Deterioration sign diagnosis method and deterioration sign diagnosis system for resin material

Abstract

To provide a deterioration sign diagnosis method and a deterioration sign diagnosis system of a resin material capable of easily diagnosing a sign of deterioration of the resin material.SOLUTION: The resin material deterioration sign diagnosis method according to the embodiment includes measuring a resin material by a nuclear magnetic resonance apparatus capable of non-destructive observation, acquiring free induction decay curve data, obtaining a spin-spin relaxation time, evaluating a change in molecular mobility of the resin material based on the spin-spin relaxation time, and diagnosing a deterioration sign of the resin material.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to a method and system for diagnosing signs of deterioration of resin materials in high-voltage electrical equipment that uses resin materials. [Background technology]

[0002] High-voltage electrical equipment, including power distribution equipment, is made up of a variety of materials, which can be broadly categorized into three types: metal, ceramic, and resin (polymer) materials. In many cases, to electrically insulate high-voltage parts made of metal materials, they are surrounded by a resin material with excellent electrical insulation properties to ensure electrical insulation.

[0003] The solid insulation method, which uses resin materials for electrical insulation, has the problem that its electrical insulation properties deteriorate as the resin material deteriorates. Of the three constituent materials mentioned above, resin materials in particular tend to deteriorate more easily and at a faster rate than the other two materials, and therefore tend to reach the end of their life the earliest. When resin materials deteriorate, problems arise, such as a decrease in electrical insulation properties and the occurrence of partial discharges that directly lead to the failure of high-voltage equipment. Therefore, detecting signs of deterioration in the properties of resin materials used as electrical insulating materials in high-voltage electrical equipment is extremely important for the stable operation of such equipment. Various methods for diagnosing deterioration of resin materials have been proposed. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 6811699 [Patent Document 2] Patent No. 6676003 [Patent Document 3] Patent No. 7223037 Summary of the Invention [Problem to be solved by the invention]

[0005] An object of an embodiment of the present invention is to provide a method and system for diagnosing signs of deterioration of a resin material that can easily diagnose signs of deterioration of a resin material. [Means for solving the problem]

[0006] According to an embodiment, the resin material is measured by a nuclear magnetic resonance apparatus capable of non-destructive observation, Obtain free induction decay curve data, Calculate the spin-spin relaxation time, Evaluating a change in molecular mobility of the resin material based on the spin-spin relaxation time; and There is also provided a method for diagnosing signs of deterioration of a resin material, which includes diagnosing signs of deterioration of the resin material. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 10 is a block diagram showing the configuration of a deterioration predictive diagnosis system for a resin material according to a second embodiment. [Figure 2] FIG. 10 is a diagram illustrating a configuration of an example of a nuclear magnetic resonance apparatus applied to a second embodiment. [Figure 3] 1 is a flow chart illustrating an example of a method for predicting deterioration of a resin material according to a first embodiment. [Figure 4] 10A and 10B are diagrams illustrating the state of a magnetic field of a probe relative to a resin material. [Figure 5] FIG. 1 is a diagram illustrating an example of the configuration of a magnet that generates a magnetic field gradient. [Figure 6] FIG. 1 is a graph showing an FID curve based on an FID signal and T2. [Figure 7] FIG. 10 is a graph showing a distribution function f(t) of relaxation time T2. [Figure 8] FIG. 1 is a diagram illustrating a configuration of an example of a high-voltage device used in an embodiment. [Figure 9] FIG. 10 is a diagram illustrating a configuration of another example of a high-voltage device used in the embodiment. [Figure 10]FIG. 1 is a graph showing the change in relaxation time over time with an increase in crystallinity due to degradation of a crystalline polymer. [Figure 11] FIG. 1 is a model diagram showing a molecular chain of a crystalline polymer. [Figure 12] FIG. 1 is a model diagram showing the degradation of molecular chains of a crystalline polymer. [Figure 13] FIG. 1 is a graph showing the initial value of the breakdown voltage of a crystalline polymer and the value after degradation. [Figure 14] FIG. 1 is a model diagram showing a molecular chain of a thermosetting resin. [Figure 15] FIG. 1 is a model diagram showing the state of deterioration of molecular chains of a thermosetting resin. [Figure 16] FIG. 1 is a graph showing the change over time in glass transition temperature and relaxation time due to an increase in free ends caused by deterioration of a thermosetting resin. [Figure 17] FIG. 1 is a model diagram showing a molecular chain of a thermosetting resin having an unreacted portion. [Figure 18] FIG. 1 is a model diagram showing molecular chains of a thermosetting resin whose crosslink density has increased due to degradation. [Figure 19] FIG. 1 is a graph showing the change in elastic modulus and T2f over time due to an increase in crosslink density caused by deterioration of a thermosetting resin. [Figure 20] FIG. 1 is a graph showing the distribution function f(t) obtained by inverse Laplace transform of the FID signal before and after degradation. [Figure 21] This is a model diagram showing peeling between a resin material and a metal conductor used in high-voltage equipment. [Figure 22] FIG. 2 is a model diagram showing a resin matrix and a filler before peeling. [Figure 23] FIG. 10 is a model diagram showing the resin matrix and filler after peeling. [Figure 24] 1 is a schematic diagram showing a comparison between the configuration of a high-voltage device and a graph of the measured T2 distribution function f(t). [Figure 25] FIG. 1 is a graph showing a distribution function f(t) obtained by inverse Laplace transformation of an FID signal obtained by locally applying heat. DETAILED DESCRIPTION OF THE INVENTION

[0008] The embodiments include a method for diagnosing a sign of deterioration of a resin material according to a first embodiment, and a system for diagnosing a sign of deterioration of a resin material according to a second embodiment. The method for diagnosing signs of deterioration of a resin material according to the first embodiment includes measuring the resin material using a non-destructively observable nuclear magnetic resonance (NMR) device, obtaining free induction decay (FID) curve data, determining the spin-spin relaxation time, evaluating changes in the molecular mobility of the resin material based on the spin-spin relaxation time, and diagnosing signs of deterioration of the resin material from the evaluation results of the changes in molecular mobility.

