JPH09170995A - Detection equipment of combustible gas in oil - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the dispersion of measured values and enable easy estimation of error level, by installing a detection chamber having a gas detection element and a thermostatic chamber provided with a heater. SOLUTION: A gas extractor 1 is installed in a thermostatic chamber 14 in which a heater is installed to make the inside temperature constant, and the temperature of oil extracted in the extractor 1 is made constant. When a stirring pump 12 is interrupted, an electromagnetic value 7 is closed, and the channels of three-way electromagnetic valves 9 and 10 are changed over, the air flowing into a gas detection chamber 3 through the valves 9, 10 flows into a storing chamber 2 through the valve 9 and a pump 12, and the extracted gas in the chamber 2 flows into the detection chamber 3 through the valve 10. The extracted gas flowing into the detection chamber 3 comes into contact with a gas detection element and burns. In proportion to the amount of the combustible gas in the extracted gas, the electric resistance of metal conductor in the gas detection element changes. By measuring the resistance change, the amount of combustible gas in insulating oil can be measured.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention separates a flammable gas dissolved in insulating oil of an oil-filled device, for example, an oil-filled transformer, and measures the amount of the separated flammable gas to transform the oil-filled transformer. The present invention relates to a device for early detection of abnormalities in vessels.

[0002]

2. Description of the Related Art When a thermal or electrical abnormality occurs inside an oil-filled electrical device, such as an oil-filled transformer, insulating oil or an insulating material around it is decomposed to generate gas. These gases are dissolved in insulating oil, and the gas concentration in oil increases, so the gas dissolved in oil (hereinafter referred to as gas in oil)
The method of extracting and analyzing the abnormal condition and diagnosing the abnormal condition inside the transformer from the analysis result is already well known, and it is widely used at home and abroad because the abnormal condition can be detected early.

A generally used method for analyzing gas in oil is to extract insulating oil from a target transformer and then extract the gas in oil using a Tricelli vacuum using mercury or a vacuum using a Tepura pump. The extracted gas is analyzed by a gas chromatograph. However, while this method can be performed easily, it is performed manually or semi-automatically, so it requires manpower during the whole process from the start to the end of the analysis.
Moreover, a skilled technician is required to perform highly accurate analysis because the operation is complicated. And considerable effort,
It takes time and money. For this reason, a field-installed automatic gas analyzer that automates these operations has also been developed (Japanese Examined Patent Publication No. 52-209, magazine “Fuji Jiho” Vol. 45, No. 11, “Petroleum Society Journal”, Vol. (See No. 2)
However, there are drawbacks in that the device is expensive and labor-intensive in terms of maintenance.

On the other hand, recently, a method of using a gas permeable material that allows only gas to pass through without allowing liquid to pass through has been devised as an alternative to a gas extraction device whose operation is complicated. In this method, a polymer membrane is attached to a part of the transformer, such as the oil discharge port, to separate the oil from the gas detection chamber, and the gas that has passed through the membrane is provided with an electrolyte electrode or a contact combustion type or semiconductor type. It is intended to detect abnormalities inside the transformer by detecting with the gas detection element of. This method is simple and inexpensive, but has the disadvantage that the gas concentration in the detection chamber does not easily reach equilibrium due to the relatively low gas permeation speed, so that the detection of an abnormality is delayed. Further, there is a disadvantage that oxygen in the detection chamber dissolves into the insulating oil inside the transformer through the membrane, which adversely affects the transformer.

In order to solve the above-mentioned problems, a patent has been applied for a device for detecting inflammable gas in oil, which is discovered by the present inventors (Japanese Patent Application Nos. 63-28525 and 63-29).
297). FIG. 3 shows a system diagram for explaining the paths of oil and gas together with the configuration of the in-oil combustible gas detection device. With reference to this figure, each component of the device and its action and The process of measuring the amount of combustible gas in the extracted gas obtained by extracting the gas dissolved in the insulating oil in the transformer with the extractor will be described.

