JP6780388B2 - Switch and how to assemble the switch - Google Patents

Description

The present invention relates to a switch and a method for assembling the switch. Specifically, by preventing or reducing the explosion caused by the flammable gas that fills the switch, the power supply equipment inside the switch is protected and the generation of scattered matter to the outside of the switch is prevented. It relates to a switch that can be used and a method of assembling the switch.

Conventionally, high-pressure power distribution lines drawn from substations are laid out in a mesh pattern by a large number of electric poles erected in the city to supply power to consumers. Switches are installed everywhere on such utility poles as a demarcation point of responsibility at the entrance of consumers, and the switches are operated, for example, when an abnormality occurs, when inspecting electrical equipment, or when repairing work. It is designed to temporarily cut off the current flow.

As for the configuration of this switch, for example, the content thereof is disclosed in Patent Document 1. Specifically, as shown in FIG. 2, the switch 101 is a metal case 102 that houses various power supply devices such as an electric circuit opening / closing mechanism 107, a transformer 112, and a lightning arrester 113, and the case 102 is a metal case 102. The upper case 103 on the upper side and the lower case 104 on the lower side that closes the opening 105 of the upper case 103 are provided detachably from the upper case 103.

Further, the case 102 is provided with a pressure release unit 114 that releases the internal pressure of the case 102 to the outside when the internal pressure inside the case 102 rises due to an internal short circuit accident or the like. As a specific configuration of the pressure release unit 114, for example, a configuration as described in Patent Document 2 is known.

That is, in the switch 201 composed of the upper case 203 and the lower case 204, the packing 216 is inserted into the packing groove 215 formed in the upper case 203, and the lower case 204 is hermetically fitted via the packing 216. If a short-circuit accident or the like occurs in the power supply device in the switch 201 in this state, the lower case 204 is deformed due to the explosive pressure, and a gap 220 is created over the entire circumference of the fitting portion between the upper case 203 and the lower case 204. It is designed to release the rising pressure of air or the like in 101.

Japanese Unexamined Patent Publication No. 2004-40849 Jikkensho 57-60199

By the way, as one of the power supply devices housed in the case of the switch, there is a transformer that transforms the electric power distributed by the high voltage to the low voltage when supplying the electric power to the customer. This transformer is mainly composed of an iron core that constitutes a magnetic circuit and an electric winding that constitutes an electric circuit and is surrounded by a synthetic resin for insulation.

Since a high voltage is always applied to this electric winding part during the operation of the switch, there is a possibility that the electric winding part may be short-circuited and generate heat due to the effects of lightning damage, aging deterioration, manufacturing defects, etc. Have. Therefore, when a short circuit or heat generation occurs due to a defect in the electric winding part, the synthetic resin covering the electric winding part is heated, and a flammable gas such as acetaldehyde is generated to fill the inside of the switch case. It will be.

Then, the flammable gas filled in the case ignites the current arc generated when the main circuit is opened and closed and the minute fire generated from the short-circuited electric winding portion, causing an explosion. According to the results of repeated experiments by the present inventors, the rate of increase in pressure at the time of explosion due to ignition of flammable gas is much higher than the rate of increase in pressure of air in the switch in the event of a normal electric short circuit accident. It is known as a finding that it is very fast.

Therefore, even if the switch has the pressure release structure disclosed in Patent Document 2, the release of the upper case and the lower case cannot follow the pressure rise speed, and the switch body is damaged due to the explosion. Was generated first, and there was a problem that internal parts were scattered to the outside from the damaged part of the main body.

The present invention has been devised in view of the above points, and protects the power supply device in the switch by preventing or reducing the explosion caused by the flammable gas filling the switch. At the same time, it is an object of the present invention to provide a switch capable of preventing the generation of scattered objects to the outside of the switch, and a method of assembling the switch.

In order to achieve the above object, the switch of the present invention includes a case in which the inside is maintained in an oxygen concentration atmosphere of less than about 5.0% by volume, and a power supply device housed in the case.

Here, since the inside of the switch case is maintained in an oxygen concentration atmosphere of less than about 5.0% by volume, the oxygen concentration is sufficiently lower than the limit oxygen concentration that may cause an explosion due to ignition of the flammable gas. It is possible to prevent an explosion inside the case.

