Transformer lightning protection system and transformer

Abstract

The invention relates to the technical field of power equipment protection, in particular to a transformer lightning protection system and a transformer, a lightning arrester is arranged at an outlet sleeve of the transformer or an electric reactor, and when lightning attack exists and lightning shock waves transmitted along a line exceed the protection level of the lightning arrester, the lightning arrester is arranged at the outlet sleeve of the transformer or the electric reactor. The lightning arrester arranged at the position of the outlet sleeve of the transformer or the electric reactor discharges firstly, lightning current is safely led into the ground, the amplitude of lightning voltage is limited below the lightning impulse level of protected equipment, and therefore the transformer or the electric reactor is effectively protected against lightning damage. As the lightning arrester is arranged at the outlet sleeve of the transformer or the electric reactor, the transformer can be protected to the maximum extent, lightning impacts are prevented from entering the transformer or the electric reactor, the propagation distance of lightning waves in a system can be shortened, attenuation and deformation of the lightning waves in the propagation process are reduced, and the protection effect of the lightning arrester is improved. The problem that an existing transformer lightning arrester cannot comprehensively protect a transformer is solved.

Description

Technical Field

[0001] The invention relates to the technical field of power equipment protection, in particular to a transformer lightning protection system and a transformer. Background Art

[0002] Transformer is a kind of static electrical equipment, which is widely used in industry, agriculture, transportation, urban communities and other fields. The main components of transformer include iron core, winding, oil tank, cooling device, voltage regulator, protective device and outlet bushing. Among them, iron core and winding are the core components of transformer, which constitute the body of transformer. The oil tank is filled with transformer oil, which plays the role of insulation and heat dissipation. The cooling device is used to dissipate the heat generated by the transformer during operation. The voltage regulator is used to adjust the output voltage. The protective device is used to cut off the power supply in time when the transformer fails to protect the equipment and personal safety. In the power system, transformers are used to increase or decrease the voltage to meet the needs of different equipment and transmission lines. At the same time, transformers can also realize functions such as electrical isolation and impedance matching to ensure the safe and stable operation of the power system. Its transformation principle is: when the primary coil of the transformer is connected to the AC power supply, an alternating magnetic flux is generated in the iron core. This alternating magnetic flux passes through the primary coil and the secondary coil at the same time, thereby generating an induced electromotive force in the secondary coil. Since the number of turns of the primary and secondary coils is different, the magnitude of the induced electromotive force is also different, thus realizing the voltage conversion.

[0003] There are many types of transformers. According to their uses, they are classified into power transformers, distribution transformers, special transformers, etc.; according to their structures, they are classified into double-winding transformers, three-winding transformers, multi-winding transformers, autotransformers, etc. According to the cooling method, they are classified into oil-immersed transformers and dry-type transformers. According to the number of power phases, they are classified into single-phase transformers, three-phase transformers, multi-phase transformers, etc. With the continuous improvement of transformer technology, the infrastructure of the power industry in various regions has also developed accordingly. However, for areas with backward power industry, the voltage is unstable and the line is prone to failure. Therefore, lightning arresters need to be arranged at the transformer line end to protect the transformer. Lightning arresters are sometimes also called overvoltage protectors and overvoltage limiters. Lightning arresters are widely used overvoltage limiters. In essence, they are absorbers of overvoltage energy. They run in parallel with the on-load switch. When the applied voltage exceeds a certain amplitude, the lightning arrester acts first, discharging a large amount of energy through itself, limiting the overvoltage, thereby protecting the on-load switch. In the prior art, since the transformer outlet adopts a non-oil-air bushing outlet structure, it is difficult to arrange a lightning arrester at the line end, and it is impossible to arrange a lightning arrester at the transformer outlet.

[0004] For example, the Chinese invention with publication number CN115579778A discloses a UHV substation and layout method for rapid replacement of the standby phase of the main transformer, by setting the incoming lightning arrester on the incoming line frame side of the main transformer and connecting it to the incoming line jumper, so that there is no other equipment blocking the main transformer operating phase and the main transformer standby phase, thereby realizing lightning protection for the transformer. However, this arrangement can only provide lightning protection for the incoming line frame side of the main transformer, and cannot protect the transformer outlet. The outlet is the key part of the transformer connecting to the external power grid. Once it is struck by lightning, it may cause serious consequences such as equipment damage and power outage.

