Deterioration diagnosis method and deterioration diagnosis device

Abstract

A degradation diagnosis method according to the present invention includes a step for arranging an insulation degradation sensor in the environment of an insulator. A plurality of pieces of metal wiring are connected in parallel at the insulation degradation sensor. The plurality of pieces of metal wiring include first metal wiring and second metal wiring that have different corrosion progression speeds. The degradation diagnosis method includes a step (S4) in which a combined resistance value for the insulation degradation sensor at measurement timing and a database that defines a first correlation between the combined resistance value for the insulation degradation sensor and the surface resistivity of the insulator are used to estimate the surface resistivity of the insulator at the measurement timing, a step (S6) in which a relational expression that indicates a second correlation between the surface resistivity of the insulator and the time of use of an electrical apparatus is used calculate the lifetime of the electrical apparatus, and a step (S7) in which the remaining lifetime of the electrical apparatus having subtracted the time of use of the electrical apparatus at the measurement timing is calculated from the lifetime.

Description

[Technical field]

[0001] The present disclosure relates to a degradation diagnostic method and a degradation diagnostic device for diagnosing degradation of an electrical device including an insulator. [Background technology]

[0002] Conventionally, a degradation diagnosis method for diagnosing the degradation of an electrical device including an insulator is known. For example, International Publication No. 2021 / 166095 (Patent Document 1) discloses a degradation diagnosis device that estimates the surface resistivity of an insulator by comparing a database that specifies the correlation between the resistance value of a metal thin film wiring and the surface resistivity of an insulator when the insulator is in contact with a specific gas with the resistance value of a metal thin film wiring installed near the insulator. The degradation diagnosis device calculates the life and remaining life of the electrical device from the estimated surface resistivity. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2021 / 166095 Summary of the Invention [Problem to be solved by the invention]

[0004] In the technology described in Patent Document 1, if the metal thin film wiring is disconnected due to exposure to a specific gas, the surface resistivity of the insulator cannot be estimated, and therefore the period during which the deterioration of the electrical device can be accurately diagnosed is limited.

[0005] The present disclosure has been made to solve the above-mentioned problems, and has an object to provide a degradation diagnosis method and a degradation diagnosis device that can accurately diagnose the degradation of an electrical device over a long period of time. [Means for solving the problem]

[0006] A degradation diagnosis method according to one aspect of the present disclosure diagnoses degradation of an electrical device including an insulator. The degradation diagnosis method includes a step of disposing an insulation degradation sensor around the insulator, the insulation degradation sensor including a plurality of metal wirings connected in parallel that corrode when exposed to a specific gas. The plurality of metal wirings include a first metal wiring and a second metal wiring that exhibit different corrosion rates when the insulation degradation sensor is exposed to the specific gas. The degradation diagnosis method further includes the steps of: creating in advance a database that specifies a first correlation between the combined resistance of the insulation degradation sensor and the surface resistivity of the insulator when both the insulator and the insulation degradation sensor are exposed to a specific gas; measuring a combined resistance value of the insulation degradation sensor at the measurement timing; estimating the surface resistivity of the insulator at the measurement timing using the combined resistance value at the measurement timing and the database; creating a relational equation that expresses a second correlation between the usage time of the electrical equipment and the surface resistivity of the insulator from the usage time of the electrical equipment at the measurement timing and the estimated surface resistivity of the insulator and the surface resistivity of the insulator when the electrical equipment is unused; calculating a lifetime of the electrical equipment corresponding to a reference surface resistivity when the insulator loses its insulating performance in the relational equation; and calculating a remaining lifetime of the electrical equipment by subtracting from the lifetime the usage time of the electrical equipment at the measurement timing or the usage time of the electrical equipment at the time when the insulation degradation sensor is placed around the insulator.

[0007] A degradation diagnosis device according to another aspect of the present disclosure diagnoses degradation of an electrical device including an insulator. The degradation diagnosis device includes an insulation degradation sensor in which a plurality of metal wirings that corrode when exposed to a specific gas are connected in parallel. The plurality of metal wirings include a first metal wiring and a second metal wiring that have different corrosion progression rates when the insulation degradation sensor is exposed to the specific gas. The degradation diagnosis device further includes a database that specifies a first correlation between the combined resistance value of the insulation degradation sensor and the surface resistivity of the insulator when both the insulator and the insulation degradation sensor are exposed to a specific gas, a measurement unit that measures the combined resistance value of the insulation degradation sensor at the measurement timing, an estimation unit that estimates the surface resistivity of the insulator at the measurement timing using the combined resistance value at the measurement timing and the database, a relational equation creation unit that creates a relational equation that expresses a second correlation between the usage time of the electrical equipment and the surface resistivity of the insulator from the usage time of the electrical equipment at the measurement timing and the estimated surface resistivity of the insulator and the surface resistivity of the insulator when the electrical equipment is unused, a lifetime calculation unit that calculates, in the relational equation, a lifetime of the electrical equipment that corresponds to a reference surface resistivity when the insulator loses its insulating performance, and a remaining lifetime calculation unit that calculates a remaining lifetime of the electrical equipment by subtracting from the lifetime the usage time of the electrical equipment at the measurement timing or the usage time of the electrical equipment at the timing when the insulation degradation sensor is placed around the insulator. Effect of the Invention

