JP2018129468A - Oil-immersed transformer with gas monitoring device - Google Patents

Abstract

An oil-filled transformer with a gas monitoring device capable of reducing power consumption is provided.
An oil-filled transformer with a gas monitoring device in which a pressurized gas and a detection gas are filled in an upper space in a container is provided in a detection chamber in which a sensor for detecting the detection gas is provided. 21, a pipe 23 that connects the container 11 and the detection chamber 21, and an electromagnetic valve 24 that is provided in the pipe 23 and is opened and closed by electric power.
[Selection] Figure 1

Description

  The present invention relates to an oil-filled transformer with a gas monitoring device in which insulating oil is placed in a container.

  In an oil-filled transformer, for example, when a discharge occurs between the windings in the insulating oil, the insulating oil between the windings in which the discharge is generated decomposes to generate a gas such as hydrogen and acetylene (hereinafter “flammable gas”). ") Occurs. Conventionally, in order to diagnose an abnormality in an oil-filled transformer, detection of combustible gas generated in the oil-filled transformer has been performed, or the concentration of the combustible gas has been measured.

  For example, in Patent Document 1, flammable gas is separated from insulating oil filled in a transformer case using a gas permeable material, and the separated flammable gas is collected in a gas reservoir chamber. When detecting the combustible gas, the combustible gas is introduced into the gas detection chamber by opening the electromagnetic valve and spontaneous diffusion of the combustible gas from the gas reservoir chamber. In the gas detection chamber, the gas sensor detects flammable gas.

  For example, in Patent Document 2, a gas chamber formed in an oil chamber into which insulating oil is introduced and a sensor chamber are separated by a plurality of electromagnetic valves, and a small-volume circulation path using a pump is provided. By reducing the volume of the circulation path, the time until the concentration of the dissolved gas, which is a combustible gas in the gas chamber, reaches equilibrium is shortened. When the concentration of the dissolved gas in the gas chamber is balanced, the dissolved gas is introduced into the sensor chamber using a pump, and the concentration of the dissolved gas is measured using a gas sensor.

JP-A-61-99309 JP-A-2-140649

  However, the technique described in Patent Document 1 uses natural diffusion of combustible gas in order to introduce combustible gas from the gas reservoir chamber into the gas detection chamber. For this reason, much time is required to make the concentration of the combustible gas in the gas detection chamber the same as the concentration of the combustible gas in the gas reservoir chamber. In order to open the solenoid valve, it is necessary to energize the solenoid coil of the solenoid valve. Therefore, if the opening time of the solenoid valve becomes long, a large amount of power is consumed, which is not preferable. When the power source of the solenoid valve is a battery, a battery having a large power supply capacity is required, which is not preferable.

  The technique described in Patent Document 2 uses a pump to circulate and introduce a dissolved gas that is a combustible gas. A large amount of electric power is required to operate the pump, which is not preferable.

  This invention is made | formed in view of the above, Comprising: It aims at obtaining the oil-filled transformer with a gas monitoring apparatus which can reduce power consumption.

  In order to solve the above-described problems and achieve the object, an oil-filled transformer with a gas monitoring device according to the present invention, in which insulating oil is put in a container, is provided with a pressurized gas in an upper space in the container. The detection gas is filled. The gas monitoring device includes a detection chamber in which a sensor for detecting a detection gas is provided. The gas monitoring device includes a first pipe that connects the container and the detection chamber. The gas monitoring device includes a valve provided on the first pipe and opened and closed by electric power.

  The oil-filled transformer with a gas monitoring device according to the present invention has an effect that power consumption can be reduced.

Sectional drawing which shows schematically the structure of the oil-filled transformer with the gas monitoring apparatus concerning Embodiment 1 of this invention. The figure for demonstrating the combustible gas detection process performed in the oil-filled transformer with the gas monitoring apparatus concerning Embodiment 1 of this invention. The expanded sectional view which shows roughly the structure of the gas monitoring apparatus concerning Embodiment 1 of this invention The expanded sectional view which shows roughly the structure of the gas monitoring apparatus in Embodiment 2 of this invention The expanded sectional view which shows schematically the structure of the gas monitoring apparatus in Embodiment 3 of this invention

  Hereinafter, an oil-filled transformer with a gas monitoring device according to an embodiment of the present invention will be described in detail with reference to the drawings. Note that the present invention is not limited to the embodiments.

Embodiment 1 FIG.
First, an oil-filled transformer with a gas monitoring device according to Embodiment 1 of the present invention will be described. 1 is a cross-sectional view schematically showing a configuration of an oil-filled transformer with a gas monitoring device according to a first embodiment of the present invention.

