electrode is connected to the grid conductor, and the lower terminal electrode is connected to the ground wire.

[0005] When the voltage is too high and the zinc oxide resistor is damaged, high-temperature and high-pressure arc gas is generated inside the arrester. In the prior art, a thin wall is provided on the insulating jacket of the arrester to relieve the pressure, allowing the high-pressure gas to break through the thin wall and release the pressure.

[0006] However, the thin wall portion can also reduce the strength of the arrester's insulation jacket at that portion, causing accidental damage. Furthermore, the thin wall portion is generally located on the circumferential sidewall of the arrester, and high-pressure, high-temperature arc gas leaking from the side of the arrester may injure personnel and equipment near the arrester.

[0007] To address this issue, our solution, proposed in patent CN114242359B, incorporates a compressed energy-storage spring outside the zinc oxide resistor in the upper portion of the insulating jacket. A retractable spring and lock bolt are housed within a latch hole in the middle of the inner wall. Normally, the latch bolt is extended, and the energy-storage spring presses a striker against the upper side of the latch bolt. A concentric double-grooved ring with a V-shaped cross section is also located on the inner side of the lower end cap. When high-temperature, high-pressure arc gas is generated within the arrester, the high-pressure gas presses against the latch bolt, triggering the energy-storage spring. This ejects the striker and impacts the inner side of the lower end cap, causing it to break and fall off along the concentric double-grooved ring, forming a pressure relief ring for exhaust. This design, by placing the pressure relief portion within the lower end cap, minimizes the hazards of leaking high-pressure, high-temperature arc gas. Furthermore, the lower end cap does not have a deliberately thinned wall; instead, the high-pressure gas triggers the internal energy-storage spring and striker to pierce the pressure relief ring. Furthermore, the slot can be positioned on the inner wall of the lower end cap, without compromising the external strength of the insulating jacket.

[0008] However, such a solution will still produce high-speed fragments when the arrester is depressurized, which still poses a safety hazard. Summary of the Invention

[0009] In view of the above-mentioned defects of the prior art, the present invention provides a lightning arrester with a pressure relief device, including an insulating jacket, a zinc oxide resistor, an upper terminal electrode and a lower terminal electrode, the upper terminal electrode is connected to the grid cable, the lower terminal electrode is connected to the grounding wire, and an annular chamber is provided in the lower end cover of the insulating jacket, an elastic filler and a plastic clamp are provided in the annular chamber, an opening and a slope are provided on the plastic clamp, and a pressure relief ring directly connected to the outside is provided at the bottom of the lower end cover. Under normal conditions, the plastic clamp is held above the pressure relief ring by the elastic filler, so that the pressure relief ring is closed. When the pressure is relieved, the high-pressure gas generated in the lightning arrester passes through the slope to cause the plastic clamp to compress the elastic filler and expand it into the annular chamber. At this time, the pressure relief ring is opened, and the high-temperature and high-pressure arc gas is discharged from here.

[0010] Furthermore, the elastic filler is made of rubber or foam material.

[0011] Compared to previous patents, this invention effectively avoids the generation of high-speed fragments, significantly reducing safety hazards and ensuring the safety of personnel and equipment near the arrester. Furthermore, through a unique combination of annular chambers, elastic fillers, and plastic clamps, a reliable pressure relief control mechanism is formed. The structural design is rational and compact, requiring minimal additional space, ensuring the overall stability of the arrester.

[0012] The concept, specific structure and technical effects of the present invention will be further described below in conjunction with the accompanying drawings to fully understand the purpose, characteristics and effects of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1is a side sectional view of the arrester of the present invention in a normal working state;

[0014] Figure 2 yes Figure 1 AA section view;

[0015] Figure 3 is a side sectional view of the arrester of the present invention in a pressure relief state;

[0016] Figure 4 yes Figure 3 AA section view;

[0017] Figure 5 It is a three-dimensional diagram of the plastic clamp in the present invention. DETAILED DESCRIPTION

[0018] The following describes several preferred embodiments of the present invention with reference to the accompanying drawings to make its technical content clearer and easier to understand. The present invention can be embodied in many different forms of embodiments, and the scope of protection of the present invention is not limited to the embodiments mentioned herein.

