JPH10332682A - Method for evaluating electrical insulation oil - Google Patents

Abstract

PROBLEM TO BE SOLVED: To evaluate deterioration of insulation oil by increasing the temperature of an electrical insulation oil and measuring the number of chemiluminescence, obtaining a specific expression for indicating the relationship between the inverse number of temperature and the number of chemiluminescence, and performing judgment from the number of chemiluminescence at a constant temperature and a constant in an expression. SOLUTION: The temperature of an electrical insulation oil is increased by heating and the number of chemiluminescence and a measurement temperature during this period are measured, thus converting into Arrhenius plot with the abscissa as an inverse number X of the measurement temperature (absolute temperature). The Arrhenius plot can be regressed nearly linearly, a regression expression Y=A.exp(-BX/ R) (R: gas constant, A, B: constants) is established, and the constant B is obtained from these. The constant B indicates an activation energy. Further, the number of chemiluminescence at an initial temperature before temperature increases is obtained from the regression expression. The value is the number of chemiluminescence while an energy from the outside is small and indicates the current degree of deterioration of an electrical insulation oil. This method allows the number of chemiluminescence to be measured quickly, thus the degree of deterioration of the electrical insulation oil can be quickly evaluated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technique for evaluating the degree of deterioration of electrical insulating oil used for oil-filled electrical equipment.

[0002]

2. Description of the Related Art Electrical insulating oil used in oil-filled electrical equipment deteriorates with the number of years of operation of the electrical equipment. In particular, a small amount of copper dissolved in the electric insulating oil becomes a catalyst and promotes oxidative deterioration. For this reason, a physical property test of the electrical insulating oil is regularly performed from the viewpoint of maintenance management, and among various test items, a test for evaluating the degree of deterioration is an important item. Regarding the conventional technology for evaluating the deterioration of electric insulating oil, for example, in the oxidation stability test of electric insulating oil based on JIS C 2101 (1993), oxygen at a constant pressure is introduced in the presence of a copper catalyst and heated for a certain period of time. Then, the electric insulating oil is deteriorated, and the sludge amount and the total acid value are measured. This oxidation stability test is described below.

[0003] First, as a pretreatment of a sample (electric insulating oil), the sample is filtered using a filter paper dried for one hour immediately before the test, and the 25 ml discharged at the beginning of the filtration is discarded. Next, the prepared copper catalyst is put in a sample container, and then a 25 ml sample is taken in the sample container, and the sample container is immersed in a constant temperature oil bath adjusted to about 120 ° C. Immediately thereafter oxygen is introduced. The introduction of oxygen is sufficient to replenish the oxygen consumed by the oxidation of the oil, but the oxidation of this sample is not interrupted.
Do time. The sample container that has been oxidized for a predetermined time is taken out of the constant temperature oil bath and left in a dark place for about 1 hour.
Thereafter, the sample is transferred to a stoppered container while washing by adding naphtha for precipitation. The copper catalyst and sample container should be thoroughly cleaned,
Add the liquid to the sample. In this case, the solvent fee is 30
Make it 0 ml. After leaving this in a dark place for 16 to 20 hours, it is filtered by filter paper or suction.

[0004] When filtered with filter paper, the sludge on the filter paper is washed with a naphtha for sedimentation, and when coloration is not observed in the washing liquid, the slurry is dried at 100 to 105 ° C for 3 hours, and the mass is measured to determine the amount of sludge. Quantify. Next, the filtrate from which the sludge was separated was collected, diluted with a naphtha for sedimentation, added with a predetermined solvent and an indicator, and then standardized at 0.05 mol / l.
Titrate with potassium hydroxide solution to determine total acid number.

As another example of a conventional method for evaluating the deterioration of an electric insulating oil, another material used for oil-filled electric equipment is immersed in the electric insulating oil, oxygen is introduced, and the electric insulating oil is heated for a certain period of time. A method of continuously measuring the dielectric loss tangent of the insulating oil or measuring the amount of sludge and the total acid value after heating the electric insulating oil in the presence of another material has also been used.

[0006]

Since the conventional method for evaluating an electric insulating oil evaluates the degree of deterioration as described above, it takes a long time for the evaluation, and the amount of oil required for the evaluation is complicated and complicated. There were many.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and is intended to evaluate the degree of deterioration of an electric insulating oil by using a small amount of the electric insulating oil in a short time and easily. The aim is to get the method.

[0008]

According to a first aspect of the present invention, there is provided a method for evaluating an electric insulating oil, comprising measuring the number of chemiluminescence by heating the electric insulating oil, and measuring the reciprocal X of the measured temperature (absolute temperature).
And a regression equation “Y = A · exp (−BX / R); R is a gas constant, and A and B are constants” satisfying a relationship between the temperature and the chemiluminescence number Y corresponding to each measurement temperature. The degree of deterioration of the electrical insulating oil is evaluated from the magnitude of the chemiluminescence number Yt and the constant B.

