JPH06221973A - Analysis method for dissolved gas concentration in oil - Google Patents

Abstract

PURPOSE:To prevent intake of mixture gas in an oil-filled device by exhausting a part of oil in gas extraction space through a gas exhaust hole until all the mixture gas is exhausted when the mixture gas is exhausted to a gas detection space. CONSTITUTION:After mixture gas is filled in a gas storage room 2, a three way valve SV4 is switched to pass a pipe P4 and a pipe P5 and to lower a piston 1b, and mixture gas is supplied from the gas storage room to a gas detection space 3 where a sensor is placed for a catalytic combastion method. By filling insulation oil to a level L0 in advance and the piston 1b is lowered to a liquid level L1, the insulation oil flows in the gas detection space through the pipes P2, P4 and P5, and is exhausted through a pipe P7 to an oil pan 4. Thus, when the oil is returned to an oil-filled device 6, there is no fear of intake of mixture gas including air.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for measuring the concentration of combustible gas dissolved in insulating oil used in oil-filled electrical equipment and the like.

[0002]

2. Description of the Related Art FIGS. 2A and 2B are schematic views for explaining a conventional method. A dissolved gas extraction device that extracts combustible gas from insulating oil is equipped with a gas extraction space whose volume is variable, and the volume of this gas extraction space is used to extract the combustible gas from the oil by vacuuming. Then, a dissolved gas extraction device of a type in which insulating oil is discharged from the gas extraction space due to a change in volume thereafter is known. Generally, a gas extraction space is formed by a cylinder and a piston, and a gas extraction space is formed by a bellows that expands and contracts. The dissolved gas extraction apparatus 1 of the illustrated example forms a gas extraction space from the cylinder 1a and the piston 1b. The piston 1b is provided with two expandable pipes P1 and P2, one end of which communicates with the chamber of the cylinder 1a. The pipe P1 is connected to the lower end portion of the container of the oil-filled electrical device (not shown) via the on-off valve SV1, and the pipe P2 is provided with the gas detection space 3 having the gas concentration sensor inside via the on-off valve SV3 and the three-way valve SV4. It is connected to the. A pipe P3 provided on the bottom wall of the cylinder 1a is connected to an upper end of a container of an oil-filled electric device (not shown) via an opening / closing valve SV2. Four
Is an oil span.

First, the opening / closing valves SV1 and SV2 are opened, and a predetermined amount of insulating oil is supplied into the cylinder 1a from an oil-filled electric device (not shown). Next, after closing the on-off valves SV1 and SV2, the on-off valve SV1 is opened again to further supply insulating oil into the cylinder 1a up to the liquid level position L1. At this time, the on-off valve SV3 'is in the closed state. After injecting the insulating oil into the cylinder 1a, the on-off valves SV1 and SV2 are closed, the piston 1b is pulled up to bring the inside of the cylinder 1a into a negative pressure state, and the dissolved gas is extracted from the insulating oil. At this time, the gas detection space formed in the cylinder 1a becomes the gas storage chamber 2. Thereafter, as shown in FIG. 1 (A), the open / close valve SV3 ′ is opened in a state where the three-way valve SV4 is open to the atmosphere space, and the atmosphere is supplied into the cylinder 1a. This makes cylinder 1
The gas storage chamber 2 formed inside a is filled with the mixed gas in which the dissolved gas and the atmosphere are mixed. The state of FIG. 1A is the state of the measurement preparation stage. For the mixed gas in the gas storage chamber 2, the on-off valve SV3 ′ is opened, the three-way valve SV4 is closed as shown in FIG. 1 (B), the piston 1b is lowered to the liquid level level L1, and the gas concentration sensor is stored. The mixed gas is supplied from the gas storage chamber 2 to the gas detection space 3. When the piston 1b reaches the liquid level position L1, the on-off valve SV3 '
Close the valve and open the on-off valve SV2 to open the piston 1
Press b down to return the oil to the container of the oil-filled electric device (not shown). The piston 1b is not completely pushed down, but some oil is left in the cylinder 1a.

[0004]

Conventionally, the piston 1b has been used.
When the liquid level level L1 reaches the liquid level position L1, even if the mixed gas remains inside the cylinder 1a, the on-off valve SV3 'is closed and at the same time the on-off valve SV2 is opened to further push down the piston 1b, so that oil is not shown. Return it to the equipment container.
Therefore, when the mixed gas remains in the cylinder 1a, the mixed gas containing air may be mixed into the container of the oil-filled electrical device. If mixed gas enters the container of oil-filled electrical equipment, the insulating oil deteriorates, and if the amount of mixed gas increases, the equipment such as the transformer body placed inside the container will suffer dielectric breakdown. is there. Note that this problem also occurs when a dissolved gas extraction device of the type that uses a bellows to extract gas is used.

