JP3157374B2 - Remaining life diagnosis device for oil-filled transformer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for diagnosing the remaining life of an oil-immersed transformer, which estimates the remaining thermal life of the oil-immersed transformer, which is the most important equipment in the substation equipment.

[0002]

2. Description of the Related Art It is conventionally known that the remaining life of an oil-filled transformer is determined by the degree of reduction in mechanical strength of insulating paper inside a main body. In order to see this degree, especially in a large-capacity oil-filled transformer, it was judged from the result of gas analysis of CO + CO _{2 in} oil. On the other hand, at present, such gas analysis has not been performed for a relatively small capacity oil-filled transformer in terms of cost.

[0003] According to the investigation results of an ultra-high pressure, large-capacity oil-filled transformer, as shown in FIG. 4, an average given as a chemical parameter corresponding to the molecular weight of the coil insulating paper used in the oil-filled transformer is shown. It has been observed that the degree of polymerization is correlated with the years of operation of the transformer. According to the experimental research data, as shown in FIG. 5, the average polymerization degree residual ratio of the insulating paper forcibly thermally degraded in oil and the tensile strength residual ratio of the insulating paper are lower than any of the thermal degradation temperatures. It is also known to be represented by a single correlation curve. On the other hand, it has been found that the dielectric strength of insulating paper of oil-immersed transformers that have been operated for a long time does not decrease so much even if the average degree of polymerization decreases. It is customary to do so.

[0004] However, since it is extremely difficult to collect insulating paper from an oil-filled transformer, it is necessary to extract the insulating oil instead and analyze the total amount of CO and CO ₂ contained in the insulating oil. Acting has been done. The CO and CO ₂ gases do not precipitate in the thermal decomposition of the oil, but only precipitate in the oil when the insulating paper is thermally oxidized and degraded, as shown in FIG.
It has also been found that the amount of O ₂ produced shows a linear correlation with the average residual polymerization degree of the insulating paper.

[0005] Based on the research results of such real transformers and model, the oil-filled transformers large capacity, conducts regular oil extraction gas analysis, the total gas amount of CO + CO ₂ the extent to which the insulating paper The service life is predicted by judging to what extent the mechanical strength has deteriorated due to thermal deterioration.

[0006]

However, in a relatively small-capacity oil-filled transformer installed in an electric room of a small or medium-sized building, oil is sampled from the transformer itself and its gas analysis is performed. Actually, it is hardly performed because of the difficulty of work and the high cost of gas analysis.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems. An oil-immersed transformer for power distribution of 1000 KVA or less without performing gas analysis based on sampling of insulating oil of the oil-immersed transformer. It is another object of the present invention to provide a device for diagnosing the remaining life of an oil-filled transformer which can relatively easily diagnose the remaining life.

[0008]

According to a first aspect of the present invention, there is provided a device for diagnosing a remaining life of an oil-immersed transformer, wherein the temperature data of the oil-immersed transformer operating at a predetermined operating load factor is obtained. A first calculating means for obtaining a temperature rise value at a rated capacity based on the operating capacity, a storage means for storing operating history data such as an operating time with respect to an operating load factor and an ambient temperature of the oil-filled transformer; A second calculating means for obtaining an operating temperature history represented by an operating time with respect to the operating temperature based on the temperature rise value, the operating time with respect to the operating load factor, and the ambient temperature of the oil-immersed transformer, and operating based on the operating history. A third calculating means for calculating the cumulative value of the time, and
Insulating paper or sealing material for the above oil-immersed transformer required
The parallel line parallel to the life line for the operating temperature of
Using the operating temperature as a parameter from the relative time difference with the lifeline
Diagnostic means for estimating the remaining life with respect to the operating load factor obtained by converting the operating temperature into a corresponding value.

According to a second aspect of the present invention, there is provided an apparatus for diagnosing remaining life of an oil-immersed transformer, wherein the diagnosing means includes a means for determining the life of the oil-immersed transformer with respect to the operating load factor of the insulating paper or the sealing material. A plurality of alert zones are provided, and each is detected when the cumulative value of the operation time reaches any of the alert zones.