According to a second aspect of the present invention, there is provided a method for evaluating an electric insulating oil, wherein the predetermined temperature t is set to a temperature at which the electric insulating oil is practically used or an initial temperature before the temperature is raised.

According to a third aspect of the present invention, there is provided a method for evaluating an electrical insulating oil, wherein a control value serving as a maintenance standard for the chemiluminescence number Yt and the constant B is set and compared with the control value. Is to evaluate the degree of

According to a fourth aspect of the present invention, in the method for evaluating an electric insulating oil, the number of chemiluminescence is measured by heating the electric insulating oil under a condition in which the electric insulating oil is acceleratedly degraded by a deterioration accelerating factor according to a use condition. Is what you do.

According to a fifth aspect of the present invention, there is provided a method for evaluating an electric insulating oil, comprising measuring the number of chemiluminescence by heating and heating under the condition that the electric insulating oil coexists with other materials used for oil-filled electric equipment. Is what you do.

According to a sixth aspect of the present invention, there is provided a method for evaluating an electrical insulating oil, wherein the electrical insulating oil is made to coexist with other materials used for oil-filled electrical equipment, and the electrical insulating oil alone is used to raise the electrical insulating oil. The effect of the coexisting material on the deterioration of the electric insulating oil is evaluated by measuring the number of chemiluminescences by heating and comparing the numbers.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION

Embodiment 1 FIG. Hereinafter, a first embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a graph showing the results of measuring the number of chemiluminescence in a new oil and a degraded oil used as an electric insulating oil using a chemical luminescence analyzer manufactured by Tohoku Electronics Co., Ltd. The new oil used was Type 4 oil of an electrical insulating oil manufacturer, and the deteriorated oil was the same type 1 oil collected from a transformer used for about 20 years. The measurement conditions were as follows: the amount of sample oil: 5 ml, the measurement wavelength: 300 to 650 nm, the temperature rising temperature section: (room temperature to 100 ° C.), the two kinds of electric insulating oils were heated and heated. Measured continuously. In FIG. 1, the vertical axis represents the number of chemiluminescence Y per unit time, and the horizontal axis represents the measurement temperature. The number of chemiluminescence increases exponentially with an increase in the measurement temperature. The time required for this measurement is about 10 to 20 minutes.

Here, the deterioration of the electric insulating oil and the accompanying chemiluminescence will be described below. FIG. 2 is a view for explaining a reaction mechanism of autoxidation, which is a process of deteriorating carbon fired hydrogen, which is a main component of electric insulating oil. As shown in the figure, the chemical reaction progresses in a chain, and molecules or atoms in an electronically excited state are generated by an oxidation reaction of an organic substance or a reaction of a peroxide with oxygen. Light emission occurs. When this chemiluminescence is considered as a phenomenon in a reaction process, it can be said that it is a precursor phenomenon of deterioration. In this embodiment, the degree of the deterioration is evaluated by capturing the chemiluminescence having a correlation with the deterioration of the electric insulating oil as described above.

FIG. 3 is a graph obtained by converting the abscissa of FIG. 1 to the reciprocal X of the measured temperature (absolute temperature) and converting it to an Arrhenius plot. As shown in the figure, the Arrhenius plot can be almost linearly regressed, and the regression equation “Y = A · exp (−BX /
R); R is a gas constant, A and B are constants, and a constant B is obtained. As a gas constant R = 1.987, in the case of new oil, Y = 3.34 × 10 ⁸ · exp (−1
1.2 × 10 ³ X / R) In the case of deteriorated oil, Y = 3.12 × 10 ⁹ · exp (−9.
(2 × 10 ³ X / R). The regression equation obtained from the Arrhenius plot is called the Arrhenius equation, and indicates the relationship between the speed of the chemical reaction and the temperature, and the constant B indicates the activation energy. That is, in order for the reaction to proceed, it is necessary to impart energy equal to or higher than the activation energy. Therefore, it can be said that if the constant B is small, the reaction proceeds easily and is likely to be deteriorated.