A certain amount of insulating oil in a transformer (not shown) is sampled in the gas extractor 1 from a pipe connected to the gas extractor 1, which will be described later in detail, and is dissolved in the insulating oil. The gas that is being extracted. A gas reservoir chamber 2 is connected to a pipe extending upward from the gas extractor 1, and a path from which a gas reservoir chamber 2 is connected to a free end outside the system via a three-way solenoid valve 10, a gas detection chamber 3 and a solenoid valve 8. A path connected from the free end outside the system to the middle of the pipe connecting the gas extractor 1 and the gas storage chamber 2 via the solenoid valve 6, the air pump 4, the flow rate control valve 5, the three-way solenoid valve 9, and the stirring pump 12. , A path connecting the midway of the pipe connecting the gas storage chamber 2 and the three-way solenoid valve 10 and the middle of the pipe connecting the stirring pump 12 and the three-way solenoid valve 9 via the solenoid valve 7, the three-way solenoid valve 10 and the three-way solenoid valve An air inlet and a gas reservoir 2 (not shown) are connected via a solenoid valve 11 from the middle of a path connecting the valve 9 and a pipe connecting the gas reservoir 2 and the three-way solenoid valve 10.
It is composed of a path connected to a vacuum pump for creating a vacuum inside. In the gas detection chamber 3, a contact combustion type gas detection element is installed for measuring the amount of combustible gas in the extracted gas. This contact combustion type gas detection element is commercially available as a combustible gas alarm. When air containing flammable gas comes in contact with a catalyst heated to an appropriate temperature and burns on the surface of the catalyst, the metal conductor in the catalyst is heated and the electrical resistance changes, so measuring this change The amount of combustible gas in the extracted gas can be measured.

The measurement of the amount of combustible gas in the extraction gas collected in the gas storage chamber 2 is performed by the following procedure. Before starting the measurement, the air introduced through the solenoid valve 6 to stabilize the output of the gas detection element provided in the gas detection chamber 3 is controlled by the air pump 4 by the flow rate control valve 5, the three-way solenoid valve 9, and the three-way valve. Sent to the gas detection chamber 3 through the solenoid valve 10,
Further, the air in the gas detection chamber 3 flows out of the system through the solenoid valve 8. Further, the extracted gas in the gas storage chamber 2 is operated by the solenoid valve 7
By opening the valve and operating the stirring pump 12, the gas circulating chamber 2 → the electromagnetic valve 7 → the stirring pump 12 → the gas storing chamber 2 is circulated and the dissolved gas in oil contained in the extracted gas and the oil Fine particles, steam, etc. are mixed. Therefore, the extracted gas which was present in a non-uniform state in the system at first becomes a uniform composition by being circulated and mixed. After that, the circulation pump 12 is stopped, the solenoid valve 7 is closed, and the flow paths of the three-way solenoid valve 9 and the three-way solenoid valve 10 are switched, so far the gas detection chamber passes through the three-way solenoid valve 9 and the three-way solenoid valve 10. The air flowing in 3 is a three-way solenoid valve 9 and a stirring pump 12.
Through which the extracted gas in the gas storage chamber 2 flows into the gas detection chamber 3 through the three-way solenoid valve 10. The extracted gas that has flowed into the gas detection chamber 3 contacts and burns the gas detection element, and the electrical resistance of the metal conductor in the gas detection element changes in proportion to the amount of combustible gas in the extracted gas.
The amount of combustible gas in the insulating oil is measured by capturing the change in resistance. The remaining gas burned in the gas detection chamber 3 and the unburned gas are discharged to the outside of the system through the solenoid valve 8.

By the way, in the gas extractor 1 which constitutes the above-described inflammable gas detecting device in the oil, a piston having one end of the bellows fixed to one surface is housed in the cylinder, and the other end of the bellows is placed on the bottom surface of the cylinder. It is fixed to the cylinder, and by repeating the forward / backward movement of the piston equipped with the bellows, the old insulating oil remaining in the extractor at the time of the previous gas detection is eliminated and the space between the bellows and the cylinder is removed. It becomes possible to collect new insulating oil in the equipment, and the gas dissolved in the collected new insulating oil penetrates the piston back and forth through the oil collected between the bellows and the cylinder. Since the gas can be extracted by violently ejecting it into the depressurized space behind the piston through the pores, the dissolved gas in the insulating oil is extracted without contacting the outside air. Further, the vacuum pump completely removes the gas remaining in the gas storage chamber at the time of the previous gas detection, before the gas extracted behind the piston is fed into the gas storage chamber by the forward / backward movement of the piston. Therefore, only completely new gas is stored in the gas storage chamber. Also, the standard mixed gas introduced into this gas reservoir chamber and fed into the gas detection chamber and used for calibration of the gas detection element installed in this chamber is also completely removed after calibration, and this calibration gas also dissolves gas. Does not affect the detection accuracy of. Further, in this device configuration, fresh air outside is sent to the gas detection chamber by the air pump before the extracted gas is sent to the gas detection chamber, and this air is discharged from the gas detection chamber to the outside of the system. From
The gas detection chamber is constantly flushed with fresh air during operation of the air pump, so that the gas detection element can start the detection operation in a new and stable state without being affected by the previous extraction gas or calibration gas.

