JPH0750807Y2 - Gas insulated switchgear - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a gas-insulated switchgear.

[Conventional technology]

FIG. 3 shows, for example, Toshiba Revue Vol. 35, No. 9, 779-783.
It is a side view which shows the conventional gas-insulated switchgear shown by the page.

In the figure, reference numeral (1) is a gas insulated conductor, which is connected to a bushing or a transformer. (2) is a disconnector,
(3) is a circuit breaker, (4) is a gas insulated conductor, and any one of A, B, C phase disconnectors (5a) (5b) (5c) and circuit breaker (3)
And connect. The disconnectors (5a) (5b) (5c) are respectively connected to the busbars (6a) (6b) (6c) extending in the front-back direction of the paper surface, and these are installed on the mount (7). (8) is a base of the circuit breaker (3), (9) is a current transformer housing of the container of the circuit breaker (3), (10) is a conductor in the gas insulated conductor (4),
Reference numeral (11) is a container of the gas insulated conductor (4), a part of which is shown in cross section.

In the conventional gas-insulated switchgear configured in this manner, the difference in thermal expansion and contraction due to the temperature difference and materials of the pedestal and each device and the displacement difference due to the vibration of the pedestal at the time of earthquake, etc. Deformation of the container (11) and conductor (10) or deformation of the tank connection (K) of the circuit breaker (3) and the tank connection (L) of the circuit breakers (5a) (5b) (5c), etc. , Is dealt with by elastic deformation within the allowable stress of each part.

[Problems to be solved by the invention]

Since the conventional gas-insulated switchgear is configured as described above, the difference in thermal expansion and contraction increases as the size of each part increases like the ultra-high pressure gas-insulated switchgear, and moreover, the gas-insulated conductor (4) The flexural rigidity of the container (10) becomes extremely large, and accordingly, it becomes difficult to absorb the displacement due to the difference in thermal expansion and contraction or the vibration of the gantry during the earthquake due to the elastic deformation of these members. However, there was a problem that excessive force and stress were generated in the container and its connection.

The present invention has been made to solve the above problems, and an object thereof is to obtain a gas-insulated switchgear that can sufficiently deal with displacement due to thermal expansion and contraction and vibration, and that is also economical. .

[Means for solving problems]

The gas-insulated switchgear according to the present invention is such that a bellows is provided in a vertical direction on a connecting device that connects respective devices arranged in upper and lower layers,
Equipment above the top end of this bellows and equipment below the bottom end of the bellows are connected by a connecting rod, and this connecting rod is made of a material that is approximately equal to the coefficient of thermal expansion of the material of each frame of the upper and lower equipment. The length of the connecting rod is set to be 1 to 1/2 times the difference in height between the racks of the upper and lower equipment.

[Action]

In the gas-insulated switchgear according to the present invention, the difference in height of the pedestal, which changes only with temperature, and the length of the connecting rod are almost equal, so there is no final difference in thermal expansion and contraction between them. Also, since the main body of the gas insulated switchgear is designed so that the temperature rise due to energization is almost the same in each part, the amount of thermal expansion and contraction in these parts is almost the same, so all gas insulated switchgear including the gantry is Deformation stress due to thermal expansion and contraction of the device in the vertical direction is absorbed by the bellows portion and hardly occurs in other portions. However, since the bellows are provided, displacement between the upper and lower layers due to an earthquake or the like can be dealt with without difficulty. Also, between the mount and the connecting rod,
Although the weight of the equipment and the load due to the internal gas pressure are different,
The deformation and stress due to such a load are constant once the operating state is entered, and do not repeatedly change like the deformation and stress due to temperature change. I won't.

〔Example〕

The invention will be described below with reference to a partial side view of a gas-insulated switchgear showing an embodiment thereof.

In FIG. 1, parts not shown in FIG. 1 and those denoted by the same reference numerals as those shown in FIG. 3 are the same as or equivalent to those shown in FIG.

In the figure, reference numeral (12) is a gas-insulated conductor as an upper and lower layer device, that is, a connecting device that connects the disconnector (5a) and the circuit breaker (3), and the gas-insulated conductor (12) as a whole. It has an inverted L shape. Gas-insulated conductor (12)
Is a conductor (10) for electrically connecting the disconnector (5a) and the circuit breaker (3), and a connection container (11) surrounding the conductor (10).
a) to (11c) and two bellows (13a) and (13b) provided in the vertical portion.