An object of the present invention is to provide a method for analyzing a dissolved gas concentration in oil, which can prevent a mixed gas containing air from being mixed into an oil-filled electric device.

[0006]

SUMMARY OF THE INVENTION In a method to be improved by the present invention, a gas extraction space having a variable volume, an oil injection hole, a gas discharge hole and an oil discharge hole are provided, and Oil is injected into the gas extraction space through the oil injection hole, the volume is increased in a state where the gas extraction space is sealed to extract combustible gas from the injected oil, and the atmosphere is supplied into the gas extraction space. The mixed gas obtained by the above is discharged from the gas extraction space through the gas discharge hole by reducing the volume of the gas extraction space, and the volume of the gas extraction space is further reduced by entering the oil from the gas extraction space through the oil discharge hole. Dissolved gas extraction device that discharges to the insulating device, gas detection space filled with the mixed gas discharged from the dissolved gas extraction device, and the gas concentration of the extracted gas in the mixed gas that is arranged in the gas detection space Gas concentration sensor Using an apparatus for analyzing dissolved gas concentration in oil, which has an on-off valve device for controlling a communication relationship between an oil-filled insulating device and the dissolved gas extraction device and between the dissolved gas extraction device, the gas detection space, and the atmospheric space This is a method for analyzing the dissolved gas concentration in oil. According to the first aspect of the invention, when the volume of the gas extraction space is reduced and the mixed gas is discharged to the gas detection space, the mixed gas is discharged from the gas extraction space through the gas discharge holes until the mixed gas is completely discharged. Drain some of the oil.

In the second aspect of the present invention, the mixed gas from the gas detection space is passed through at least a part of the flow passage between the gas detection space and the dissolved gas extraction device and the exhaust flow passage to the analyzer for dissolved gas concentration in oil. Forced exhaust means for discharging is further provided, and after measuring the gas concentration, the forced exhaust means is operated to discharge the oil discharged from the gas discharge hole to the outside.

[0008]

When the mixed gas is discharged to the gas detection space by reducing the volume of the gas extraction space as in the invention of claim 1,
When a part of the oil in the gas extraction space is discharged through the gas discharge holes until the mixed gas is completely discharged from the gas extraction space,
When returning the oil to the oil-filled insulation device, there is no risk of mixing a mixed gas containing air into the oil-filled insulation device.

According to a second aspect of the present invention, a forced exhaust means for exhausting the mixed gas from the gas detection space through at least a part of the flow path between the gas detection space and the dissolved gas extraction device and the exhaust flow path is further provided. If provided, the oil that has entered the flow path between the gas detection space and the dissolved gas extraction device and the gas detection space will be discharged together with the residual mixed gas when the forced exhaust means is operated after measuring the gas concentration. You can

[0010]

Embodiments of the present invention will be described below with reference to the drawings. 1 (A) to 1 (C) are views for explaining the schematic configuration and operation of the dissolved gas concentration analyzer in oil of the present invention. In these figures, 1 is a dissolved gas extraction device for extracting a combustible gas from oil to store the combustible gas in a gas storage chamber, and a gas extraction whose volume changes depending on a combination of a gas extraction cylinder 1a and a piston 1b. Form a space. One end of the piston 1b communicates with the interior of the cylinder 1a 2
Two expandable pipes P1 and P2 are provided, and the opening end of the pipe P1 into the cylinder 1a has an oil-filled insulation device 6
The oil injection hole for receiving the oil supplied from the container 6a of the cylinder 1a to the cylinder 1 of the pipe P2 is formed.
The end of the opening into a constitutes a gas discharge hole for discharging the mixed gas obtained by supplying the atmosphere into the cylinder 1a from the inside of the cylinder 1a. Further, a pipe P3 is provided on the bottom wall of the cylinder 1a, and an opening end of the pipe P3 into the cylinder 1a is filled with oil from the cylinder 1a.
An oil discharge hole for discharging the oil to the container 6a.
The oil-filled insulation device 6 includes a conservator 6b. The pipe P1 is connected to the lower portion of the container 6a of the oil-filled insulation device 6 via the on-off valve SV1 and the connection pipe, and the pipe P3 is connected to the container 6a of the oil-filled insulation device 6 via the on-off valve SV2 and the connection pipe. Connected to the top. In addition, the pipe P
2 is selectively connected to one end of a pipe P4 or one end of a pipe P6 via a three-way valve SV3, and the other end of the pipe P4 is selectively connected to one end of a pipe P5 via a three-way valve SV4.
It also selectively communicates with the atmosphere. The other end of the pipe P5 is connected to the gas detection space 3, and the gas detection space 3 is connected to one end of a pipe P7 forming an exhaust passage. The other end of the pipe P7 opens toward the oil span 4, and the other end of the pipe P6 is connected to the pipe P7. Gas detection space 3
An air pump 5 as a forced exhaust means is connected to. As the sensor arranged in the gas detection space 3, for example, a gas concentration detection sensor by a contact combustion method can be used. This sensor adsorbs air containing a flammable gas on the surface of a catalyst heated to an appropriate temperature and utilizes the fact that the flammable gas catalytically burns by reacting with oxygen in the air to burn metal objects. It is heated and the change in the electric resistance of the metal body is measured to detect the concentration of the combustible gas.

