JP2016205874A - Resin degradation measurement sensor and degradation measurement system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a resin degradation measurement sensor and degradation measurement system with which it is possible to know the progress of resin degradation in a mold transformer with high accuracy.SOLUTION: A resin degradation measurement sensor for detecting a mass change in order to estimate the progress of resin degradation according to the present invention is designed to include at least a first and a second crystal resonator coated with a resin to detect the progress of degradation, an oscillation circuit of each of the first and second crystal resonators, and a first cover covering the first crystal resonator and suppressing the resin from being exposed to the cause of resin degradation. Meanwhile, a resin degradation measurement system according to the present invention comprises the resin degradation measurement sensor, a counter for counting vibrations due to the respective oscillation circuits of the sensor, and a processing device for calculating the amount of a temperature-compensated frequency change that corresponds to a reduction in the amount of mass of the resin coated on the sensor, the life of the resin being predicted from the reduced amount of mass of the resin on the basis of the measured value of the counter.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a resin material for electrical equipment, particularly to a mold resin of a power receiving / transforming facility, and relates to a deterioration measuring sensor and a deterioration measuring system for detecting a deterioration state thereof.

Resin materials are used in many electrical equipment, but in molded transformers where the entire surface of the primary and secondary windings is covered with an insulating base material containing resin or resin, the resin that is the insulating base material It is said that the lifetime of the device is determined by thermal deterioration of (mainly epoxy resin).
As a method for diagnosing deterioration of the mold transformer, there is a method of performing deterioration diagnosis by measuring the light reflectance of the epoxy resin. The diagnosis based on the light reflectance characteristic is a method of diagnosing the degree of deterioration by measuring the light reflectance of the epoxy resin by utilizing the correlation between the mass reduction due to thermal evaporation of the resin component and the darkening.

  In the diagnosis based on the above-described light reflectance characteristics, since the quantitative deterioration degree can be grasped by the light reflectance value, it is easy to grasp the replacement time of the mold transformer and it is easy to make a maintenance plan for the equipment. However, since it is necessary to power out the transformer for measurement, it is not possible to frequently measure in operation of the power receiving / transforming equipment.

  For the resin degradation diagnosis, in addition to the above-described diagnosis based on the light reflectance characteristic, for example, a method of applying a micro-measurement with a crystal resonator disclosed in Patent Document 1 in order to measure a mass decrease due to resin degradation. There is. Specifically, in Patent Document 1, a crystal resonator having electrodes attached thereto is excited by applying a voltage to a surface of a crystal resonator coated with an electrode, thereby obtaining oscillation at a specific frequency. And it is disclosed that the decrease in the coating film thickness after the elapse of time is detected and the coating film deterioration is detected by utilizing the decrease in the natural frequency according to the coating film thickness.

JP 2003-149128 A

According to the technology disclosed in Patent Document 1, a resin is applied to the surface of a crystal resonator, and the principle of micromeasurement by a so-called crystal resonator method can be applied to detect a decrease in the mass of the resin. And the progress of resin deterioration can be known from the detected mass reduction. For example, in the quartz crystal method, it is said that a 9 MHz AT-cut quartz has a sensitivity of 1 nanogram per 1 Hz.
However, the temperature rise of the molded transformer varies depending on the load. Although the crystal resonator has frequency temperature characteristics, Patent Document 1 does not consider the frequency temperature characteristics of crystal vibration, and the degree of progress of resin deterioration of the mold transformer cannot be accurately known.

  This invention is made | formed in view of such a situation, and provides the degradation measurement sensor and degradation measurement system of the resin which can know the progress of resin degradation of a mold transformer accurately.

  In order to solve the above-described problem, the deterioration measuring sensor for detecting a change in mass in order to estimate the progress of the deterioration of the resin according to the present invention includes at least two first and first coated with a resin for detecting the progress of the deterioration. 2 crystal oscillators, the oscillation circuits of the first and second crystal oscillators, and the first crystal oscillator, and the resin is prevented from being exposed to a deterioration factor of the resin. And a first cover.

  Specifically, the resin applied to the first and second crystal units includes an epoxy resin that is an insulating member of a mold transformer, and the first cover is attached to the first crystal unit. Oxygen was blocked so that the applied resin was not exposed to oxygen.

