JP2018041609A - Circuit breaker, and assembly method for circuit breaker - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a circuit breaker capable of protecting power supply equipment within the circuit breaker by preventing or reducing an explosion caused by a combustible gas filling the inside of the circuit breaker, and preventing generation of a dispersion substance to the outside of the circuit breaker, and an assembly method for the circuit breaker.SOLUTION: A circuit breaker 1 comprises: an upper case 3 in which a cable run switch 7 capable of performing an on/off operation of electrical connection between a distribution line 6a and a distribution line 6b is accommodated; and a lower case 4 in which a transformer 12 is accommodated. The inside of the circuit breaker 1 is replaced under an inert gas concentration atmosphere in about 99.0 vol.% as required. In the vicinity of the transformer 12, a deoxidizer capable of sucking oxygen being present within the circuit breaker 1 or oxygen generated by inhalation of the circuit breaker 1 is disposed, thereby preventing an explosion within the circuit breaker 1 caused by a combustible gas such as acetaldehyde generated from an organic resin.SELECTED DRAWING: Figure 1

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 filling the switch, the power supply equipment in the switch is protected and the occurrence of scattered objects outside the switch is prevented. The present invention relates to a switch that can be used and a method for assembling the switch.

  Conventionally, high-voltage power distribution lines drawn out from substations have been stretched in a mesh form by a large number of power poles standing in the city to supply power to consumers. In such utility poles, switches are installed everywhere at the entrance of the customer for the purpose of demarcation. For example, when an abnormality occurs, electrical equipment is inspected and repaired, the switch is operated. The current flow is temporarily interrupted.

  For example, Patent Document 1 discloses the contents of this switch. 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 switching mechanism 107, a transformer 112, and a lightning arrester 113. An upper case 103 mainly on the upper side and a lower case 104 on the lower side that closes the opening 105 of the upper case 103 are detachably provided on the upper case 103.

  In addition, the case 102 is provided with a pressure release portion 114 that releases the internal pressure of the case 102 to the outside when the internal pressure in 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 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. In this state, when a short circuit accident or the like occurs in the power supply device in the switch 201, the lower case 204 is deformed by the explosion pressure, and a gap 220 is generated around the entire fitting portion of the upper case 203 and the lower case 204. The rising pressure of air or the like in 101 is released.

JP 2004-40849 A Japanese Utility Model Publication No. 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 electric power distributed at a high voltage to a low voltage when supplying it to a consumer. 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 covered with a synthetic resin for insulation.

  Since the high voltage is always applied to the 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 lightning damage, aging deterioration, manufacturing failure, etc. Have. Therefore, when a short circuit or heat generation occurs due to a failure in the electric winding part, the synthetic resin covering the electric winding part is heated, and a combustible gas such as acetaldehyde is generated and fills the case of the switch. It will be.

  The combustible gas filled in the case is ignited by a current arc generated when the main circuit is opened and closed and a minute fire generated from the short-circuited electric winding portion, thereby causing an explosion. The pressure increase rate at the time of the explosion due to the ignition of the combustible gas is much higher than the pressure increase rate of the air in the switch when a normal electrical short-circuit accident occurs, as a result of repeated experiments by the present inventors. Is known to be 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 increase rate, and the switch body is damaged due to an explosion. Has occurred first, and there was a problem that internal parts scattered from the damaged part of the main body to the outside.

  The present invention was devised in view of the above points, and protects power supply equipment in a switch by preventing or reducing an explosion caused by a combustible gas filling the switch. Another object of the present invention is to provide a switch that can prevent the occurrence of scattered objects outside the switch, and a method for assembling the switch.

  In order to achieve the above object, a switch according to the present invention includes a case whose 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, it is well below the limit oxygen concentration that can cause an explosion due to the flammable gas, Explosion in the case can be prevented in advance.

  In order to achieve the above object, a switch according to the present invention includes a case for housing a power supply device covered with an insulating synthetic resin, and an oxygen scavenger disposed at a predetermined position in the case.

  Here, by providing an oxygen scavenger at a predetermined position in the case, oxygen present in the case is absorbed. In other words, even if the synthetic resin covering the power supply device housed in the case is heated for some reason and emits a flammable gas such as acetaldehyde, the oxygen causing the explosion is absorbed by the oxygen scavenger. , Explosion in the case can be prevented or reduced in advance. Since the oxygen scavenger absorbs oxygen in the sealed container, it can function basically at any position in the case.