[0005] The Chinese utility model with the authorization publication number CN217847669U discloses a transformer integrated lightning arrester installation structure, which involves the application of an integrated arrangement of a transformer and a lightning arrester. The utility model includes a transformer body, and an upper support plate is fixedly installed on the top of the transformer body. The transformer integrated lightning arrester installation structure is connected to the lightning arrester body and the bushing through an upper slot steel frame installed on the transformer body box cover through a copper busbar, and then a bracket is installed on the upper oil tank of the transformer body. The lightning arrester body is grounded and integrated by leading the copper busbar under the lightning arrester body to the mounting bracket of the lower oil tank, which is convenient for observing and recording data when the main transformer is installed, saving materials and space. Compared with the prior art, the distance between the lightning arrester body and the bushing is shortened and grounding is integrated, which enhances the lightning resistance and aesthetics of the transformer body, is easy to install, saves space, improves the reliability of transformer operation, saves costs, and makes the operating performance of the transformer body more stable. However, this arrangement has complicated line layout, and when the lightning wave invades from the direction other than the lightning arrester installation direction, it is impossible to intercept the lightning wave in that direction, so it is impossible to effectively protect the transformer. Summary of the invention

[0006] In view of the problem that the transformer lightning protection device in the prior art cannot provide comprehensive protection for the transformer, the present invention provides a transformer lightning protection system and a transformer.

[0007] In order to achieve the above object, the present invention adopts the following technical solutions: The invention provides a transformer lightning protection system, comprising a lightning arrester, wherein the lightning arrester is connected to a transformer or reactor outlet bushing and a cable plug-in connector in sequence.

[0008] Optionally, a first transition bushing is provided between the arrester and the transformer or reactor outlet bushing.

[0009] Optionally, a voltage-equalizing ball is arranged between the first transition bushing and the transformer or reactor outlet bushing.

[0010] Optionally, a second transition sleeve is provided between the first transition sleeve and the arrester.

[0011] Optionally, a closed chamber is provided on the outside of the second transition sleeve.

[0012] Optionally, the sealed chamber is filled with SF6 gas.

[0013] Optionally, a raised seat is provided outside the transformer or reactor outlet bushing and the cable plug.

[0014] Optionally, the interior of the riser is filled with oil or SF6 gas.

[0015] Optionally, a valve is provided at the bottom of the raised seat.

[0016] The present invention also provides a transformer, comprising the above-mentioned transformer lightning protection system.

[0017] Compared with the prior art, the present invention has the following beneficial effects: The present invention provides a transformer lightning protection system, including a lightning arrester, which is connected to a transformer or reactor outlet bushing and a cable plug in sequence. When there is a lightning attack, when the lightning shock wave transmitted along the line exceeds the protection level of the lightning arrester, the lightning arrester arranged at the transformer or reactor outlet bushing will discharge first, and safely introduce the lightning current into the earth, so that the lightning voltage amplitude is limited to below the lightning shock level of the protected equipment, thereby effectively protecting the transformer or reactor from lightning damage. Since the lightning arrester is arranged at the transformer or reactor outlet bushing, it can achieve maximum protection of the transformer, prevent lightning from shocking the inside of the transformer or reactor, and shorten the propagation distance of the lightning wave in the system, reduce the attenuation and deformation of the lightning wave during the propagation process, thereby improving the protection effect of the lightning arrester. In addition, this transformer lightning protection system has a simple structure, low maintenance cost, and better stability and reliability of the system.

[0018] A first transition bushing is arranged between the arrester and the transformer or reactor outlet bushing. The first transition bushing serves as a connecting bridge between the arrester and the transformer or reactor outlet bushing, which can not only increase the electrical insulation between the arrester and the transformer or reactor outlet bushing, but also effectively prevent equipment damage and failure caused by electrical breakdown. In addition, the first transition bushing can absorb and disperse part of the lightning energy, reduce the burden on the arrester, thereby extending the service life of the arrester and improving the lightning protection performance of the entire system.