  The deterioration measurement system according to the present invention includes at least two first and second crystal resonators coated with a resin for detecting the degree of deterioration, and each oscillation of the first and second crystal resonators. A circuit, a first cover that covers the first crystal unit and prevents the resin from being exposed to a deterioration factor of the resin, and an oscillation circuit of each of the first and second crystal units A counter that counts vibration due to the above, and a processing device that calculates a temperature-compensated frequency change amount corresponding to a mass decrease amount of the resin applied to the second crystal resonator based on a count value of the counter; The lifetime of the resin is predicted from the amount of mass reduction of the resin.

  According to the present invention, it is possible to accurately detect the degree of progress of resin deterioration of an insulating member or the like of the mold transformer, and therefore, the operation management of the mold transformer is facilitated.

It is a block diagram of the sensor element of an Example. It is a figure which shows the structure of the degradation measurement sensor and degradation measurement system of a present Example. It is a figure which shows an example of the mold transformer in which a deterioration measurement sensor is installed. It is a figure which shows the structure of the deterioration measurement system which can estimate the progress degree of deterioration inside mold resin. It is a figure which shows the structure of the deterioration measurement system which estimates the progress of deterioration of an epoxy resin in combination with a reflectometer.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a configuration diagram of sensor elements 21 and 22 (see FIG. 2) used in a deterioration measuring sensor and a deterioration measuring system of the present embodiment, which will be described in detail later.
The sensor elements 21 and 22 utilize quartz thickness shear vibration, and a thin epoxy resin (silica weight content 75%) 13 of about 100 μm is applied to the AT-cut quartz crystal resonator 11. The crystal unit 11 is sandwiched between surface electrodes 14 to which a voltage is applied, and is connected to an oscillator 24 to be described later via the application electrode 12.
Here, the epoxy resin 13 is the same material as the resin of an insulating base material such as a mold transformer that detects the degree of progress of deterioration.

  The sensor elements 21 and 22 are mass sensors that utilize the property that the resonance frequency fluctuates according to the mass of the substance that adheres when the quartz crystal resonator 11 undergoes thickness shear vibration. Specifically, utilizing the fact that the frequency change and mass change of the crystal unit 11 are linear, the frequency change is detected and the mass change of the applied epoxy resin 13 is measured.

  It is known that the epoxy resin 13 that is an insulating base material of a mold transformer undergoes thermal oxidation degradation due to heat generated during operation of the mold transformer, resulting in a decrease in mass. On the other hand, the resonance frequency of the crystal unit 11 has temperature characteristics, and furthermore, the temperature of the mold transformer varies due to the load variation of the mold transformer. The value will fluctuate with temperature.

For this reason, in the deterioration measuring sensor and the deterioration measuring system of the present embodiment, at least two sensor elements 21 and 22 are provided to perform temperature compensation for detecting a frequency change.
Example 1
The configuration of the deterioration measuring sensor and the deterioration measuring system of this embodiment will be described in detail with reference to FIG.

  The deterioration measuring sensor 20 of the present embodiment includes at least two sensor elements 21 and 22 described above, and the sensor element 22 includes a cover 23 for shielding from the environment. More specifically, the cover 23 is a stainless steel box that blocks oxygen.

  An oscillation circuit 24 is connected to the two sensor elements 21 and 22 and oscillates at the resonance frequency of the crystal unit 11. The oscillation circuit 24 includes a known negative feedback amplifier circuit, a feedback resistor, a load capacitor, an amplitude limiting resistor, and the like.

  The deterioration measuring sensor 20 consumes very little power and can be driven at about 3.3 V, so that it can be driven by a battery. In this case, the deterioration measuring sensor 20 can be realized with a size of about 5 cm square, and can be installed at any place of the molded transformer.