In order to achieve the above object, the switch of the present invention includes a case for accommodating a power supply device coated with an insulating synthetic resin, and an oxygen scavenger arranged at a predetermined position in the case.

Here, by providing the deoxidizer at a predetermined position in the case, the oxygen existing in the case is absorbed. That is, even if the synthetic resin that covers the power supply equipment housed in the case is heated for some reason and emits a flammable gas such as acetaldehyde, oxygen that causes an explosion is absorbed by the oxygen scavenger. , Explosion in the case can be prevented or reduced. Since the oxygen scavenger absorbs oxygen in the closed container, it can basically exert its function at any position in the case.

In addition, when a deoxidizer is placed around the transformer, for example, the transformer generates heat due to an abnormality such as a short circuit, and the synthetic resin that covers the transformer is heated, so that the synthetic resin component is used. Even if a flammable gas such as acetaldehyde is generated, the area around the transformer, which has a high possibility of explosion and ignition, can be deoxidized more quickly.

In order to achieve the above object, the method of assembling the switch of the present invention includes a step of accommodating the electric circuit opening / closing mechanism and the transformer coated with the insulating synthetic resin in the first case having an opening, and the above-mentioned. A step of closing the opening and installing a second case that can be attached to and detached from the first case, and a step of arranging an oxygen scavenger in either the first case or the second case. To be equipped.

Here, the deoxidizer is applied to either the first case or the second case in which the switch is composed of the first case and the second case and is around the transformer coated with the insulating synthetic resin. By providing a step of arranging the above, for example, the transformer generates heat due to an abnormality such as a short circuit, and the synthetic resin covering the transformer is heated, so that a flammable gas such as acetaldehyde, which is a component of the synthetic resin, is released. Even if it occurs, the area around the transformer, which has a high possibility of explosion, can be deoxidized sooner.

Further, when the inert gas is supplied into the switch and has a process of substituting under an atmosphere having an inert gas concentration of about 99.0% by volume, only oxygen mixed by the intake action of the switch is absorbed. Therefore, the amount of the oxygen scavenger can be small.

The switch and the method of assembling the switch according to the present invention protect the power supply device in the switch and protect the power supply device in the switch by preventing or reducing the explosion caused by the flammable gas filling the switch. It is possible to prevent the generation of scattered objects to the outside of the switch.

It is sectional drawing explanatory view of the switch according to embodiment of this invention. It is a figure which shows the prior art. It is a figure which shows the prior art.

Hereinafter, embodiments of the present invention relating to the switch and the method of assembling the switch will be described with reference to the drawings, and the present invention will be understood. In each figure, for convenience of explanation, in the state where the switch 1 is installed, the direction from the bottom surface to the top surface is defined as the upward direction, and the direction opposite to the upward direction is defined as the downward direction.

First, the overall configuration of the switch 1 according to the embodiment to which the present invention is applied will be described with reference to FIG. The switch 1 is, for example, a pole switch installed on a utility pole at the entrance of a customer for a demarcation point of responsibility, and includes a metal main body case 2 for storing various power supply devices.

Here, the switch 1 does not necessarily have to be a pole switch. For example, the switch may be used for any purpose as long as it can switch the load current in normal times and can also input an abnormal current in a short-circuited state of the electric circuit.

The main body case 2 closes the upper case (first case) 3 having a lower opening 5 that opens downward and the lower opening 5 of the upper case 3 in a state where the switch 1 is installed on a utility pole. As such, it is composed of a lower case (second case) 4 that is removable from the upper case 3 and functions as a lid member.

Here, the main body case 2 does not necessarily have to be in a form in which the lower case 4 is removable from the upper case 3. For example, the upper case 3 may be detachable from the lower case 4, and the upper case 3 may function as a lid member.

The upper case 3 is provided with a distribution line 6a and a distribution line 6b in the distribution system, respectively. The electrical connection and disconnection of the distribution wire 6a and the distribution wire 6b are controlled by the on / off operation of the electric circuit opening / closing mechanism 7 including the movable contact portion 9 and the fixed contact portion 8.

