Porcelain bushings and arrester bushings with shielding and voltage balancing functions

Abstract

The utility model belongs to the field of porcelain sleeves for electrical equipment, and specifically relates to a porcelain sleeve with shielding and voltage-equalizing functions and a lightning arrester porcelain sleeve. The porcelain sleeve includes a porcelain part and a shielding cover arranged inside the porcelain part; the shielding cover is arranged on the upper inner wall of the porcelain part; or, the shielding cover is arranged on the lower inner wall of the porcelain part; or, there are two shielding covers; the two shielding covers are respectively arranged on the upper inner wall and the lower inner wall of the porcelain part. The utility model arranges the shielding cover on the porcelain part, installs the shielding cover inside the porcelain part, reduces the installation space, and is simple to install and simple in layout.

Description

Technical Field

[0001] The utility model relates to a porcelain sleeve, in particular to a porcelain sleeve with shielding and voltage-equalizing functions and a lightning arrester porcelain sleeve. Background Art

[0002] The porcelain sleeves used in existing electrical equipment such as lightning arresters and mutual inductors will cover a part of the electrical connection parts in the porcelain sleeve during the assembly process due to the downward extension of the porcelain sleeve flange, which will play an electric field shielding role for these parts, preventing these parts from having sharp burr discharges, causing the partial discharge of the product to exceed the standard. However, due to factors such as the obstruction of the umbrella skirt of the porcelain part on the porcelain sleeve, the downward extension of the flange is limited, which is prone to incomplete shielding, that is, the electrical connection parts outside the flange still have sharp discharges, causing the partial discharge of the product to exceed the standard. For lightning arrester products, affected by stray capacitance, the higher the height of the product, the more uneven the voltage distribution of the internal resistor components in the vertical direction. The resistor located at the top of the product bears the largest voltage and ages quickly, posing a safety hazard to the operation of the entire lightning arrester.

[0003] Due to the limited internal space of the porcelain sleeve, it is difficult to set up an independent shielding device inside the porcelain sleeve. In order to shield the excessive local discharge caused by the discharge of the tip of the electrical connection parts and improve the potential distribution in the vertical direction of the equipment, in the prior art, voltage balancing and shielding elements are generally set outside the porcelain sleeve to achieve the purpose of shielding the electric field and improving the potential distribution. However, this method will increase the installation space of the product, and the installation is complicated and the layout is messy. Utility Model Content

[0004] The utility model aims to solve the technical problems that the existing porcelain sleeves have external voltage balancing and shielding elements, which increase the installation space, and are complex to install and have messy layout, and to provide a porcelain sleeve and a lightning arrester porcelain sleeve with shielding and voltage balancing functions.

[0005] In order to achieve the above purpose, the technical solution adopted by the utility model is:

[0006] A porcelain sleeve with shielding and voltage-equalizing function, comprising a porcelain part;

[0007] Its special features are:

[0008] Also included is a shielding cover disposed inside the porcelain piece;

[0009] The shielding cover is arranged on the inner wall of the upper end of the porcelain piece;

[0010] Alternatively, the shielding cover is arranged on the inner wall of the lower end of the porcelain piece;

[0011] Alternatively, there are two shielding covers; the two shielding covers are respectively arranged on the upper inner wall and the lower inner wall of the porcelain component.

[0012] Furthermore, the inner wall of the porcelain piece is provided with an annular groove extending downward or upward from its end surface for a set length;

[0013] The shielding cover is arranged on the inner wall of the porcelain component and extends into the annular groove.

[0014] Furthermore, the shielding cover is a conductive layer coated on the inner wall of the porcelain part and the surface of the annular groove.

[0015] Furthermore, the shielding cover is a cylindrical conductor; a circular ring matching the annular groove is arranged at one end of the cylindrical conductor; the cylindrical conductor is mounted on the inner wall of the porcelain part, and the circular ring is mounted in the annular groove.

[0016] Furthermore, the cylindrical conductor is a cylindrical metal mesh.

[0017] Furthermore, a mounting groove is arranged on the inner wall of the end surface of the porcelain component, and the bottom of the mounting groove is arc-shaped; the shielding cover is arranged in the mounting groove.

[0018] Furthermore, the shielding cover is a conductive layer coated on the surface of the mounting groove.

[0019] Furthermore, the shielding cover is a cylindrical conductor, and the cylindrical conductor is embedded in the installation groove.

[0020] Furthermore, the cylindrical conductor is a cylindrical metal mesh.

[0021] At the same time, the utility model also provides a lightning arrester porcelain sleeve, which adopts the above-mentioned porcelain sleeve with shielding and voltage-equalizing function, and its special feature is that the axial length h of the shielding cover satisfies the following formula:

[0022] h = a × H;

[0023] Where: a is the adjustment coefficient between 0.1 and 0.3, H is the total height of all resistor groups in the arrester;

[0024] The inner diameter φ of the shielding case satisfies the following formula:

[0025] φ=η×Ur×(h / H)÷m+D;

[0026] In the formula: η is the insulation coordination coefficient of the lightning arrester; Ur is the rated voltage of the lightning arrester, in kV; m is the dielectric strength of the insulating medium in the lightning arrester, in kV / mm; D is the diameter of the resistor used in the lightning arrester, in mm.