[0010]

In the apparatus for diagnosing the remaining life of an oil-immersed transformer according to the first aspect of the present invention, the first calculating means performs a predetermined operation.
A temperature rise value at the rated capacity is obtained based on the temperature data of the oil-immersed transformer operated at the operation load factor, and stored in the storage means and the temperature rise value at the rated capacity by the second calculating means. The operating temperature history represented by the operating time with respect to the operating temperature is obtained based on the operating time with respect to the operating load factor and the ambient temperature of the oil-filled transformer, and the third calculating means calculates the operating time based on the operating temperature history. The cumulative value is obtained, and the diagnosis means predicts the accumulated value by passing the cumulative value of the operation time.
Insulation paper or seal for the above oil-immersed transformer required
The parallel line parallel to the life line for the operating temperature of the material and the above
The operating temperature is used as a parameter based on the relative time difference from the life line.
Then, the remaining life with respect to the operating load factor obtained by converting the operating temperature is estimated. Therefore, the remaining life can be estimated based on the temperature data of the oil-immersed transformer operated at a predetermined load factor and the past operation history data, and it is relatively unnecessary to collect the insulating oil and the like. Diagnosis of the remaining life can be easily performed.

Further, in the remaining lifetime diagnosing device for an oil-filled transformer according to claim 2, in the diagnosis means, insulating Kamima other oil-filled transformer vigilance zone to life against the operation load of the sealing member Providing a plurality of notification when the cumulative value of the operation time reaches any of the inside of the alert zone enables appropriate maintenance.

[0012]

【Example】

Embodiment 1 FIG. Hereinafter, a first embodiment of the present invention will be described with reference to the drawings. First, in the present invention, in a small-capacity oil-immersed transformer, thermal oxidative degradation of insulating paper is more remarkable than in a large-capacity transformer, so it is necessary to estimate the remaining life. It is possible to estimate the remaining life in the future from the operating history data of past years and the operating temperature data at the time of diagnosis of the oil-immersed transformer, instead of performing the above-mentioned estimation of the life from gas analysis which is difficult in terms of cost. Things.

FIG. 1 is a schematic configuration diagram showing an apparatus for diagnosing the remaining life of an oil-immersed transformer according to the first embodiment. The input of this device uses the temperature data and the operation history data of the oil-filled transformer. For example, when the thermal data of the oil-immersed transformer is displayed on the display 10 by an infrared camera (not shown) on the display 10, the display 10 displays the color image 11 of the oil-immersed transformer, the imaging condition data 12, and the temperature θmin. A color bar 13 indicating a color gradation display from to θmax is displayed. Assuming that this thermal image is taken by the oil-immersed transformer at a load factor K, the thermal image 11 is indicated by hatching in the figure. Since the temperature rise value θ _K of the highest temperature portion is obtained, this temperature rise value θ _K is input as a numerical value as temperature data.

The load factor K (hereinafter also referred to as an operation load factor)
The first computing unit to) and the temperature rise value theta _K is input 20
The following (1) to the logical expression of factory testing of the oil-filled transformer is preprogrammed Temperature Rise in the expression, the rated capacity of the oil-filled transformer is diagnosed based on the temperature rise value theta _K (A proportional coefficient unique to the oil-filled transformer, and at this time, the load factor K is K = 1). _{θ K = θo · f (K} ) ··· (1) where, f (K) = {( 1 + R K 2) / (1 + R)} 0.8 ··· (2) f (K): load temperature rise Dependency function R: Total loss / no-load loss of oil-immersed transformer (usually 3 to 4, fixed value in this embodiment)