  In addition, when an oxygen scavenger is arranged around the transformer, 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 the component of the synthetic resin is heated. Even if a combustible gas such as a certain acetaldehyde is generated, a deoxygenation state can be made earlier around a transformer that has a high possibility of explosion ignition.

  In order to achieve the above object, a method for assembling a switch according to the present invention includes a step of storing an electric circuit switching mechanism and a transformer covered with an insulating synthetic resin in a first case having an opening, A step of closing an opening and installing a second case removable from the first case; a step of disposing an oxygen scavenger in either the first case or the second case; Is provided.

  Here, the switch is composed of the first case and the second case, and the oxygen absorber is provided in either the first case or the second case around the transformer covered with the insulating synthetic resin. 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 combustible gas such as acetaldehyde, which is a component of the synthetic resin, is generated. Even if it occurs, it can be deoxidized more quickly around the transformer where there is a high possibility of explosion.

  Further, in the case of having a process of supplying an inert gas into the switch and replacing it with an inert gas concentration atmosphere of approximately 99.0% by volume, it is necessary to absorb only oxygen mixed by the intake action of the switch. Since it is good, a small amount of oxygen scavenger can be used.

  The switch according to the present invention and the assembly method of the switch protect the power supply device in the switch by preventing or reducing the explosion caused by the flammable gas filling the switch, Generation of scattered matter outside the switch can be prevented.

It is a section explanatory view of a switch concerning an embodiment of the present invention. It is a figure which shows a prior art. It is a figure which shows a prior art.

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

  First, the whole structure of the switch 1 which concerns on embodiment to which this invention is applied is demonstrated using FIG. The switch 1 is, for example, a pole switch that is installed on a utility pole at the entrance of a customer as a responsibility demarcation point, and includes a metal main body case 2 that houses various power supply devices.

  Here, the switch 1 does not necessarily need to be a pole switch. For example, a switch used for any application may be used as long as it can switch a load current in a normal state and can also input an abnormal current in a short circuit state of an 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 the utility pole. As shown, the lower case (second case) 4 is detachable from the upper case 3 and functions as a lid member.

  Here, the main body case 2 does not necessarily need to be of a type in which the lower case 4 can be attached to and detached 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. The electrical connection and disconnection between the distribution line 6a and the distribution line 6b are controlled by turning on / off the electric circuit opening / closing mechanism 7 composed of 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 so that the shaft portion thereof is pivotally attached to the load side terminal 10 so as to turn to the link device 11 operated by an operation handle (not shown). It is configured. Thereby, 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 (input operation), the distribution line 6a and the distribution line 6b are electrically connected. On the other hand, when the fixed contact portion 8 and the movable contact portion 9 are opened (cutting operation), the electrical connection between the distribution line 6a and the distribution line 6b is interrupted.

  Here, the on / off operation of the fixed contact portion 8 and the movable contact portion 9 is not necessarily 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, the fixed contact portion 8, the movable contact portion 9, and the link device 11 as described above are provided as a set, and a total of three sets are provided. Each set has a bottomed opening that opens upward. A cover 19 is 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 need to be provided in a total of three sets. For example, 4 sets or more, or 1 to 2 sets may be provided.

  In the vicinity of the upper case 3 where the distribution line 6b is connected, an operation bushing 21 is installed to detect that excessive power has flowed and open the circuit to prevent power supply equipment failure and fire. ing.

  The lower case 4 is provided with a transformer 12 that transforms electric power distributed at a high voltage into a low voltage when supplying it to a consumer. The transformer 12 has a known structure, and includes, for example, an iron core that forms a magnetic circuit (not shown) and an electric winding that forms an electric circuit and is covered with an organic resin for insulation. The transformer 12 is connected to a lightning arrester 13 for protecting various power supply devices from a transient abnormal high voltage caused by lightning.

  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 through the packing 16. In this state, when a short circuit accident or the like occurs in the power supply device in the switch 1, the lower case 4 is deformed by the explosion pressure, and a gap is generated around the entire fitting portion of the upper case 3 and the lower case 4. It is configured to release the rising pressure of the air inside.

  Here, the configuration of the pressure release portion 14 does not necessarily need to be a configuration 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 oxygen in the sealed switch 1, and the switch 1 has less than the limit oxygen concentration (oxygen concentration less than 8.0% by volume). Preferably, the powder-like degassing enclosed in the sachet 18 which can be less than the controlled oxygen concentration (oxygen concentration less than 5.0% by volume) or deoxygenated (oxygen concentration of 0.1% by volume or less). An oxygen agent is arranged.