[0008] According to the degradation diagnostic method and degradation diagnostic device of the present disclosure, the corrosion rates of the first metal wiring and the second metal wiring caused by a specific gas are different from each other. Therefore, the range of the surface resistivity of the insulator, which correlates with the combined resistance value of the multiple metal wirings including the first metal wiring and the second metal wiring, is widened. This allows the surface resistivity of the insulator to be estimated with high accuracy over a wider range. As a result, the period during which the degradation of the insulator can be diagnosed with high accuracy is extended. [Brief description of the drawings]

[0009] [Figure 1] 1 is a cross-sectional view showing a schematic configuration of a switch gear, which is an example of high-voltage electrical equipment. [Diagram 2] 4 is a flowchart showing the flow of a degradation diagnosis method according to the first embodiment. [Diagram 3] 1 is a graph showing a schematic relationship between the number of years (time of use) of an electrical device and the surface resistivity. [Figure 4] 1 is a schematic diagram of an insulation deterioration sensor according to a first embodiment. [Diagram 5] 4 is a diagram showing the relationship between the exposure time and the resistance value of the metal wiring when the metal wiring according to the first embodiment is exposed to a specific gas. FIG. [Figure 6] 1 is a diagram showing the correlation between the surface resistivity of an insulator and the resistance value of a metal wiring when a specific gas is exposed to the insulator and metal wiring that are the subject of diagnosis. [Figure 7] FIG. 1 is a diagram showing the correlation between the surface resistivity of an insulator and the combined resistance value of metal wiring when a specific gas is exposed to the insulator and metal wiring connected in parallel. [Figure 8] 1 is a block diagram showing a schematic configuration of a degradation diagnosis device that executes a degradation diagnosis method according to a first embodiment. [Figure 9] 9 is a hardware configuration diagram of a main part of the control unit in FIG. 8. [Figure 10] 9 is a block diagram showing a functional configuration of a control unit shown in FIG. 8. [Figure 11] FIG. 11 is a schematic diagram of an insulation deterioration sensor according to a second embodiment. [Figure 12] 13 is a diagram showing the relationship between the exposure time and the resistance value of the metal wiring when the metal wiring according to the second embodiment is exposed to a specific gas. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are designated by the same reference characters, and their description will not be repeated in principle.

[0011] Embodiment 1 The degradation diagnosis method for an electric device according to the first embodiment is a degradation diagnosis method for an electric device having an insulator. The electric device is, for example, a high-voltage electric device or a special high-voltage electric device composed of main circuit components such as a circuit breaker, a disconnecting switch, a transformer, a busbar, and a conductor, and a measuring device. "High voltage" means that the DC voltage is more than 750V and is not more than 7000V, or that the AC voltage is more than 600V and is not more than 7000V. "Special high voltage" means that the DC voltage or the AC voltage is more than 7000V.

[0012] Fig. 1 is a cross-sectional view showing a schematic configuration of a switchgear 49, which is an example of high-voltage electrical equipment. The switchgear 49 includes main circuit components such as a circuit breaker, a disconnecting switch, and a busbar / conductor, which are supported by an insulator, and a measuring device. In Fig. 1, the X-axis, the Y-axis, and the Z-axis are perpendicular to each other. In the explanation of Fig. 1, the + direction of the Z-axis is the upper side, and the - direction of the Z-axis is the lower side.

[0013] As shown in FIG. 1, the switchgear 49 includes circuit breakers 50a and 50b, three horizontal busbars 52, connecting conductors 53a, 54a, 53b, and 54b, a busbar support plate 56, cables 57a and 57b, and a plurality of insulators 58. The circuit breaker 50a includes an operating mechanism 51a and a molded frame 55a. The circuit breaker 50b includes an operating mechanism 51b and a molded frame 55b. The connecting conductors 53a, 54a, 53b, and 54b are supported by the plurality of insulators 58. The three horizontal busbars 52 correspond to the three phases of the three-phase AC, respectively. The busbar support plate 56 collectively supports the three horizontal busbars 52.

