JP3054285B2 - Analysis method for dissolved gas concentration in oil - Google Patents

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 flammable gas dissolved in insulating oil used for oil-filled electric equipment and the like.

[0002]

2. Description of the Related Art FIGS. 2A and 2B are schematic views for explaining a conventional method. Equipped with a gas extraction space with a variable volume in a dissolved gas extraction device that extracts flammable gas from insulating oil, utilizing the change in volume of this gas extraction space to extract flammable gas from oil by evacuation Dissolved gas extraction devices of the type that discharges insulating oil from a gas extraction space according to a change in volume thereafter are known. Generally, a gas extraction space is formed by a cylinder and a piston, or a gas extraction space is formed by an expandable and contractable bellows. The dissolved gas extraction device 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 extendable pipes P1 and P2 whose one ends communicate with the interior of the cylinder 1a. The pipe P1 is connected to the lower end of the container of the oil-filled electric device (not shown) via the on-off valve SV1, and the pipe P2 is connected to the on-off valve SV3 '.
And a gas detection space 3 internally provided with a gas concentration sensor via a three-way valve SV4. 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 on-off valve SV2.
4 is an oil span.

First, the on-off 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 the insulating oil into the cylinder 1a to the liquid level L1. At this time, the on-off valve SV3 'is in the closed state. After the insulating oil is injected into the cylinder 1a, the on-off valves SV1 and SV2 are closed, and the piston 1b is pulled up 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. Thereafter, as shown in FIG. 1A, with the three-way valve SV4 released to the atmosphere, the on-off valve SV3 'is opened to supply the atmosphere into the cylinder 1a. This allows cylinder 1
The mixed gas in which the dissolved gas and the atmosphere are mixed is filled in the gas storage chamber 2 formed inside a. The state of FIG. 1A is a state of a measurement preparation stage. The mixed gas in the gas reservoir 2 opens the on-off valve SV3 ', closes the three-way valve SV4 as shown in FIG. 1B, lowers the piston 1b to the liquid level position L1, and houses the gas concentration sensor. 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 '
Is closed and the on-off valve SV2 is opened, and the piston 1
b is pushed 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 leaves some oil in the cylinder 1a.

[0004]

Conventionally, the piston 1b
Reaches the liquid level level L1, even if the mixed gas remains inside the cylinder 1a, the on-off valve SV3 'is closed and the on-off valve SV2 is opened at the same time, and the piston 1b is further pushed down, so that the oil is supplied to the oil-injected electric device (not shown). Returned to the equipment container.
Therefore, when the mixed gas remains in the cylinder 1a, there is a possibility that the mixed gas containing air may be mixed into the container of the oil-filled electric device. If mixed gas is mixed into the container of oil-filled electrical equipment, the insulating oil will be degraded, and if the amount of mixed gas increases, insulation breakdown of transformers and other equipment placed inside the container will occur. is there. This problem also occurs when a dissolved gas extracting device of the type that extracts gas using bellows is used.

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

[0006]

SUMMARY OF THE INVENTION According to the present invention, there is provided a method comprising: a gas extraction space having a variable volume; an oil injection hole; a gas discharge hole and an oil discharge hole; Inject oil into the gas extraction space through the oil injection hole, extract the flammable gas from the injected oil by increasing the volume while sealing the gas extraction space, and supply the atmosphere into the gas extraction space. The mixed gas obtained by reducing the volume of the gas extraction space is discharged from the gas extraction space through the gas discharge hole, and further reducing the volume of the gas extraction space to allow oil to enter the oil from the gas extraction space through the oil discharge hole. A dissolved gas extraction device to be discharged to an insulating device, a gas detection space filled with a mixed gas discharged from the dissolved gas extraction device, and a gas detection space, which is disposed in the gas detection space and detects a gas concentration of the extracted gas in the mixed gas. Gas concentration sensor Using an oil-dissolved gas concentration analyzer having an on-off valve device for controlling 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. This is a method for analyzing the dissolved gas concentration in oil. According to the first aspect of the present invention, when the mixed gas is discharged to the gas detection space by reducing the volume of the gas extraction space, the gas extraction hole passes through the gas discharge hole until all the mixed gas is discharged from the gas extraction space. Drain some of the oil.

According to the second aspect of the present invention, the mixed gas is supplied from the gas detection space to the dissolved gas concentration analyzer in oil 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. A forced exhaust means for discharging is further provided, and after the gas concentration is measured, 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 into the gas detection space by reducing the volume of the gas extraction space as in the first aspect of the present invention,
When part of the oil in the gas extraction space is discharged through the gas discharge holes until all the mixed gas is discharged from the gas extraction space,
When returning the oil to the oil-filled insulating device, there is no possibility that the mixed gas containing air is mixed into the oil-filled insulating device.