The bellows (13a) (13b) are usually made to have the same diameter, and the length and the shape are preferably almost the same. Of course, the number of bellows (13a) (13b) may be one, but it is preferable that two bellows are provided because it is easy. These bellows (13
a) and (13b) are provided on substantially the same axis as each other with the axis direction substantially vertical, and the gas-insulated conductor (12) is provided between them.
A connection container (11a) that is a part of the above is provided for connection, and the connection containers (11b) (11c) are often provided at both ends.

In addition, the uppermost end of the bellows, for example, the device above the upper end of the bellows (13a), that is, the connecting device (11b), and the lowermost end of the bellows (13b) below the lower end of the bellows (13b), that is, the connecting device (11c), mounting brackets such as Flange (14) (1
5) is fixedly installed and this flange (14) (1
5) are connected by connecting rods (16) as shown in FIG. In this example, the mounts (7) and (8) and the connecting rod (16) are made of a material having the same thermal expansion coefficient, for example, carbon steel.

If the lengths of the mounts (7), (8) and the connecting rod (16) are L ₃ , L ₂ , and L ₁ , L ₁ ≈ (L ₃ −L The length of the connecting container (11a) between the bellows (13a) (13b) is adjusted so as to have a function of ₂ ).

Furthermore, in this example, the tank of the circuit breaker (3) and the disconnector (5a), and the connection container (11) that constitutes the gas insulated conductor (12).
Normally, a), (11b) and (11c) are made of the same material, for example, aluminum alloy.

Since the gas-insulated switchgear according to the embodiment of the present invention is configured as described above, the vertical displacement difference between each layer device is related to the temperature / material / length difference between each device and each member. It is caused by the difference in thermal expansion and contraction. However, in the above embodiment, the length of the mount (7) of the disconnector (5a), which is the upper layer device,
L ₃ and the length of the frame (8) of the lower layer circuit breaker (3)
The difference from L ₂ (L ₃ −L ₂ ) is almost the same as the length L ₁ of the connecting rod (16), and is made of the same carbon steel, and
Since there is no heat generation due to energization and the temperatures are almost the same, there is almost no difference in heat shrinkage between the gantry (7) and the connecting rod (16). Here, the pedestals (7) and (8) and the connecting rod (16)
, The weight of the equipment and the load due to the internal gas pressure are different, but the deformation and stress due to such load are constant once the operating state is entered, and the deformation and stress due to temperature change are repeated. It does not fluctuate and its value is small, so there is no problem in strength.

Further, the materials of the containers (11a) to (11c) of the circuit breaker (3), the disconnecting switch (5a) and the gas insulated conductor (16) are usually composed of the same material, and all of them are made to have the same degree by energization. exothermed to have almost the same temperature, yet the length of the disconnector (5a) is, from the length L ₁ + L ₅ of the vertical portion of the gas insulated conductor (12) connecting rod (16) the length L ₁ Deducted length L ₅ and circuit breaker (3)
The height difference between the height L ₄ and the height L ₄ is made substantially equal to each other, so that the vertical displacement difference due to the difference in thermal expansion and contraction hardly occurs.

Here, regarding the mounts (7), (8) and the connecting rod (16), the thermal expansion coefficient of the steel material, which is the material thereof, is β ₁ , the temperature change amount is ΔT ₁ , and the circuit breaker (3) and the disconnector ( For each container of 5a) and the gas insulated conductor (12), the coefficient of thermal expansion of the aluminum alloy, which is the material thereof, is β ₂ , and the amount of temperature change is ΔT ₂ .

First, the height of the left part of FIG. 1, that is, the height of the gantry (7)
The expansion amount ΔL ₁ due to the temperature change of the height obtained by adding L ₃ and the height L _{6 of the} disconnector (5a) is represented by L ₃ × ΔT ₁ × β ₁ + L ₆ × ΔT ₂ × β ₂ .

The height of the right part of FIG. 1, that is, the height L ₁ of the connecting rod (16), the height L ₅ of a part of the vertical portion of the gas insulated conductor (12) and the height of the circuit breaker (3). The amount of expansion and contraction ΔL ₂ due to the temperature change of the height obtained by adding L ₄ and the height L ₂ of the mount (8) is L ₁ × ΔT ₁ × β ₁ +
It is represented by L ₅ × ΔT ₂ × β ₂ + L ₄ × ΔT ₂ × β ₂ + L ₂ × ΔT ₁ × β ₁ .

On the other hand, L ₃ ＋ L ₆ ≒ L ₁ ＋ L ₅ ＋ L ₄ ＋ L ₂ and L ₁ ≒ L ₃ −L ₂
Therefore, L ₅ ≈L ₆ −L ₄ . Further, when the above formula of ΔL ₂ is arranged, ΔL ₂ = (L ₁ + L ₂ ) × ΔT ₁ × β ₁ + (L ₄ +
L ₅ ) × ΔT ₂ × β ₂ .