[0027] The beneficial effects of the utility model are:

[0028] 1. The utility model arranges the shielding cover inside the porcelain part, thereby reducing the installation space, and the installation is simple and the layout is concise.

[0029] 2. The shielding cover of the utility model adopts the method of coating the conductive layer on the inner wall of the porcelain part, which has a simple manufacturing process, low cost and is easy to mass produce.

[0030] 3. The utility model can avoid the occurrence of tip discharge and improve the shielding effect by setting the annular groove. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a structural schematic diagram of the first embodiment of the utility model;

[0032] Figure 2 It is a structural schematic diagram of the second embodiment of the utility model;

[0033] Figure 3 It is a structural schematic diagram of the third embodiment of the utility model;

[0034] Figure 4 It is a partial structural schematic diagram of an existing lightning arrester porcelain sleeve without a voltage-equalizing shielding cover;

[0035] Figure 5 It is a partial structural schematic diagram of a lightning arrester porcelain sleeve provided with a voltage-equalizing shielding cover in an embodiment of the utility model;

[0036] Figure 6 It is a simulation diagram of the electric field strength of the porcelain sleeve of the existing lightning arrester without a voltage-equalizing shielding cover;

[0037] Figure 7 It is a simulation diagram of the potential distribution of the porcelain sleeve of the existing lightning arrester without a voltage-equalizing shielding cover;

[0038] Figure 8 It is a simulation diagram of the electric field strength of the porcelain sleeve of the lightning arrester provided with a voltage-equalizing shielding cover in the embodiment of the utility model;

[0039] Fig. 9 It is a simulation diagram of the potential distribution of the porcelain sleeve of the lightning arrester provided with a voltage-equalizing shielding cover in the embodiment of the utility model.

[0040] In the figure: 1-ceramic part, 2-shielding cover. DETAILED DESCRIPTION

[0041] In order to make the purpose, advantages and features of the utility model clearer, the following is a further detailed description of a porcelain sleeve with shielding and voltage balancing function and a lightning arrester porcelain sleeve proposed by the utility model in combination with the accompanying drawings and specific embodiments. According to the following specific implementation methods, the advantages and features of the utility model will be clearer.

[0042] Embodiment 1

[0043] See also Figure 1 The present embodiment provides a porcelain sleeve with a shielding and voltage-equalizing function, including a porcelain component 1 and a shielding cover 2 arranged inside the porcelain component 1 .

[0044] The shielding cover 2 is arranged on the inner wall of the upper end of the porcelain part 1. Specifically, an annular groove is arranged after the inner wall of the porcelain part 1 extends downward from its end surface for a set length. In this embodiment, the shielding cover 2 can be a conductive layer coated on the inner wall of the porcelain part 1 and the surface of the annular groove, so that the end of the conductive layer close to the middle of the porcelain part 1 covers the groove surface of the annular groove to achieve the purpose of balancing the electric field and avoiding tip discharge. Of course, the shielding cover 2 can also be a cylindrical conductor; and a circular ring adapted to the annular groove is arranged at one end of the cylindrical conductor, the cylindrical conductor is installed on the inner wall of the porcelain part 1, and the circular ring is installed in the annular groove.

[0045] Preferably, the cylindrical conductor in this embodiment is a cylindrical metal mesh. Of course, in other embodiments of the utility model, it may also be a cylindrical thin-walled structure.

[0046] Embodiment 2

[0047] See also Figure 2 The difference between this embodiment and the first embodiment is that a mounting groove is provided on the inner wall of the end surface of the porcelain part 1, and the bottom of the mounting groove is set to be an arc shape, so as to achieve the purpose of balancing the electric field and avoiding tip discharge. The shielding cover 2 is set in the mounting groove. Specifically, in this embodiment, the shielding cover 2 can be a conductive layer coated on the surface of the mounting groove, or a cylindrical conductor, which is embedded in the mounting groove.

[0048] Embodiment 3

[0049] See also Figure 3 In this embodiment, there are two shielding covers 2, which are respectively arranged on the upper inner wall and the lower inner wall of the porcelain part 1, so as to shield the electric field strength of the electrical connection components arranged at the upper and lower ends of the porcelain part 1. The specific structure of the shielding cover 2 in this embodiment can be set with reference to the first embodiment or the second embodiment.

[0050] Embodiment 4

[0051] In this embodiment, the shielding cover is arranged on the inner wall of the lower end of the porcelain piece, so as to meet the needs of different use environments. The specific structure of the shielding cover 2 in this embodiment can be arranged with reference to the first embodiment or the second embodiment.

[0052] When the porcelain sleeve of this embodiment plays a shielding role, the axial length of the shielding cover 2 is set according to the position of the product's electrical connection components, so that the shielding cover 2 can completely cover the high-voltage electrical connection components in principle.