[0009]

However, according to the subsequent research conducted by the inventors of the present invention on the above-described inflammable gas detection device in oil, despite the device configuration considering the measurement accuracy as described above, the oil It was found that the measured values vary depending on the change in temperature. FIG. 2 is a diagram showing an example of the relationship between the oil temperature and the measured value of the inflammable gas amount in the oil, and it can be seen that the measured value of the inflammable gas amount in the oil decreases as the oil temperature decreases.

An object of the present invention is to configure a combustible gas detection device in oil that reduces variations in measured values, thereby facilitating evaluation of error levels, or combustible oil in oil in which errors in measured values themselves are small. The purpose of the present invention is to provide a configuration of a volatile gas detection device.

[0011]

In order to solve the above-mentioned problems, in the present invention, a device for detecting flammable gas in oil is used to collect insulating oil in an oil-filled electric device by advancing and retracting a piston equipped with a bellows. And a gas extractor for extracting the dissolved gas in the insulating oil, a gas reservoir chamber connected to the extractor for storing the extracted gas, and a vacuum pump for evacuating the gas reservoir chamber,
An agitation pump for agitating while circulating the extraction gas in the gas storage chamber, an air pump for delivering the extraction gas in the gas storage chamber, the gas detection chamber provided with a gas detection element for detecting a flammable gas, and the extractor. It is configured by using a temperature-controlled room equipped with a heater for keeping the temperature of the oil sampled inside, and the gas is extracted after the temperature of the oil sampled inside the extractor becomes constant, and the extracted gas Sent to the gas detection chamber,
It is assumed that the extracted gas flowing out from the gas detection chamber is sent to the outside of the system by air and the amount of combustible gas in the extracted gas is measured.

And, in the case of an apparatus equipped with a temperature-controlled room,
Install the gas extractor in a temperature-controlled room, or install a tank on the oil extraction side of the gas extractor to store insulating oil from which dissolved gas is extracted, and install this tank in the temperature-controlled room. Shall be This invention, because the gas extraction efficiency varies depending on the temperature of the oil when the gas dissolved in the oil is extracted by the gas extractor, the amount of flammable gas in the extracted gas changes as a result, which is flammable. It focuses on the cause of variation when measuring the gas amount. That is, as described above, when a piston equipped with a bellows is advanced and retracted in a cylinder and oil is violently ejected into a decompressed space behind the piston through pores penetrating the piston, the oil is decompressed into this decompressed space. Although the medium dissolved gas is extracted, the extraction efficiency of the oil dissolved gas varies depending on the oil temperature at this time. Therefore, the amount of extracted gas stored in the gas storage chamber varies depending on the number of extraction operations, and the measured value is obtained when the amount of combustible gas in the extracted gas is measured by sending the extracted gas in the gas storage chamber into the gas detection chamber. There are variations.

Therefore, as in the present invention, a constant temperature chamber provided with a heater for keeping the oil temperature in the gas extractor constant is provided and the oil temperature at the time of gas extraction is made constant, so that the gas extraction efficiency is constant. And the dispersion of the measured values is significantly reduced. In the case of a device equipped with a temperature-controlled room, if the gas extractor is installed in the temperature-controlled room, the gas extraction efficiency can be kept constant by maintaining a simple device configuration. A tank for storing the insulating oil from which the dissolved gas is extracted is installed on the oil collecting port side of the tank, and this tank is installed in a temperature-controlled room. In this case, of course, the cylinder of the gas extractor is kept warm. Although an additional measure such as wrapping is required, there is an advantage that the gas extraction efficiency can be kept constant regardless of the extraction rate when extracting the dissolved gas from a fixed amount of insulating oil.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described based on embodiments. FIG. 1 shows a system diagram for explaining the oil and gas paths together with the configuration of the in-oil combustible gas detection apparatus according to the embodiment of the present invention. Below, the respective constituent members of the apparatus and the operation are shown in the drawings. I will explain.