[0019] A voltage-equalizing ball is arranged between the first transition bushing and the transformer or reactor outlet bushing. The arrangement of the voltage-equalizing ball can disperse the electric field, stabilize the electric field distribution inside the transformer or reactor, reduce the concentration of the electric field, and avoid the generation of local discharge and arc caused by electric field concentration in a high-voltage environment, thereby reducing the risk of local discharge and arc. In addition, the arrangement of the voltage-equalizing ball can balance the capacitive current to the ground through its inductance effect, so that the distribution of lightning overvoltage is relatively uniform, thereby making full use of the full length of the insulator to withstand the impact of lightning. This helps to reduce the damage to equipment caused by lightning and protect the equipment from lightning damage.

[0020] A second transition sleeve is provided between the first transition sleeve and the arrester. By providing the second transition sleeve, the lightning resistance level of the arrester can be further improved. The second transition sleeve can absorb and disperse part of the lightning energy, reduce the burden of the arrester, and thus extend the service life of the arrester. At the same time, it can also optimize the electric field distribution and reduce the impact and damage of lightning on the equipment. The provision of the second transition sleeve allows the arrester to maintain a certain distance from the first transition sleeve, which is convenient for the installation and maintenance of the equipment. At the same time, the second transition sleeve can also serve as a bridge connecting the two to ensure the reliability and stability of the electrical connection. This design not only improves the flexibility and adaptability of the equipment, but also provides convenience for the upgrading and transformation of the power system.

[0021] A closed chamber is arranged on the outside of the second transition bushing. The setting of the closed chamber provides an additional electrical insulation layer for the second transition bushing, which helps to reduce the risk of electrical breakdown, ensure the stable operation of the power system, provide a good electromagnetic shielding layer, reduce the interference of external electromagnetic fields on the second transition bushing and its internal electrical components, and ensure the stability of electrical performance.

[0022] The interior of the sealed chamber is filled with SF6 gas, which also has good arc extinguishing performance. During the arc discharge process, SF6 gas can quickly absorb free electrons in the arc to form negative ions, which combine with positive ions in the arc to rapidly reduce the charged ions in the arc, thereby increasing the breakdown voltage of the arc and extinguishing the arc quickly. Due to the excellent insulation and arc extinguishing performance of SF6 gas, the sealed chamber filled with SF6 gas can significantly improve the lightning resistance level of electrical equipment. In thunderstorm weather, the SF6 gas in the sealed chamber can quickly disperse and absorb the impact energy of lightning, reduce the burden on lightning arresters and electrical equipment, and thus reduce the risk of equipment damage. It plays an important role in protecting electrical equipment from arc damage and extending the service life of equipment.

[0023] The transformer or reactor outlet bushing and the cable plug-in head are provided with an elevation seat on the outside. The setting of the elevation seat not only provides necessary support and fixation for the transformer or reactor outlet bushing and the cable plug-in head, but also provides an additional electrical insulation layer for the outlet bushing and the cable plug-in head. Under high voltage environment, these components are easily affected by the electric field, and the design of the elevation seat can reduce the interference of the electric field on these components and reduce the risk of electrical breakdown. The elevation seat can also prevent external dust, moisture and other harmful factors from damaging the equipment, thereby improving the reliability and service life of the equipment.

[0024] The interior of the lifting seat is filled with oil or SF6 gas. The oil has good thermal conductivity and can effectively transfer the heat inside the equipment to the outside, thereby maintaining the temperature of the equipment stable. It is of great significance to prevent the equipment from overheating and prolong the service life. SF6 gas has extremely high insulation strength, and its insulation performance is better than oil and air. Filling the interior of the lifting seat with SF6 gas can further improve the insulation level of electrical equipment and ensure the stable operation of the equipment under high-voltage environments. For high-voltage, large-capacity equipment or application scenarios that require high insulation performance, it is more suitable to fill with SF6 gas; for application scenarios with high heat dissipation requirements or that require buffering and shock absorption, it is more suitable to fill with oil.

[0025] A valve is provided at the bottom of the lifting seat. The setting of the valve facilitates the discharge and sampling analysis of the filling inside the lifting seat, so as to take corresponding maintenance measures in time.