[0009] Furthermore, a resin material deterioration predictive diagnostic system according to a second embodiment is a system applicable to the resin material deterioration predictive diagnostic method according to the first embodiment, and includes a measurement unit that includes an NMR and non-destructively measures the resin material, a data processing unit that acquires FID curve data from the NMR and determines the spin-spin relaxation time, a data evaluation unit that evaluates changes in the molecular mobility of the resin material based on the spin-spin relaxation time, and a deterioration predictive diagnostic unit that diagnoses signs of deterioration in the resin material from the evaluation results of the data evaluation unit. The NMR used includes a probe unit that non-destructively detects magnetic moments, a magnet unit that generates a magnetic field, a spectrometer that processes detection signals from the probe unit, and a computer that processes signals from the spectrometer.

[0010] According to the first and second embodiments, by using NMR, which performs measurements non-destructively, it is possible to easily diagnose signs of deterioration of a resin material without having to cut out a piece of the resin material for inspection and insert it into the NMR. Hereinafter, embodiments will be described with reference to the drawings. The disclosure is merely an example, and appropriate modifications that are easily conceivable by those skilled in the art while maintaining the gist of the invention are naturally included within the scope of the present invention. Furthermore, in order to clarify the explanation, the drawings may show the width, thickness, shape, etc. of each part schematically compared to the actual embodiment, but these are merely examples and do not limit the interpretation of the present invention. Furthermore, in this specification and each drawing, elements similar to those described above with reference to the previous drawings may be designated by the same reference numerals, and detailed descriptions may be omitted as appropriate.

[0011] FIG. 1 is a block diagram showing the configuration of a deterioration predictive diagnosis system for resin materials according to the second embodiment. As shown in the figure, a resin material degradation predictive diagnostic system 30 according to the second embodiment includes a nuclear magnetic resonance (NMR) spectrometer 20 capable of non-destructive observation, and has a measurement unit 21 that measures the resin material non-destructively, a data processing unit 22 that acquires FID curve data from the NMR 20 and determines the spin-spin relaxation time, a data evaluation unit 23 that evaluates changes in the molecular mobility of the resin material based on the spin-spin relaxation time, and a degradation predictive diagnostic unit 24 that diagnoses signs of degradation of the resin material from the evaluation results of the data evaluation unit 23. The resin material degradation predictive diagnostic system 30 can be used, for example, to measure high-voltage equipment 10 that uses a resin material.

[0012] The high-voltage equipment 10 is arranged at a distance from the deterioration sign diagnostic system 30, and has a high-voltage metal member 2 and a resin material 1 arranged to cover the periphery of the metal member, and is electrically insulated. The resin material 1 can include at least one of a crystalline or amorphous thermoplastic resin, a thermosetting resin, or a rubber material. Examples of thermosetting resins that can be used include epoxy resins, phenolic resins, and polyurethane resins. Examples of thermoplastic resins that can be used include crystalline thermoplastic resins such as polyethylene terephthalate, polyethylene, and polyamide, and amorphous thermoplastic resins such as polyimide, polymethyl methacrylate, polyvinyl chloride, and polystyrene. Examples of rubber materials that can be used include ethylene propylene rubber and silicone. It is also possible to use a combination or mixture of these materials. The resin 1 can be filled with inorganic particles such as silica, alumina, magnesium oxide, aluminum nitride, silicon nitride, or a filler such as rubber particles.

[0013] The metal member 2 is made of copper, aluminum, or the like, and is used by being connected to a high voltage section. The high-voltage device 10 may be, for example, a resin-molded product for receiving and distributing electricity, a motor, or the like. In the case of a resin-molded product for receiving and distributing electricity, a resin material may be coated on the outer surface of a high-voltage portion embedded in the resin-molded product for receiving and distributing electricity. In the case of a motor, the resin material may be embedded on the outer periphery of the motor winding or in gaps. The resin-molded product for receiving and distributing electricity may be, for example, a switchgear or a circuit breaker, and the outer periphery of the metal member 2 may be coated with, for example, epoxy resin.

[0014] By using the deterioration predictive diagnostic system 30, it is possible to perform highly accurate predictive diagnostics of deterioration of, for example, the resin material 1 of the high-voltage equipment 10, making it possible to replace the equipment at the appropriate time and minimizing failures of power equipment including the high-voltage equipment 10, thereby realizing a stable supply of electricity. FIG. 2 shows a diagram illustrating the configuration of an example of an NMR applied to the second embodiment. As shown in the figure, the NMR 20 comprises a probe section 4 that irradiates RF waves and detects energy to non-destructively detect magnetic moments, a magnet section 3 that generates a magnetic field, a spectrometer 5 that includes an amplifier for processing the detection signal from the probe section 4 and a phase detector, and a computer 6 that performs Fourier transforms of the detection signal from the spectrometer 5, processes the spectrum, and sets the spectrometer 5.

