JP2572836B2 - Calibration method of dissolved gas concentration indicated value of display means in dissolved gas concentration measuring device in oil - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for calibrating a dissolved gas concentration indicated value of a display means in a dissolved gas concentration measuring device in oil, that is, a method of calibrating a transformer, a circuit breaker, or the like. High-boiling oils such as insulating oils for oil-filled electrical equipment and lubricating oils for rotating equipment, etc., deteriorate with time due to long-term use. In particular, insulating oil decomposes due to discharges such as arc discharge and corona discharge, or abnormalities such as local overheating and CO, CO ₂ , H ₂ , CH ₄ , C ₂ H ₂ , C ₂ H ₄ , C ₂ H ₆ , C ₃ H ₆ , C
₃ H _8, C ₄ H _10, etc. of the gas is generated, the generated gas is easily and dissolved in the oil, by measuring the concentration of combustible gases that are dissolved in these oil, insulating oil and lubricants It is possible to accurately diagnose the degree of deterioration of the oil and the abnormality of the electric equipment. Therefore, the present invention relates to a method for calibrating a dissolved gas concentration indication value on a display means in a dissolved gas concentration measuring device for oil in order to know the concentration of dissolved gas in oil more accurately.

[Conventional technology]

Conventionally, in order to measure the concentration of dissolved gas in oil, a suction pump for extracting and extracting dissolved gas from the oil to be tested is provided, and a gas chromatograph for analyzing the detected gas extracted by the suction pump is provided. The concentration of the dissolved gas in the test oil was measured by this gas chromatograph. However, in order to remove dissolved gas from the oil to be inspected by a suction pump, the device needs to have pressure resistance or a suction pump with high decompression capability is required, and it becomes large and expensive.
Furthermore, the gas chromatograph itself that analyzes the gas to be detected,
There was a disadvantage that it was large and expensive. Therefore, the present inventor provided a blow-in pipe for bubbling a carrier gas inserted into a high-boiling oil to be inspected as a small and inexpensive dissolved gas concentration measuring instrument. And a gas sensor for measuring the concentration of the flammable gas in the carrier gas is provided in the recovery path, and a display means for displaying a measuring device by the gas sensor is provided. In order to know the dissolved gas concentration accurately, it is necessary to check and calibrate whether the indicated value of the dissolved gas concentration on the display means is accurate. Is desired.

[Problems to be solved by the invention]

However, in order to perform the above calibration, a gas similar to the gas generated during use from the oil to be inspected is diluted with air to form a standard gas of a set concentration, and this standard gas is directly It is conceivable to adjust the sensitivity of the gas sensor so that the value indicated by the display means at this time becomes a set value by measuring with a sensor, but since there is no bubbling operation at the time of calibration, the error is large, and the gas Has the drawbacks that it is easy to lose weight by leaking to the outside, it is difficult to control the gas concentration by storing the standard gas, and calibration tends to be inaccurate.

 An object of the present invention is to perform calibration more accurately.

[Means for solving the problem]

The characteristic means of the dissolved gas concentration indication value calibration method of the display means in the dissolved gas concentration measuring device in oil in the present invention, for unused test oil, with a lower boiling point than the test oil,
In addition, a standard oil is formed by mixing a hydrocarbon for sensing a gas sensor which is a liquid at ordinary temperature so as to have a set ratio, and a blowing pipe is inserted into the standard oil to bubble a carrier gas. Gas is measured by a gas sensor, and the indication value of the display means at this time is to adjust the sensitivity of the gas sensor so as to be a set value,
The operation and effect are as follows.

(Operation)

In other words, hydrocarbons that have a lower boiling point than the oil to be inspected and that are liquid at room temperature are less likely to escape to the outside than the above-mentioned gases, and therefore, the unused oil to be inspected is set so that the hydrocarbons reach the set ratio. The standard oil mixed in the above can contain hydrocarbons in a stable ratio. Then, by bubbling the carrier gas into the standard oil, the hydrocarbons for sensing the gas sensor in the standard oil are vaporized at a fixed rate and mixed in the carrier gas, and the carrier gas is measured by the gas sensor. By adjusting the sensitivity of the gas sensor so that the indicated value of the display means at this time becomes the set value, stable calibration can be performed.

〔The invention's effect〕

Therefore, the concentration of the hydrocarbon in the standard oil can be easily stored in a stable state, and the dissolved gas concentration indicated value of the display means can be accurately calibrated for a long period of time, so that the economy and reliability can be improved. .

〔Example〕

 Next, an embodiment of the present invention will be described with reference to the drawings.