Returning to the description of the degradation measurement system in FIG. 2, the degradation measurement sensor 20 is connected to the frequency counter 26, and the oscillation frequencies of the sensor elements 21 and 22 of the degradation measurement sensor 20 are detected. The detected oscillation frequencies of the sensor elements 21 and 22 are notified to a processing device 28 such as an embedded microcomputer.
The external power source 27 is a power source for the deterioration measuring sensor 20, the frequency counter 26, and the processing device 28, and may be connected to the output of the mold transformer.
It is desirable that the frequency counter 26, the processing device 28, and the external power supply 27 are installed apart from the mold transformer in order to avoid the influence of heat generation of the mold transformer.

Next, the function of the deterioration measurement system will be described.
The processing device 28 uses the frequency counter 26 to acquire the oscillation frequencies of the sensor elements 21 and 22 of the deterioration measurement sensor 20 at a predetermined cycle. At this time, in the sensor element 22, the applied epoxy resin is not thermally oxidized and deteriorated by the cover 23 that blocks oxygen. Therefore, if the deterioration measurement sensor 20 is installed in the mold transformer so that the sensor elements 21 and 22 of the deterioration measurement sensor 20 have the same temperature environment, the difference between the oscillation frequencies of the sensor elements 21 and 22 is temperature compensated. The amount of frequency change due to the decrease in the mass of the applied epoxy resin.
The processing device 28 can obtain the correspondence relationship between the mass decrease amount of the epoxy resin and the frequency change amount in advance, and can convert the mass decrease amount of the epoxy resin from the detected frequency change amount.

In addition, the processing device 28 obtains a correspondence relationship between the life of the mold transformer (the degree of progress of resin deterioration) and the mass decrease amount of the epoxy resin, and the mass decrease amount of the epoxy resin from the time change of the detected frequency change amount. It is also possible to predict the life of the mold transformer from the predicted value of the mass reduction amount.
In this case, when the processing device 28 predicts the mass reduction amount of a predetermined epoxy resin and predicts the life of the mold transformer, the display device (not shown) connected to the processing device 28 is connected to the inspection and maintenance of the mold transformer. Warning display can also be performed.

In addition, the processing device 28 notifies the management center that centrally monitors the power receiving and distribution equipment such as the mold transformer by using the built-in priority or wireless network communication means. The management center may convert the mass loss of the epoxy resin and predict the life of the mold transformer from the time conversion of the mass decrease. Thereby, the remote lifetime monitoring of a mold transformer can be performed.
Furthermore, taking into account the operation information (power fluctuation information, etc.) of the power distribution equipment acquired by the management center, estimating the acceleration of the mass decrease due to the increase in the load of the molded transformer, and predicting the life of the transformer , The accuracy can be improved.

  Further, the processing device 28 compares the oscillation frequencies of the two sensor elements 21 and 22 of the deterioration measuring sensor 20 and determines whether or not there is a large deviation beyond the mass decrease or the fluctuation range of the temperature characteristic. Thereby, the abnormality of the deterioration measurement sensor 20 is detected, and the failure of the deterioration measurement system is detected.

The deterioration measuring sensor 20 of the present embodiment is provided with a cover 23 for blocking oxygen, paying attention to the point that the epoxy resin of the mold transformer is thermally oxidized and deteriorated in order to detect the degree of deterioration of the epoxy resin of the mold transformer. The sensor element 22 performs temperature compensation.
In order to eliminate other deterioration factors other than the thermal oxidation deterioration of the resin deterioration, a filter may be provided in the sensor element 21 to block the deterioration factor.

For example, a very thin HEPA (High Efficiency Particulate Air Filter) filter or polymer film filter having the same box shape as the cover 23 is attached to the sensor element 21. Thereby, dew condensation, salt adhesion, etc. can be avoided.
At this time, the same filter is also provided in the sensor element 22 for performing temperature compensation.
Thereby, the degradation measurement sensor 20 which can exclude a disturbance factor can be provided.

Next, an installation example of the deterioration measuring sensor 20 will be described.
FIG. 3 is a diagram illustrating an example of a molded transformer in which the deterioration measurement sensor 20 of the present embodiment is installed. Note that FIG. 3 shows only the main part, and the description of the constituent members such as the case support part is omitted.

The main parts of the mold transformer are an iron core 31 provided in the center, a secondary winding 32 provided around the iron core 31 and having a plurality of winding conductors for outputting current, and the secondary coil. A primary side winding 33 provided on the outer periphery of the side winding 32 and a housing support portion 34 for supporting them are roughly configured.
Each of the secondary winding 32 and the primary winding 33 has a plurality of winding conductors and is molded with a mold resin 35 such as an epoxy resin.