[0015] FIG. 3 is a flow diagram illustrating an example of a method for predicting deterioration of a resin material according to the first embodiment. In the method for diagnosing a sign of deterioration of a resin material according to the first embodiment, a degradation sign diagnosing system 30 shown in FIG. 1 is used. As shown in the figure, first, the resin material 1 is measured non-destructively by NMR 20 in the measurement unit 21 (ST1). The NMR measurement can be performed by bringing the probe unit 4 close to the resin material 1 of the high-voltage device 10 at a predetermined distance, for example, 0 to 10 cm. Next, the data processing unit 22 acquires FID curve data from the NMR 20 (ST2). This makes it possible to acquire FID curve data of 1H (protons) contained in the surface layer and inside of the resin material 1 without destroying the resin material by sampling.

[0016] Subsequently, the data processing unit 22 determines the spin-spin relaxation time from the FID curve data by, for example, data processing (ST3). Thereafter, the data evaluation unit 23 evaluates the change in molecular mobility based on the spin-spin relaxation time (ST4). Finally, the deterioration sign diagnosis unit 24 diagnoses the deterioration sign of the resin material from the evaluation of the change in molecular mobility (ST5), thereby obtaining the result of the deterioration sign diagnosis. In the deterioration sign diagnosis, for example, by comparing the obtained data with a database acquired in advance, the deterioration sign of the resin material can be diagnosed with high accuracy.

[0017] The change in molecular mobility can be evaluated based on two or more components by separating the FID curve into at least two or more components with different spin-spin relaxation times. Furthermore, changes in molecular mobility can be evaluated by comparing the proportions of components with different spin-spin relaxation times or the absolute values ​​of the spin-spin relaxation times.

[0018] The NMR is equipped with a magnet section with a gradient in magnetic field strength, and by changing the resonant frequency with the magnet section, FID curve data can be obtained for each resonant frequency, and from each FID curve, the spatial distribution of spin-spin relaxation time inside the resin material can be determined and changes in the molecular mobility of the resin material can be evaluated. This makes it possible to evaluate defects inside the resin material and diagnose signs of deterioration.

[0019] FIG. 4 shows a diagram illustrating the state of the magnetic field generated by the probe 4 with respect to the resin material 1. As shown in FIG. In a deterioration sign diagnosis system 30 according to the embodiment, a magnet 3 is arranged so as to have a magnetic field gradient in the z-axis direction toward the resin material 1 to be measured. 31 schematically represents the magnetic field lines of the magnet 3. A signal can be acquired by bringing a probe 4 installed near the magnet 3 close to the resin material 1 to be measured. FIG. 5 shows a diagram illustrating an example of the configuration of a magnet that generates a magnetic field gradient. The magnet 3 uses a Halbach array, which can increase the magnetic field strength in a specific direction by arranging multiple permanent magnets 32 while rotating their magnetization direction, to generate a magnetic field gradient in the direction of the resin 1. As shown in Figure 4, when the magnetic field strength is changed along the z-axis direction in the interior (depth) direction of the resin material 1 as a sample, the resonant frequency at each magnetic field strength changes, so by using different resonant frequencies, FID can be obtained at different positions in the depth direction of the resin material 1.

[0020] FIG. 6 shows a graph representing an FID curve based on the acquired FID signal and T2. Curve 101 shows an FID curve obtained by applying an RF pulse using, for example, a Spin-Echo or Carr-Purcell-Meiboom-Gill sequence and acquiring it at probe unit 4. T2 of 1H can be obtained from this FID curve 101. In the figure, M(t) represents the magnitude of magnetization, which decays with time t. Figure 4 shows the T2 of two components with different relaxation times obtained by curve fitting this FID curve 101 with the exponential function shown in the following formula (1). Curve 102 represents the fast component T2f, and curve 103 represents the slow component T2s.

[0021]

number

[0022] In the formula, t represents time, M(t) represents the magnitude of magnetization at time t, M0 represents the magnitude of magnetization at time 0, and T2 represents the spin-spin relaxation time.

[0023] When a molecule is composed of multiple components with different molecular motility, the relaxation times T2 of each component, such as the fast component T2f and the slow component T2s, can be determined by curve fitting using multiple curves, as shown in Figure 8. Furthermore, by comparing the M0 of each component, the proportion of each component can be determined.

[0024] FIG. 7 is a graph showing the distribution function f(t) of the relaxation time T2. In the figure, 201 denotes the distribution function f(t). The distribution function f(t) is obtained by performing an inverse Laplace transform on the FID signal, and has peaks at the slow component T2s and the fast component T2f of the relaxation time T2. By using the inverse Laplace transform, in addition to the abundance ratio obtained from the absolute value of T2 and the peak integral value, the distribution of relaxation times obtained from the peak width can be obtained as a characteristic quantity of the resin material.

[0025] Changes in the molecular mobility of resin materials, such as changes in the chemical structure and higher-order structure associated with resin degradation, include an increase in crystallinity, the severing of covalent bonds, and an increase in crosslink density. Resin 1 can also become plasticized by absorbing water. Changes in the physical properties of resin 1 can also lead to the formation of voids between resin 1 and metal component 2, or between resin 1 and the filler if resin 1 contains inorganic particles or rubber particles, which can cause delamination. Larger voids tend to generate partial discharges that can cause equipment failure.

[0026] The relaxation time T2 is a characteristic quantity that indicates molecular mobility, and molecular chains that have strong interactions with crystalline parts or metals, etc., relax quickly, exhibiting a fast (short) relaxation time T2f. On the other hand, in amorphous parts with large molecular motion, the relaxation of molecular chains that have little interaction with surrounding molecules proceeds slowly, exhibiting a slow (long) relaxation time T2s. In this way, by comparing the proportions of components with different T2 values ​​and the absolute values ​​of T2, it is possible to detect changes in the molecular mobility of the resin material.