As shown in FIGS. 1 and 2, in order to measure the concentration of the flammable dissolved gas in the insulating oil in the transformer, the carrier gas is inserted into the insulating oil collected in the oil collecting container (1). A blowing pipe (2) for bubbling is provided, and a pump (P) for supplying a carrier gas incorporated in the measuring instrument body (3) is connected to the blowing pipe (2), so that the bubbling carrier gas in the oil is removed. The recovery path (R) is fitted to the mouth (1A) of the oil collecting container (1) with the tip side of the blowing pipe (2) immersed in insulating oil in the oil collecting container (1). A semiconductor gas sensor (4) formed in 4) and provided with an exhaust port (5) for the carrier gas connected to the recovery path (R) in the cylindrical section (4) to measure the concentration of the flammable gas in the carrier gas ( 6) is provided in the recovery path (R) in the cylindrical portion (4), and the measurement from the gas sensor (6) is performed. The digital display panel (7) provided on the measuring device main body (3) as display means for displaying the values, have configured dissolved gas concentration measuring device in the oil.

The pump (P) is configured to supply air as a carrier gas into the blowing pipe (2).

 Next, a method for measuring the concentration of dissolved gas in oil will be described.

B. Insulating oil is sampled in the oil collection container (1) in a set amount.

B Injecting pipe (2) into the insulating oil in the oil container (1)
The tube (4) is fitted into the mouth (1A) while being inserted and immersed at the tip end of.

(C) Activate the pump (P) to suck air into the insulating oil via the blowing pipe (2).

(D) While exhausting the air bubbling in the oil from the exhaust port (5) through the recovery path (R), the flammable gas in the air is detected by the gas sensor (6), and the concentration thereof is displayed on the display panel (7). ).

E. The maximum value of the measured concentration displayed on the display panel (7) is taken as the concentration of the dissolved gas in the oil.

Next, a method for calibrating the dissolved gas concentration indication value of the display panel (7) will be described. However, the calibration method described below is preferably performed before performing the above-described measurement method. Standard oil is formed by mixing the unused oil to be inspected with a hydrocarbon with a lower boiling point than the oil to be inspected and a liquid for sensing gas sensors at room temperature at a set ratio. The carrier gas is bubbled by inserting the blowing pipe (2) into the standard oil stored in the oil collecting container (1), and the bubbled carrier gas is measured by the gas sensor (6) in the recovery path (R). The sensitivity of the gas sensor (6) is adjusted so that the indicated value of the display means (7) at this time becomes the set value.

That is, the gas sensor sensing hydrocarbon is CnH
_{2n + 1} OH (where n is 3 to 7) and CnHm (where n is 5
To 11), for example, pentane, hexane, peptane, ophthane, nonane, decane, undecane and the like can be used, and their vapor pressures and boiling points are shown in the following table.

The insulating oil has many hydrocarbons having about 20 carbon atoms, and has a boiling point of 300 ° C. or higher.As can be seen from the above table, the boiling point of the hydrocarbon is lower than that of the insulating oil. It is.

Next, as shown in FIG. 3 to FIG. 5, the concentration and gas sensor (6) of hydrocarbons having 1 or 3 carbon atoms and hydrocarbons having 6 or 10 carbon atoms were mixed into the oil to be inspected. ) (FIG. 3), the change of the output of the gas sensor (6) through H (FIG. 4), and the relationship between the number of times used for the calibration and the output of the gas sensor (6) (FIG. 3). Fifth
Figure), By comparison, as shown in FIG. 3, because the content level for obtaining a predetermined output is determined by the hydrocarbon, the inspection oil, for example, even CH ₄ C ₆ even H ₁₄ with either the mixed but it is understood that may be formed standard oil content than Figure 4, hydrocarbons 1 or 2 carbon atoms with increasing age exerts from the inspected oil And the output of the gas sensor decreases, whereas hydrocarbons with 6 or 7 carbon atoms have a small oral change in sensor output, and C ₈
Since the above does not change at all, it can be seen that the standard oil mixed with the hydrocarbon is stable and can be stored for a long period of time.
However, as the molecular weight increases, the vapor pressure decreases as shown in the above table, so that the sensor output is low and there is a problem that it is not suitable for calibration.

Also, as shown in FIG. 5, the standard oil containing low molecular weight hydrocarbons was vaporized and released from the oil to be inspected by the majority of low molecular weight hydrocarbons when used only once for calibration. Thereafter, the sensor output greatly decreases. However, in the case of the standard oil containing a hydrocarbon having 6 or more carbon atoms, the rate of decrease in the sensor output with the number of uses is low, and the calibration can be repeated a plurality of times.