On the other hand, a storage means (not shown) which stores the operation history data of the oil-immersed transformer is stored in the past year, for example, 197
The operation history data from 0 to 1993 is read.
Here, the display 30 shows an example in which the driving history data stored in the storage means is displayed.
For example, the number N31 of days in which the operating load factor K of the designated year divided into the middle season and the winter is shown in increments of 10%, and the year list 32 from the installation year to the current year are displayed. The number of days N corresponding to the year list 32 selected in step is displayed and changed one by one on the matrix display screen. In addition to the above display example, the storage means stores the ambient temperature of the oil-immersed transformer (the room temperature of the electric room at the site where the oil-immersed transformer is housed) θa at the time of this data input in summer, middle season, and winter. Separately, the average value is numerically input and stored, and the number N of days and the ambient temperature θa of the oil-immersed transformer are read out from this storage means with respect to the operating load factor K for each season and for each year.

Next, the second computing unit 40 calculates the temperature rise value θo at the rated capacity of the oil-filled transformer calculated by the first computing unit 20, the operating load factor K from the storage means, and By inputting the number of days N and the ambient temperature θa of the oil-filled transformer, a value of a function f ( K ) indicating the load dependency of the temperature rise shown in Expression (2) is obtained for each operating load factor K. The temperature rise value θ _K shown in equation (1) is obtained from the function value, and the ambient temperature θa is further added thereto to obtain the actual temperature, that is, the operating temperature θ according to equation (3). θ
As shown in the display example in the second computing unit 40, the number of days N corresponding to (operating load factor K ) is added for all seasons and past years for all seasons, and the added value is converted to the number of operating years Y. As a result, the data of the bar chart of the operating years Y related to the operating temperature θ, that is, the operating temperature history is output. θ = θ _K + θa (3)

Further, the third computing unit 50 performs a simulation for estimating the remaining life of the oil-immersed transformer based on the relationship between the operating temperature θ obtained from the second computing unit 40 and the operating years Y. The relationship between logY and the operating temperature θ in which the operating years Y are logarithmically displayed on the vertical axis is obtained. That is, as shown in a simulation diagram of the operating years logY versus the operating temperature θ, the operating temperature histories output from the second computing unit 40 are sequentially plotted. In the simulation diagram, reference numerals 51 and 52 denote the experimental results of the operating years Y at which the residual tensile strength of the insulating paper in the oil-immersed transformer is reduced by half with respect to the previously determined operating temperature θ, and the oil seal of the oil-immersed transformer case. The experimental results of the operating years Y with respect to the operating temperature θ at which the hardness of the packing ( for example, corkprene) frequently used as a material reaches a predetermined control limit are shown.

As shown in the simulation display example of the third arithmetic unit 50, first, the operating years Y corresponding to the operating temperature θ ₁ in the first step of the operating temperature history output from the second arithmetic unit 40 are obtained. obtains the logarithmic transformation value (similarly, also all the operating life corresponding to other operating temperature determines the log conversion value), the operating temperature theta ₁ and its operating life logy ₁ coordinates of tensile strength retention of the insulating paper experiments 51 , And the value of the operating years logY ₂ is added in the vertical axis direction from the intersection of this and the operating temperature θ _{2 of} the second step to calculate the coordinates of the operating years logY versus the operating years θ of the second step. Determine. In this manner, the coordinates obtained by adding the value of the operating temperature θ ₆ of the final step and the value of the operating years logY _{6 in} the vertical axis direction are obtained as shown by a plot 53 indicated by a black circle.

Here, the line of the experimental results 51 of the operating years Y and the operating temperatures θ at which the tensile strength residual ratio of the insulating paper is reduced by half is shown in FIG.
And contrasts the facts of Fig. 6, CO + CO ₂ generation amount approximately 1m
1 / g, and the empirical formula is given by a known formula (4). Y = A · exp {−B / (273 + θ)} (4) where A: proportional constant, B: activation energy In the case of the embodiment, the above equation (4) is modified to obtain the proportional constant A and the activity. When the value is obtained by substituting a numerical example for the activation energy B, the following expression is obtained. log ₁₀ Y = (7289.7445 / 273 + θ) -1
9.951869 Similarly, an experimental line 52 of the experimental results Y of the operating years Y and the operating temperature θ at which the hardness of the packing ( for example, corkprene) frequently used as the oil seal material of the oil-immersed transformer case reaches a predetermined control limit. The equation is also represented by the above equation (4), and in the case of the embodiment, it is as follows. log ₁₀ Y = (5416.3768 / 273 + θ) −1
5.265395