As in the 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. 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. Can be.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. FIGS. 1A to 1C are diagrams for explaining the schematic configuration and operation of the dissolved gas concentration analyzer in oil of the present invention. In these figures, reference numeral 1 denotes a dissolved gas extraction device that extracts a flammable gas from oil and stores the flammable gas in a gas storage chamber. The gas extraction device changes in volume by a combination of a gas extraction cylinder 1a and a piston 1b. Form a space. One end of the piston 1b communicates with the chamber of the cylinder 1a 2
The pipes P1 and P2 are provided so that they can be extended and retracted.
And an oil injection hole for receiving oil supplied from the container 6a into the cylinder.
An open end into the cylinder a forms a gas discharge hole for discharging a mixed gas obtained by supplying the atmosphere into the cylinder 1a from the cylinder 1a. Also in the bottom wall portion of the cylinder 1a and the pipe P3 is provided, the oil for the open end of the cylinder 1a of the pipe P3 is discharged oil from the cylinder 1a into a container 6a of the oil Nyuze' edge equipment 6 It constitutes a discharge hole. Incidentally oil Nyuze' edge device 6 is provided with a conservator 6b.
The pipe P1 is connected to the lower part of the container 6a of the oil -insulating / insulating device 6 via the on-off valve SV1 and the connection pipe, and is connected to the pipe P3.
It is connected via an on-off valve SV2 and the connecting pipe to the top of the container 6a of the oil Nyuze' edge device 6. The pipe P2 is selectively connected to one end of the pipe P4 or one end of the pipe P6 via the three-way valve SV3, and the other end of the pipe P4 is connected to the three-way valve SV4.
And selectively connected to one end of the pipe P5, and selectively communicates with the atmosphere. The other end of the pipe P5 is connected to the gas detection space 3, and one end of a pipe P7 forming an exhaust passage is connected to the gas detection space 3. The other end of the pipe P7 opens toward the oil span 4, and the pipe P7 has a pipe P6.
Are connected to each other. The gas detection space 3 is connected to an air pump 5 as a forced exhaust means. As a sensor arranged in the gas detection space 3, for example, a gas concentration detection sensor using a contact combustion method can be used. This sensor adsorbs air containing flammable gas on the surface of a catalyst heated to an appropriate temperature, and uses a combustible gas that reacts with oxygen in the air to contact and burn a metal body. Heating is performed, and the change in the electrical resistance of the metal body is measured to detect the concentration of the flammable gas.

When supplying the insulating oil into the cylinder 1a, first, the three-way valve SV3 is closed with respect to the pipe P2, the on-off valve SV1 is opened, the on- off valve SV2 is closed, and the piston 1b is set to L.
Then, a predetermined amount of insulating oil is supplied from an oil-filled electric device into the cylinder 1a by raising the pressure from 2 to L1. After the insulating oil is injected into the cylinder 1a, the on-off valves SV1 and SV2 are then closed, the piston 1b is pulled up to L3, and the inside of the cylinder 1a is brought 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.

[0012] Next, into the cylinder 1a by opening the on-off valve SV1 again supplies an insulating oil by utilizing the height h of the insulating oil in the oil amount in the container 6a of the oil filled electrical equipment 6 until L0. 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 as described above,
The insulating oil is supplied up to the liquid level position L0 above the liquid level position L1. At this time, the three-way valve SV3 is in a closed state with respect to the pipe P2. Thereafter, as shown in FIG. 1A, a three-way valve SV3 connected to the pipe P2 and a three-way valve SV connected to the other end of the pipe P4 having one end connected to the three-way valve SV3.
4 are in the open state shown in the figure. At this time, the three-way valve SV4
The pipe P4 is communicated with the atmosphere, and the cylinder 1a is connected via the pipes P2 and P4 which are communicated by the three-way valve SV3.
The atmosphere is supplied inside. As a result, the gas storage chamber 2 formed inside the cylinder 1a is filled with a mixed gas in which the dissolved gas and the atmosphere are mixed. The state of FIG. 1A is a state of a 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 pipes P4 and P5 communicate with each other, the piston 1b is lowered, and a gas storage chamber is provided in the gas detection space 3 in which the contact combustion type gas concentration sensor is stored. 2 to supply a mixed gas. A gas supply flow path is formed by the communicating pipe P4, the pipe P5, and the three-way valve SV4. The mixed gas is gradually and naturally exhausted from the gas detection space 3 through the pipe P7.
In this embodiment, the insulating oil is previously applied to the conventional liquid level position L1.
The piston 1b
Is lowered to the conventional liquid level position L1, the 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. In this case, since all the mixed gas remaining in the cylinder together with the insulating oil is discharged, when returning the oil to the oil-filled insulating device, there is a possibility that the mixed gas containing air may be mixed into the oil-filled insulating device. Disappears.