  As shown in FIG. 1, the oil-filled transformer 10 includes a cylindrical container 11 and an upper lid 12 that engages with the upper part of the container 11. The container 11 is sealed with an upper lid 12.

  The oil-filled transformer 10 includes an insulating oil 13 placed in a container 11, an iron core 14 accommodated in the insulating oil 13, and a winding 15 wound around the iron core 14. The upper space 16 in the container 11 is previously filled with a gas such as air and nitrogen that has been pressurized to a pressure higher than atmospheric pressure. Hereinafter, gas such as air and nitrogen pressurized to a pressure higher than the atmospheric pressure filled in the space 16 will be referred to as pressurized gas. The combustible gas generated from the insulating oil 13 is discharged into the space 16. The combustible gas is an example of a detection gas, and is a gas detected by a gas monitoring device. In the space 16, the pressurized gas and the combustible gas are mixed. Hereinafter, the gas in which the pressurized gas and the combustible gas are mixed in the space 16 is referred to as a mixed gas.

  The gas monitoring device 20 includes a box-shaped detection chamber 21. The detection chamber 21 is opened to the atmosphere via a pipe 25 described later. In the detection chamber 21, combustible gas generated from the insulating oil 13 is detected. A sensor 22 for detecting flammable gas is provided in the detection chamber 21.

  The gas monitoring device 20 includes a pipe 23. One end of the pipe 23 is connected to the upper lid 12 of the oil-filled transformer 10, and the other end is connected to the detection chamber 21. The pipe 23 introduces the pressurized gas or mixed gas in the container 11 into the detection chamber 21. The pipe 23 is an example of a first pipe. The piping 23 is provided with an electromagnetic valve 24 that allows the inside of the container 11 and the inside of the detection chamber 21 to communicate with each other or to be shut off. When the electromagnetic coil of the electromagnetic valve 24 is energized, the electromagnetic valve 24 is opened, and the pressurized gas or mixed gas in the container 11 is detected in the detection chamber by the pressure difference between the container 11 and the detection chamber 21 of the oil-filled transformer 10. 21 is introduced. The power source of the electromagnetic valve 24 is, for example, a battery (not shown). The electromagnetic valve 24 is an example of a valve that opens and closes by electric power.

  The gas monitoring device 20 includes a pipe 25. One end of the pipe 25 is connected to the detection chamber 21 and the other end is opened to the atmosphere. The pipe 25 discharges the pressurized gas or mixed gas introduced into the detection chamber 21 from the detection chamber 21 and introduces the atmosphere into the detection chamber 21. The pipe 25 is an example of a second pipe.

  Next, the combustible gas detection process performed in the oil-filled transformer with a gas monitoring device according to the present embodiment will be described. FIG. 2 is a diagram for explaining the combustible gas detection process executed in the oil-filled transformer with a gas monitoring device according to the present embodiment.

  In the oil-filled transformer 10, for example, when a discharge occurs between the windings 15 in the insulating oil 13, the insulating oil between the windings in which the discharge is generated decomposes to generate a combustible gas. The combustible gas generated in the insulating oil 13 dissolves in the insulating oil 13, but a part of the incombustible combustible gas escapes from the insulating oil 13 and is discharged into the space 16. In the present embodiment, pressurized gas is present in the space 16. In the space 16, the pressurized gas and the combustible gas are uniformly mixed with time. In the present embodiment, the mixed gas in the space 16 is introduced into the detection chamber 21 due to a pressure difference between the container 11 of the oil-filled transformer 10 and the detection chamber 21. In the detection chamber 21, the concentration of the combustible gas is measured using the sensor 22, and abnormality of the oil-filled transformer 10 is diagnosed. In the present embodiment, the sensor 22 is provided on the side of the pipe 23 in the detection chamber 21, that is, closer to the pipe 23 than the pipe 25.

  First, when the electromagnetic coil of the electromagnetic valve 24 is energized, the electromagnetic valve 24 is opened. As shown in FIG. 2A, the container is caused by the pressure difference between the container 11 of the oil-filled transformer 10 and the detection chamber 21. 11 is introduced into the detection chamber 21 through the pipe 23. Energization of the electromagnetic coil of the electromagnetic valve 24 is controlled by a control device (not shown). The mixed gas 30 introduced into the detection chamber 21 flows in the direction of the pipe 25. At this time, the sensor 22 provided on the pipe 23 side in the detection chamber 21 is exposed to the introduced mixed gas 30. The sensor 22 outputs a sensor output corresponding to the concentration of the combustible gas in the mixed gas 30 to a control device (not shown).

