JPH06267754A - Bushing - Google Patents

Abstract

PURPOSE:To improve vibrationproof by arranging a damper whose natural frequency is made coincide with that of a bushing in a lower part of a bushing connection tank and by forming a sub-vibration system in a lower part of the bushing by the damper. CONSTITUTION:A tube stand 8 and a connection tank 9 are arranged below a bushing 3. An upper part of the connection tank 9 is fixed to a frame 10 and a damper 11 is mounted on a lower part of the connection tank 9. The damper 11 is fixed to a lower part of the connection tank 9 by a bolt 13 through a container 12 and a cover 14, and forms a sub-vibration system. A round rod- like deadweight 15 arranged at a center of the container 12, tubular spring fixing stand 16 and spring fixing stand 17, a plurality of springs 18 extended and arranged in a radius direction between both spring fixing stands 16, 17 and viscous fluid 19 are contained inside the container 12. Meanwhile, the natural frequency of the damper 11 is made coincide with that of the bushing 3. Thereby, response of the bushing during earthquake can be reduced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bushing used for ultra high voltage power transmission with improved seismic resistance.

[0002]

2. Description of the Related Art In recent years, the demand for electric power in the Tokyo metropolitan area has continued to increase, and in the summer when air conditioning is heavily used, the amount of power used approaches the full power generation capacity of electric power companies, and there is a danger of stable power supply. As is well known.

In order to deal with such a problem, load leveling on the demand side, promotion of energy saving, and electric power companies are studying securing a supply amount by adding a power plant. However, this power transportation requires a long power transmission system from a remote power plant to the center of the city, and there is no problem if a power transmission line is secured each time a power plant is added. Is extremely difficult.

Then, the practical means adopted next is
It is an increase in the transmission voltage. Of course, it can be said that the most rational solution is not only the remodeling of the equipment for the power transmission route, but also the high-density power transportation using the existing land. In order to transport such electric power, it is common practice to raise the voltage sent from the power plant once and reduce it near the place of demand. This voltage is currently up to 550 KV in Japan, but if the transmission voltage is further increased for the reasons mentioned above 11
00KV (UHV, Ultra High Voltage) is a candidate.

Therefore, at least six UHV bushings per line are installed at the substations installed at both ends of the power transmission line. Considering the creepage distance in the air, this bushing is estimated to be 12 m in the air porcelain tube section. If the bushing is long in this way, it will be disadvantageous in terms of seismic strength, and some seismic strength improvement measures will be required.

[0006]

Conventionally, in order to protect substation equipment from disasters caused by vibrations such as earthquakes, a method of isolating the entire equipment (Fujita et al., 2 persons, vibration isolation of heavy equipment using laminated rubber) Support, Proceedings of the Japan Society of Mechanical Engineers, 50-454, C (Sho 59-
6) may be used. An example of a transformer, which is a transformer device, will be described with reference to FIG.

As shown in FIG. 8, a transformer 1 is provided with a bushing 3 and an expansion chamber 4 via a bushing pocket 2, and a terminal 7 is attached to the upper portion of the expansion chamber 4. Further, a seismic isolation device 5 such as laminated rubber is provided between the entire transformer 1 and the foundation 6 to protect the device from vibration during an earthquake.

However, in the transformer provided with such a seismic isolation device, the natural frequency of the system including the transformer and the seismic isolation device is suppressed to about 0.5 Hz in order to reduce the response acceleration of the device. Therefore, the response speed of the equipment during an earthquake is reduced, but the relative displacement with the foundation is increased. Therefore, in order to prevent collisions and tensions at the connection with the peripheral device, it is necessary to have a structure that allows a large displacement at the connection.

As described above, according to the conventional method of isolating the entire transformer, the relative displacement between the device body and the peripheral device becomes large at the time of an earthquake, and the connection between the peripheral device and the peripheral device is prevented in order to prevent collision and tension. There was a problem that a structure that allows a large displacement in the part was required. The present invention has been made to solve the above problems, and an object thereof is to provide a bushing having a simple structure and stable seismic resistance.

[0010]

In order to achieve the above object, in the present invention, an elastic body such as a spring and a weight are used, and the natural frequency is made to coincide with the natural frequency of the bushing, so that the damping body Is disposed below the bushing connection tank to form a width vibration system, and this damping body reduces the response of the bushing during an earthquake.

