CN201270174Y - Combined insulator - Google Patents

Abstract

The utility model discloses a composite insulator, which comprises a mandrel and a plurality of large umbrellas with the same diameter outside the mandrel. The umbrella diameter of the large umbrella, the three umbrellas are respectively the middle umbrella, the second middle umbrella and the small umbrella. Compared with the traditional composite insulator, this product basically does not increase the production cost, does not increase the installation cost, reduces the maintenance cost, and improves the anti-ice flash ability of the composite insulator. The utility model enhances the anti-ice flash ability of the composite insulator, and is especially suitable for transmission lines with a rated voltage above 110kV in heavy ice areas.

Description

composite insulator

technical field

The utility model relates to the field of high-voltage insulators, in particular to a suspension rod-type composite insulator for transmission lines above 110kV.

Background technique

Snow and ice is a common natural phenomenon. For transmission lines, ice and snow will cause serious accidents. my country is one of the countries with the most severe icing on transmission lines in the world. The icing of transmission lines is very serious. Over the years, transmission lines have caused many accidents. The main ones are the flashover of insulator strings caused by icing, the collapse of towers and the breakage and damage of conductors caused by icing overload. In addition to possible mechanical failures after the insulator is covered with ice, the leakage distance is shortened after the insulator is covered with ice or bridged, and when the ice is melted, the surface resistance of the ice-coated insulator is significantly reduced, resulting in a flashover accident, and during the development of the flashover Continuous arcing may also burn the insulator, causing damage to the insulator and a reduction in electrical strength.

The anti-pollution flashover capability of composite insulators is higher than that of porcelain and glass insulators, and under the same icing conditions, the flashover (withstand) voltage of composite insulators is much lower than that of porcelain and glass insulators of the same voltage level. The main reason for this problem is that when the composite insulator is covered with ice, due to the small distance between the umbrellas and the small diameter of the umbrella, the ice edge can easily bridge some of the sheds, shortening the creepage distance, and making most of the voltage from the composite insulator. The air gap between the ice edge and the umbrella group near the high-voltage end of the insulator is responsible, and the field strength of these air gaps increases rapidly. In the electric field simulation of composite insulators and traditional porcelain insulator strings by CIGELE and Chongqing University in Canada, it is found that at the same coverage Under ice conditions, the maximum field strength along the surface of composite insulators is about 5kV/cm higher on average than that of porcelain insulator strings, and the maximum is about 10kV/cm higher. Such a high field strength causes local arcs to occur along the air gap, and the conductivity of the water film produced by melting ice on the ice surface is as high as 100-1000 μS/cm, making it easy for local arcs to penetrate the insulator and form a flashover. At present, the sharp decline in the electrical performance of composite insulators under ice-covered conditions has attracted extensive attention from researchers at home and abroad.

However, the commonly used composite insulators with 2-umbrella and 3-umbrella structures cannot completely and effectively solve the flashover problem of composite insulators caused by ice coating.

Utility model content

The purpose of the utility model is to provide a composite insulator which can prevent flashover caused by ice coating.

The technical scheme of the utility model is:

A composite insulator, comprising a mandrel and several large umbrellas with the same diameter outside the mandrel, three umbrellas are arranged between two adjacent large umbrellas, the umbrella diameters of the three umbrellas are all smaller than the umbrella diameter of the large umbrella, the three umbrellas The three umbrellas are respectively a middle umbrella, a second middle umbrella and a small umbrella. The umbrella diameter of the middle umbrella is greater than the umbrella diameters of the second middle umbrella and the small umbrella, and the middle umbrella is arranged next to the big umbrella.

The diameter of the large umbrella ranges from 225mm to 245mm.

The umbrella diameter range of the middle umbrella is between 145mm and 190mm.

The diameter range of the secondary umbrella and the small umbrella is between 90mm and 110mm.

The umbrella spacing between the two adjacent large umbrellas is ≤140mm.

The ratio of umbrella spacing to umbrella extension is ≥1.

The diameter of the small umbrella is smaller than that of the secondary umbrella, and the medium umbrella, the secondary umbrella and the small umbrella are arranged in sequence from top to bottom.

The diameter of the small umbrella is smaller than that of the secondary umbrella, and the medium umbrella, the small umbrella and the secondary umbrella are arranged sequentially from top to bottom.

The umbrella diameter of described small umbrella is equal to the umbrella diameter of second middle umbrella, and middle umbrella, second middle umbrella and small umbrella are arranged sequentially from top to bottom.

In the utility model, three umbrellas are added between two adjacent large umbrellas to form the basic shed structure of the composite insulator, which improves the voltage distribution uniformity of the insulator under various icing conditions and ensures the self-cleaning property of the insulator at the same time.

When the utility model is used in the experiment, the air gap distance between the various umbrellas of the ice edge is relatively large, and the field strength on the air gap is reduced, making it difficult to bridge the air gap when the arc develops, and the leakage distance of the insulator along the surface is fully utilized. The results of the electric field calculation also show that the air gap has a great influence on the electric field distribution along the surface of the ice-coated composite insulator. To increase the flashover voltage of the ice-coated composite insulator, the field strength between the air gaps on the ice edges must be reduced. The creepage distance of the insulator is fully utilized, and the flashover path is as far as possible from the surface of the insulator instead of developing along the air gap. Therefore, the results of the test are consistent with the results of the electric field calculation, that is, the arrangement of four umbrellas with more complicated umbrella shapes can effectively increase the flashover voltage of the insulator.