When supplying insulating oil into the cylinder 1a, first, the three-way valve SV3 is closed with respect to the pipe P2, the opening / closing valve SV1 is opened, SV2 is closed, and the piston 1b is pulled up from L2 to L1. Supply a certain amount of insulating oil from the oil-filled electrical equipment to. After injecting the insulating oil into the cylinder 1a, the on-off valves SV1 and SV2 are then closed, and the piston 1b is pulled up to L3 to bring the inside of the cylinder 1a into a negative pressure state to extract the dissolved gas from the insulating oil. At this time, the gas detection space formed in the cylinder 1a becomes the gas storage chamber 2.

Next, the on-off valve SV1 is opened again, and the insulating oil is further supplied to the cylinder 1a up to L0 by utilizing the height h of the amount of insulating oil in the container 6a of the oil-filled electric device 6.
Conventionally, the supply of the insulating oil was stopped at the liquid level position L1, but in the present embodiment, the insulating oil is further supplied to insulate up to the liquid level position L0 above the liquid level position L1. Supply oil. At this time, the three-way valve SV3 is connected to the pipe P2.
Is closed against. Thereafter, as shown in FIG. 1 (A), a three-way valve SV3 connected to the pipe P2 and a three-way valve SV are connected.
The three-way valve SV4 connected to the other end of the pipe P4, one end of which is connected to 3, is opened as shown in the figure. At this time, the three-way valve SV
4 is a three-way valve S
Atmosphere is supplied to the inside of the cylinder 1a through the pipes P2 and P4 which are connected by V3. As a result, the gas storage chamber 2 formed inside the cylinder 1a is filled with a mixed gas of a dissolved gas and the atmosphere. This Figure 1 (A)
Is the state at the measurement preparation stage.

After filling the gas storage chamber 2 with the mixed gas,
As shown in FIG. 1 (B), the three-way valve SV4 is closed so that the pipe P4 and the pipe P5 communicate with each other, the piston 1b is lowered, and the gas storage chamber 3 is provided in the gas detection space 3 in which the catalytic combustion type gas concentration sensor is housed. The mixed gas is supplied from 2. Note that the pipe P4, the pipe P5, and the three-way valve SV4 that are in communication form a gas supply flow path. The mixed gas is gradually discharged from the gas detection space 3 through the pipe P7.
In this embodiment, insulating oil is previously added to the conventional liquid level position L1.
Since it is inserted to the position L0 above it, the piston 1b
At the stage of lowering to the conventional liquid level position L1, insulating oil flows into the gas detection space 3 through the pipes P2, P4 and P5 and is gradually discharged to the oil span 4 through the pipe P7. The amount of insulating oil flowing into the gas detection space 3 is about 2
It is about 3 cc. By doing so, the mixed gas remaining in the cylinder together with the insulating oil is exhausted, so that when the oil is returned to the oil-filled insulating device, the mixed gas containing air may be mixed in the oil-filled insulating device. Disappear.

When the piston 1b reaches the liquid level position L1, the three-way valve SV3 is connected to the pipe P4 as shown in FIG. 1 (C).
And the pipe P6 are closed so as to communicate with each other, and then the on-off valve S
Open V2 and push down piston 1b further. As a result, the insulating oil is discharged from the cylinder 1a. The piston 1b is stopped at the liquid level level L2 so as to leave a predetermined amount of insulating oil in the cylinder 1a without lowering it to the lowermost position.