Thus, specifically, taking a case where calibration is performed with a standard oil in which hexane is mixed with an unused oil to be inspected, as shown in FIG. 6, for example, when the hexane concentration is 5 vol%,
It suffices if a meter reading of 400 is output. At this time, calibration can be performed by adjusting the sensitivity of the gas sensor (6) so that the display on the display panel (7) is adjusted to 400.

(Another embodiment)

The hydrocarbon mixed with the oil to be tested to form a standard oil is not limited to a saturated hydrocarbon as described above, but may be an alcohol or an unsaturated hydrocarbon, or may be an isomer. For example, propanol (C ₃ H ₇ OH), butanol (C ₄ H ₉ OH), pentanol (C ₅
H ₁₁ OH), Hexal (C ₆ H ₁₃ OH), Heptanol (C ₇ H
₁₅ OH), isohexane _{(C 5 H 11 -CH 3)} , methylcyclopentane (C ₈ H _12), 3-ethyl pentane _{((C 2 H 5) 3} CH),
Cyclohexane (C ₆ H _12), 1,3- cyclohexadiene (C ₆ H _8), hexane (C ₆ H _12), methylcyclohexane _{(C 6 H 11 -CH 3)} , methylcyclohexene (C ₇ H _12), benzene (C ₆ H _6), toluene _{(C 6 H 5 -CH 3)} , cyclooctane (C ₈ H _16), xylene _{(C 6 H 4 (CH 3} ) 2), cyclononane (C ₉ H _18), dimethyl cyclohexane (C ₈ H ₁₆₎ dimethylhexane (C ₈ H _18), and the like.

The carrier gas supplied from the pump (P) to the blowing pipe (2) may be other noncombustible gas besides air.

The gas sensor (6) may be a small gas sensor other than a semiconductor gas sensor, such as a contact combustion gas sensor or an electrochemical gas sensor.

A digital display panel (7) as the display means;
Alternatively, an analog meter display may be used.

INDUSTRIAL APPLICABILITY The present invention can also be used for measuring the concentration of dissolved gas in insulating oil or lubricating oil in electrical equipment, in addition to insulating oil for transformers.

The pump (P) is connected to the recovery path (R) in addition to being connected to the blowing pipe (2) to reduce the pressure inside the oil collecting container (1) by suction and to reduce the pressure of air from the blowing pipe (2). (1) Bubbling may be performed in the oil inside.

The air may be circulated from the recovery path (R) to the blowing pipe (2).

In the claims, reference numerals are provided for convenience of comparison with the drawings, but the present invention is not limited to the structure shown in the attached drawings.

[Brief description of the drawings]

The drawings show an embodiment of a method for calibrating the dissolved gas concentration indicated value of the display means in the dissolved gas concentration measuring device in oil according to the present invention, FIG. 1 is a sectional view of a main part of the dissolved gas concentration measuring device, and FIG. FIG. 3 to FIG. 6 are overall perspective views of the dissolved gas concentration measuring instrument, and FIG. 3 to FIG. 6 are change graphs showing respective instruction outputs. (2) ... blow-in pipe, (6) ... gas sensor,
(7) ... display means, (P) ... pump, (R) ... collection path.

 ──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-2-189452 (JP, A) JP-A-63-98555 (JP, A) JP-A 64-30436 (JP, U)

Claims (2)

(57) [Claims] An injection pipe (2) is provided for bubbling a carrier gas inserted into a high boiling point oil to be inspected, and a recovery path (R) for the carrier gas bubbled in the oil to be inspected is provided. A gas sensor (6) for measuring the concentration of a flammable gas in a gas is provided in the recovery path (R), and a display means (7) for displaying a measurement value of the gas sensor (6) is provided. In the dissolved gas concentration measurement device, the unused oil to be inspected has a lower boiling point than the oil to be inspected, and
A standard oil is formed by mixing a hydrocarbon for sensing a gas sensor at room temperature so as to have a set ratio, and the blowing pipe (2) is inserted into the standard oil to bubble a carrier gas. The measured carrier gas is measured by the gas sensor (6), and the display means (7) at this time is used.
A method of calibrating the dissolved gas concentration indicated value of the display means in the dissolved gas concentration measuring device for oil, which adjusts the sensitivity of the gas sensor (6) so that the indicated value becomes the set value. 2. The gas sensor-sensing hydrocarbon is CnH.
_{2n + 1} OH (where n is 3 to 7) and CnHm (where n is 5
2. The method for calibrating a dissolved gas concentration indication value of a display means in a device for measuring a dissolved gas concentration in oil according to claim 1, wherein the method includes at least one of the following.