[0027] Furthermore, because molecular chains move cooperatively due to interactions with surrounding molecular chains, when degradation causes breakage of molecular chains or changes in higher-order structure, differences in the mobility of each molecular chain occur, resulting in different relaxation times. Therefore, an increase in the peak width obtained by the inverse Laplace transform indicates an increase in structural heterogeneity.

[0028] Before acquiring FID curve data, FID curve data is acquired using a standard resin material similar to the resin material, and the absolute value of the spin-spin relaxation time, the ratio of different components of the spin-spin relaxation time, or the distribution of the spin-spin relaxation time can be determined by inverse Laplace transform of the FID curve, and a correlation with the properties of the standard resin material can be determined in advance. This makes it possible to diagnose signs of deterioration of the resin material based on the correlation.

[0029] The properties of a resin material can be expressed by its electrical breakdown strength. The correlation can be expressed as a threshold. FID curve data can be obtained by locally heating the resin material and changing its temperature. When the resin material is in a glassy state and molecular motion is frozen, such as with crystalline thermoplastic resins, the resin material can be heated above its glass transition temperature to improve the molecular motion of the amorphous portion, making it possible to clearly extract and evaluate the characteristics of the slow-relaxing T2s component originating from the amorphous portion.

[0030] Before acquiring FID curve data, a standard resin material similar to the resin material is used, and the temperature of the standard resin material is locally changed to acquire FID curve data. The absolute value of the spin-spin relaxation time, the ratio of different components of the spin-spin relaxation time, or the distribution of the spin-spin relaxation time obtained by inverse Laplace transform of the FID curve is measured to determine in advance the correlation between the temperature dependence obtained and the properties of the standard resin material. For example, even when the resin material is in a glassy state and molecular motion is frozen, signs of deterioration of the resin material can be diagnosed based on the correlation obtained in advance.

[0031] FIG. 8 shows a diagram illustrating the configuration of an electric power receiving and distributing resin molded product, such as a resin molded vacuum switch, as an example of the high-voltage device 10. As shown in the figure, the resin-molded vacuum switch 10-1 as high-voltage equipment 10 is composed of a vacuum valve 50 as a metal member 2 having a pair of contacts in the center that can be freely connected and disconnected, and a resin insulating part 51 as a resin material 1 formed on its outer periphery.

[0032] The vacuum interrupter 50 has a fixed-side sealed end plate 45 and a movable-side sealed end plate 46 hermetically sealed to both end openings of a cylindrical vacuum insulating container 41. A fixed-side conductive shaft 42, which forms one of the electric paths, is fixedly secured to and passes through the fixed-side sealed end plate 45, and a fixed-side contact 52, which can be freely moved toward and away from the fixed-side conductive shaft 42, is attached to the end of the fixed-side conductive shaft 42 within the vacuum insulating container 41. Opposite the fixed-side contact 52, a movable-side contact 53 is attached to the end of the movable-side conductive shaft 43. The movable-side conductive shaft 43 passes through the movable-side sealed end plate 46 so as to be able to move back and forth, and forms the other electric path.

[0033] The free end of an expandable bellows 54 is airtightly fixed inside the vacuum insulating container 41 of the movable side current-carrying shaft 43, and the fixed end is airtightly fixed to the movable side sealing end plate 46. As a result, the internal pressure inside the vacuum insulating container 41 is reduced to 1×10 -2 The movable-side current-carrying shaft 43 is maintained at a vacuum of less than 100 Pa. The movable-side current-carrying shaft 43 is connected to an operating mechanism 56 outside the vacuum insulating container 41 via an insulating operating rod 55, and the fixed-side contact 52 and the movable-side contact 53 are opened and closed.

[0034] Resin insulating part 51 has an insulating layer 44 molded with an insulating material such as epoxy resin on the outer periphery of vacuum interrupter 50, exposing the end of fixed-side current-carrying shaft 42 and also exposing movable-side current-carrying shaft 43. This insulating layer 44 has a predetermined insulation thickness that can withstand the rated voltage of vacuum interrupter 50 on the outer peripheries of fixed-side and movable-side shield electrodes 47 and 48, which will be described later, and its movable side is fixed to operating mechanism 56.

[0035] The high-voltage device 10 may also be a motor, and may use an enameled wire in which the outer periphery of a metal member 2 made of copper is covered with one or more types of resin, such as polyethylene terephthalate, polyimide, or polyamideimide. The outside of the enameled wire may also be covered with an epoxy resin or the like.

[0036] FIG. 9 shows a partial vertical cross-sectional configuration of a stator of a motor as another example of the high-voltage device 10. As shown in the figure, a plurality of slots 62a are concentrically arranged at equal intervals in an iron core 62 of a stator 61 of a motor. The slots 62a are generally trapezoidal in shape. U-shaped slot insulators 63 are inserted into the slots 62a. A winding 67 is formed by inserting an enameled wire 66 as a magnet wire inside the slot insulator 63. A wedge material 71 formed from a sheet material into a half U-shape is driven into the opening of the slot 62a of the iron core 62 to fix the winding 67. Furthermore, the winding 67 housed in the slot 62a is impregnated with varnish 72 to fix the winding 67 together. This process is, for example, a drip impregnation varnish process, in which varnish 72 is dripped from a nozzle onto both sides of the coil end of the winding 67 while the stator 61 is rotating, and the varnish 72 fills the winding 67 in the slot 62a by capillary action, and the varnish 72 also impregnates the slot 62a, after which it is subjected to a heat curing process.