[0014] The molded frame 55a incorporating the operation mechanism 51a and the circuit breaker (not shown) is mounted on the carriage 61a. The molded frame 55b incorporating the operation mechanism 51b and the circuit breaker (not shown) is mounted on the carriage 61b. The carriages 61a and 61b are movable in the X-axis direction. One end of the connection conductor 53a is electrically connected to the cable 57a. The other end of the connection conductor 53a is electrically connected to the upper terminal of the circuit breaker 50a. One end of the connection conductor 54a is electrically connected to the lower terminal of the circuit breaker 50a. The other end of the connection conductor 54a is electrically connected to one end of the connection conductor 53b via the horizontal busbar 52. The other end of the connection conductor 53b is connected to the upper terminal of the circuit breaker 50b. One end of the connection conductor 54b is connected to the lower terminal of the circuit breaker 50b. The other end of the connection conductor 54b is electrically connected to the cable 57b.

[0015] Each of the mold frames 55a and 55b, the bus bar support plate 56, and the insulators 58 is an insulator and is the subject of deterioration diagnosis (diagnosis subject) in this disclosure. Examples of the material of the insulator include polyester resin, epoxy resin, and phenol resin.

[0016] The insulation deterioration sensor 10 is formed as a separate body from the insulator to be diagnosed, and is arranged around the diagnosis object. In Fig. 1, the insulation deterioration sensor 10 is arranged near the molded frame 55b. By forming the insulation deterioration sensor 10 as a separate body from the diagnosis object, electric field concentration from the insulation deterioration sensor 10 to the diagnosis object can be suppressed. Also, the insulation deterioration sensor 10 can be easily replaced.

[0017] Next, the degradation diagnosis method according to the embodiment 1 will be described with reference to Fig. 2 and Fig. 3. Fig. 2 is a flowchart showing the flow of the degradation diagnosis method according to the embodiment 1. Fig. 3 is a graph showing a schematic relationship between the number of years of use (time of use) of an electrical device and the surface resistivity.

[0018] As shown in FIG. 2, in step S1, a specific gas (e.g., nitrogen oxides (NOx) or sulfur oxides (SOx)) that affects the deterioration of the diagnosis target is exposed (contacted) to the insulation deterioration sensor 10 and the diagnosis target used in the electrical equipment. By measuring the resistance value of the insulation deterioration sensor 10 and the surface resistivity of the insulator after the exposure, a database that defines the correlation (first correlation) between the resistance value of the insulation deterioration sensor 10 and the surface resistivity of the diagnosis target is created in advance. Next, in step S2, the insulation deterioration sensor 10 is arranged around the diagnosis target. The area around the diagnosis target is the area covered by the specific gas when the diagnosis target is exposed to the specific gas. Next, in step S3, the resistance value of the insulation deterioration sensor 10 is measured at each measurement timing by a simple resistance meter such as a tester. The resistance value is measured regularly or constantly. In step S4, the resistance value of the insulation deterioration sensor 10 measured in step S3 is collated with the database created in step S1, and the surface resistivity SR1 of the diagnosis target at the measurement timing of the resistance value is estimated. The measurement timing of the resistance value at which the surface resistivity SR1 is estimated is defined as the service life L1 (years).

[0019] As shown in FIG. 3, in step S5, from the surface resistivity SR1 and the surface resistivity SR0 of a new (unused) diagnosis target, a relational expression representing the correlation (second correlation) between the surface resistivity and the service life of the electrical equipment is created. For example, the relational expression represents a deterioration straight line RF1 in which the logarithm of the surface resistivity and the service life of the electrical equipment have a linear relationship. In step S6, the service life years L2 (life time) corresponding to the threshold surface resistivity SR2 (reference surface resistivity) is calculated from the deterioration straight line RF1. The threshold value SR2 is the surface resistivity when the diagnosis target loses its insulation performance and a discharge occurs in the diagnosis target. In step S7, the remaining life RL1 (remaining life time) of the diagnosis target is calculated by subtracting the service life L1 (<L2) of the diagnosis target at the measurement timing or the arrangement timing of the insulation deterioration sensor 10 from the service life years L2 of the diagnosis target.