Therefore, ΔL ₂ ≈ (L ₃ −L ₂ + L ₂ ) × ΔT ₁ × β ₁ + (L ₄ + L ₆
−L ₄ ) × ΔT ₂ × β ₂ = L ₃ × ΔT ₁ × β ₁ + L ₆ × ΔT ₂ × β ₂
= ΔL ₁ . That is, it can be confirmed from this equation that ΔL ₁ ≈ΔL ₂ .

For example, L ₁ = 2750mm, L ₂ = 500mm, L ₃ = 3250mm, L ₄ = 120
0 mm, L ₅ = 800 mm, L ₆ = 2000 mm, L ₁ = L _{3 −} L ₂ = 27
It becomes 50 mm, and the difference in the amount of thermal expansion and contraction due to changes in electricity and temperature becomes zero.

Thus, almost no vertical force is exerted on the disconnector (5a) and the circuit breaker (3) due to the difference in thermal expansion and contraction, and a difference in thermal expansion due to a slight temperature difference or a difference in length is caused by the disconnector. It is absorbed by a slight deformation of the container of (5a) and the circuit breaker (3), and no large stress is generated.

Also, the horizontal displacement difference between the equipment of each layer due to thermal expansion or vibration during an earthquake is, for example, about 15 mm on a 7 m pedestal (7), which is easy by bending deformation of the bellows (13a), (13b). Can be absorbed into the device and does not generate large stress in the device.

Moreover, since the bellows (13a), (13b) generate a large thrust of several tens of tons due to the internal gas pressure, which is supported by the connecting rod (16), the breaker (3) and the disconnector (5a). No large force is applied to (1), and therefore the pedestals (7) and (8) do not require large rigidity, and a normal structure is sufficient, which is economically advantageous.

Next, the influence of the load applied to the gantry (7), (8) and the connecting rod (16) on the thermal expansion / contraction rate (thermal expansion / contraction amount) will be considered.

First, the pedestal (8) supports the circuit breaker (3) and requires a wide support surface to directly support the tank of the circuit breaker (3) that is short and thin, and has a very large cross section (see FIG. 1). It has a large depth dimension in the direction perpendicular to the paper surface.). Therefore, the amount of expansion and contraction due to the load of the gantry (8) is very small and can be ignored.

In addition, the gantry (7) includes disconnectors (5a) to (5c) and a bus bar (6).
The vertical load that supports a) to (6c) and the like and is applied to each leg of the pedestal (7) is about 2 tons in this example. However, since a part of the thrust due to the gas pressure inside the busbar, that is, a large horizontal force of about several tens of tons, is applied to the gantry (7), a large bending stress is generated in the legs of the gantry (7). Therefore, for example, the legs of the pedestal (7) have a thickness of 10
A large-section H-section steel with a cross-sectional area of 11930 mm ^{2 in} mm is used.

Here, the stress generated in the gantry (7) due to the vertical load is about its own weight / (cross-sectional area of two legs) = 2000 (kg)
/ (2 × 11930 (mm ² )) = 0.084 (kg / mm ² ), and the expansion / contraction strain is the stress due to its own weight / the elastic modulus of steel = 0.084 (kg /
mm ² ) / 21000 (kg / mm ² ) = 4 × 10 ^-6 . And, the amount of expansion and contraction of the legs of the gantry (7) is strain × leg length = 4 × 10 ^-6 × 3250 (mm) = 0.013 (m, if the leg length is 3250 (mm)
m), which is negligible.

Next, the connecting rod (16) can be roughly calculated as follows.
First, assuming that the bellows (13a) and (13b) have a diameter of 900 mm and a gas pressure of 5 kg / cm ² , the thrust is (π / 4) × 90 ² (cm ² ) ×
5 (kg / cm ² ) = 25446 (kg). On the other hand, when four M36 threaded connecting rods (16) with a diameter of 40 mm are used, the stress of the portion with a diameter of 40 mm that occupies most of the connecting rod (16) is 25446 (kg) / {4 × (π / 4) × 40 ² (mm ² )} =
5.07 (kg / mm ² ) and elongation is 5.07 (kg / mm ² ) × 2750
(Mm) / 21000 (kg / mm ² ) = 0.66 (mm).

