JPH0414749B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical field to which the invention pertains] The present invention relates to a method of operating an apparatus for automatically analyzing gas dissolved in sample oil collected from an oil-immersed transformer or the like.

[Prior art and its problems]

When a thermal or electrical abnormality occurs inside an oil-filled electrical device, such as a transformer, the insulating oil or insulating material around it decomposes and generates gas. These gases dissolve in the insulating oil and the gas concentration in the oil increases, so the gas dissolved in the oil (hereinafter referred to as gas in oil) is extracted and analyzed, and based on the analysis results, the inside of the transformer can be detected. A method for diagnosing abnormal conditions is already well known, and because abnormal conditions can be detected early, it is widely used and effective both in Japan and abroad.

Methods for analyzing gas in oil include, for example: (1) Extracting gas in oil using a Torrichieri vacuum using mercury, and analyzing the extracted gas using a gas chromatograph.

(2) Gas in oil is extracted using a combination of a mercury diffusion pump and a tetra pump, and the extracted gas is analyzed using a gas chromatograph.

etc., and are widely used.

However, while these methods are easy to implement, they also have the following problems.

(1) Because the operation is performed manually or semi-automatically,
Manpower is required throughout the entire process from start to finish.

(2) Operation is complicated, and operator skill is required to perform highly accurate analysis.

(3) Since mercury is used, there is a risk of harm to the human body due to deterioration of the working environment due to mercury volatilization.

(4) The device is made of glass and is easily damaged.

In order to solve the above problems, the present inventors are currently applying for a patent for an automatic analysis device for gas in oil.

Figure 2 shows the configuration of this automatic gas-in-oil analyzer and a system diagram to explain the paths of oil and gas. The process will be divided into the following steps: sample oil collection process, deaeration process, extraction gas mixing process, extraction gas injection process into the gas chromatograph, and system cleaning process.

1 Collection of Sample Oil into Extraction Cylinder A piston 2 is arranged in the extraction cylinder 1 so as to be slidable in the axial direction by a piston rod 3 provided at its center. A bellows 4 is provided on the lower part of the outer circumference of the piston 2 up to the bottom, and a first chamber 40 is formed between the bellows 4 and the extraction cylinder 1 . The piston 2 is provided with several small holes 6 that penetrate through the inside from the side surface thereof and reach the top surface.
An O-ring 5 is disposed between a portion of the side surface of the piston 2 above the opening of the pore 6 and the inner surface of the extraction cylinder 1, and a second A chamber 41 is formed.

On the other hand, the flow path of the sample oil flowing into the extraction cylinder 1 and being discharged is from the container 8 containing the sample oil 7 collected from the oil-immersed equipment via the electromagnetic valve 9, the check valve 13, and the electric valve 10. A solenoid valve 11, a check valve 14, which is connected to a passage piped to communicate with the chamber 40 of the extraction cylinder 1, and a pipe extending upward from the extraction cylinder 1.
It consists of a path that is piped to the external free end of this system via the solenoid valve 12, and a pipe that connects these two paths.

Next, the procedure for collecting the sample oil 7 into the extraction cylinder 1 with the configuration up to this point will be explained. The piston 2 stops at the uppermost position in the extraction cylinder 1, the solenoid valves 9, 10, 11, and 12 are open, and the check valve 13 is closed because oil flows only from the side of the container 8. 14
Since oil flows only from the side of the extraction cylinder 1, when the piston 2 is lowered to the lowest position by the piston rod 3 in this state, the pressure in the second chamber 41 formed between the extraction cylinder 1 and the piston 2 is reduced. The sample oil 7 flows into the extraction cylinder 1 through the solenoid valve 9, the check valve 13 and the solenoid valve 11 in order to be extracted. At this time, the oil existing in the first chamber 40 is pressurized by the downward movement of the piston 2 and is forced out through the solenoid valve 10, but the flow is blocked toward the check valve 13 and the oil is removed from the container 8. Sample oil 7 flowing in
and is collected into the second chamber 41 through the solenoid valve 11.