[0011]

According to the present invention, since the vibration of the bushing body can be reduced, the relative displacement between the substation equipment and the peripheral equipment can also be reduced.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. 1 to 3 are block diagrams of an embodiment of the present invention. As shown in these figures, a nozzle 8 and a connection tank 9 are arranged below the bushing 3. Also,
The upper part of the connection tank 9 is fixed to the pedestal 10, and the damping body 11 is attached to the lower part of the connection tank 9. This damping body 11
Is fixed to the lower part of the connection tank 9 by a bolt 13 via a container 12 and a cover 14 to form a width vibration system.

Inside the container 12, a round bar-shaped weight 15 arranged at the center, a cylindrical spring fixing base 16 inserted and attached to the outer circumference of the weight 15, and an inner circumference of the container 12 are provided. A cylindrical spring fixing base 17 inserted and attached to the springs, a plurality of springs 18 stretched along the radial direction between the fixing bases 16 and 17 of both springs, and a viscous fluid 19 are accommodated. 18 is Figure 3
As shown in FIG. On the other hand, the vibration damping body 11 having the above-mentioned configuration has its natural frequency adjusted to the bushing 3
It matches the natural frequency of.

Next, the operation of the embodiment configured as described above will be described. First, the above-described system of the vibration control body and the bushing is modeled by a two-degree-of-freedom system as shown in FIG. However, m is mass, k is spring constant, c is damping constant, x is displacement, y is basic displacement, subscript 1 is bushing, subscript 2 is damping body.

The frequency response characteristic of such a system is shown in FIG. However, the frequency f is made dimensionless by the natural frequency f ₁ of the bushing, and the response acceleration z ₁ (= x ₁ −y) is
It is dimensionless due to the maximum acceleration. In the figure, curve a
Shows the case where there is no damping body, and the curve b shows the response when this damping body is attached. As is clear from the figure, by installing the damping body having the above-mentioned configuration under the bushing connecting tank, the maximum response acceleration of the bushing head can be reduced to about 60% of that without the damping body. it can.

Therefore, the relative displacement with the peripheral device can be reduced as compared with the conventional case where the entire device is isolated. The present invention is not limited to the above embodiment. For example, as shown in FIG. 6, the same effect can be expected by disposing the damping body 20 composed of the laminated rubber 21 and the weight 22 in the lower part of the bushing connection tank.

Further, as shown in FIG. 7, a damping body 24 in which a movable member 27 and a viscous fluid 28 are enclosed in containers 25 and 26 having spherical inner walls, and a damping body 20 is arranged below a bushing connection tank. However, the same effect can be expected.

[0018]

As described above, according to the present invention, the damping body, which is composed of the elastic body such as the spring and the weight, and the natural frequency of which is matched with the natural frequency of the bushing, is provided at the bottom of the bushing connection tank. Since the sub-vibration system is formed in the lower part of the bushing by this damper, it is possible to reduce the response of the bushing at the time of an earthquake, and to provide a bushing with a simple structure and stable vibration resistance. it can.

[Brief description of drawings]

FIG. 1 is a front view showing an embodiment of the present invention.

FIG. 2 is a sectional view of an essential part of the present invention.

FIG. 3 is a cross-sectional view of a main part of the present invention.

FIG. 4 is an explanatory diagram showing characteristics of the present invention.

FIG. 5 is an explanatory diagram showing characteristics of the present invention.

FIG. 6 is a front view showing another embodiment of the present invention.

FIG. 7 is a front view showing another embodiment of the present invention.

FIG. 8 is a front view showing a conventional seismic isolation device.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Transformer main body, 2 ... Bushing pocket, 3 ... Bushing, 4 ... Expansion chamber, 5 ... Seismic isolation device, 6 ... Foundation, 7 ... Terminal, 8 ... Pipe stand, 9 ... Bushing connection tank, 10 ... Stand,
11 ... Damper, 12 ... Container, 13 ... Bolt, 14 ... Cover, 15 ...
Weight, 16, 17 ... Spring fixing base, 18 ... Spring, 19 ... Viscous fluid, 20 ... Damper, 21 ... Laminated rubber, 22 ... Weight, 23 ... Bolt, 24 ... Damper, 25, 26 ... Container, 27 ... Movable member, 28 ... Viscous fluid, 29 ... Bolt.

Claims (1)

[Claims] 1. A damping body comprising an elastic body such as a spring and a weight, the natural frequency of which is matched with the natural frequency of the bushing, is disposed below the bushing connecting tank, and the damping body is used by this damping body. Bushing characterized by forming a width vibration system in the lower part.