[0037] Example Hereinafter, the embodiment will be described in detail with reference to examples. Example 1 Increased crystallinity In Example 1, a crystalline polymer is used as the resin material for high-voltage equipment, such as a switchgear, and the increase in crystallinity due to deterioration is evaluated. The ratio of components with different T2 is used as an evaluation index for changes in the molecular mobility of the resin material.

[0038] FIG. 10 is a graph showing the change in relaxation time over time with increasing crystallinity due to degradation of a crystalline polymer. Polyphenylene sulfide was used as the crystalline polymer. Crystalline polymers were measured using NMR as shown in Figure 4, and FID curve data was obtained. Based on the FID curve data, T2 was fitted with two components using equation (1), and the spectrum can be separated into a T2f component 301, which has fast relaxation due to the crystal, and a T2s component 302, which has slow relaxation due to the amorphous portion, as shown in Figure 10. 303 is the threshold value.

[0039] Figure 11 shows a model diagram of a molecular chain of a crystalline polymer. FIG. 12 shows a model diagram of the degradation of molecular chains of a crystalline polymer. Reference numeral 11 denotes a molecular chain of a crystalline polymer that shows no degradation, and reference numeral 12 denotes a crystal that has partially formed in the molecular chain of a degraded crystalline polymer. Because local molecular motion of a crystalline polymer is not frozen even at temperatures below its melting point, the molecular orientation changes when annealed for a long period of time. As a result, the degraded crystalline polymer forms tiny crystals 12 locally, as shown in Figure 12, and in some cases the thickness of the lamellar layer of the crystals 12 increases. As the degree of crystallinity increases with the aging time, the proportion of components with a fast relaxation time T2f derived from crystals increases with the aging time, as shown in 301 in Figure 10. As the degree of crystallinity increases, the brittleness of the resin increases, making it more susceptible to microcracks occurring in the resin material.

[0040] FIG. 13 shows a graph of the initial value of the breakdown voltage of a crystalline polymer and the value after degradation. When cracks in the resin material eventually become electrical defects, as shown in 402 in FIG. 13, it can be seen that the electrical insulation is significantly reduced compared to 401. For this reason, it is possible to similarly obtain the correlation between the reduction in electrical insulation and the relaxation characteristics in advance, and set a threshold value 303 in advance, as shown in FIG. 10. When it is determined that the proportion of the T2f component, which is derived from crystals and has fast relaxation, exceeds the threshold value 303, it is possible to diagnose signs of deterioration in the resin material. This makes it possible to determine whether or not there are signs of deterioration.

[0041] The evaluation index may be electrical breakdown strength, or may be selected from mechanical strengths such as bending strength, erosion resistance, and brittleness that contribute to the occurrence of cracks that are the starting points of dielectric breakdown. In this case, before acquiring the FID curve data, standard FID curve data is acquired in advance using a similar standard crystalline polymer, and the correlation between the evaluation index and the electrical properties is similarly acquired, and the threshold value 303 of the evaluation index shown in FIG. 10 can be set.

[0042] Example 2 molecular chain scission In Example 2, a thermosetting resin is used as a resin material applicable to high-voltage equipment, such as switchgear, and the dissociation of molecular bonds due to deterioration is evaluated. The ratio of components with different T2 and the glass transition temperature are used as evaluation indicators for changes in the molecular mobility of the resin material. An epoxy resin was used as the thermosetting resin.

[0043] FIG. 14 shows a model diagram of a molecular chain of a thermosetting resin. FIG. 15 shows a model diagram showing the state of degradation of molecular chains of thermosetting resin. As shown in Figure 14, thermosetting resins have a structure with many constraints 13 where molecules are chemically cross-linked, and molecular motion is significantly restricted. Therefore, there are many components with a short relaxation time T2f. As shown in FIG. 15, when the molecular bonds of the deteriorated thermosetting resin are dissociated by oxidative decomposition or hydrolysis, free ends 14 are generated. FIG. 16 is a graph showing the change in glass transition temperature and relaxation time with time due to the increase in free ends caused by the degradation of a thermosetting resin.

[0044] Thermosetting resins are measured using NMR (see Figure 4) to obtain FID curve data. Based on the FID curve data, T2 can be fitted to two components using Equation (1) to separate the spectrum into a fast T2 component 501 and a slow T2 component 502. 503 is a threshold. The free end 14 exhibits high mobility because molecular motion is unconstrained. As a result, as shown in Figure 16, the proportion of the fast T2 component (T2f) decreases over time (see 501), while the proportion of the slow T2 component (T2s) increases above threshold 503 (see 502). This evaluation result allows for the diagnosis of signs of deterioration in resin materials. This molecular chain scission also occurs in thermoplastic resins and is not limited to thermosetting resins. Molecular chain scission is thought to cause a decrease in the glass transition temperature and elastic modulus. The threshold value 503 can be set in advance by obtaining the correlation between the decrease in glass transition temperature and the change over time of relaxation time using a similar standard thermosetting resin.

