JPH03155319A - Bus-bar in duct line - Google Patents

Abstract

PURPOSE:To reduce stress generated in a bus-bar container by providing a support member which suppresses the displacement of a long bus-bar to its axial direction, at the curve of the long bus-bar having a bellows joint for absorbing thermal expansion. CONSTITUTION:A bus-bar 12 meeting at right angles with a long bus-bar 11 is connected to the long bus-bar 11 through the medium of a bellows joint 13. Furthermore a support member 30 for suppressing the axial-direction displacement of the long bus-bar 11 is fitted from the opposite side of the long bus-bar 11. Hereupon, the reasons why the support member 20 is fitted from the direction parallel to the axial line of the long bus-bar 11 are not to apply any bending load to the support member 20 and to make it most effective to strengthen its rigidity. By doing this way the spring constant of the long bus-bar against its bending to its axial direction becomes extremely larger compared to the case where no support member 20 is used, and stress generated in the container of the bus-bar 12 can be greatly reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a pipe line aerial bus bar that has been improved so that it can efficiently absorb expansion and contraction due to heat.

(Prior art) Pipeline aerial busbars are made by supporting a current-carrying conductor inside a metal cylindrical container made of aluminum alloy, stainless steel, welded structural steel plate, etc. After that, an insulating gas such as SF6 gas is filled inside the container to ensure insulation of the current-carrying conductor inside the container. In recent years, there has been a tendency for reduced-sized gas-insulated switchgears to be used frequently, and this type of conduit aerial busbar is also used instead of electric cables for connections to transformers or the first steel tower.

FIG. 3 shows an example of a conventionally used pipe aerial busbar. That is, circuit breaker, disconnector, grounding device, CT, P
Gas insulated switchgear 1 consisting of T, lightning arrester, bus bar, etc.
Increasingly, a long pipeline aerial bus 4 is used to connect the transmission line to the bushing 3 of the power tower entrance 2. Such a gas-insulated switchgear 1 is much smaller than an air-insulated substation, and devices that generate noise, such as circuit breakers, must be kept away from the substation fence 5 for noise countermeasures. It is often installed. On the other hand, it is best to install the inlet 2 from the power transmission line near the fence 5 of the substation in order to make effective use of the substation site, so the arrangement as shown in Figure 3 is recommended. It is increasing.

This type of pipeline air bus 4 has the following features compared to the gas insulated switchgear 1.

■Since there is no relationship with equipment, the insulation design can be considered as a simple shape (for example, a coaxial cylinder), and the dimensions can be made extremely small.

■There is no need to consider the equipment in terms of thermal design, so
It is possible to approach the size limit.

⑤Since the pipe air busbar is used between the transformer and the gas-insulated switchgear, and between the bushing of the power transmission line entrance and the gas-insulated switchgear, the amount of current flowing through it is limited. Also, unlike gas-insulated switchgear, which includes main busbars, ties, banks, line circuits, etc., where the rated current value is determined by considering the power flow, the rated current value of the pipe air busbar is determined by the power transmission line or transformer. The current value can be smaller than that of gas-insulated switchgear because it only needs to be matched to the capacity. Therefore, the generatrix diameter can be reduced by that amount.

(Problems to be Solved by the Invention) However, in the conventional pipe air busbar as described above, there were problems to be solved as described below. In other words, since the pipeline aerial busbar is used to connect the gas-insulated switchgear with bushings and transformers located far away, its overall length is often long, which can lead to the problem of thermal expansion and contraction. .

That is, during normal operation, the temperature of the container of the pipe air bus changes due to temperature changes due to energization, changes in ambient temperature, etc., and the container expands and contracts accordingly.

This expansion/contraction amount ΔL is given by ΔL−LXα×Δt where the generatrix length is the linear expansion coefficient α and the temperature change is Δt. Therefore, the longer the generatrix is, the more the amount of expansion and contraction will be.

Such expansion and contraction of the pipe air busbar due to heat is absorbed by the bending and twisting of the busbar 4 itself and the support frame 6 that supports the busbar 4, as shown in FIG.

However, such bending or twisting causes stress in the material that makes up the bus bar container. If the amount of expansion and contraction becomes significantly large, there is a risk that the generated stress will exceed the allowable stress of the material. Therefore, as shown in FIG. 5, a bellows joint 13 is usually provided between the long busbar 11 and the busbar 12 perpendicular thereto, and the expansion and contraction of the long busbar is absorbed by the bellows joint 13, and the busbar and support frame are It is designed to suppress the displacement that occurs.

However, the effectiveness of the bellows joint 13 depends on the rigidity of the pipe air bus including the bellows joint 13, and in some cases, the bellows joint may not be able to exhibit its effectiveness. That is, as shown in FIG. 5(A), when the generatrix 12 perpendicular to the long generatrix 11 is bent in a direction perpendicular to its axis, the spring constant is Kl, and the spring constant of the bellows joint 13 is Kl. 2, the amount g absorbed by the expansion and contraction of the bellows joint 13 out of the thermal expansion and contraction iL of the long generatrix is II −
(2 to 1) / (2 to 1/K)
) given in XL. And the remaining amount of expansion and contraction g
' is (1-=L-1 = (+ to 1/)/(+ to 1/ + 2 to 1/)X
This is given by L, which is the amount of bending of the generatrix 12.

As is clear from the above equation, the amount of expansion and contraction of the bellows joint 13 and the amount of bending of the generatrix 12 change depending on the magnitude relationship of 2 and 1 in the respective spring constants. That is, when K>K2, gα
L, most of the expansion and contraction of the long generatrix 11 is absorbed by the bellows joint 13, and the bellows joint 13 acts effectively, but when Kl < K2, gΣ0.1-:L, and most of the expansion and contraction of the long generatrix 11 is absorbed. All of this acts as a bend to the generatrix 12. In such a situation, not only will the bellows joint 13 not be effective, but the bellows joint 1
3, there is a risk of excessive stress in the container of the bus bar 12.