Next, when the piston rod 3 is operated to raise the piston 2 to the upper limit position, a portion of the oil accumulated in the second chamber 41 flows into the first chamber 40 through the pore 6 of the piston 2. However, most of it is extracted to the outside through the solenoid valve 11, check valve 14, and solenoid valve 12. At the same time, the first chamber 40 is depressurized and the sample oil 7
The oil flows into this area through the electromagnetic valve 9, the check valve 13, and the electromagnetic valve 10, but at this time, some of the oil discharged from the pipe connecting the two paths is mixed in.

When the above operation is repeated, for example, six times, the oil sampled in the extraction cylinder 1 is replaced with new sample oil 7. Finally, by stopping the piston 2 at the upper limit position, the second chamber 41 in the extraction cylinder 1 is opened.
The oil accumulated in the chamber is discharged and a certain amount of sample oil 7 is collected in the first chamber 40.

2. Degassing the collected sample oil In order to extract the gas in the sample oil 7 collected in the extraction cylinder 1 and guide it to the analyzer, the extraction cylinder 1
An extraction gas path is provided outside the upper part of the extraction cylinder 1 so as to communicate with the extraction cylinder 1 . That is, the extracted gas is guided from the extraction cylinder 1 through the solenoid valve 16 and through the oil detector 17 to the extracted gas sampling cylinder 19. Solenoid valves 18 and 20 are provided before and after this cylinder 19, respectively, and the extracted gas is further automatically Six-way valves 60, 61 and measuring tube 60 attached to these
a, 61a and the extraction gas mixing cylinder 29. Hereinafter, the path from the solenoid valve 20 to the extraction gas mixing cylinder 29 will be collectively referred to as a metering valve system.
Note that detailed description of the configuration and operation of the gas chromatograph 42 will be omitted.

The oil detector 17 is a beam switch consisting of a light emitting diode that emits light with a wavelength of 9400 Å and its light receiver.The piping in this part uses a glass tube that transmits light, and the oil is sent from the extraction cylinder 1. A signal is output when the oil rises inside the glass tube and blocks the light. This signal closes the solenoid valve 16 to prevent oil from rising.

Next, the procedure for extracting dissolved gas from the sample collected in the extraction cylinder 1 will be explained. When the piston 2 at the highest limit position is lowered to the lowest position with the solenoid valves 9, 10, 11, 12, and 16 closed, the pressure in the upper second chamber 41 in the extraction cylinder 1 is reduced, and the lower pressure is reduced. As the pressure in the first chamber 40 increases, the sample oil collected in the first chamber 40 is violently injected into the second chamber 41 in the extraction cylinder 1 through the pore 6 in the upper part of the piston 2. At this time, since the area is in a vacuum state, the gas and oil dissolved in the sample oil 7 are separated. Piston 2
When the solenoid valve 16 is opened when the oil reaches the lowest position and starts rising again, the gas separated and extracted from the sample oil 7 passes through the oil detector 17 and enters the extracted gas sampling cylinder 1.
9, but at this time, the solenoid valve 18 is
is opened and the solenoid valve 20 is closed, and the extracted gas sampling cylinder 19 is kept in a reduced pressure state by lowering the piston 19a. The extracted gas collected in the cylinder 19 is transferred to the piston 19a by closing the solenoid valve 18 and opening the solenoid valve 20.
When the piston 29a is raised, the piston 29a is lowered and introduced into the metering valve system, which has been depressurized in advance. By repeating these piston and valve operations about 30 times, the extracted gas collected in the extracted gas sampling cylinder 19 is finally collected in the metering valve system, and almost all of the gas dissolved in the sample oil 7 is extracted. be done.

3 Mixing of extracted gas in the metering valve system The gas extracted by the above operations has a different composition before and after the extraction operation, so the following operation is performed to make it uniform.