  The deterioration measurement sensor 20 of the present embodiment is provided on the outer peripheral surface of the mold resin 35 and detects the degree of deterioration of the mold resin 35. At this time, in order to make the temperature state of the mold resin 35 and the sensor elements 21 and 22 of the deterioration measurement sensor 20 the same, the deterioration measurement sensor 20 is preferably embedded in the mold resin 35.

  The frequency counter 26, the external power supply 27, and the processing device 28 of the deterioration measuring system avoid the influence of heat generation due to the loss load of the winding resistance of the primary side winding 33 and the secondary side winding 32. You may install in a protective case which accommodates a mold transformer.

As described above, by installing the deterioration measuring sensor 20 of this embodiment in the mold transformer, it is possible to detect the degree of deterioration of the mold resin 35, but the mold resin 35 has a temperature gradient in the thickness direction. Since the inside is hotter, the oxygen diffusivity of the epoxy resin is small, and it takes time until the internal oxygen state becomes high, the inside of the mold resin 35 and the surface on which the deterioration measuring sensor 20 is installed. In some cases, the deterioration state of the resin may be different.
In order to estimate the progress of deterioration inside the mold resin 35, the deterioration measuring sensor 20 may be configured as follows.

Example 2
FIG. 4 shows a configuration of a deterioration measurement system that can estimate the degree of deterioration inside the mold resin 35.
The deterioration measurement sensor 20 in the deterioration measurement system of FIG. 2 differs from the deterioration measurement sensor 20 in that a sensor element 41 for the deterioration measurement sensor 40 to estimate the progress of deterioration inside the mold resin 35 is added.

  The sensor element 41 is provided with an oxygen filter cover 42 that restricts permeation of oxygen (permeates a certain amount of oxygen), and restricts the amount of oxygen diffused in the epoxy resin applied to the sensor element 41. As a result, the state of thermal oxygen deterioration at a predetermined depth of the mold resin 35 is simulated, and the degree of deterioration is estimated from the frequency change.

  At this time, the temperature of the sensor element 41 is lower than the temperature inside the mold resin 35 due to the temperature gradient in the thickness direction of the mold resin 35. Therefore, the degree of progress of deterioration estimated from the frequency change of the sensor element 41 is multiplied by the temperature acceleration coefficient to obtain the degree of progress of deterioration of the epoxy resin at a predetermined depth of the mold resin 35.

Here, the temperature gradient in the thickness direction of the mold resin 35 can be obtained in advance.
Further, the temperature of the sensor element 41 may be obtained from the frequency of the sensor element 22 based on the frequency temperature characteristics of the crystal unit 11, or a temperature detection element such as a thermocouple or thermistor may be provided separately. .

  In the deterioration measurement system of FIG. 4, the sensor element 22 compensates the temperature of the frequency change detected by each of the sensor elements 21 and 41, and estimates the degree of progress of deterioration on the surface and inside of the mold resin 35. Then, the average value of the estimated degree of deterioration is obtained, or the maximum value of the estimated degree of deterioration is obtained to diagnose the degree of deterioration of the mold transformer.

  In the deterioration measurement system of FIG. 4, an example in which the degree of progress of deterioration of the epoxy resin is detected by two sensor elements 21 and 41, and in the deterioration measurement system of FIG. 2 by one sensor element 21, the present invention is not limited to this. Even if the deterioration degree of the mold transformer is diagnosed from the average value or the maximum value of the deterioration degree as described above, the degree of deterioration is estimated by detecting each sensor element. Good. Thereby, the diagnostic accuracy can be improved.

  Further, by estimating the degree of deterioration inside the mold resin 35 as in the sensor element 41 described above, it is not necessary to provide the sensor element inside the mold resin 35. Therefore, there is no decrease in the mechanical strength of the mold resin 35 due to the inclusion of the sensor element, so there is no need to increase the thickness of the mold resin 35 and a small shape can be maintained.

