JP3004149B2 - Simple detection method of total combustible gas amount in oil by catalytic combustion type detector - 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 of separating a gas in oil from insulating oil or the like in a specific oil-filled electrical device to be detected by a vacuum method using an installation type detection device. The present invention relates to a simple method for detecting the amount of TCG in oil, in which the total combustible gas amount (hereinafter, referred to as “TCG amount”) is detected by a contact combustion type detector.

[0002]

2. Description of the Related Art When abnormalities such as arc discharge and overheating occur in large oil-filled electrical equipment such as transformers, capacitors, and rectifiers, insulating paper and filled insulating oil are decomposed to generate flammable gas. Since most of the flammable gas dissolves in the insulating oil, the abnormality of the oil-filled electric device can be detected by measuring the amount of the flammable gas in the insulating oil.

[0003] Various detection methods and devices have been proposed and marketed based on such a principle.

The most accurate method of measuring the amount of combustible gas in insulating oil is to measure the amount of individual gas by a precision analysis method such as gas chromatography, but the apparatus is complicated and expensive. In addition, it takes a long time for analysis, and it is difficult to install it on individual oil-filled electrical devices.

Therefore, a method using a contact combustion detector is known as the next best method (Japanese Patent Publication No. Sho 58-46045).
No., JP-A-60-245424). The contact combustion detection method is to detect the change in electrical resistance based on the temperature rise of the sensing element due to the heat of combustion by burning the combustible gas on the sensing element. It is noted for its advantages such as ease of use, small size and low cost, and short time required for analysis, and has been adopted for a stationary simple oil-in-oil gas detection device.

[0006] In the stationary type simple gas detection device in oil, a vacuum system is usually used for separating gas from oil.
In this method, insulating oil extracted from oil-filled electrical equipment is placed under reduced pressure to separate flammable gas in the oil into the air (for example, Japanese Patent Publication No. 50-8763, Japanese Patent Publication No. 58-46).
No. 045).

[0007]

Although the catalytic combustion detection method has the above advantages, it deviates greatly from the result of precision analysis such as gas chromatography which is considered to be close to the actual value. Lack of reliability.

As a result of various studies of the cause, the present inventors have found that: (1) Since combustibles react not only with the gas to be detected but also with oil droplets and oil smoke of insulating oil, TCG in the air (2) In principle, it corresponds to the total heat of combustion of the combustible gas mixture. Since the combustion heat differs depending on the type of combustible gas, even if the TCG amount is the same, Depending on the composition of the combustible gas mixture, there is a difference in the total combustion calorie, that is, the detected output. (3) Since the conversion from the detected output to the TCG amount is performed using a calibration curve based on one kind of combustible gas, can not respond to changes in the type and composition of the combustible gas, (4) because the resolution differs depending on the type of combustible gas,
It has been found that a major factor is that the composition of combustible gas in oil and the composition of gas in separated gas are different.

[0009] It is considered that these various causes overlap, and the conventional stationary type simple gas detection device greatly differs from the result of precision analysis such as gas chromatography.

According to the present invention, when the amount of combustible gas in oil separated by a vacuum separation method is detected by a contact combustion type detection method, the detection result is made as close to an actual value as possible, and a more reliable installation type simple gas detector is provided. Is to provide a law.

[0011]

SUMMARY OF THE INVENTION The simple method of detecting the amount of TCG in oil according to the present invention uses an installation-type detection device to detect the amount of TCG in oil from a specific oil-filled electrical device to be detected by using a vacuum method. In a simple method for detecting the amount of TCG in oil, in which the TCG amount in the separated gas is detected by a catalytic combustion type detector, the TCG amount in the specific insulating oil measured by the catalytic combustion type detector is determined. The measured value corresponding to the quantity is obtained from the detection sensitivity ratio of two or more combustible gases in the contact combustion detector and the quantity of the two or more combustible gases in the specific insulating oil measured by precision analysis. The correction is performed using a correction coefficient specific to the specific insulating oil.

[0012]

One of the features of the present invention is that a unique correction can be made for each specific insulating oil to be detected.

The correction coefficient used for the correction determines the detection sensitivity ratio in the contact combustion type detector for each flammable gas, and uses this and the amount of each flammable gas measured by precision analysis such as gas chromatography to obtain a precise value. It is determined as the degree of deviation from the TCG amount obtained in the analysis. Therefore, the influence of each combustible gas can be taken in, and the amount of low-concentration TCG close to the detection limit of the contact combustion type detector can be made as close as possible to the actual value.

Hereinafter, an installation-type detection device that can be used in the simple detection method of the present invention will be described, and then a correction method and the like will be described.