Further, the chemiluminescence number Yt at the initial temperature t ° C. before the temperature rise is obtained from the regression equation. This value Yt is
This is the number of chemiluminescence in a state where the energy applied from the outside is low due to the low temperature, and indicates the degree of deterioration of the electric insulating oil at the current state (at the time of measurement). The constant B obtained from the Arrhenius plot and the chemiluminescence number Y ₃₀ at 30 ° C. of the new oil and the deteriorated oil of FIG. 3 are shown in the table of FIG. Comparing new oil and the degraded oil, as shown in FIG., The constant B towards new oil is large, Y ₃₀ is as small as much. That is, it can be seen that the new oil is less likely to deteriorate, and the degree of deterioration under the present conditions is much smaller. In this case, Y ₃₀ was determined. The temperature t ° C. of the chemiluminescence number Yt indicating the degree of deterioration of the electric insulating oil at the present time may be a temperature at which the electric insulating oil is practically used. Is suitable, but not particularly limited.

In this embodiment, the number of chemiluminescence can be measured in a short time, so that the degree of deterioration of the electrical insulating oil can be evaluated in a much shorter time than in the conventional case. In addition, a small amount of oil is required for the evaluation, and both the current degree of deterioration and the ease of deterioration can be evaluated, so that highly reliable evaluation can be performed.

Embodiment 2 Next, a second embodiment of the present invention will be described. For example, at a room temperature of 30 ° C., the degree of deterioration of the electric insulating oil is evaluated by the chemiluminescence number Y ₃₀ and the constant B derived from the regression equation according to the first embodiment.
At this time, management values Y ₃₀ x and Bx which are maintenance standards are set in advance. Thus, the various electrical insulating oil different degrees of degradation, respectively determined chemiluminescent number Y ₃₀ and constants B, it can be evaluated by comparing them with the control value Y ₃₀ x and Bx. As shown in FIG. 5, can be by the management value Y ₃₀ x and Bx divide the electrical insulating oil into four areas to D, for example, D region; normal, B region; unusable, A and C region; It is important to note that if it is in area B, use should be discontinued, and if it is in area A and C, it is necessary to continuously monitor it. Take.

Further, it is necessary to perform an initial evaluation for confirming that the new oil is in a good state, and a new oil control value is separately provided for the evaluation. In this way, by setting the management values Y ₃₀ x and Bx as the maintenance standards in advance and evaluating the degree of deterioration of the electrical insulating oil, the accuracy of the evaluation method can be improved.

Embodiment 3 Next, a third embodiment of the present invention will be described. The expected life of oil-filled electrical equipment is as long as several tens of years, and therefore, the electrical insulating oil used is also expected to have a long life. In addition, maintenance work such as overhaul work is regularly performed on oil-filled electric equipment, which changes the environment to which the electric insulating oil is exposed, and sometimes accelerates deterioration. For this reason, the degree of deterioration is evaluated by accelerating and degrading the electrical insulating oil under conditions such as the addition of a copper catalyst and the atmosphere of air in accordance with the use conditions. Similarly to the first embodiment of the case above described, by measuring the chemiluminescence count was heated heating leads to chemiluminescence number Y ₃₀ and the constant B from the regression equation, as in the second embodiment of the control value Set and evaluate.

In this embodiment, it is possible to easily evaluate the current degree of deterioration of the electric insulating oil and the easiness of deterioration assuming long-term deterioration by using a small amount of electric insulating oil in a short time. Can be.

Embodiment 4 Next, a fourth embodiment of the present invention will be described. Degradation of the electric insulating oil may be promoted by the coexistence of the material. For this reason, prior to application to oil-filled electrical equipment, these materials coexist with other materials used in oil-filled electrical equipment, such as solid insulating materials, other insulating materials, and metal materials. Evaluate the effect on electrical insulation oil degradation. Other materials used in the oil-filled electric device are coexisted with the electric insulating oil, and the temperature is increased and heated to measure the number of chemiluminescence as in the first embodiment. Again, lead to chemiluminescent number Y ₃₀ and the constant B from the regression equation can be evaluated by setting the same manner control value and the second embodiment.

In this case, the sample of the electric insulating oil alone was heated and heated to measure the number of chemiluminescence. By comparing the sample coexisting with other materials and the electric insulating oil alone, The influence of the material can be accurately evaluated. FIG. 6 shows the transition of the number of chemiluminescence in the case of coexisting with other materials and in the case of using only electric insulating oil. As shown in the figure, in the case of the electric insulating oil coexisting with other materials, the number of chemiluminescence increases rapidly with the measurement time. In this case, it can be determined that this material has a large effect on deterioration. When the influence on the deterioration is small, the increase in the number of chemiluminescence becomes slow. Also, as shown in the figure,
In the case of the electric insulating oil alone, the increase in the number of chemiluminescence is extremely slow.

Further, from FIG. 6, the integrated value of the number of chemiluminescence during the measurement period was obtained for each of the coexistence with other materials and the one for electric insulating oil alone, and the difference between the values was used as the difference. The magnitude of the influence on the deterioration of the metal is understood.
Further, in this embodiment, a new oil is usually used as the electric insulating oil, but other oils can be evaluated.