Example 3
Next, a deterioration measurement system that estimates the degree of deterioration of the epoxy resin using a reflectometer will be described. FIG. 5 is a diagram showing a configuration of a deterioration measurement system that estimates the degree of progress of deterioration of an epoxy resin in combination with a reflectometer.
In this embodiment, the discoloration and the light reflectivity decrease due to the thermal oxidation degradation of the epoxy resin are detected, and the light reflectivity of the surface of the mold resin 35 is measured by the reflectometer 51 connected to the processing device 28 of FIG. Then, the color change or reflectance change due to thermal oxidation deterioration of the epoxy resin is detected. The degree of progress of deterioration of the mold resin 35 is estimated from the change in the measurement value measured by the reflectometer 51.

In the measurement by the reflectometer 51, the deterioration state inside the mold resin 35 cannot be estimated. For this reason, in the degradation measurement system of FIG. 5, the degradation degree diagnosis of the mold transformer is performed in combination with the degradation measurement sensor 50 including the internal progress detection sensor element 41 and the temperature compensation sensor element 22 described above.
Since the reflectometer 51 can perform measurement without contact, it is possible to realize a deterioration measurement system with a high degree of freedom in sensor installation.

5 includes a sensor element 22 for temperature compensation, a sensor element 21 for detecting the progress of deterioration of the surface of the mold resin 35, and a sensor element for detecting the progress of deterioration inside the mold resin 35. 41 may be used.
At this time, the degree of progress of deterioration of the surface of the mold resin 35 is estimated from the detection results of the sensor element 21 and the reflectometer 51. At the initial stage of the deterioration diagnosis of the mold transformer, the detection result of the sensor element 21 is calculated. Priority is given to the detection result of the reflectometer 51 later in the deterioration diagnosis.
As described above, estimating the degree of progress of deterioration using two different detection methods improves the estimation accuracy and can determine the abnormality of the sensor, thereby improving the reliability of the deterioration measurement system.

  According to the first to third embodiments, since the degree of progress of the deterioration of the mold resin 35 of the mold transformer can be estimated, the epoxy resin is thermally oxidized and deteriorated, the mechanical strength is reduced, and the mold resin 35 is cracked. Since a decrease in insulation strength such as partial discharge can be predicted in advance, preventive maintenance of the mold transformer can be easily performed.

  Further, in the above-described Examples 1 to 3, an example in which the mold resin 35 of the mold transformer is an epoxy resin has been described. The same effect can be obtained even if it contains an inorganic substance or an organic substance such as rubber. In general, silica and alumina, which are inorganic substances, do not decrease in weight due to thermal oxidative degradation, and therefore the rate of decrease in the amount of resin becomes slower by the amount other than that.

  Further, the same effect is exhibited even when the material applied to the crystal unit 11 includes an epoxy resin or an epoxy resin and an inorganic compound. In particular, epoxy resins contain a large amount of silica and other fillers when used for high voltage equipment. In this case, the amount of deterioration and evaporation of the resin is reduced, but a very sensitive quartz crystal unit can detect this. In addition, PTFE (polytetrafluoroethylene) which is not easily deteriorated other than the epoxy resin has the same effect.

  The present invention is not limited to the above-described embodiments, and includes various modifications. For example, the above-described embodiments have been described in detail for easy understanding by the present invention, and are not necessarily limited to those having all the configurations described. Further, a part of the configuration of an embodiment can be replaced with the configuration of another embodiment, and the configuration of another embodiment can be added to the configuration of an embodiment.

20, 40, 50 Deterioration measurement sensor 21, 22 Sensor element 23 Cover 24 Oscillation circuit 26 Frequency counter 27 External power supply 28 Processing device

Claims (14)