Specifically, the movable contact portion 9 is attached to the load side terminal 10 with its shaft portion rotatably attached to the shaft portion, and is rotated by a link device 11 operated by an operation handle (not shown). It is configured in. As a result, the fixed contact portion 8 and the movable contact portion 9 can be turned on and off. That is, when the fixed contact portion 8 and the movable contact portion 9 are brought into contact with each other (on operation), the distribution wire 6a and the distribution wire 6b are electrically connected. On the other hand, when the fixed contact portion 8 and the movable contact portion 9 are opened (cut operation), the electrical connection between the distribution line 6a and the distribution line 6b is cut off.

Here, the on / off operation of the fixed contact portion 8 and the movable contact portion 9 does not necessarily have to be performed manually by the operation handle. For example, when an abnormality such as a short circuit is detected in the power supply device in the switch 1, the fixed contact portion 8 and the movable contact portion 9 may be automatically opened.

In the present invention, a total of three sets of the fixed contact portion 8, the movable contact portion 9, and the link device 11 as described above are provided as one set, and each set has a bottomed surface opened upward. Covers 19 are attached to cover them.

Here, the fixed contact portion 8, the movable contact portion 9, and the link device 11 housed in the switch 1 do not necessarily have to be provided in a total of three sets. For example, four or more sets, or one or two sets may be provided.

In the vicinity of the distribution wire 6b of the upper case 3, an operation bushing 21 is installed to detect the flow of excessive power, open the circuit, and prevent failure of the power supply equipment or fire. ing.

In the lower case 4, a transformer 12 that transforms the electric power distributed by the high voltage to a low voltage when supplying the electric power to the consumer is installed. The transformer 12 has a known structure, and is composed of, for example, an iron core constituting a magnetic circuit (not shown) and an electric winding forming an electric circuit and the periphery thereof being coated with an organic resin for insulation. Further, a lightning arrester 13 for protecting various power supply devices from a transient abnormally high voltage caused by lightning is connected to the transformer 12.

Further, as described above, the pressure release portion 14 is provided at the joint portion between the upper case 3 and the lower case 4. That is, the packing 16 is inserted into the packing groove 15 formed in the lower case 4, and the upper case 3 is hermetically fitted via the packing 16. If a short-circuit accident or the like occurs in the power supply device in the switch 1 in this state, the lower case 4 is deformed by the explosive pressure, and a gap is created over the entire circumference of the fitting portion between the upper case 3 and the lower case 4, so that the switch 1 It is configured to release the rising pressure of the air inside.

Here, the structure of the pressure release portion 14 does not necessarily have to be a structure in which the upper case 3 is hermetically fitted via the packing 16. It is possible to appropriately select from known pressure release structures.

In the vicinity of the transformer 12, the bottom 17 of the lower case 4 absorbs the oxygen in the sealed switch 1 and the inside of the switch 1 is less than the limit oxygen concentration (oxygen concentration less than 8.0% by volume). The powdery desorption enclosed in a pouch 18 which can be preferably less than the controlled oxygen concentration (oxygen concentration less than 5.0% by volume) or deoxidized state (oxygen concentration 0.1% by volume or less). Oxygen agent is arranged.

Here, the deoxidizer does not necessarily have to be arranged at the bottom 17 of the lower case 4. As long as the inside of the switch 1 can be deoxidized, its position is not particularly limited. However, in order to prevent an explosion in the switch 1 due to a flammable gas such as acetaldehyde generated from the organic resin covering the transformer, it is necessary to create an oxygen scavenging atmosphere in the vicinity of the transformer 12. It is preferably arranged around the transformer 12.

Also, the oxygen scavenger does not necessarily have to be one. For example, the oxygen scavenger may be subdivided and sealed in a plurality of sachets 18 and arranged around the transformer 12.

Further, the oxygen scavenger does not necessarily have to be powdered and enclosed in the pouch 18. For example, a base sheet in which a powdered oxygen scavenger is fixed to a resin is used, and a sheet-type oxygen scavenger such as a label type, a card type, or a packing type can be appropriately selected.

Next, the results of a verification experiment for confirming the effect of the examples according to the present invention are shown. The present invention is not limited to the following examples.