A certain amount of insulating oil in a transformer (not shown) is sampled from the pipe connected to the gas extractor 1 into the gas extractor 1, where the gas dissolved in the insulating oil is extracted. To be done. Further, the gas extractor 1 is provided in a constant temperature chamber 14 in which a heater is provided to keep the room temperature constant, and the temperature of the oil collected in the gas extractor 1 is kept constant. A gas storage chamber 2 is connected to a pipe extending upward from the gas extractor 1, and further from this, a three-way solenoid valve 10 and a gas detection chamber 3 are connected.
And a path connected to the free end outside the system via the solenoid valve 8, the gas extraction from the free end outside the system via the solenoid valve 6, the air pump 4, the flow rate control valve 5, the three-way solenoid valve 9, and the stirring pump 12. A path connected in the middle of the pipe connecting the container 1 and the gas storage chamber 2, in the middle of the pipe connecting the gas storage chamber 2 and the three-way solenoid valve 10, and in the middle of the pipe connecting the stirring pump 12 and the three-way solenoid valve 9. Is connected via the solenoid valve 7, a path connected to connect the three-way solenoid valve 10 and the three-way solenoid valve 9, and a solenoid valve 11 from the middle of the pipe connecting the gas reservoir 2 and the three-way solenoid valve 10. It is constituted by a path connected to an air inlet (not shown) or a vacuum pump for evacuating the inside of the gas storage chamber 2 via the above. In the gas detection chamber 3, a contact combustion type gas detection element is installed for measuring the amount of combustible gas in the extracted gas. This contact combustion type gas detection element is commercially available as a combustible gas alarm. When air containing flammable gas comes in contact with a catalyst heated to an appropriate temperature and burns on the surface of the catalyst, the metal conductor in the catalyst is heated and the electrical resistance changes, so measuring this change The amount of combustible gas in the extracted gas can be measured.

The measurement of the amount of combustible gas in the extracted gas collected in the gas storage chamber 2 is carried out by the following procedure. Before starting the measurement, the air introduced through the solenoid valve 6 to stabilize the output of the gas detection element provided in the gas detection chamber 3 is controlled by the air pump 4 by the flow rate control valve 5, the three-way solenoid valve 9, and the three-way valve. Sent to the gas detection chamber 3 through the solenoid valve 10,
Further, the air in the gas detection chamber 3 flows out of the system through the solenoid valve 8. Further, the extracted gas in the gas storage chamber 2 is operated by the solenoid valve 7
By opening the valve and operating the stirring pump 12, the gas circulating chamber 2 → the electromagnetic valve 7 → the stirring pump 12 → the gas storing chamber 2 is circulated and the dissolved gas in oil contained in the extracted gas and the oil Fine particles, steam, etc. are mixed. Therefore, the extracted gas that initially existed in a heterogeneous state in this system was circulated and
A uniform composition is obtained by mixing. After that, the circulation pump 12 is stopped, the solenoid valve 7 is closed, and the flow paths of the three-way solenoid valve 9 and the three-way solenoid valve 10 are switched, so far the gas detection chamber passes through the three-way solenoid valve 9 and the three-way solenoid valve 10. Three
The air flowing in the three-way solenoid valve 9 and the stirring pump 1
2 and flows into the gas storage chamber 2 and the extracted gas in the gas storage chamber 2 flows into the gas detection chamber 3 through the three-way solenoid valve 10. The extracted gas that has flowed into the gas detection chamber 3 contacts and burns the gas detection element, and the electrical resistance of the metal conductor in the gas detection element changes in proportion to the amount of combustible gas in the extracted gas.
The amount of combustible gas in the insulating oil is measured by capturing the change in resistance. The remaining gas burned in the gas detection chamber 3 and the unburned gas are discharged to the outside of the system through the solenoid valve 8.

The following table shows the results of studying whether or not the dispersion of the measured values of the inflammable gas amount in oil is actually reduced with this apparatus.