  As shown in FIG. 2B, when the detection chamber 21 is filled with the mixed gas 30, energization of the electromagnetic coil of the electromagnetic valve 24 is stopped, the electromagnetic valve 24 is closed, and the mixed gas 30 into the detection chamber 21. Stop the introduction of. The mixed gas 30 is continuously discharged from the detection chamber 21 through the pipe 25, and the pressure in the detection chamber 21 is reduced to be equal to the atmospheric pressure. When the electromagnetic valve 24 is opened, the pressure of the mixed gas 30 in the space 16, that is, the pressurized gas, is reduced. However, by closing the electromagnetic valve 24 and introducing the pressurized gas into the space 16, the pressure in the space 16 is increased. The pressure of the pressurized gas can be increased again. The pressurized gas is introduced into the space 16 from a pipe different from the pipe 23.

  As shown in FIG. 2C, when the pressure in the detection chamber 21 becomes equal to the atmospheric pressure, the air 31 flows into the detection chamber 21 by natural diffusion, and the mixed gas 30 is discharged.

  According to the processing shown in FIG. 2 described above, the mixed gas 30 in the container 11 is introduced into the detection chamber 21 through the pipe 23 due to a pressure difference between the container 11 and the detection chamber 21 of the oil-filled transformer 10. Is done. Thereby, compared with the case where the mixed gas 30 is introduced into the detection chamber 21 using natural diffusion, the moving time of the mixed gas 30, that is, the opening time of the electromagnetic valve 24 can be shortened. As a result, since the operation time of the solenoid valve 24 that consumes a large amount of power can be shortened, the power consumption can be reduced. When the power source of the electromagnetic valve 24 is a battery, the power supply capacity of the battery can be reduced.

  According to the above-described gas monitoring apparatus according to the present embodiment, the mixed gas 30 can be introduced into and discharged from the detection chamber 21 without using a pump. Compared with the case where the mixed gas 30 is introduced and discharged, power consumption can be reduced.

  Further, as described in the present embodiment, when the concentration of the combustible gas is measured by using only one electromagnetic valve 24 in the pipe 23 which is a gas introduction part to the detection chamber 21, a plurality of electromagnetic valves Compared with the case where the concentration of the combustible gas is measured using the power consumption, the power consumption can be reduced. The technique described in Patent Document 2 described above uses a plurality of electromagnetic valves in order to separate the gas chamber from the sensor chamber. In order to open the solenoid valve, it is necessary to energize the solenoid coil of the solenoid valve. Therefore, if the number of solenoid valves increases, a large amount of power is consumed, which is not preferable.

  According to the gas monitoring apparatus according to the present embodiment, as shown in FIG. 2A, the sensor 22 is provided on the pipe 23 side in the detection chamber 21, and therefore the sensor 22 is installed in the detection chamber 21. Compared with the case where it is provided on the 25th side, the time until the sensor 22 is exposed to the mixed gas 30 is shortened. That is, the time during which the sensor 22 is exposed to the mixed gas 30 can be made longer than when the sensor 22 is provided on the pipe 25 side in the detection chamber 21.

  Thereby, even when the amount of the mixed gas 30 introduced into the detection chamber 21 is small, it is possible to secure the time during which the sensor 22 is exposed to the mixed gas 30, and thus the mixed gas 30 introduced into the detection chamber 21. Therefore, it is not necessary to increase the time of opening the electromagnetic valve 24, that is, it is not necessary to lengthen the opening time of the electromagnetic valve 24, and the power consumption can be reduced.

  As shown in FIG. 2C, the air 31 flows into the detection chamber 21 by natural diffusion, but the sensor 22 is provided on the pipe 23 side in the detection chamber 21. Compared to the case where the sensor 22 is provided on the pipe 25 side, the time during which the sensor 22 reacts to the mixed gas 30 is increased until the sensor 22 is not exposed to the mixed gas 30. That is, the time during which the sensor 22 is exposed to the mixed gas 30 can be made longer than when the sensor 22 is provided on the pipe 25 side in the detection chamber 21.

  Thereby, even when the amount of the mixed gas 30 introduced into the detection chamber 21 is small, it is possible to secure the time during which the sensor 22 is exposed to the mixed gas 30, and thus the mixed gas 30 introduced into the detection chamber 21. Therefore, it is not necessary to increase the time of opening the electromagnetic valve 24, that is, it is not necessary to lengthen the opening time of the electromagnetic valve 24, and the power consumption can be reduced.