The specifications for the verification experiment for confirming the effect of the examples according to the present invention are as follows.
<Presence or absence of nitrogen substitution in the switch>
Nitrogen substitution is not performed for the air component in the switch 1, and the air component in the switch 1 is 78.0% by volume of nitrogen, 21.0% by volume of oxygen, and 1.0 other, which are general mixing ratios. It is in the state of volume%.
<Type of oxygen scavenger>
As the oxygen scavenger, a carbon dioxide-releasing organic oxygen scavenger was used.
<Encapsulation of flammable gas in the switch>
Acetaldehyde, which is a flammable gas, was sealed in the switch 1 so as to have a concentration showing maximum explosiveness.
<Explosion conditions>
An electrical short circuit was intentionally generated in the switch 1 to cause an explosion.

In order to compare the effects with the above examples, experiments were conducted on Comparative Examples 1 to 3 as follows.

[Comparative Example 1]
For the examples, nitrogen was supplied to the switch 1 as an inert gas without using an oxygen scavenger, and nitrogen substitution of the air component in the switch 1 was performed so that the nitrogen content was 99.0% by volume. It was.

Here, it is not always necessary to supply nitrogen as an inert gas. Any gas with poor reactivity may be used, and for example, a known inert gas such as helium, neon, krypton, or xenon can be appropriately selected. However, since nitrogen has the lowest cost, it is preferable to supply nitrogen in consideration of the total cost of the product.

[Comparative Example 2]
For the examples, the specifications were such that no oxygen scavenger was placed.

[Comparative Example 3]
In contrast to the examples, the specifications were such that no oxygen scavenger was placed and no flammable gas was sealed.

Table 1 shows the results of the explosiveness evaluation of the above Examples and Comparative Examples 1 to 3.

[Table 1]

From the above results, it can be confirmed that even if flammable gas is generated, by using an oxygen scavenger, it is possible to prevent an explosion caused by the flammable gas and prevent damage to the switch as in the case of nitrogen replacement. It was.

When the air component in the switch 1 is not replaced with nitrogen during the manufacture of the switch 1, for example, if a carbon dioxide non-releasing deoxidizer is used, the oxygen component in the mixed gas (the entire mixed gas) 21.0% by volume) will be lost, while the air component in the switch 1 will be insufficient. Therefore, the inside of the switch 1 becomes decompressed, which may cause a failure of the power supply equipment or the like accommodated. Therefore, when the switch 1 is manufactured, the air component in the switch 1 is not replaced with nitrogen. , It is preferable to use a carbon dioxide-releasing oxygen scavenger as in this example.

As described above, in the switch and the switch assembly method to which the present invention is applied, the power supply device in the switch can be used by preventing or reducing the explosion caused by the flammable gas that fills the switch. In addition to protecting the switch, it is possible to prevent the generation of scattered matter to the outside of the switch.

1, 101, 201 Switch 2, 102, Case 3, 103, 203 Upper case (first case)
4, 104, 204 Lower case (second case)
5,105 Lower opening 6a, 6b Distribution line 7,107 Electric circuit opening / closing mechanism 8 Fixed contact part 9 Movable contact part 10 Load side terminal 11 Link mechanism 12,112 Transformer 13,113 Lightning arrester 14,114 Pressure release part 15,215 Packing groove 16, 216 Packing 17 Bottom 18 Pouch (with deoxidizer)
19 Insulation cover 21 Operation bushing

Claims (3)

A case for accommodating power supply equipment coated with insulating synthetic resin,
In a switch provided with a deoxidizer placed at a predetermined position in the case .
The case houses the electric circuit opening / closing mechanism and the transformer coated with the insulating synthetic resin, and closes the first case having an opening and the opening, and is attached / detached to / from the first case. With a possible second case,
A switch in which the oxygen scavenger is arranged around the transformer . The process of accommodating the electric circuit opening / closing mechanism and the transformer coated with the insulating synthetic resin in the first case having an opening, and
A step of closing the opening and installing a second case that can be attached to and detached from the first case,
A method for assembling a switch, comprising a step of arranging an oxygen scavenger in either the first case and the second case. It has a process of supplying an inert gas into the switch and substituting it under an atmosphere having an inert gas concentration of about 99.0% by volume.
The method for assembling a switch according to claim 2 .

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