Further, the remaining life estimation / diagnosis unit 60 includes a simulation display example of the third computing unit 50,
Final plot 53 of simulation of operating temperature history
And the remaining life with respect to the operating load factor obtained by converting the operating temperature from the logarithmic relative age difference based on the experimental results 51 and 52.
Since the line 2 is positioned as the life line of the insulating paper and the packing of the oil-immersed transformer, the remaining life can be estimated from the logarithmic relative years difference from the final plot 53 of the simulation of the operating temperature history. Accordingly, the remaining life can be diagnosed relatively inexpensively and easily without the need to collect insulating oil or the like as in the conventional example.

Embodiment 2 FIG. FIG. 2 is a diagram illustrating a relative relationship with the final plot 53 of the simulation of the operating temperature history in the simulation display example of the third arithmetic unit 50 in the first embodiment. In FIG. 2, the difference between the line of the experimental result 51 as the life line of the insulating paper and the final plot 53 is logY _LO −logY.
_O indicates that the oil-immersed transformer will continue to operate at θ ₀ (= FIG.
Shows the remaining life when the operation is considered to be performed at the operation temperature θ ₆ ) in the final plot 53 in FIG. In the second embodiment, as shown in FIG. 2, a description will be given using a broken line 54 drawn through the final plot 53 and parallel to the line of the experimental result 51 as the life line of the insulating paper. That is, the final plot 5
_Assuming that the operation was continued at an operation temperature θ ₀₁ lower than the operation temperature θ ₀ or an operation temperature θ ₀₂ higher than the operation temperature θ ₀ , the remaining life at these operation temperatures was low.
It is determined from gY _L1 -logY ₀₁ or logY _L2 -logY ₀₂ . Thus, in the second embodiment,
The result of the operating temperature simulation can be used to express the remaining life with the operating temperature in the future as a parameter. Here, since the operating temperature θ can be expressed by the functional forms shown in Expressions (1) and (3), the remaining life in the future can be expressed by using the operating load factor K of the oil-immersed transformer as a parameter. It will provide vital information about the operating guidelines of the vessel. That is, the operating temperature history
The final plot 53 of the simulation (cumulative running time
Value) and the parallel line parallel to the experimental result 51 or 52
Driving from logarithmic relative time difference with test result 51 or 52
Operating load factor converted from operating temperature using temperature as a parameter
Can be estimated .

Embodiment 3 FIG. In the second embodiment, means for achieving the effect of remaining life prediction at a single temperature such as the operating temperature θ ₀ of the final plot 53 of the operating temperature simulation or the operating temperature θ ₀₁ or θ ₀₂ different from the operating temperature θ ₀ will be described. However, in the third embodiment, it is possible to estimate a remaining life corresponding to a combination of two or more temperature levels as a future operating temperature. That is, it can be easily achieved by developing the operating years corresponding to the operating temperatures θ ₀₁ and θ ₀₂ shown in FIG. 2 in the same manner as the simulation display example of the third computing unit 50 shown in FIG. In addition, the future remaining life is 2
It can be made more realistic by expressing the combination of the above operation load factors.

Embodiment 4 FIG. In the first to third embodiments, the remaining life estimation / diagnosis unit 60 shown in FIG. 1 quantitatively expresses the estimation of the remaining life. However, in the fourth embodiment, a standard thermal diagnosis finding is automatically performed at the same time. Output.
That is, in Example 4, as shown in FIG. 3, the experimental results 51 and 52 as the life line of the insulating paper and the packing were used.
Are provided with lines 51a and 52a below the number of years to be warned, for example, three years. By providing a notifying means in the remaining life estimation / diagnosis unit 60 so that a predetermined diagnosis finding is automatically output by any of the five zones A to E divided by these four lines. , Enabling appropriate maintenance response.