  Here, the oxygen scavenger does not necessarily need to be disposed on the bottom 17 of the lower case 4. The position is not particularly limited as long as the inside of the switch 1 can be deoxygenated. However, in order to prevent explosion in the switch 1 due to combustible gas such as acetaldehyde generated from the organic resin covering the transformer, it is necessary to make the vicinity of the transformer 12 a deoxygenated atmosphere, It is preferable to arrange around the transformer 12.

  Moreover, the number of oxygen scavengers is not necessarily one. For example, the oxygen scavenger may be subdivided and enclosed in a plurality of sachets 18, and these may be disposed around the transformer 12.

  Further, the oxygen scavenger does not necessarily need 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 can be appropriately selected from sheet-type oxygen scavengers such as a label type, a card type, and a packing type.

  Next, the result of a verification experiment for confirming the effect of the embodiment according to the present invention will be shown. The present invention is not limited to the following examples.

The specifications for the verification experiment for confirming the effects of the embodiment according to the present invention are as follows.
<With or without nitrogen replacement in the switch>
Nitrogen replacement of the air component in the switch 1 is not performed, and the air component in the switch 1 is 78.0% by volume of nitrogen, which is a general mixing ratio, 21.0% by volume of oxygen, and other 1.0 It is in a volume% state.
<Types of oxygen scavenger>
As the oxygen scavenger, a carbon dioxide-releasing organic oxygen scavenger was used.
<Encapsulation of flammable gas in switch>
Acetaldehyde, which is a flammable gas, was sealed in the switch 1 so as to have a concentration exhibiting maximum explosive properties.
<Explosion occurrence conditions>
In the switch 1, an electrical short was intentionally generated and exploded.

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

[Comparative Example 1]
In contrast to the embodiment, nitrogen is supplied into the switch 1 as an inert gas without using an oxygen scavenger, and the air component in the switch 1 is replaced with nitrogen so as to be 99.0% by volume of nitrogen. It was.

  Here, it is not always necessary to supply nitrogen as an inert gas. Any gas may be used as long as the inert gas has poor reactivity. For example, it can be appropriately selected from known inert gases such as helium, neon, krypton, and xenon. 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]
It was set as the specification which does not arrange | position an oxygen scavenger with respect to an Example.

[Comparative Example 3]
For the examples, no oxygen scavenger was placed and no flammable gas was enclosed.

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

[Table 1]

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

  In addition, when the nitrogen component of the air component in the switch 1 is not replaced when the switch 1 is manufactured, for example, when a non-carbon dioxide deoxygenating agent is used, the oxygen component in the mixed gas (the entire mixed gas) 21.0% by volume) is lost, but the air component in the switch 1 becomes insufficient. Therefore, there is a concern that the inside of the switch 1 is in a depressurized state and may cause a failure of a power supply device or the like that is housed. It is preferable to use a carbon dioxide-releasing oxygen scavenger as in this example.

  As described above, in the switch and the assembly method of the switch to which the present invention is applied, the power supply device in the switch can be reduced by preventing or reducing the explosion caused by the combustible gas filling the switch. While protecting, generation | occurrence | production of the scattered material to the switch exterior can be prevented.

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 portion 9 Movable contact portion 10 Load side terminal 11 Link mechanism 12, 112 Transformer 13, 113 Lightning arrester 14, 114 Pressure release portion 15, 215 Packing groove 16, 216 Packing 17 Bottom 18 Small bag (with oxygen scavenger)
19 Insulation cover 21 Operation bushing

Claims (5)

A case where the interior is maintained in an oxygen concentration atmosphere of less than about 5.0% by volume;
And a power supply device housed in the case. A case for housing a power supply device covered with an insulating synthetic resin;
And a deoxidant disposed at a predetermined position in the case. The case is
A first case in which an electric circuit opening and closing mechanism and a transformer covered with an insulating synthetic resin are housed and having an opening;
A second case that closes the opening and is detachable from the first case;
The switch according to claim 2, wherein the oxygen scavenger is disposed around the transformer. Storing the electric circuit opening / closing mechanism and the transformer covered with the insulating synthetic resin in the first case having the opening; and
Installing a second case that closes the opening and is detachable from the first case;
A method for assembling a switch, comprising: disposing an oxygen scavenger in either the first case or the second case. Supplying an inert gas into the switch, and replacing the inert gas in an atmosphere of an inert gas concentration of approximately 99.0% by volume;
The assembly method of the switch of Claim 4.

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