FIG. 1 is a block diagram of an installation type detection device 1 having a piston 2 and a cylinder 3 for separating combustible gas from insulating oil in a vacuum system, and a contact combustion type detector 4. At the time of detection, the insulating oil is extracted from the oil-filled electric device 5 and the like, sent to the gap between the piston 2 and the cylinder 3, and the piston 2 rises to make the inside of the gap a negative pressure so that the flammable gas in the insulating oil is brought into the air. To separate. Then, after introducing air into the separated gas, the piston 2 is lowered to send the separated gas to the contact combustion type detector 4, the TCG amount is measured, and a voltage change is obtained as a detection output.

According to the present invention, the amount of TCG converted by the conventional method from the detected output is corrected, or the amount of the detected output is corrected and then converted to the amount of TCG by the conventional method, thereby making it easier to obtain the amount obtained by the precision analysis. It is a detection method. According to the present invention, since the correction coefficient used for the correction is a value specific to the specific insulating oil to be detected, the operation at the time of detection may be the same as that of the related art.

Hereinafter, the method of correction in the present invention will be described.

First, a specific insulating oil (hereinafter, referred to as a “specific oil to be detected”) in an oil-filled electrical device in which the detecting device is installed is precisely analyzed, and the amount of each flammable gas in the specific oil to be detected is determined. Measure. Examples of the precision analysis method include gas chromatography.

Two or more kinds of flammable gases to be analyzed are used, for example, inorganic flammable gases such as hydrogen gas and carbon monoxide gas, and organic flammable gases such as methane, ethane, propane, butane, ethylene and acetylene. Although hydrogen gas is usually generated when oil-filled electrical equipment is abnormal,
Targets methane, ethane, ethylene, etc.

As described above, TCG obtained by precision analysis
Although the amount differs from the TCG amount measured by the contact combustion type detector, in order to correct the difference for each flammable gas, the detection sensitivity ratio of each flammable gas is determined in the present invention.

The detection sensitivity ratio is determined for each flammable gas by preparing a sample oil in which one kind of flammable gas is contained in an insulating oil and measuring this sample oil with a contact combustion type detection device shown in FIG. It is a relative value of the detected output of each combustible gas obtained, and it is usually preferable to set the detected output of one kind of combustible gas as 1. Note that the detection output of the insulating oil containing no flammable gas may be used as a reference. As the insulating oil for preparing the sample oil, the same oil as the specific oil to be detected is preferable.

Methane is preferably used as the reference gas for the detection sensitivity ratio. Methane is a gas that is almost always generated when an internal abnormality occurs in oil-filled electrical equipment, etc.
Moreover, since the molecular combustion heat is the smallest among the hydrocarbon-based gases, the detection sensitivity per unit amount is low, and therefore, the measurement error is relatively unlikely to occur in comparison with other gases.
In addition, other flammable gases such as insulating oil and electrical equipment,
The reference gas can be appropriately set according to the type of abnormality that may occur.

A correction coefficient (k _v ) is determined from the detection sensitivity ratio (α _i ) of each combustible gas obtained and the amount (L _i ) of each combustible gas obtained by precision analysis. The correction coefficient (k _v ) is calculated based on the detection amount ratio (α _i ) of the total amount of combustible gas obtained by the precise analysis and the amount (L _i ) of each combustible gas obtained by the precise analysis. And the ratio to the total amount multiplied by .times.

[0024]

(Equation 1)

The denominator on the right side indicates the sum of the measured quantities that would be obtained if the combustible gas in the amount obtained by the precision analysis was measured by the catalytic combustion detector. In this equation, if the type (n) of the combustible gas is increased, the accuracy is improved accordingly.

This correction coefficient is determined before starting the detection of the TCG amount for each insulating oil such as an oil-filled electric device for which the TCG amount is to be detected.

The simple detection method of the present invention is obtained by multiplying the measured TCG amount (G _o ) obtained by the detection device shown in FIG. 1 by a correction coefficient (k _v ) (formula (2)). An accurate TCG amount value (G) is obtained.

G = k _v · G _o (2) The amount of TCG is detected at appropriate time intervals by the simple method of detecting the amount of TCG of the present invention, and a change in the value causes an abnormality in each oil-filled electric device or the like. Can be known in a short time without the need for complicated operation analysis, and equipment maintenance can be facilitated.

Examples of oil-filled electrical equipment to be detected include, but are not limited to, transformers, capacitors, rectifiers, switches and the like.

Next, the simple detection method of the present invention will be described based on embodiments, but the present invention is not limited to only such embodiments.

Example 1 (Determination of Detection Sensitivity Ratio) The detection output of each gas of methane, ethane, ethylene and hydrogen was examined in the following manner using the detection device shown in FIG.