The flashover voltage of the utility model is higher than the flashover voltage of the composite insulator with 2-umbrella structure by more than 40kV at most, and about 35kV on average. This is because the air gap formed by the insulators under the same icing conditions under the 4-shroud structure is larger than that of the 2-shroud and 3-shroud, and the maximum field strength along the surface is also smaller than the maximum field strength under the 2-shroud and 3-shroud, which makes the arc start The voltage is higher than the arcing voltage of 2 umbrella and 3 umbrella composite insulators, thus increasing its flashover voltage. The insulator with 4 shed structures has fully utilized its surface leakage distance. In the final flashover, except for the arc of the second group of sheds near the high-voltage end along the air gap, the other shed arcs all develop along the leakage distance, and the leakage distance is obtained fully applied. At the same time, due to the increase of umbrellas, the development of the arc is not rapid, and it has undergone many projects from the purple arc to the white arc and then to the purple arc. .

Compared with the traditional composite insulator, this product basically does not increase the production cost, does not increase the installation cost, reduces the maintenance cost, and improves the anti-ice flash ability of the composite insulator. The utility model enhances the anti-ice flash ability of the composite insulator, and is especially suitable for transmission lines with a rated voltage above 110kV in heavy ice areas.

Description of drawings

Fig. 1 is the structural representation of the utility model embodiment one;

Fig. 2 is the structural representation of embodiment two;

Fig. 3 is a schematic structural diagram of the third embodiment.

Detailed ways

Embodiment one

As shown in Figure 1, the umbrella structure of the present utility model comprises mandrel 5 and the large umbrella 1 of some equal diameters outside mandrel 5, is provided with three umbrellas between adjacent two big umbrellas 1, three umbrellas The umbrella diameters are all smaller than the umbrella diameter of the large umbrella 1, and the three umbrellas are respectively the middle umbrella 2, the second middle umbrella 3 and the small umbrella 4, and the umbrella diameter of the middle umbrella 2 is larger than the umbrella diameters of the second middle umbrella 3 and the small umbrella 4 , the middle umbrella 2 is arranged next to the big umbrella 1 below.

The umbrella diameter range of the large umbrella 1 is between 225mm and 245mm.

The umbrella diameter range of the middle umbrella 2 is between 145mm and 190mm.

Secondary umbrella 3 and small umbrella 4 umbrella diameter range between 90 ~ 110mm.

The umbrella spacing between two adjacent large umbrellas 1 is ≤140mm,

The ratio of umbrella spacing to umbrella extension ≥ 1,

The umbrella diameter of the small umbrella 4 is less than the umbrella diameter of the secondary umbrella 3, and the secondary umbrella 2, the secondary umbrella 3 and the small umbrella 4 are arranged sequentially from top to bottom.

Embodiment two

The difference from Embodiment 1 is that the diameter of the small umbrella 4 is smaller than that of the second-middle umbrella 3, and the middle umbrella 2, the small umbrella 4 and the second-middle umbrella 3 are arranged sequentially from top to bottom.

Embodiment three

The difference from Embodiment 1 is that the diameter of the small umbrella 4 is equal to that of the secondary umbrella 3, and the middle umbrella 2, the secondary umbrella 3 and the small umbrella 4 are arranged in sequence from top to bottom.

Claims (9)

1. A composite insulator, comprising a mandrel and several large umbrellas with the same diameter outside the mandrel, characterized in that three umbrellas are arranged between two adjacent large umbrellas, and the umbrella diameters of the three umbrellas are all smaller than that of the large umbrellas. Umbrella diameter, the three umbrellas are the middle umbrella, the second middle umbrella and the small umbrella respectively, the umbrella diameter of the middle umbrella is larger than the umbrella diameter of the second middle umbrella and the small umbrella, and the middle umbrella is arranged next to the large umbrella. 2. The composite insulator according to claim 1, characterized in that: the diameter of the large umbrella ranges from 225 mm to 245 mm. 3. The composite insulator according to claim 1, characterized in that the diameter of the middle umbrella is between 145 mm and 190 mm. 4. The composite insulator according to claim 1, characterized in that: the diameter of the secondary umbrella and the small umbrella is between 90mm and 110mm. 5. The composite insulator according to claim 1, characterized in that: the spacing between the two adjacent large umbrellas is ≤140mm. 6. The composite insulator according to claim 1, characterized in that the ratio of the spacing between the umbrellas and the protrusion of the umbrellas is ≥1. 7. The composite insulator according to any one of claims 1-6, characterized in that: the umbrella diameter of the small umbrella is smaller than that of the second middle umbrella, and the middle umbrella, second middle umbrella and small umbrella are arranged in sequence from top to bottom . 8. The composite insulator according to any one of claims 1-6, characterized in that: the umbrella diameter of the small umbrella is smaller than that of the second middle umbrella, and the middle umbrella, the small umbrella and the second middle umbrella are arranged in sequence from top to bottom . 9. The composite insulator according to any one of claims 1-6, characterized in that: the umbrella diameter of the small umbrella is equal to the umbrella diameter of the second middle umbrella, and the middle umbrella, second middle umbrella and small umbrella are arranged in sequence from top to bottom .

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