The present invention was proposed in order to eliminate the above-mentioned drawbacks, and its purpose is to efficiently absorb the thermal expansion and contraction that occurs in the air bus bar of the pipe, and to reduce the stress that occurs in the bus bar container. An object of the present invention is to provide a pipeline aerial busbar with excellent reliability.

[Structure of the Invention (Means for Solving the Problems) The present invention is characterized in that a long busbar extending linearly and a busbar perpendicular to the long f3 line are connected via an expandable bellows joint. In the pipe aerial busbar consisting of, a support member for suppressing displacement of the long busbar in the axial direction is provided on or near the axis of the long busbar at a portion where the long busbar and the busbar intersect perpendicularly,
It is characterized in that it is attached to the long bus bar in a direction along the axis of the long bus bar.

(Function) According to the pipe line p) line of the present invention, a support portion for suppressing displacement of the elongated generatrix in the axial direction is provided at the bent portion of the elongate generatrix having a bellows joint for absorbing thermal expansion and contraction. By providing this, it is possible to strengthen the rigidity of the generatrix container near the curved portion where the rigidity is low, and increase the spring constant against the bending.

(Example) Hereinafter, an example of the present invention will be specifically described based on FIGS. 1 and 2. Note that the same members as those of the conventional type shown in FIG. 5 are given the same reference numerals, and explanations thereof will be omitted.

In this embodiment, as shown in FIG.
1 is connected to a busbar 12 perpendicular thereto via a bellows joint 13, and furthermore, on or near the axis of the long busbar 11 where the long busbar 11 and the busbar 12 are orthogonal to each other,
A support member 20 is attached from the opposite side of the long bus bar 11 to suppress displacement of the long bus bar 11 in the axial direction. The reason why the support member 20 is attached in the direction along the axis of the elongated generatrix is to prevent bending loads from being applied to the support member 20 and to most effectively strengthen its rigidity.

Note that FIG. 2 shows an example in which the pipeline aerial bus shown in FIG. 1 is applied to a substation. That is, the long busbar 24. Bellows joint 25. They are connected by busbars 26°27.

Further, a support member 28 according to the present invention is disposed between the bus bar 26 and the building 21. Note that a support frame 29 is generally disposed below the bus bar 26.

In the pipeline aerial busbar of this embodiment having such a configuration, the busbar 12 orthogonal to the long busbar 11 is connected to the support member 20.
Since the elongate generatrix is supported from the opposite side of the elongated generatrix by The bellows joint 13 becomes effective and the stress generated in the container of the bus bar 12 can be significantly reduced.

Moreover, in the embodiment shown in FIG. 2, the spring constant for bending the long CJ line in the axial direction of the system constituted by the generatrix 26 and the support frame 29! is significantly larger than in the case without the support member 28. Similarly to the embodiment shown in FIG. The stress generated in the container can be reduced. In particular, the building 2 that houses the gas-insulated switchgear serves as the fulcrum of the support member 28.
Since one wall surface is used, there is no need to provide a foundation for attaching the support member, so it is also economically advantageous.

Note that the present invention is not limited to the embodiments described above, and the shape, number, and position of the support members can be set as appropriate. In addition, as long as the supporting member is attached in a direction along the axis of the long bus bar, it can be installed not only from the opposite side of the long bus bar as shown in Figures 1 and 2, but also from the same direction as the long bus bar. It is also possible to form a foundation for attaching the support member on the side and attach the support member from the same side as the elongated bus bar.

[Effects of the Invention] As described above, according to the present invention, displacement in the axial direction of the long generating line is suppressed on or in the vicinity of the axis of the long generating line at the part where the long generating lines intersect perpendicularly. By simply attaching a supporting member to the busbar in the direction along the axis of the long busbar, it is possible to efficiently absorb the thermal expansion and contraction that occurs in the pipe air busbar and reduce the stress generated in the busbar container. , it is possible to provide a pipeline air bus with excellent reliability.

[Brief explanation of the drawing]

Fig. 1 is a side view showing an embodiment of the pipe air bus of the present invention, Fig. 2 is a side view showing an example of applying the pipe air bus of the invention to a substation, and Fig. 3 is a general view. Fig. 4 is a schematic diagram showing the expansion and contraction state of the conventional pipe aerial bus bar, and Fig. 5 is a side view showing the displacement state of the conventional pipe air bus bar. , (A) shows before displacement, and (B) shows after displacement. DESCRIPTION OF SYMBOLS 1...Gas insulated switchgear, 2...Power transmission line entrance, 3...Bushing, 4...Pipeline aerial busbar, 5...
- Fence, 6... Support frame, 11... Long bus bar, 12.
... Bus bar perpendicular to the long bus bar, 13... Bellows joint,
20... Support member, 21... Building, 22... Gas insulated switchgear, 23... Transformer, 24... Long bus bar, 25... Bellows joint, 26.27... Bus line, 28
...Support member, 29...Support frame.

Claims (1)

[Scope of Claims] A conduit aerial bus bar comprising a linearly extending long bus bar and a bus bar perpendicular to the long bus bar connected via an expandable bellows joint, wherein the long bus bar and A support member for suppressing displacement of the elongated generatrix in the axial direction is attached to said generatrix from a direction along the axis of the elongate generatrix on or near the axis of the elongate generatrix at a portion perpendicular to the generatrix. Features: Pipeline aerial busbar.