[0045] Example 3 Increased crosslink density In Example 3, a thermosetting resin is used as a resin material applicable to high-voltage equipment, such as switchgear, and the increase in crosslink density due to deterioration is evaluated. The proportion of components with different T2 and the elastic modulus are used as evaluation indices for changes in the molecular mobility of the resin material. Here, an epoxy resin was used as the thermosetting resin. FIG. 17 shows a model diagram of a molecular chain of a thermosetting resin having an unreacted portion. FIG. 18 shows a model diagram of a molecular chain of a thermosetting resin in which the crosslink density increases due to degradation. As shown in Fig. 17, the thermosetting resin contains unreacted portions 15 that have reactivity with, for example, epoxy groups, amino groups, carboxy groups, etc. Due to deterioration in a high-temperature environment, as shown in Fig. 18, it is thought that these unreacted portions 15 polymerize with adjacent unreacted portions to form crosslinked portions 16, thereby increasing the crosslink density.

[0046] FIG. 19 is a graph showing the change over time in the elastic modulus and the proportion of components with a fast T2 (T2f) as the crosslink density increases due to deterioration of the thermosetting resin. A thermosetting resin is measured using NMR as shown in Figure 4 to obtain FID curve data. Based on the FID curve data, T2 can be fitted with two components using equation (1), allowing separation into a T2f component 602 with a fast T2 and a T2s component 601 with a slow T2. 603 is a threshold value.

[0047] As a result, the free ends with high molecular mobility disappear, and as shown in Figure 12, an increase in the T2f component exceeds threshold 603, or this can be evaluated as a decrease in the T2s component. Based on this evaluation result, signs of deterioration in the resin material can be diagnosed. An increase in crosslink density is thought to cause an increase in the glass transition temperature, an increase in elastic modulus, and embrittlement. The threshold value 603 can be set in advance by obtaining a correlation between the elastic modulus and the change over time of the relaxation time using a similar thermosetting resin.

[0048] Example 4 water absorption In Example 4, a resin that deteriorates due to moisture absorption is evaluated as a resin material. A graph showing the distribution function f(t) of the relaxation time T2 is used as an evaluation index for the change in molecular mobility of the resin material. Here, polyethylene terephthalate was used as the resin material for the high voltage equipment. Resin materials can absorb moisture from the atmosphere when used in high humidity environments. When resin materials absorb water, the highly mobile water molecules interact with the molecular chains, increasing molecular mobility.

[0049] FIG. 20 is a graph showing the distribution function f(t) obtained by inverse Laplace transform of the FID signal before and after degradation. In the figure, 702 indicates the distribution function f(t) before degradation, and 701 indicates the distribution function f(t) after degradation. When moisture is absorbed due to degradation, the relaxation time is shorter in 701 after degradation compared to 702 before degradation, making it possible to detect and evaluate the improvement in molecular mobility. Furthermore, if moisture absorption occurs unevenly, the peak width increases, confirming that a distribution occurs in the relaxation time. When moisture absorption causes plasticization, although toughness improves, it tends to cause a decrease in the glass transition temperature, a decrease in elastic modulus, a decrease in electrical resistance, and so on. Based on the evaluation results, it is possible to diagnose signs of deterioration in such resin materials.

[0050] Example 5 Peeling between resin and conductor Example 5 evaluates peeling that occurs due to deterioration between a resin material 1 and a metal conductor 2 used in high-voltage equipment, such as a switchgear. An increase in T2 is used as an evaluation index for changes in the molecular mobility of the resin material. Figure 21 shows a model diagram of peeling between a resin material and a metal conductor used in high-voltage equipment. As shown in the figure, when a void 116 occurs due to peeling between the resin 1 and the metal conductor 2, the molecular chains that make up the resin 1 at the interface with the metal conductor 2 are released from the constraints caused by the interaction, improving molecular mobility, which can be detected and evaluated as an increase in T2. ​​Based on this evaluation result, signs of deterioration of the resin material can be diagnosed.

[0051] Example 6 Resin / filler peeling Example 6 evaluates the delamination that occurs between the resin matrix and the filler due to deterioration in a resin material containing a filler used in high-voltage equipment, such as switchgear. The increase in T2 is used as an evaluation index for the change in molecular mobility of the resin material. 22 and 23 show model diagrams showing the delamination between the resin matrix and the filler. Figure 22 shows the state of the resin matrix and filler before peeling, and Figure 23 shows the state after peeling. As shown, degradation can lead to the formation of a peeled area 19 between the matrix resin portion 17 and the filler portion 18 that make up the resin material 1. Generally, the interface of the filler portion 18 is subjected to a surface modification treatment to improve adhesion with the matrix resin portion 17. Therefore, the molecular chains at the interface are constrained by interaction with the filler, shortening their relaxation time. When a peeled area 19 forms between the resin matrix portion 17 and the filler portion 18 filled in the resin due to degradation, molecular motion is unconstrained and increases, resulting in an increase in molecular mobility and an increase in the absolute value of T2. The presence of a peeled area 19 around the filler portion 18 tends to cause partial discharge, leading to equipment failure. Therefore, by diagnosing signs of resin material degradation based on the above evaluation results, equipment failure can be prevented.

[0052] Example 7 spatial distribution Example 7 evaluates the occurrence of delamination and crack growth inside a resin material used in high-voltage equipment, such as a motor. Different resonance frequencies are used as evaluation indices for changes in the molecular mobility of the resin material, and T2 is measured at different positions in the depth direction of the resin material, i.e., in the z-axis direction indicated by arrow 7. Here, epoxy resin was used as the resin material for the high voltage equipment. FIG. 24 shows a schematic diagram illustrating the configuration of a high-voltage device and a graph of the measured T2 distribution function f(t).