As described above, in this embodiment, the effect of the electric insulating oil on the deterioration of the coexisting material can be easily evaluated in a short time by using a small amount of the electric insulating oil.

[0027]

As described above, according to the present invention, the number of chemiluminescences is measured by heating and heating the electric insulating oil, and the regression satisfying the relationship between the reciprocal X of the measured temperature (absolute temperature) and the chemiluminescence number Y is obtained. The expression “Y = A · exp (−BX / R)” is obtained, and the degree of deterioration of the electric insulating oil is evaluated from the magnitude of the chemiluminescence number Yt and the constant B at a predetermined temperature t. The oil amount is small, the evaluation can be performed easily in a remarkably short time, and both the degree of deterioration at the predetermined temperature and the easiness of deterioration can be evaluated.

According to the present invention, the predetermined temperature t in the chemiluminescence number Yt used for evaluating the electric insulating oil is set to a temperature at which the electric insulating oil is practically used or an initial temperature before the temperature rise. The current degree of deterioration can be evaluated by the number of light emission Yt, and highly reliable electric insulating oil can be easily evaluated.

According to the present invention, a control value serving as a maintenance standard for the chemiluminescence number Yt and the constant B is set, and the degree of deterioration of the electrical insulating oil is evaluated by comparing the control value with the control value. Can evaluate electrical insulating oil.

According to the present invention, the number of chemiluminescences is measured by heating and heating under a condition in which the electrical insulating oil is acceleratedly degraded by a deterioration accelerating factor in accordance with the use condition. The degree of deterioration can be easily evaluated in a short time using a small amount of electric insulating oil.

According to the present invention, the number of chemiluminescence is measured by heating and heating under the condition that the electric insulating oil coexists with other materials used for oil-filled electric equipment. The effect on deterioration can be easily evaluated in a short time using a small amount of electric insulating oil.

Further, according to the present invention, the electric insulating oil coexisting with another material and the single oil are separately heated and heated to measure the number of chemiluminescence. The effect on insulation oil deterioration can be evaluated with high accuracy.

[Brief description of the drawings]

FIG. 1 is a graph showing a measurement result of the number of chemiluminescence of an electric insulating oil according to Embodiment 1 of the present invention.

FIG. 2 is a table illustrating a reaction mechanism in a deterioration process of the electric insulating oil according to the first embodiment of the present invention.

FIG. 3 is a graph obtained by converting the graph of FIG. 1 into an Arrhenius plot.

FIG. 4 shows a constant B obtained from the Arrhenius plot of FIG.
And the number of chemiluminescence Y ₃₀ are shown in the form of a table.

FIG. 5 is a diagram showing categories of deterioration of an electric insulating oil according to a second embodiment of the present invention.

FIG. 6 is a graph showing a measurement result of a chemiluminescence number of the electric insulating oil according to the fourth embodiment of the present invention.

Claims (6)

[Claims] 1. A method for measuring the number of chemiluminescence by heating and heating an electrically insulating oil, and regression equation “Y” satisfying a relationship between a reciprocal X of a measurement temperature (absolute temperature) and a number Y of chemiluminescence corresponding to each measurement temperature. = A
Exp (−BX / R); R is a gas constant, A and B are constants, and the degree of deterioration of the electric insulating oil is determined from the chemiluminescence number Yt at a predetermined temperature t and the above constant B. A method for evaluating an electric insulating oil, characterized by evaluating. 2. The method for evaluating an electric insulating oil according to claim 1, wherein the predetermined temperature t is set to a temperature at which the electric insulating oil is practically used or an initial temperature before the temperature is raised. 3. The method according to claim 1, wherein a control value serving as a maintenance reference for the chemiluminescence number Yt and the constant B is set, and the degree of deterioration of the electric insulating oil is evaluated by comparing the control value with the control value. 2. The method for evaluating an electrical insulating oil according to 2. 4. The method according to claim 1, wherein the number of chemiluminescence is measured by heating and heating the electric insulating oil under the condition of accelerated deterioration by the deterioration promoting factor according to the use condition. The method for evaluating an electrical insulating oil according to the above. 5. The method according to claim 1, wherein the number of chemiluminescence is measured by heating and heating under a condition in which the electric insulating oil coexists with another material used for the oil-filled electric device. The method for evaluating an electrical insulating oil according to the above. 6. A method in which an electric insulating oil is made to coexist with another material used for an oil-filled electric device, and the above-mentioned electric insulating oil alone is heated and heated to measure the number of chemiluminescence and compare. The method for evaluating an electric insulating oil according to any one of claims 1 to 4, wherein the influence of the coexisting material on the deterioration of the electric insulating oil is evaluated.