[0026] A transformer includes the above-mentioned transformer lightning protection system. The transformer has better lightning protection performance, stable operation of the power system, equipment safety and durability, can adapt to different working environments and conditions, provides strong guarantee for the safe operation and reliable power supply of the power system, has low maintenance cost and long service life. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 A schematic diagram of a transformer lightning protection system provided in Example 1 of the present invention.

[0028] Figure 2 A schematic diagram of a transformer lightning protection system provided in Example 2 of the present invention.

[0029] Among them, 1-the first transition bushing, 2-the lightning arrester, 3-the transformer or reactor outlet bushing, 4-the cable plug, 5-the pressure equalizing ball, 6-the closed chamber, 7-the rising seat, 8-the valve, 9-the first gas density detector, 10-the second gas density detector, 11-the first installation hand hole, 12-the second installation hand hole, and 13-the second transition bushing. DETAILED DESCRIPTION

[0030] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0031] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0032] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0033] In the description of the embodiments of the present invention, it should be noted that if the terms "upper", "lower", "horizontal", "inner", etc. indicate an orientation or positional relationship based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship in which the product of the invention is usually placed when in use, it is only for the convenience of describing the present invention and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. In addition, the terms "first", "second", etc. are only used to distinguish the description, and cannot be understood as indicating or implying relative importance.

[0034] In addition, if the term "horizontal" appears, it does not mean that the component must be absolutely horizontal, but can be slightly tilted. For example, "horizontal" only means that its direction is more horizontal than "vertical", which does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0035] In the description of the embodiments of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "set", "install", "connect", and "connect" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal connection of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0036] The present invention is further described in detail below in conjunction with specific embodiments, which are intended to explain the present invention rather than to limit it.

[0037] Example 1 See also Figure 1 The present invention provides a transformer lightning protection system, including a lightning arrester 2, which is connected to a transformer or reactor outlet bushing 3 and a cable plug-in head 4 in sequence. Optionally, the lightning arrester 2 is connected to the transformer or reactor outlet bushing 3 and the cable plug-in head 4 through a conductor; the lightning arrester 2 is provided with a first installation hand hole 11 and a first gas density detector 9, and the lightning arrester 2 is filled with SF6 gas; the transformer or reactor outlet bushing 3 and the cable plug-in head 4 are provided with an elevated seat 7 outside, the elevated seat 7 is a T-shaped elevated seat, and is filled with SF6 gas inside, and a valve 8 is provided at the bottom of the elevated seat 7 for discharging or sampling and analyzing the SF6 gas.

[0038] When there is a lightning attack, when the lightning shock wave transmitted along the line exceeds the protection level of the arrester 2, the arrester 2 set at the outlet bushing 3 of the transformer or reactor will discharge first, safely introduce the lightning current into the earth, and limit the lightning voltage amplitude to below the lightning shock level of the protected equipment, thereby effectively protecting the transformer or reactor from lightning damage. Since the arrester 2 is set at the outlet bushing 3 of the transformer or reactor, it can achieve maximum protection of the transformer, prevent lightning from striking the inside of the transformer or reactor, and shorten the propagation distance of the lightning wave in the system, reduce the attenuation and deformation of the lightning wave during the propagation process, thereby improving the protection effect of the arrester. The riser 7 filled with SF6 gas inside provides necessary support and fixation for the outlet bushing 3 of the transformer or reactor and the cable plug 4. Since SF6 gas has excellent insulation properties and good arc extinguishing ability, during the arc discharge process, SF6 gas can quickly absorb free electrons in the arc to form negative ions, thereby inhibiting the expansion and maintenance of the arc. This enables the SF6 gas-filled riser to quickly extinguish the arc and prevent equipment damage when a short circuit or fault occurs in the equipment.

[0039] Example 2 See also Figure 2 The present invention provides a lightning arrester system, comprising a lightning arrester 2, a first transition bushing 1 and a second transition bushing 13; the lightning arrester 2 is connected in sequence to the second transition bushing 13, the first transition bushing 1, the transformer or reactor outlet bushing 3 and the cable plug head 4; optionally, the lightning arrester 2 is connected in sequence to the second transition bushing 13, the first transition bushing 1, the transformer or reactor outlet bushing 3 and the cable plug head 4 through a conductor; the transformer or reactor outlet bushing 3 and the cable plug head 4 are provided with an elevated seat 7 on the outside, the elevated seat 7 is a T-shaped elevated seat, the inside of which is filled with oil, and a valve 8 is provided at the bottom of the elevated seat 7 for discharging or sampling the oil for analysis.