[0053] As shown in the figure, the resin material of the high-voltage equipment (high-voltage equipment 10) is constructed by winding an enameled wire, which is covered with a resin coating 113 around a copper wire 112, and then sealing the periphery with a resin portion 114. A probe 4, installed near a magnet 3, is brought close to the high-voltage equipment 10 to be measured to acquire a signal. As an example, the high-voltage equipment 10 is constructed with four layers of enameled wire. The resin material was measured at four different depths of the resin material using different resonant frequencies. The distribution function f(t) based on the FID signals obtained is shown in comparison with the different depths of the resin material. Reference numeral 801 denotes the resin coating of the innermost enameled wire, 802 the resin coating of the second-inmost enameled wire, 803 the resin coating of the third-inmost enameled wire, and 804 the resin coating of the nearest enameled wire. In this example, a peel 115 has occurred between the second-inmost and third-inmost enameled wires. Therefore, for 801, 803, and 804, the ratio of T2s is greater than T2f, but for 802 where peeling 115 occurred, the ratio of T2f is greater than T2s, so the results can be evaluated. Based on the evaluation results, signs of deterioration of the resin material can be diagnosed. In this way, by using different resonance frequencies from the surface toward the interior of the resin material, it is possible to identify a defect that exhibits a different relaxation phenomenon from the others.

[0054] Example 8 temperature In Example 8, when a crystalline thermoplastic resin is used as a resin material applicable to high-voltage equipment such as a switchgear, the measurement location is heated to improve the amorphous molecular mobility and perform evaluation. As shown in Fig. 6, when a probe 4 installed near a magnet 3 is brought close to a high-voltage device 10 to be measured to acquire an FID signal, the measurement location can be heated by an infrared heater (not shown) or the like. This improves the molecular mobility of the amorphous portion, allowing it to be detected and evaluated. FIG. 25 is a graph showing the distribution function f(t) obtained by inverse Laplace transform of the FID signal obtained by locally applying heat. In the figure, 901 indicates the case without heating, and 902 indicates the case with heating. The glass transition temperature of resin materials generally used as electrical insulating materials is sufficiently higher than room temperature, and the resin material enters a glassy state in which molecular motion is frozen. For example, in the case of a crystalline thermoplastic resin, as shown in 901, the T2f component, which has fast relaxation due to the crystals, and the T2s component, which has slow relaxation due to the amorphous portion, have their high molecular mobility frozen, and no significant difference is apparent between the mobility of the amorphous portion and that of the crystalline portion, which has low molecular mobility. In contrast, by heating the measurement point using an infrared heater or similar, as shown in 902, the molecular mobility of the amorphous portion can be improved, making it possible to clearly extract and evaluate the characteristics of the T2s component, which has slow relaxation due to the amorphous portion. Based on the evaluation results, signs of deterioration of the resin material can be diagnosed.

[0055] Although several embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be embodied in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their modifications are included within the scope and spirit of the invention, and are also included in the scope of the invention and its equivalents as defined in the claims. [Explanation of symbols]

[0056] 1...resin material, 3...magnet part, 4...probe part, 5...spectrometer, 6...computer, 10...high-voltage electrical equipment, 18...filler, 10-1...resin molded product for power receiving and distribution, 20...nuclear magnetic resonance apparatus, 21...measuring part, 22...data processing part, 23...data evaluation part, 24...deterioration sign diagnosis part, 30...deterioration sign diagnosis system, 303,503,603...threshold

Claims

1. Resin materials were measured using a nuclear magnetic resonance device. Obtain free induction decay curve data, Calculate the spin-spin relaxation time, Evaluating a change in molecular mobility of the resin material based on the spin-spin relaxation time; and A method for diagnosing signs of deterioration of a resin material, comprising diagnosing signs of deterioration of the resin material.

2. 2. The method of claim 1, wherein the change in molecular mobility comprises separating the free induction decay curve into at least two or more components having different spin-spin relaxation times and evaluating the change in molecular mobility based on the two or more components.

3. The method of claim 1 , wherein each of the magnetic resonance devices comprises a probe capable of detecting a magnetic moment.

4. Before obtaining the free induction decay curve data, the free induction decay curve data is obtained using a standard resin material similar to the resin material; determining the absolute value of the spin-spin relaxation time, the ratio of different components of the spin-spin relaxation time, or the distribution of the spin-spin relaxation time by inverse Laplace transform of the free induction decay curve, and determining in advance a correlation with the properties of the standard resin material; The method according to claim 1 , wherein the deterioration sign of the resin material is diagnosed based on the correlation.

5. The method of claim 4, wherein the property of the resin material is electrical breakdown strength.

6. The method of claim 4 , wherein the correlation is expressed as a threshold value.

7. 2. The method according to claim 1, wherein the nuclear magnetic resonance apparatus includes a magnet unit having a gradient in magnetic field strength, the magnet unit continuously changing the magnetic field strength inside the resin material to change the resonance frequency, thereby acquiring free induction decay curve data at any spatial position for each resonance frequency, and evaluating a change in molecular mobility of the resin material at any position inside the resin material from each free induction decay curve.

8. the resin material includes at least one of a crystalline or amorphous thermoplastic resin, a thermosetting resin, or a rubber material; the thermoplastic resin is at least one of polyethylene terephthalate, polyimide, polyamide, or polyamideimide; the thermosetting resin is at least one of an epoxy resin and a urethane resin, The method of claim 1 , wherein the rubber material is a silicone rubber.

9. The method of claim 1 , wherein the resin material includes a filler of at least one of silica, alumina, magnesium oxide, aluminum nitride, or silicon nitride.