  Even when the response speed of the sensor 22 is slow, the time during which the sensor 22 is exposed to the mixed gas 30 can be made longer than when the sensor 22 is provided on the pipe 25 side in the detection chamber 21. Therefore, the concentration of the combustible gas in the mixed gas 30 can be accurately measured.

  FIG. 3 is an enlarged sectional view schematically showing the configuration of the gas monitoring apparatus according to the first embodiment of the present invention. In the present embodiment, as shown in FIG. 3, the sensor 22 is preferably provided at a position separated from the connection portion 25a of the pipe 25 in the detection chamber 21 by a distance L1. The value of the distance L1 is the time taken for the detection of the combustible gas by the sensor 22 and the time when the atmosphere flows into the detection chamber 21 by natural diffusion, that is, the time until the detection chamber 21 is filled with the atmosphere. Is calculated by In the present embodiment, the sensor 22 is provided on the pipe 23 side in the detection chamber 21, but depending on the shape and size of the detection chamber 21 and the value of the distance L <b> 1, the sensor 22 is on the pipe 25 side in the detection chamber 21. May be provided. Even in this case, the time during which the sensor 22 is exposed to the mixed gas 30 can be secured.

For example, if the time required for detecting the combustible gas by the sensor 22 is 6 minutes and the opening time of the electromagnetic valve 24 is 1 minute, the time for the atmosphere to flow into the detection chamber 21 by natural diffusion is 5 minutes, The value of the distance L1 is calculated as a value of 8 cm or more by the following formulas (1) to (3) according to Fick's law. In addition, the time t in Formula (1) is time until the inside of the detection chamber 21 is filled with air | atmosphere by natural diffusion. A value of 8 cm or more is an example of the distance L1. This value is calculated with a diffusion coefficient D of 2 × 10 ⁻⁵ m ² / s in consideration of oxygen in the air as a typical example of the flammable gas, but the diffusion coefficient D of many flammable gases such as acetylene is also calculated. It is known that the value is similar.

Embodiment 2. FIG.
Next, an oil-filled transformer with a gas monitoring device according to a second embodiment of the present invention will be described. FIG. 4 is an enlarged cross-sectional view schematically showing the configuration of the gas monitoring apparatus according to Embodiment 2 of the present invention. 20 A of gas monitoring apparatuses in Embodiment 2 of this invention differ from Embodiment 1 mentioned above in the point by which the resistor 26 is provided in the piping 25. FIG. The description of the same configuration and operation as those in the first embodiment will be omitted, and a description of the different configuration and operation will be given below.

  As shown in FIG. 4, the pipe 25 is provided with a resistor 26 that prevents a gas flow at the connection portion 25 a. The resistor 26 is, for example, a porous body. An example of the porous body is activated carbon. In the present embodiment, the resistor 26 is provided in the connection portion 25a, but the installation location of the resistor 26 is not limited to this. As long as the flow of the gas passing through the pipe 25 can be prevented, the installation place of the resistor 26 in the pipe 25 may be any place. Although the resistor 26 is provided in the pipe 25 in the present embodiment, it may be provided in a space on the pipe 25 side in the detection chamber 21 so as to prevent the flow of gas passing through the detection chamber 21.

  According to the present embodiment, the resistor 26 that prevents the gas flow is provided in the pipe 25. The resistor 26 prevents the mixed gas 30 and the atmosphere 31 from passing through the pipe 25. Thereby, the time for which the mixed gas 30 stays in the detection chamber 21 can be further increased. Since the opening time of the solenoid valve 24 can be further shortened, the power consumption can be further reduced as compared with the first embodiment described above.

  In this embodiment, the resistor 26 is provided in the pipe 25 to prevent passage of the mixed gas 30 and the atmosphere 31 in the pipe 25, but the inner diameter of the pipe 25 is made smaller than the inner diameter of the pipe 23. Therefore, the passage of the mixed gas 30 and the atmosphere 31 in the pipe 25 may be prevented.

Embodiment 3 FIG.
Next, an oil-filled transformer with a gas monitoring device according to Embodiment 3 of the present invention will be described. FIG. 5 is an enlarged cross-sectional view schematically showing the configuration of the gas monitoring apparatus according to Embodiment 3 of the present invention.

  As shown in FIG. 5, the gas monitoring device 20B includes a detection chamber 21A that opens downward in FIG. A part of the detection chamber 21A is configured as a pipe 25A, and the detection chamber 21A is open to the atmosphere via the pipe 25A. In the detection chamber 21A, a combustible gas generated from the insulating oil 13 is detected. A sensor 22A for detecting combustible gas is provided in the detection chamber 21A. The detection chamber 21A and the pipe 25A may be integrally formed.