[0040] The arrester 2 is provided with a first mounting hand hole 11 and a first gas density detector 9. The interior of the arrester 2 is filled with SF6 gas. The first gas density detector 9 is used to detect the gas density of the SF6 gas inside the arrester 2. The first transition sleeve 1 is arranged inside the elevation seat 7, and a voltage grading ball 5 is arranged between the first transition sleeve 1 and the transformer or reactor outlet sleeve 3, which is used to stabilize the electric field distribution inside the transformer or reactor, reduce the concentration of the electric field, and reduce the risk of partial discharge and arc; The second transition sleeve 13 is connected to the first transition sleeve 1 through a flange. A closed chamber 6 is arranged outside the second transition sleeve 13. The closed chamber 6 is a steel structure barrel. A second installation hand hole 12 is opened on the closed chamber 6 to facilitate the installation of the second transition sleeve 13 in the closed chamber 6. A second gas density detector 10 is installed on the closed chamber 6. The closed chamber 6 is filled with SF6 gas. The second gas density detector 10 is used to detect the SF6 gas density inside the closed chamber 6. The end of the closed chamber 6 is connected to the lightning arrester 2 through a flange.

[0041] A transformer includes the above-mentioned transformer lightning protection system. The transformer has better lightning protection performance, stable operation of the power system, equipment safety and durability, can adapt to different working environments and conditions, provides strong guarantee for the safe operation and reliable power supply of the power system, has low maintenance cost and long service life.

[0042] In summary, the present invention provides a transformer lightning protection system and a transformer. By setting the lightning arrester at the transformer or reactor outlet bushing 3, when there is a lightning attack, when the lightning shock wave transmitted along the line exceeds the protection level of the lightning arrester, the lightning arrester 2 set at the transformer or reactor outlet bushing 3 will discharge first, and safely introduce the lightning current into the earth, so that the lightning voltage amplitude is limited to below the lightning shock level of the protected equipment, thereby effectively protecting the transformer or reactor from lightning damage. Since the lightning arrester is set at the transformer or reactor outlet bushing, it can achieve maximum protection of the transformer, prevent lightning from shocking the inside of the transformer or reactor, and shorten the propagation distance of the lightning wave in the system, reduce the attenuation and deformation of the lightning wave during the propagation process, thereby improving the protection effect of the lightning arrester.

[0043] The above description is only a preferred embodiment of the present invention and is not intended to impose any limitation on the technical solution of the present invention. Those skilled in the art should understand that, without departing from the spirit and principles of the present invention, the technical solution can also be subjected to several simple modifications and substitutions, and these modifications and substitutions are also within the scope of protection covered by the claims.

Claims

1. A transformer lightning protection system, characterized in that: The utility model comprises a lightning arrester, which is connected to a transformer or reactor outlet bushing and a cable plug-in connector in sequence.

2. The transformer lightning protection system according to claim 1, characterized in that: A first transition bushing is arranged between the arrester and the transformer or reactor outlet bushing.

3. The transformer lightning protection system according to claim 2, characterized in that: A voltage grading ball is arranged between the first transition bushing and the transformer or reactor outlet bushing.

4. The transformer lightning protection system according to claim 2, characterized in that: A second transition sleeve is arranged between the first transition sleeve and the arrester.

5. The transformer lightning protection system according to claim 4, characterized in that: A sealed chamber is arranged outside the second transition sleeve.

6. The transformer lightning protection system according to claim 5, characterized in that: The sealed chamber is filled with SF6 gas.

7. The transformer lightning protection system according to any one of claims 1 to 6, characterized in that: The transformer or reactor outlet bushing and the cable plug-in connector are provided with a raised seat outside.

8. The transformer lightning protection system according to claim 7, characterized in that: The interior of the raising seat is filled with oil or SF6 gas.

9. The transformer lightning protection system according to claim 8, characterized in that: A valve is arranged at the bottom of the lifting seat.

10. A transformer, characterized in that: The invention comprises a transformer lightning protection system as described in any one of claims 1 to 9.

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