10. The method of claim 1 , wherein the resin material is provided in a high voltage electrical device.

11. The method according to claim 10, wherein the high-voltage electrical equipment is a resin-molded product for receiving and distributing electricity, and the resin material is coated on the outer surface of a high-voltage section embedded in the resin-molded product for receiving and distributing electricity.

12. The method according to claim 10, wherein the high-voltage electrical equipment is a motor, and the resin material is embedded in the outer periphery or gaps of a winding of the motor.

13. The method of claim 1 , wherein the free induction decay curve data is obtained by locally heating the resin material to change the temperature of the resin material.

14. before acquiring the free induction decay curve data, a standard resin material similar to the resin material is used, the temperature of the standard resin material is locally changed to acquire the free induction decay curve data, and the absolute value of the spin-spin relaxation time, the ratio of different components of the spin-spin relaxation time, or the distribution of the spin-spin relaxation time obtained by performing an inverse Laplace transform of the free induction decay curve is measured, thereby obtaining a correlation between the temperature dependency and the properties of the standard resin material; The method according to claim 13, wherein the sign of deterioration of the resin is diagnosed based on the correlation.

15. a probe section for detecting the magnetic moment; The magnet part that generates the magnetic field, a spectrometer for processing a detection signal from the probe portion; and a measurement unit for measuring a resin material, the measurement unit including a nuclear magnetic resonance apparatus having a computer for processing signals from the spectrometer; a data processing unit that acquires free induction decay (FID) curve data from the nuclear magnetic resonance apparatus and determines spin-spin relaxation time; a data evaluation unit that evaluates a change in molecular mobility of the resin material based on the spin-spin relaxation time; a deterioration sign diagnosis unit that diagnoses a deterioration sign of the resin material from the evaluation result of the data evaluation unit.

16. The data evaluation unit includes separating the free induction decay curve into at least two or more components with different spin-spin relaxation times; and The deterioration predictive diagnostic system for a resin material according to claim 15 , wherein the deterioration predictive diagnostic unit evaluates a change in molecular mobility of the resin material based on the two or more components.

17. the data processing unit, before acquiring the free induction decay curve data of the resin material, acquires standard free induction decay curve data using a standard resin material having a similar composition to the resin material; the data evaluation unit measures, for the standard free induction decay curve, an absolute value of the spin-spin relaxation time, a ratio of different components of the spin-spin relaxation time, or a distribution of the spin-spin relaxation time obtained by performing an inverse Laplace transform on the free induction decay curve data, and determines in advance a correlation with the properties of the standard resin material; The deterioration sign diagnostic system for a resin material according to claim 15, wherein the deterioration sign diagnostic unit diagnoses a deterioration sign of the resin based on the correlation.

18. 18. The system for predicting deterioration of a resin material according to claim 17, wherein the characteristic of the resin material is an electrical breakdown strength.

19. The deterioration predictive diagnosis system for a resin material according to claim 17 , wherein the correlation is expressed as a threshold value.

20. the magnet portion has a gradient in the strength of the magnetic field, 19. The deterioration predictive diagnosis system for a resin material according to claim 18, further comprising: acquiring the free induction decay curve data for each resonance frequency from the nuclear magnetic resonance apparatus by changing the resonance frequency; determining a spatial distribution of spin-spin relaxation time; and evaluating a change in molecular mobility of the resin material.

21. the resin material includes at least one of a crystalline or amorphous thermoplastic resin, a thermosetting resin, or a rubber material; the thermoplastic resin is at least one of polyethylene terephthalate, polyimide, polyamide, or polyamideimide; the thermosetting resin is at least one of an epoxy resin and a urethane resin; The deterioration predictive diagnosis system for a resin material according to claim 18, wherein the rubber material is silicone rubber.

22. The deterioration predictive diagnosis system for a resin material according to claim 15, wherein the resin material contains at least one filler selected from the group consisting of silica, alumina, magnesium oxide, aluminum nitride, and silicon nitride.

23. The deterioration predictive diagnosis system for a resin material according to claim 15, wherein the resin material is provided in a high-voltage electrical device.

24. 24. The resin material deterioration predictive diagnosis system according to claim 23, wherein the high-voltage electrical equipment is a resin-molded product for power reception and distribution, and the resin material is coated on the outer surface of a high-voltage section embedded in the resin-molded product for power reception and distribution.

25. 24. The deterioration predictive diagnosis system for a resin material according to claim 23, wherein the high-voltage electrical equipment is a motor, and the resin material is embedded in the outer periphery or gaps of a winding of the motor.

26. the measuring unit further includes a heating unit that locally heats the resin material and a temperature measuring unit that non-destructively measures the temperature of the resin material; The deterioration predictive diagnosis system for a resin material according to claim 15, wherein the measurement unit measures the free induction decay curve data by locally heating the resin material and changing the temperature of the resin material.

27. the data evaluation unit further includes, before acquiring the free induction decay curve data of the resin material, locally acquiring the free induction decay curve data using a standard resin material similar to the resin material, changing the temperature of the standard resin material, and measuring the absolute value of the spin-spin relaxation time, the ratio of different components of the spin-spin relaxation time, or the distribution of the spin-spin relaxation time obtained by performing an inverse Laplace transform on the free induction decay curve data, and thereby determining in advance a correlation with properties of the standard resin material and temperature dependency; The deterioration sign diagnostic system for a resin material according to claim 21 , wherein the deterioration sign diagnostic unit diagnoses the deterioration sign of the resin based on the evaluation result of the data evaluation unit and the correlation.

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