  The gas monitoring device 20B includes a pipe 23A. One end of the pipe 23A is connected to the upper lid 12 of the oil-filled transformer 10, and the other end is connected to the detection chamber 21A. The pipe 23A introduces the pressurized gas or mixed gas in the container 11 into the detection chamber 21A. The pipe 23A is an example of a first pipe. The piping 23A is provided with an electromagnetic valve (not shown) similar to the electromagnetic valve 24 that allows the inside of the container 11 and the inside of the detection chamber 21A to communicate with or be shut off. When the solenoid coil of the solenoid valve is energized, the solenoid valve is opened, and the pressurized gas or mixed gas in the container 11 is moved into the detection chamber 21A due to the pressure difference between the container 11 of the oil-filled transformer 10 and the detection chamber 21A. To be introduced.

  In the present embodiment, the pipe 25A is provided so as to surround the pipe 23A. The pipe 25A discharges the pressurized gas or mixed gas introduced into the detection chamber 21A from the detection chamber 21A, and introduces the atmosphere into the detection chamber 21A. The pipe 25A is an example of a second pipe.

  In the present embodiment, as shown in FIG. 5, the sensor 22A is provided on the upper wall portion in FIG. 5 of the detection chamber 21A, that is, the ceiling wall 21B. In the detection chamber 21A, the pressurized gas or mixed gas introduced through the pipe 23A is folded back at the ceiling wall 21B of the detection chamber 21A and discharged through the pipe 25A. A gas flow path F is formed which proceeds from the pipe 23A to the ceiling wall 21B, turns back at the ceiling wall 21B, and proceeds to the pipe 25A. Since the sensor 22A is provided in the ceiling wall 21B of the detection chamber 21A, that is, the folded portion R of the gas flow path F, the time during which the sensor 22A is exposed to the mixed gas becomes long. This is because the time in which the mixed gas stays in the detection chamber 21A in the upper space in the detection chamber 21A is longer than the time in which the mixed gas stays in the detection chamber 21A in the space on the piping 25A side in the detection chamber 21A. is there. Thereby, the same effects as those of the first embodiment described above can be obtained.

  According to the present embodiment, the pipe 25A is provided so as to surround the pipe 23A. Thereby, the gas monitoring apparatus 20B can be reduced in size compared with the gas monitoring apparatuses 20 and 20A of Embodiment 1 and 2 mentioned above. Further, as shown in FIG. 5, the gas monitoring device 20B can have a shape similar to the shape of the pipe 25A, and is downsized as compared with the gas monitoring devices 20 and 20A of the first and second embodiments described above. be able to.

  In this embodiment, a part of the detection chamber 21A is a pipe 25A and the gas flow path is folded. However, the detection chamber 21A is formed in a U-shape so that the folding part is provided. A sensor 22A may be provided.

  The configuration described in the above embodiment shows an example of the contents of the present invention, and can be combined with another known technique, and can be combined with other configurations without departing from the gist of the present invention. It is also possible to omit and change the part.

  DESCRIPTION OF SYMBOLS 10 Oil-filled transformer, 11 Container, 12 Top cover, 13 Insulating oil, 14 Iron core, 15 Winding, 16 Space, 20, 20A, 20B Gas monitoring device, 21, 21A Detection room, 21B Ceiling wall, 22, 22A Sensor, 23, 23A, 25, 25A Piping, 25a connection, 24 solenoid valve, 26 resistor, 30 mixed gas, 31 atmosphere.

Claims (5)

An oil-filled transformer with a gas monitoring device in which insulating oil is placed in a container,
The oil-filled transformer is
The upper space in the container is filled with pressurized gas and detection gas,
The gas monitoring device includes:
A detection chamber in which a sensor for detecting the detection gas is provided;
A first pipe connecting the container and the detection chamber;
An oil-filled transformer with a gas monitoring device, comprising: a valve provided in the first pipe and opened and closed by electric power.   The gas monitoring device includes a second pipe that discharges the pressurized gas and the detection gas introduced into the detection chamber from the detection chamber and introduces the atmosphere into the detection chamber. Item 3. An oil-filled transformer with a gas monitoring device according to Item 1.   3. The oil-filled transformer with a gas monitoring device according to claim 2, wherein the sensor is provided closer to the first pipe than to the second pipe in the detection chamber.   4. The oil-filled transformer with a gas monitoring device according to claim 2, wherein a resistor that prevents a gas flow is provided in the second pipe. 5. The detection chamber has a folded portion of the flow path of the pressurized gas and the detection gas,
5. The oil-filled transformer with a gas monitoring device according to claim 1, wherein the sensor is provided in the folded portion.

Images