The concentration of the mixed gas supplied to the gas detection space 3 is measured by a catalytic combustion type gas concentration sensor. When the measurement is completed, the air pump 5 is driven to discharge the gas from the gas detection space 3. At this time, the three-way valves SV3 and S
V4 is in the state shown in FIG. 1C, and the atmosphere forcibly supplied from the air pump 5 to the gas detection space 3 is
First exhaust flow path composed of pipe P7 and three-way valve SV3
And a second exhaust flow path composed of a pipe P5, a pipe P4, a pipe P6, and a pipe P7 which are communicated with each other by the SV4, and gas is rapidly discharged from the gas detection space 3 through these two flow passages. . At this time, the gas and oil droplets remaining in the pipes P5 and P4 forming the gas supply passage to the gas detection space 3 are simultaneously discharged through the second exhaust passage. Therefore, according to the present embodiment, not only the gas detection space 3 but also the gas and oil drops remaining inside the pipes P5 and P4 can be discharged at the same time, so that the insulating oil in the cylinder 1a is discharged to the outside through the gas detection space 3. However, it is possible to suppress a decrease in detection accuracy due to residual gas or oil droplets. In order to eliminate residual gas and oil drops as much as possible, the three-way valve S
V3 is preferably provided as close as possible to the outlet of the gas reservoir of the dissolved gas extraction device.

In this embodiment, since the pipe P6 is connected to the pipe 7, there is an advantage that the discharged oil droplets can be easily treated. Needless to say, the pipe P6 may not be connected to the pipe 7.

In the above embodiment, the cylinder and the piston are used to form the gas extraction space whose volume changes.
It goes without saying that the present invention can also be applied to the case of using a dissolved gas extraction device of a type in which a gas extraction space whose volume changes using a bellows is used.

[0018]

According to the first aspect of the present invention, when the volume of the gas extraction space is reduced and the mixed gas is discharged to the gas detection space, the gas discharge hole is discharged until the mixed gas is completely discharged from the gas extraction space. Since a part of the oil in the gas extraction space is discharged through the through, there is no risk of mixing a mixed gas containing air into the oil-filled insulation device when returning the oil to the oil-filled insulation device.

According to the invention of claim 2, there is further provided a forced exhaust means for exhausting the mixed gas from the gas detection space through at least a part of the flow path between the gas detection space and the dissolved gas extraction device and the exhaust flow path. In order to provide it, when the forced exhaust means is operated after measuring the gas concentration, the oil that has entered the flow path between the gas detection space and the dissolved gas extraction device and the gas detection space is discharged together with the residual mixed gas. There is an advantage that can be.

[Brief description of drawings]

1 (A) to 1 (C) are views for explaining the schematic configuration and operation of an apparatus for analyzing dissolved gas concentration in oil for carrying out the method of the present invention.

2A and 2B are diagrams for explaining a schematic configuration and operation of an apparatus for analyzing dissolved gas concentration in oil, which implements a conventional method.

[Explanation of symbols]

 1 Dissolved Gas Extractor 1a Cylinder 1b Piston 2 Gas Reservoir 3 Gas Detection Space 4 Oil Span 5 Air Pump (Forced Exhaust Device) SV1 Open / close valve SV2 Open / close valve SV3 Three-way valve SV4 Three-way valve P1-P7 Piping

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Junji Koyama 1-8-24, Chuo-cho, Meguro-ku, Tokyo Komei Rikagaku Corporation

Claims (2)

[Claims] 1. A gas extraction space having a variable volume, an oil injection hole, a gas discharge hole and an oil discharge hole, wherein oil is injected into the gas extraction space from an oil-filled insulating device through the oil injection hole. , A combustible gas is extracted from the oil injected by increasing the volume in a state where the gas extraction space is sealed, and a mixed gas obtained by supplying the atmosphere into the gas extraction space is supplied to the gas extraction space. The volume is reduced and discharged from the gas extraction space through the gas discharge hole, and the volume of the gas extraction space is further reduced to allow the oil from the gas extraction space to pass through the oil discharge hole to the oil-filled insulating device. Dissolved gas extraction device to be discharged, a gas detection space filled with the mixed gas discharged from the dissolved gas extraction device, the gas concentration of the extracted gas in the mixed gas is arranged in the gas detection space To detect Concentration sensor, and an on-off valve device that controls the communication relationship between the oil-filled insulation device and the dissolved gas extraction device and between the dissolved gas extraction device, the gas detection space, and the atmospheric space A method for analyzing a dissolved gas concentration in oil using a dissolved gas concentration analyzer, wherein when the mixed gas is discharged to the gas detection space by reducing the volume of the gas extraction space, A part of the oil in the gas extraction space is discharged through the gas discharge hole until all the mixed gas is discharged from the above. 2. The in-oil dissolved gas concentration analyzer analyzes the mixed gas from the gas detection space through at least a part of a flow path between the gas detection space and the dissolved gas extraction device and an exhaust flow path. The method for analyzing a dissolved gas concentration in oil according to claim 1, further comprising a forced exhaust means for discharging, and operating the forced exhaust means after measuring the gas concentration to discharge the oil discharged from the gas discharge hole to the outside. ..