Insulating oil (JIS C 2320-1988)
No. 7-2) is degassed to obtain a reference oil. A sample oil is prepared by adding one kind of combustible gas to the reference oil so as to be 100 ppm by volume. 100 ml of this sample oil is introduced into the cylinder 3, and the piston 2 is further raised by 100 ml to make the inside of the cylinder 3 a negative pressure, thereby separating the combustible gas in the sample oil into air. Thereafter, air is introduced into the cylinder 3 to return the pressure to the atmospheric pressure, then the piston 2 is lowered, and the separated gas is sent to the catalytic combustion type detector 4 to obtain a detection output (voltage).

This operation is performed for each gas of methane, ethane, ethylene and hydrogen, and the detection outputs shown in Table 1 are obtained. Then, the detection sensitivity ratio (α) of each gas based on the detection output of methane is calculated. did. Table 1 shows the results.

[0034]

[Table 1]

(Precision analysis of specific oil to be detected) As the specific oil to be detected, an insulating oil sampled from a transformer in which insulating oil (Type 7-2 of JIS C 2320-1988) is sealed is used as a gas. When the amounts (L) (volume ppm) of methane, ethane, ethylene and hydrogen gas contained in this oil were precisely analyzed by chromatography, Table 2 was obtained.
And the TCG amount was 678 ppm by volume.
Met.

[0036]

[Table 2]

(Determination of Correction Coefficient) The correction coefficient (k _v = 0.
717) was determined by the above equation (1).

[0038]

(Equation 2)

(Correction of Actual Measured Value) For the specific oil to be detected, dissolved gas is separated using the detection device shown in FIG. 1 in the same manner as in the determination of the detection sensitivity ratio, and the TCG amount is detected by the catalytic combustion method. As a result of measurement with a vessel, the measured value was 850 ppm by volume. In addition, the correction coefficient 0.717 according to the above equation (2)
To obtain 609 ppm by volume as a corrected TCG amount. As described above, since the total amount of gas obtained by precise analysis by gas chromatography is 678 ppm by volume, it can be seen that the result of the correction according to the present invention greatly approaches the precise analysis value.

Example 2 Insulating oil (JIS) collected from a transformer different from that of Example 1
Using C2320-1988, No. 7-2, as a specific oil to be detected, a precise analysis was carried out in the same manner as in Example 1, and the amount of combustible gas shown in Table 3 was detected (total 694 ppm by volume). When a correction coefficient was obtained from the result of the precise analysis in the same manner as in Example 1, a value of 0.623 was obtained. In this precise analysis, a gas was separated from the insulating oil containing a total of 694 ppm by volume of combustible gas in the same manner as in Example 1, and the TCG amount was measured to show 1870 ppm by volume. Then, a correction coefficient of 0.6 is calculated according to the equation (2).
23 and 1165 volume ppm as corrected TCG amount
I got By this correction, the value of the TCG amount was changed from 1870 ppm by volume to 1165 ppm by volume, and the value of the precise analysis was 694.
It can be seen that the capacity is very close to ppm.

[0041]

[Table 3]

[0042]

According to the simple detection method of the present invention, it is possible to obtain the TCG amount approximate to the precision analysis by examining the insulating oil of the oil-filled electric equipment or the like by a simple operation. It is possible to more accurately know whether or not there is an abnormality in the electrical input device and the like, and maintenance management becomes easy.

[Brief description of the drawings]

FIG. 1 is a block diagram of a stationary detection device that can be used in the method of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Installation type detection apparatus 2 Piston 3 Cylinder 4 Contact combustion type detector 5 Oil-filled electric equipment

Continued on the front page. (72) Inventor: Junhide Setoguchi 2150, Shioi-michi, Fukuma-cho, Munakata-gun, Fukuoka Prefecture Inside Kyushu Transformer Co., Ltd. (72) Inventor: Hideyasu Tanno 8--24, Chuocho, Meguro-ku, Tokyo No. Akira Meiri Chemical Industry Co., Ltd. (58) Field surveyed (Int. Cl. ⁷ , DB name) H01F 27/00

Claims (2)

(57) [Claims] 1. An installation-type detection device separates a gas in oil from insulating oil or the like in a specific oil-filled electric device to be detected by a vacuum method, and determines a total flammable gas amount in the separated gas. In a simple detection method of the total flammable gas amount in oil detected by a contact combustion type detector, an actual measurement value corresponding to the total flammable gas amount in the specific insulating oil measured by the contact combustion type detector is contacted. Specific to the specific insulating oil obtained from the detection sensitivity ratio of two or more flammable gases in the combustion type detector and the amount of the two or more flammable gases in the specific insulating oil measured by precision analysis A simple detection method of the total flammable gas amount in oil by a catalytic combustion type detector, wherein the correction coefficient is corrected by a correction coefficient. 2. The simple detection method according to claim 1, wherein the detection sensitivity ratio of each combustible gas is a ratio when methane is set to 1.00.