A deterioration measurement sensor that detects a change in mass in order to estimate the progress of resin deterioration,
At least two first and second crystal resonators coated with a resin for detecting the degree of deterioration;
An oscillation circuit for each of the first and second crystal units;
A first cover that covers the first crystal unit and prevents the resin from being exposed to a deterioration factor of the resin;
A resin deterioration measuring sensor comprising: In the resin degradation measurement sensor according to claim 1,
The resin applied to the first and second crystal units includes an epoxy resin that is an insulating member of a mold transformer,
The resin degradation measurement sensor, wherein the first cover blocks oxygen so that the resin applied to the first crystal unit is not exposed to oxygen. The resin degradation measurement sensor according to claim 2, further comprising:
A third crystal unit coated with the resin;
An oscillation circuit of the third crystal resonator;
A second cover that covers the third crystal unit and has a predetermined oxygen permeation amount and limits the amount of oxygen to which the resin applied to the third crystal unit is exposed;
A resin deterioration measuring sensor comprising: The resin degradation measurement sensor according to claim 2,
A second cover that covers the second crystal unit and has a predetermined oxygen permeation amount and limits an amount of oxygen to which a resin applied to the second crystal unit is exposed;
A resin deterioration measuring sensor comprising: The resin degradation measurement sensor according to any one of claims 1 to 4,
A sensor for measuring deterioration of a resin, which is installed on an outer peripheral surface of an insulating member of a mold transformer. In the sensor for measuring deterioration of resin according to any one of claims 1 to 4,
The resin deterioration measuring sensor, wherein the resin is an epoxy resin and an inorganic compound. In the sensor for measuring deterioration of resin according to any one of claims 1 to 4,
The resin is a base material of a composite electrical insulating resin, is an epoxy thermosetting resin, and includes an inorganic substance such as silica or alumina or an organic substance such as rubber as a filler, and a resin deterioration measuring sensor. At least two first and second crystal resonators coated with a resin for detecting the degree of deterioration;
An oscillation circuit for each of the first and second crystal units;
A first cover that covers the first crystal unit and prevents the resin from being exposed to a deterioration factor of the resin;
A counter that counts vibrations by the oscillation circuits of the first and second crystal units;
A processing device that calculates a temperature-compensated frequency change amount corresponding to a mass decrease amount of the resin applied to the second crystal resonator based on a count value of the counter;
A resin deterioration measurement system, wherein a resin life prediction is performed from a resin mass reduction amount corresponding to the frequency change amount. In the resin degradation measurement system according to claim 8,
The resin applied to the first and second crystal units includes an epoxy resin that is an insulating member of a mold transformer,
The resin deterioration measurement system, wherein the first cover blocks oxygen so that the resin applied to the first crystal unit is not exposed to oxygen. In the resin degradation measurement system according to claim 9,
The said processing apparatus performs the warning display of the inspection and maintenance of a mold transformer, when the mass reduction | decrease amount of the resin corresponding to the said frequency change amount is more than predetermined value, The resin deterioration measuring system characterized by the above-mentioned. The resin degradation measurement system according to claim 9, further comprising:
A third crystal unit coated with the resin;
An oscillation circuit of the third crystal resonator;
A second cover that covers the third crystal unit and has a predetermined oxygen permeation amount and limits the amount of oxygen to which the resin applied to the third crystal unit is exposed;
The counter counts vibrations generated by the oscillation circuits of the first, second, and third crystal units,
The processing device calculates two temperature-compensated frequency changes corresponding to the respective mass reduction amounts of the resin applied to the second and third crystal resonators based on the count value of the counter. This is a resin degradation measurement system. In the resin degradation measurement system according to claim 9,
A second cover that covers the second crystal unit and has a predetermined oxygen permeation amount and limits an amount of oxygen to which a resin applied to the second crystal unit is exposed;
A reflectometer for measuring the light reflectivity of the mold resin,
A resin deterioration measurement system, wherein the second quartz crystal resonator is used to predict the life of the resin inside the resin, and the reflectometer is used to predict the life of the resin on the resin surface. The resin degradation measurement system according to claim 11, further comprising:
A reflectometer for measuring the light reflectivity of the mold resin,
Deterioration of the resin characterized in that the lifetime of the resin inside the resin is predicted by the third crystal resonator, and the lifetime of the resin on the resin surface is predicted by the reflectometer and the second crystal resonator. Measuring system. In the resin degradation measurement system according to claim 12 or 13,
In the initial stage of diagnosis, the lifetime of the resin surface is predicted by the second crystal unit,
In the latter stage of diagnosis, the resin deterioration measurement system is characterized in that the lifetime of the resin surface is predicted by the reflectometer.

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