[0018]

[Table 1] Measurement result of inflammable gas amount in oil Oil temperature Combustible gas concentration (ppm) (° C) Conventional device Device of the present invention Maximum 46.4 123 98 Minimum 2.9 76 78 Average 36.5 94 87 Fluctuation Coefficient (%) 10.9 11.5 6.1 As a result, in the apparatus of the present invention, by mounting a heater on the gas extractor 1 and controlling the oil temperature at a constant level, the dispersion of the measured values is reduced to about half of the conventional value. You can see that

[0019]

As described above in the embodiments of the invention,
According to the present invention, the bellows piston method is used for extracting the gas in the oil, and the old insulating oil remaining in the gas extractor at the time of the previous gas detection is removed by collecting the new insulating oil by repeating the forward / backward movement of the piston. In addition, it is possible to extract the gas dissolved in the new insulating oil by moving the piston back and forth again, so that the dissolved gas in the insulating oil is extracted without contacting the outside air,
Oxygen in the outside air does not dissolve in the insulating oil as in the case of extracting gas using a polymer membrane, and it is possible to avoid adverse effects on equipment. The purpose of gas detection is to detect the presence or absence of an internal abnormality in oil-filled electrical equipment, especially the power transformer, which greatly affects the operation of the power system. Because you only have to start
Since a much cheaper gas detection element is used instead of an expensive gas chromatograph that can determine the type of gas required for investigating the cause, it is inexpensive, practical, and maintenance that does not adversely affect the equipment. It is possible to obtain a gas detection device with less labor. Moreover, the gas detection device according to the present invention is equipped with a vacuum pump, and the extraction gas remaining at the previous gas detection in the system of the device prior to the gas detection is completely eliminated by the vacuum pump, and only the newly extracted gas is obtained. It is the target of detection. Furthermore, a stirring pump that stirs this extracted gas while circulating it is provided, and the extracted gas in the gas reservoir chamber is circulated and mixed by the stirring pump prior to measurement, and after it has a uniform composition, it is sent to the gas detection chamber, so the oil temperature When the value is constant, the variation in the detection result is reduced, the reliability of the detection result is significantly improved, the error level in the detection result is easily evaluated, and the true value can be estimated with relatively high accuracy. Moreover, in order to solve the problem that the gas extraction efficiency differs due to the fluctuation of the oil temperature during the actual gas extraction, and the measured value of the combustible gas amount varies, a heater is provided to keep the room temperature constant. By providing a constant temperature chamber and keeping the oil temperature constant during gas extraction, the dispersion of measured values is reduced, the reliability of the detection results is significantly improved compared to the conventional device, and the level of error in the detection results can be easily evaluated. Therefore, the true value can be estimated with relatively high accuracy.

In the case of a device equipped with a temperature-controlled room, the gas extractor is installed in the temperature-controlled room.
A gas extraction efficiency can be kept constant by maintaining a simple device configuration, and a tank for storing insulating oil from which dissolved gas is extracted is installed on the oil extraction port side of the gas extractor. By installing the device in a thermostatic chamber, there is an advantage that the gas extraction efficiency can be kept constant regardless of the extraction speed when extracting the dissolved gas from a fixed amount of insulating oil.

[Brief description of the drawings]

FIG. 1 is a system diagram showing a configuration of a gas detection device according to an embodiment of the present invention and paths of oil and gas.

FIG. 2 is a diagram showing the correlation between the oil temperature and the amount of combustible gas in oil.

FIG. 3 is a system diagram showing a configuration of a conventional gas detection device and paths of oil and gas.

[Explanation of symbols]

1 ... Gas extractor, 2 ... Gas storage chamber, 3 ... Gas detection chamber, 4
... air pump, 12 ... stirring pump, 14 ... thermostatic chamber.

Claims (3)

[Claims] 1. A gas extractor for collecting insulating oil in an oil-filled electric device by a forward / backward movement of a piston provided with a bellows and extracting dissolved gas in the insulating oil; A gas storage chamber for storing, a vacuum pump for evacuating the gas storage chamber, a stirring pump for agitating while circulating the extracted gas stored in the gas storage chamber, and sending the extracted gas in the gas storage chamber to the gas detection chamber An air pump for delivering air, the gas detection chamber in which a detection element for detecting a combustible gas is installed, and a thermostatic chamber for keeping the oil in the gas extractor at a constant temperature, and the extracted gas from the gas storage chamber An inflammable gas detection device in oil, which measures the amount of inflammable gas in the extracted gas while sending it out of the system through a gas detection chamber. 2. The apparatus for detecting flammable gas in oil according to claim 1, wherein the gas extractor is housed in a temperature-controlled room. 3. The apparatus according to claim 1, wherein a tank for storing insulating oil from which dissolved gas is extracted is arranged on the oil collecting port side of the gas extractor, and the tank is housed in a temperature-controlled room. The combustible gas detection device in oil, which is characterized in that