Close the solenoid valve 20 and close the extraction gas mixing cylinder 29.
Solenoid valve 31 of the gas release path to the outside connected to
is closed, and the piston 29a in the extraction gas mixing cylinder 29 is moved up and down. By driving the piston 29a up and down, the extracted gas within the metering valve system is stirred and has a substantially uniform composition. Finally, when stopping the drive of the piston 29a, it is set to the uppermost position.

4 Injecting the extraction gas into the gas chromatograph The uniformly mixed extraction gas is injected into the automatic six-way valve 6.
The liquid is injected into the flow path of the gas chromatograph 42 by switching the flow paths 0 and 61 using an electric motor (not shown). This extracted gas is transported to a column and a detector (not shown) of the gas chromatograph 42 by argon piped into the angone gas cylinder 50 and is analyzed.

5. Cleaning inside the metering valve system A part of the extracted gas collected in the metering valve system as described above is injected into the gas chromatograph 42 and analyzed. However, at this time, the measuring tubes 60a, 61
The extracted gas collected in the metering valve systems other than a remains in the piping and causes an error in the next analysis value. Cleaning is therefore required to remove residual extraction gas in this system. This cleaning procedure is performed as follows.
A solenoid valve 30 and a solenoid valve 18 are provided in the middle of the piping from the argon gas cylinder 50 connected to the path connecting the extraction cylinder 1 to the extraction gas sampling cylinder 19.
20 and 31, and close the solenoid valve 16 to supply argon gas from the cylinder 50 into the metering valve system.
The remaining extraction gas is discharged from the system by flowing it for seconds. Next, close the solenoid valves 30 and 31 and move the piston 29a inside the mixing cylinder 29 up and down several times. , 31 are opened, argon gas is flowed from the cylinder 50 for 30 seconds, and the extracted gas is discharged to the outside of the system. This cleaning process is normally performed twice in one analysis process: during the collection of the sample oil 7 into the extraction cylinder 1 and during the analysis of the extracted gas.

The composition and operation of the automatic gas-in-oil analyzer have been outlined above.

As described above, when analyzing gas in oil using this device, the extracted gas in the metering valve system extracted from the sample oil is stirred to have a uniform composition, and then the extracted gas is sent to the gas chromatograph 42. The piston 29a inside the mixing cylinder 29 is driven up and down, but as a result of further detailed experiments by the present inventors regarding this extraction gas mixing method, it has been found that this operation is not possible if only the piston 29a is moved up and down.
It was found that even after several cycles, the uniformity of the extracted gas within the metering valve system was still insufficient.

Therefore, it is desirable to use more effective means to achieve a uniform composition of the extracted gas within the metering valve system.

[Purpose of the invention]

The present invention has been made in view of the above points, and its purpose is to provide a method for uniformly mixing gases extracted from sample oil in order to perform accurate analysis using the above-mentioned automatic gas-in-oil analyzer. It is about providing.

[Key points of the invention]

The present invention uniformly mixes the extracted gas sampled in the metering valve system by alternately driving the piston in the extracted gas sampling cylinder and the piston in the extracted gas mixing cylinder.

[Embodiments of the invention]

The present invention will be explained below based on examples.

Since the structure of the apparatus to which the present invention is applied is the same as that shown in FIG. 2, its explanation will be omitted, and only the points that differ from the conventional method will be described below. The present invention differs from the conventional method in the process of mixing the extracted gas in the metering valve system to make it uniform, which will be explained with reference to FIG. 2 again.