[0019] In the drawings, components with identical structures are denoted by the same reference numerals, and components with similar structures or functions are denoted by similar reference numerals. The size and thickness of each component shown in the drawings are arbitrary and are not limited by the present invention. For clarity, the thickness of components in some places in the drawings is appropriately exaggerated.

[0020] like Figure 1-5 As shown, the lightning arrester with a pressure relief device of the present invention includes an insulating jacket 1, a zinc oxide resistor 2, an upper terminal electrode 3, and a lower terminal electrode 4. Among them, the upper terminal electrode 3 is connected to the grid cable, and the lower terminal electrode 4 is connected to the ground wire. An annular chamber 5 is provided in the lower end cover 9 of the insulating jacket 1. An elastic filler 8 and a plastic clamp 7 are provided in the annular chamber 5. An opening 71 and a slope 72 are provided on the plastic clamp 7. A pressure relief ring 6 that directly passes through the outside is provided at the bottom of the lower end cover 9. Under normal working conditions, the plastic clamp 7 is held above the pressure relief ring 6 by the elastic filler 8, so that the pressure relief ring 6 is closed. When the pressure is relieved, the high-pressure gas generated in the lightning arrester passes through the slope 72 to cause the plastic clamp 7 to compress the elastic filler 8 and open it into the annular chamber 5. At this time, the pressure relief ring 6 is opened, and the high-temperature and high-pressure arc gas is released from here.

[0021] The elastic filler can be made of rubber, foam and other materials.

[0022] Compared to previous patents, this invention effectively avoids the generation of high-speed fragments, significantly reducing safety hazards and ensuring the safety of personnel and equipment near the arrester. Furthermore, through a unique combination of annular chambers, elastic fillers, and plastic clamps, a reliable pressure relief control mechanism is formed. The structural design is rational and compact, requiring minimal additional space, ensuring the overall stability of the arrester.

[0023] The preferred embodiments of the present invention have been described in detail above. It should be understood that numerous modifications and variations based on the concepts of the present invention are possible without inventive effort by those skilled in the art. Therefore, any technical solution that can be derived by one skilled in the art through logical analysis, reasoning, or limited experimentation based on the concepts of the present invention and the prior art should be within the scope of protection defined by the claims.

Claims

1. A lightning arrester with a pressure relief device, characterized in that: The invention comprises an insulating jacket (1), a zinc oxide resistor (2), an upper terminal electrode (3) and a lower terminal electrode (4), wherein the upper terminal electrode (3) is connected to a grid cable, and the lower terminal electrode (4) is connected to a grounding wire. An annular chamber (5) is provided in the lower end cover (9) of the insulating jacket (1), wherein an elastic filler (8) and a plastic clamp (7) are provided in the annular chamber (5), wherein the plastic clamp (7) is provided with an opening (71) and an inclined surface (72), and a pressure relief ring (6) which directly passes through the outside is provided at the bottom of the lower end cover (9). Under normal working conditions, the plastic clamp (7) is held above the pressure relief ring (6) by the elastic filler (8), so that the pressure relief ring (6) is closed. When the pressure is relieved, the high-pressure gas generated in the arrester passes through the inclined surface (72) to cause the plastic clamp (7) to compress the elastic filler (8) and expand it into the annular chamber (5). At this time, the pressure relief ring (6) is opened, and the high-temperature and high-pressure arc gas is discharged from it.

2. The lightning arrester with a pressure relief device according to claim 1, characterized in that: The elastic filler (8) is made of rubber material.

3. The arrester with pressure relief device according to claim 1, characterized in that: The elastic filler (8) is made of foam material.

Images