As described above, if L ₁ = L ₃ −L ₂ , the difference between the thermal expansion / contraction amount of the height of the gantry (7) + the height of the disconnector (5a) and the thermal expansion / contraction amount of other parts is theoretical. Although the upper value is 0, the elongation due to the load of the connecting rod (16) actually remains as a difference in elongation between the two. However, the stress generated by the expansion and contraction due to the load does not change after the equipment is installed and the gas is press-fitted, and the value is as small as about 0.66 (mm), so there is no risk of destruction.

On the other hand, the stress generated by thermal expansion and contraction repeatedly changes due to changes in the weather and the amount of energization. For example, even if it changes once a day between night and day, it will take about 50
It is repeated 18,000 times. Therefore, while repeated stress such as this thermal stress may cause fatigue failure,
In this embodiment, since the difference in thermal expansion / contraction amount is 0, fatigue fracture is prevented.

Although the case where L ₁ and L ₃ −L ₂ are almost equal has been shown above, let us next consider the case where L ₁ is half of L ₃ −L ₂ .

For example, L ₁ = 2750mm, L ₂ = 500mm, L ₃ = 6000mm, L ₄ = 200
0mm, L ₅ = 2500mm, L ₆ = 1750mm.

Now, the temperature has risen by 3 ° C from the time of assembly, and the current-carrying part is 20 more.
Considering the case where ℃ severe elevated gantry (7) of the height L ₃ and the disconnector relative to the height L ₆ height plus the (5a), the other part height, i.e. the connecting rod The height L ₁ of (16) and the height L ₅ of a part of the vertical portion of the gas insulated conductor (12) and the circuit breaker (3)
The difference in the amount of expansion and contraction of the height, which is the sum of the height L ₄ and the height L ₂ of the gantry (8), is calculated as follows.

That is, (pedestal (7) height + disconnector (height 5a)) thermal expansion and contraction amount of _{= L 3 × ΔT 1 × β} 1 + L 6 × ΔT 2 × β 2 = 6000 (mm)
X 30 (° C) x 11.7 x 10 ^-6 (1 / ° C) + 1750 (mm) x 50
(℃) × 23.9 × 10 ^-6 (1 / ℃) = 4.20 (mm) Similarly, the amount of thermal expansion and contraction at the height of other parts is L ₁ × ΔT ₁ ×
β ₁ + L ₅ × ΔT ₂ × β ₂ + L ₄ × ΔT ₂ × β ₂ + L ₂ × ΔT ₁ × β
₁ = 2750 (mm) x 30 (° C) x 11.7 x 10 ^-6 (1 / ° C) + 2500
(Mm) x 50 (° C) x 23.9 x 10 ^-6 (1 / ° C) + 2000 (mm) x
50 (° C) x 23.9 x 10 ^-6 (1 / ° C) + 500 (mm) x 30 (° C)
× 11.7 × 10 ^-6 (1 / ° C) = 6.53 (mm) Therefore, the difference in expansion and contraction amount is 6.53-4.20 ≒ 2.3mm.

If the difference in the amount of expansion and contraction is about this amount, the connection part (K) of the circuit breaker (3), the connection part (L) of the disconnector (5a), the gas insulated conductor (12), etc. will be bent and the stress will not exceed It is possible to deal with it.

In general, the coefficient of thermal expansion of a solid does not need to consider the effect of pressure, so see page 11-4 of "Mechanical Engineering Handbook, Revised 5th Edition" (published by the Japan Society of Mechanical Engineers in 1968). When the elongation of the connecting rod (16) due to the temperature rise of 30 ° C is calculated in consideration of the elongation due to the load, it is (2750 (mm) + 0.66
(Mm)) × 30 (℃) × 11.7 × 10 ^-6 (1 / ℃) = 0.96548 (m
m). On the other hand, if the elongation due to load is not taken into consideration, as described above, 2750 (mm) x 30 (° C) x 11.7 x 10
^-6 (1 / ° C) = 0.96525 (mm).

In this way, there is only a 0.0001 mm unit difference between when the elongation due to load is taken into consideration and when it is not taken into consideration. That is, since both the expansion ratio due to load and the expansion ratio due to heat are small, there is no problem from an engineering point of view if there is no problem if the product of the expansion ratio and the original length is added together. Is taking.