[0053] When the porcelain sleeve of this embodiment is applied to the arrester as the porcelain sleeve of the arrester and plays the role of equalizing the voltage of the resistor, the shielding cover 2 calculates the effective height h of the portion of the equalizing element covering the resistor according to formula ①, and the effective height h is also the set length in the above-mentioned embodiment 1:

[0054] h=a×H Formula①

[0055] Where: a is the adjustment coefficient between 0.1 and 0.3, and H is the total height of all resistor groups in the lightning arrester.

[0056] The inner diameter φ of the shielding cover 2 is calculated according to formula ②:

[0057] φ=η×Ur×(h / H)÷m+D formula ②

[0058] Where: η is the insulation coordination coefficient of the arrester, not less than 1.0, generally 1.5-2.0;

[0059] Ur is the rated voltage of the entire arrester, in kV;

[0060] h is the effective height of the voltage-equalizing element covering the resistor, in mm;

[0061] H is the total height of all resistor groups in the entire arrester, in mm;

[0062] m is the dielectric strength of the insulating medium in the arrester, in kV / mm;

[0063] D is the diameter of the resistor used in the arrester, in mm.

[0064] According to the first embodiment, two geometric models for lightning arresters are established: Figure 4 , a model without shielding cover 2; see Figure 5 , a model provided with a shielding cover 2, Figure 5 The axial dimension of the middle shield 2 adopts an effective height of 150 mm.

[0065] The corresponding boundary conditions are input into the simulation software, and then the size is divided. After the electrostatic field is calculated, it is found that after adding the shielding cover 2 according to the above calculated size, the electric field strength and the resistor sheet non-uniformity coefficient are significantly improved.

[0066] like Figure 6 , Figure 7 As shown in Table 1, the maximum electric field strength of the arrester without the shielding cover 2 is 2.4 kV, and the potential distribution unevenness coefficient of the arrester without the shielding cover 2 is 1.248.

[0067] Table 1

[0068]

[0069] like Figure 8 , Fig. 9As shown in Table 2, the maximum electric field strength of the arrester with the shielding cover 2 added is 1.69 kV, and the potential distribution unevenness coefficient of the arrester with this structure is only 1.187.

[0070] Table 2

[0071]

[0072] It can be seen from the calculation that the calculation process and results of the above formula are operational and practical.

Claims

1. A porcelain sleeve with shielding and voltage-equalizing function, comprising a porcelain part (1); Features: It also includes a shielding cover (2) arranged inside the porcelain part (1); The shielding cover (2) is arranged on the inner wall of the upper end of the porcelain component (1); Alternatively, the shielding cover (2) is arranged on the inner wall of the lower end of the porcelain component (1); Alternatively, the number of the shielding covers (2) is two; the two shielding covers (2) are respectively arranged on the upper inner wall and the lower inner wall of the porcelain part (1).

2. The porcelain sleeve with shielding and voltage balancing function according to claim 1 is characterized in that: The inner wall of the porcelain piece (1) is provided with an annular groove extending downward or upward from its end surface for a set length; The shielding cover (2) is arranged on the inner wall of the porcelain component (1) and extends into the annular groove.

3. The porcelain sleeve with shielding and voltage balancing function according to claim 2 is characterized in that: The shielding cover (2) is a conductive layer coated on the inner wall of the porcelain part (1) and the surface of the annular groove.

4. The porcelain sleeve with shielding and voltage balancing function according to claim 2 is characterized in that: The shielding cover (2) is a cylindrical conductor; one end of the cylindrical conductor is provided with a circular ring that matches the annular groove; The cylindrical conductor is installed on the inner wall of the porcelain part (1), and the circular ring is installed in the annular groove.

5. The porcelain sleeve with shielding and voltage balancing function according to claim 4 is characterized in that: The cylindrical conductor is a cylindrical metal mesh.

6. The porcelain sleeve with shielding and voltage balancing function according to claim 1 is characterized in that: The inner wall of the end surface of the ceramic component (1) is provided with a mounting groove, and the bottom of the mounting groove is in an arc shape; The shielding cover (2) is arranged in the installation groove.

7. The porcelain sleeve with shielding and voltage balancing function according to claim 6 is characterized in that: The shielding cover (2) is a conductive layer coated on the surface of the installation groove.

8. The porcelain sleeve with shielding and voltage balancing function according to claim 6 is characterized in that: The shielding cover (2) is a cylindrical conductor, and the cylindrical conductor is embedded in the installation groove.

9. The porcelain sleeve with shielding and voltage balancing function according to claim 8 is characterized in that: The cylindrical conductor is a cylindrical metal mesh.

10. A lightning arrester porcelain sleeve, using the porcelain sleeve with shielding and voltage balancing function as claimed in any one of claims 1 to 9, characterized in that: The axial length h of the shielding cover (2) satisfies the following formula: h = a × H; Where: a is the adjustment coefficient between 0.1 and 0.3, H is the total height of all resistor groups in the arrester; The inner diameter φ of the shielding cover (2) satisfies the following formula: φ=η×Ur×(h / H)÷m+D; In the formula: η is the insulation coordination coefficient of the lightning arrester; Ur is the rated voltage of the lightning arrester, in kV; m is the dielectric strength of the insulating medium in the lightning arrester, in kV / mm; D is the diameter of the resistor used in the lightning arrester, in mm.

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