[0024]

As described above, according to the apparatus for diagnosing the remaining life of an oil-immersed transformer according to the first aspect of the present invention, the oil-immersed transformer operating at a predetermined operation load factor is determined. First calculating means for calculating a temperature rise value at a rated capacity based on temperature data, and storage means for storing operating history data such as an operating time with respect to an operating load factor and an ambient temperature of the oil-immersed transformer;
A second operation temperature history expressed by an operation time with respect to the operation temperature is obtained based on the temperature rise value at the rated capacity, the operation time with respect to the operation load factor, and the ambient temperature of the oil-filled transformer.
Calculating means for calculating the cumulative value of the operating time based on the operating temperature history, and calculating the cumulative value of the operating time.
The insulation paper of the above oil-filled transformer is
Or flat parallel to the life line for the operating temperature of the sealing material.
The operating temperature is calculated based on the relative time difference between the line and the life line.
Diagnostic means for estimating the remaining life with respect to the operating load factor obtained by converting the operating temperature as a parameter, so that it is based on the temperature data of the oil-immersed transformer operating at the predetermined load factor and the past operating history data. The remaining life can be estimated, and there is an effect that the remaining life can be diagnosed relatively inexpensively and easily without the need to collect insulating oil or the like.

Further, according to the remaining lifetime diagnosing device for an oil-filled transformer according to claim 2, in the diagnosis means, warning zone to life insulation Kamima other oil-filled transformer for operation load of the sealing member Are provided, and when the cumulative value of the operation time reaches any of the inside of the alert zone, each is notified, so that it is possible to achieve an appropriate and prompt maintenance.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a device for diagnosing remaining life of an oil-filled transformer according to Embodiment 1 of the present invention.

FIG. 2 is related to the second embodiment of the present invention, and is an explanatory diagram when obtaining the remaining life using the operating temperature as a parameter.

FIG. 3 relates to a fourth embodiment of the present invention, and is an explanatory diagram when a warning zone is provided for notification.

FIG. 4 is a characteristic diagram illustrating a decrease in the average degree of polymerization of insulating paper with the years of operation of an oil-immersed transformer.

FIG. 5 is a characteristic diagram showing a relationship between an average polymerization degree residual ratio and a tensile strength residual ratio of insulating paper of an oil-immersed transformer.

FIG. 6 shows the average polymerization degree residual ratio of insulating paper and the C per unit weight of insulating paper when insulating paper of an oil-immersed transformer is acceleratedly degraded in oil.
O + CO ₂ production of the relationship is a characteristic diagram showing.

[Explanation of symbols]

Reference Signs List 20 first computing unit 40 second computing unit 50 third computing unit 60 remaining life estimation diagnosis unit

Claims (2)

(57) [Claims] A first calculating means for calculating a temperature rise value at a rated capacity based on temperature data of an oil-immersed transformer operated at a predetermined operating load factor; A storage means for storing operation history data such as the ambient temperature of the input transformer, and an operating time for the operating temperature based on the temperature rise value at the rated capacity, the operating time for the operating load factor, and the ambient temperature of the oil-immersed transformer. A second calculating means for obtaining an operating temperature history represented by an operating time; a third calculating means for obtaining an accumulated value of the operating time based on the operating history;
The oil that is obtained in advance through the cumulative value of the operation time
Service life of the transformer at the operating temperature
Relative time between the parallel line parallel to the life line and the above life line
And a diagnostic means for estimating the remaining life with respect to the operating load factor obtained by converting the operating temperature from the difference using the operating temperature as a parameter . Wherein said means for diagnosing the oil-filled transformers insulating Kamima <br/> others by providing a plurality of guard zones to life against the operation load of the sealing member, the cumulative value is the warning zone of the operating time The remaining life diagnostic device for an oil-filled transformer according to claim 1, wherein the oil-filled transformer is detected when it reaches any one of the following.