This can be expressed as a general formula as follows. However,
l ₀ : original length, Δl ₁ : expansion / contraction amount due to load, Δl ₂ : expansion / contraction amount due to heat, l: length expanded due to load and heat, Δl ₁ , Δ
Let l ₂ be much smaller than l ₀ .

l = l ₀ (1 + Δl ₁ / l ₀ ) {1 + Δl ₂ / (l ₀ + Δl ₁ )} = l ₀ [1 + Δl ₁ / l ₀ + Δl ₂ / (l ₀ + Δl ₁ ) + (Δl ₁ /
l ₀ ) × {Δl ₂ / (l ₀ + Δl ₁ )}] ≈l ₀ (1 + Δl ₁ / l ₀ +
Δl ₂ / l ₀ ) Normally, the height difference between the mount (7) and the mount (8) (L ₃ −L ₂ )
The length L ₁ of the connecting rod (16) is smaller than
Even if it is 0.5, it may be applicable as described above. That is, the length L ₁ of the connecting rod is equal to the difference (L ₃ −
L ₂ ) does not have to be exactly equal to it, so it is preferable to make the ratio 0.5 or more and as close to 1 as possible.

In this way, by providing the bellows (13a), (13b) and the connecting rod (16) in a part of the vertical portion of the gas insulated conductor (12), the temperature can be increased within the range of the connecting rod (16) of the vertical portion. The expansion / contraction amount due to the change becomes the expansion / contraction amount of the connecting rod (16). Since the pedestal (7) and the connecting rod (16) change in temperature in the same manner, the length of the connecting rod (16) is subtracted from the height of the gantry (7) by the height of the gantry (8). Be approximately equal to the length,
That is, the height of the pedestal (8) is subtracted from that of the pedestal (7) and the vertical portion by making the material of the connecting rod (16) the same as that of the gantry (8). The extent of expansion and contraction in the height direction due to temperature change is almost equal to that of the connecting rod (16). Also, disconnector (5a), gas insulated conductor (1
The constituent materials of 2) and the circuit breaker (3) are generally the same material, and the circuit breaker (3) is provided at the height of the disconnector (5a) and the portion outside the connecting rod (16) of the gas insulated conductor (12). Is equal to the sum of the heights of the two, and both have the same temperature change, so the amount of expansion and contraction in the height direction due to these temperature changes is also substantially equal. Therefore, on the right side and the left side in FIG. 1, there is almost no difference in the amount of expansion and contraction in the vertical direction due to temperature changes, and the stress caused thereby is prevented.

[Effect of device]

As described above, according to the present invention, the bellows is interposed in the container of the connecting device, which is a portion that connects the layers of the multi-layer gas-insulated switchgear, and is provided above and below the upper and lower ends of the bellows. A connecting rod is attached between the equipment, and the connecting rod is made of a material that has the same expansion coefficient as the pedestal of each equipment, and its length is 1 to 1/2 times the difference between the heights of both pedestals. It has the ability to withstand thermal expansion and contraction due to the difference and large rolling in the event of an earthquake, and the thrust due to the internal gas pressure is applied to the connecting rods and not to the pedestal. It is sufficient to use a tool to provide a gas insulated switchgear having excellent economical efficiency and safety.

[Brief description of drawings]

FIG. 1 is a partial side view of a gas-insulated switchgear according to an embodiment of the present invention, FIG. 2 is a detailed sectional view of a portion II of FIG. 1, and FIG. 3 is a side view of a conventional gas-insulated switchgear. Is. (3) …… Equipment (circuit breaker), (5a) (5b) (5c) …… Equipment (disconnector), (6a) (6b) (6c) …… Bus, (7)
(8) ... frame, (11a) (11b) (11c) ... connection container, (12) ... coupling device (gas insulated conductor), (13a) (1
3b) ...... Bellows, (14) (15) ...... Mounting bracket (flange), (16) ...... Connecting rod. In the drawings, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Scope of utility model registration request] 1. A first frame, a circuit breaker supported by the first frame, a second frame higher than the first frame, and a second frame that is higher than the circuit breaker. A disconnector supported in an upper layer, a conductor electrically connecting the circuit breaker and the disconnector, a bellows provided in a vertical direction and surrounding the conductor,
An upper connection container airtightly connected between the upper part of the bellows and the container of the disconnector to surround the conductor, and an upper connection container airtightly connected between the lower part of the bellows and the container of the circuit breaker to surround the conductor. A connecting device having a lower connecting container, and a connecting rod connected between an upper end of the upper connecting container and a fitting provided on the lower connecting container. The sum of the heights of the breaker container and the connecting device is substantially equal to the sum of the heights of the second mount and the disconnecting container, and the connecting rod is the first And a material having a coefficient of thermal expansion substantially equal to that of the second mount, and the length thereof is configured to be 1 to 1/2 times the difference in height between the first and second mounts. A gas-insulated switchgear characterized in that