When the piston 1b reaches the liquid level level L1, the three-way valve SV3 is connected to the pipe P4 as shown in FIG.
And the pipe P6 are closed so as to communicate with each other.
V2 is opened and the piston 1b is further pushed down. As a result, the insulating oil is discharged from the cylinder 1a. The piston 1b is stopped at the liquid level L2 so that a predetermined amount of insulating oil is left in the cylinder 1a without being lowered to the lowest position.

The concentration of the mixed gas supplied to the gas detection space 3 is measured by a contact combustion type gas concentration sensor. When the measurement is completed, the air pump 5 is driven to discharge gas from the gas detection space 3. At this time, the three-way valves SV3 and S3
V4 is in the state shown in FIG. 1 (C), 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 communicated by the SV4, and the gas is quickly discharged from the gas detection space 3 through these two flow paths. . At this time, gas and oil droplets remaining in the pipes P5 and P4 constituting the gas supply flow path to the gas detection space 3 are simultaneously discharged through the second exhaust flow path. Therefore, according to this embodiment, not only the gas detection space 3 but also the gas and oil droplets remaining inside the pipes P5 and P4 can be simultaneously discharged, so that the insulating oil in the cylinder 1a is discharged to the outside through the gas detection space 3. However, a decrease in detection accuracy due to residual gas or oil droplets can be suppressed. In order to eliminate residual gas and oil droplets as much as possible, a 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 droplet can be easily treated. Needless to say, the pipe P6 may not be connected to the pipe 7.

In the above embodiment, the gas extraction space whose volume changes using the cylinder and the piston is constituted.
Of course, the present invention can also be applied to a case where a dissolved gas extraction device of a type that forms a gas extraction space whose volume changes using a bellows is used.

[0018]

According to the first aspect of the present invention, when the mixed gas is discharged to the gas detection space by reducing the volume of the gas extraction space, the gas discharge holes are kept until all the mixed gas is discharged from the gas extraction space. When the oil is returned to the oil-filled insulating device, there is no possibility of mixing the mixed gas containing air into the oil-filled insulating device when the oil is returned to the oil-filled insulating device.

According to the second aspect of the present invention, the 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. 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 are advantages that can be.

[Brief description of the drawings]

FIGS. 1A to 1C are diagrams for explaining a schematic configuration and operation of an apparatus for analyzing a concentration of a dissolved gas in oil that implements the method of the present invention.

FIGS. 2A and 2B are diagrams for explaining a schematic configuration and operation of a dissolved gas concentration analyzer in oil for implementing a conventional method.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Dissolved gas extraction device 1a Cylinder 1b Piston 2 Gas storage chamber 3 Gas detection space 4 Oil span 5 Air pump (forced exhaust device) SV1 On-off valve SV2 On-off valve SV3 Three-way valve SV4 Three-way valve P1-P7 Piping

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Junji Koyama 1-8-24 Chuo-cho, Meguro-ku, Tokyo Hikari Meiri Chemical Industry Co., Ltd. (56) References JP-A-60-253842 (JP, A) JP-A-2-47531 (JP, A) JP-A-1-202675 (JP, A) JP-A-63-277954 (JP, A) JP-A-2-44239 (JP, A) (58) Int.Cl. ⁷ , DB name) G01N 1/22 G01N 1/00 101

Claims (2)

(57) [Claims] 1. A gas extraction space having a variable volume, an oil injection hole, a gas discharge hole and an oil discharge hole, and oil is injected into the gas extraction space from the oil-filled insulation device through the oil injection hole. In a state where the gas extraction space is sealed, a flammable gas is extracted from the injected oil by increasing the volume thereof, and a mixed gas obtained by supplying air into the gas extraction space is supplied to the gas extraction space. by reducing the volume discharged from the gas extraction space through the gas discharge hole, the oil Nyuze' edge device through the oil discharge hole of the oil from further reduce the volume of the gas extraction space the gas extraction space A gas detection space filled with the mixed gas discharged from the dissolved gas extraction device; and a gas concentration of the extracted gas in the mixed gas, which is disposed in the gas detection space. Detect ga A concentration sensor, and an on-off valve device that controls a 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 the concentration of dissolved gas in oil using a gas concentration analyzer, wherein the volume of the gas extraction space is reduced and the mixed gas is discharged to the gas detection space, from within the gas extraction space. A method of analyzing the concentration of dissolved gas in oil, wherein a part of the oil in the gas extraction space is discharged through the gas discharge hole until all of the mixed gas is discharged. 2. The apparatus for analyzing a concentration of a dissolved gas in oil, wherein the mixed gas is supplied 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. 2. The method according to claim 1, further comprising a forced exhaust unit that discharges the oil, and after the gas concentration is measured, the forced exhaust unit is operated to discharge the oil discharged from the gas discharge hole to the outside. 3. .