In the present invention, first open the solenoid valves 18 and 20,
The piston 29a in the extraction gas mixing cylinder 29 is lowered from the uppermost position to the lowermost position and stopped. Then, the pressure inside the mixing cylinder 29 is reduced and the extracted gas collected in the metering valve system flows into the mixing cylinder 29 while being stirred. Next, when the piston 19a in the extracted gas sampling cylinder 19 is similarly lowered from the uppermost position to the lowermost position and stopped, the extracted gas that had flowed into the mixing cylinder 29 is conversely moved inside the sampling cylinder 19, which has become depressurized. It flows into the water while being stirred. Next, when the piston 19a in the sampling cylinder 19 is raised from the lowest position to the highest position, the extraction gas flows into the mixing cylinder 29, and in the same way, the piston 29a in the mixing cylinder 29 is raised from the lowest position to the highest position. By repeating this series of piston operations in which the piston is raised to the upper limit position and then stopped, the extracted gas within the metering valve system is effectively stirred and mixed to have a uniform composition.

FIG. 1 is a diagram showing the relationship between the ratio of the analysis values of nitrogen gas components in the measuring tubes 60a and 61a and the number of times the piston is driven. In FIG. 1, curve A is the piston 29a of the mixing cylinder 29, as in the conventional case.
Curve B represents the case in which the piston 29a of the mixing cylinder 29 and the piston 19a of the sampling cylinder 19 are actuated alternately according to the invention.

Comparison of the two curves A and B in Figure 1 reveals that in the conventional method, the amount of nitrogen gas in the measuring tubes 60a and 61a is initially significantly different, and even after the piston is driven 20 times, the gas compositions of both do not become the same. On the other hand, according to the present invention, the gas composition in the metering tubes 60a and 61a is made uniform by driving the piston at least five times.

This is because the flow of the extracted gas sampled in the metering valve system is greater in the present invention, so stirring and mixing is performed extremely efficiently, and the extracted gas with a uniform composition is produced by the gas chromatography. It can be sent to a tograph to perform highly accurate gas-in-oil analysis.

〔Effect of the invention〕

An automatic gas-in-oil analyzer consisting of an extraction cylinder, an extraction gas sampling cylinder, a mixing cylinder, a six-way automatic valve between the extraction gas sampling cylinder and the mixing cylinder, and the necessary piping and solenoid valves is used to analyze sample oil. When the extracted gas is mixed to have a uniform composition and then injected into the gas chromatograph, the extracted gas cannot be mixed sufficiently by simply operating the piston of the mixing cylinder. The piston operation of the sampling cylinder was also used to alternately drive the piston of the mixing cylinder and the piston of the sampling cylinder to increase the flow of the extracted gas sampled into the metering valve system, so that this extracted gas was only a small amount. The oil is stirred and mixed efficiently with a certain number of piston movements, and is injected into the gas chromatograph with a uniform composition.As a result, the true gas concentration can be obtained without any variation in the analysis value of gas in oil. ,
This greatly improves analysis accuracy.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the relationship between the number of piston drives and the ratio of gas analysis values in two measuring tubes, and FIG. 2 is a system diagram of an automatic gas-in-oil analyzer to which the method of the present invention is applied. 1... Extraction cylinder, 19... Collection cylinder,
19a, 29a... Piston, 29... Mixing cylinder, 60, 61... Automatic six-way valve, 60a,
61a...Measuring tube.

Claims (1)

[Claims] 1. An extraction cylinder that collects sample oil by operating a piston equipped with a bellows and extracts dissolved gas in the sample. An extracted gas sampling cylinder that is piped to the extraction cylinder and temporarily stores the extracted gas and then injects it by operating the piston. , a mixing cylinder that uniformly stirs the composition of the extracted gas sent from the extracted gas sampling cylinder by piston operation, and a measuring tube that is installed between the extracted gas sampling cylinder and the mixed gas cylinder and injects the extracted gas into the gas chromatograph. A method of operating an automatic gas-in-oil analyzer equipped with a six-way automatic valve, in which the piston operation of the extraction gas sampling cylinder is used in combination with the piston operation of the mixing cylinder to uniformly stir and mix the composition of the extracted gas. A method of operating an automatic gas-in-oil analyzer characterized by alternately operating a piston of an extracted gas sampling cylinder.