[0020] Next, the deterioration diagnosis method according to the first embodiment will be described in detail with reference to Figs. 4 and 5. Fig. 4 is a schematic diagram of the insulation deterioration sensor 10 according to the first embodiment. As shown in Fig. 4, metal wirings 31a and 31b connected in parallel are formed on the main surface of an insulating substrate 32. The metal wirings 31a and 31b shown in Fig. 4 are made of a metal thin film and have a comb-like shape. However, the shape of the metal wirings 31a and 31b may be other than the comb-like shape as long as the ratio (L / W) of the wiring length L to the wiring width W of the metal wirings 31a and 31b is adjusted (for example, the ratio is 1000 or more) so that the metal wirings 31a and 31b have a resistance (several hundred Ω level) that can be easily measured by a tester or the like. If the metal wirings 31a and 31b are excessively thin or long, the impedance of the metal wirings 31a and 31b increases and the detection sensitivity decreases, so it is desirable for the metal wirings 31a and 31b to have an appropriate width and length. Moreover, if the metal wirings 31a, 31b are too short, it may be difficult to form and solder the metal wirings 31a, 31b, so it is desirable that the metal wirings 31a, 31b have an appropriate length. Furthermore, from the viewpoint of suppressing an increase in the impedance of the metal wirings 31a, 31b due to the cross-sectional area, it is desirable that the thickness of the metal wirings 31a, 31b is 0.1 μm or more. However, it is desirable that the thickness of the metal wirings 31a, 31b is 30 μm or less so that the metal wirings 31a, 31b have a resistance (several hundred Ω level) that can be easily measured by a tester or the like. Furthermore, in order to measure the resistance of the metal wirings 31a, 31b, the metal wirings 31a, 31b must be formed on a substrate having insulating properties. Examples of materials for the insulating substrate 32 include glass, glass-epoxy, and paper phenol.

[0021] The thickness or type of metal of the metal wirings 31a, 31b is set in advance so that the corrosion rates of the metal wirings 31a, 31b due to the specific gas differ from each other when the insulation degradation sensor 10 is exposed to the specific gas. For example, in order to make the corrosion rate of the metal wiring 31b slower than that of the metal wiring 31a, the material of the metal wirings 31a, 31b is set to be the same, and the thickness of the metal wiring 31b is set to be greater than that of the metal wiring 31a. Alternatively, in order to make the corrosion rate of the metal wiring 31b slower than that of the metal wiring 31a, the thickness of the metal wirings 31a, 31b is set to be the same, and the material of the metal wiring 31b is set to be less corrosive to the specific gas than the material of the metal wiring 31a.

[0022] The metal wirings 31a and 31b are made of a metal that can accurately evaluate the exposure environment of a specific gas, that is, a metal that corrodes when it comes into contact with a specific gas. Examples of metals that corrode when they come into contact with a specific gas include copper (Cu), copper alloys, silver (Ag), silver alloys, nickel (Ni), nickel alloys, iron (Fe), and iron alloys. However, other metal materials may be used as long as they can evaluate the exposure environment of a specific gas. Film-forming methods for the metal wirings 31a and 31b include sputtering, vapor deposition, plating, and the like, but are not limited to these.

[0023] An electrode pad 33a_1 is disposed near one end of the metal wiring 31a, and an electrode pad 33a_2 is disposed near the other end of the metal wiring 31a. An electrode pad 33b_1 is disposed near one end of the metal wiring 31b, and an electrode pad 33b_2 is disposed near the other end of the metal wiring 31b. The electrode pads 33a_1 and 33b_1 are connected to a lead wire 34_1. The electrode pads 33a_2 and 33b_2 are connected to a lead wire 34_2. This allows the metal wirings 31a and 31b to be connected in parallel.

[0024] Fig. 5 is a diagram showing the relationship between the exposure time and the resistance value of the metal wiring according to the first embodiment when the metal wiring is exposed to a specific gas. Fig. 5 shows graphs 35a, 35b, and 37 with the horizontal axis representing the exposure time and the vertical axis representing the resistance value. Graph 35a shows the change in the resistance value of the metal wiring 31a between the electrode pads 33a_1 and 33a_2. Graph 35b shows the change in the resistance value of the metal wiring 31b between the electrode pads 33b_1 and 33b_2. Graph 37 shows the change in the resistance value between the lead wires 34_1 and 34_2, i.e., the combined resistance value of the metal wirings 31a and 31b connected in parallel.

[0025] Since the corrosion rates of the metal wirings 31a and 31b are different from each other, the range 36a of exposure time in which the resistance value of the metal wiring 31a changes when exposed to a specific gas and the range 36b of exposure time in which the resistance value of the metal wiring 31b changes when exposed to a specific gas do not overlap each other. Note that the range 36a is a range of exposure time in which the time rate of change of the resistance value of the metal wiring 31a when exposed to a specific gas is ΔRmax_a or more. Similarly, the range 36b is a range of exposure time in which the time rate of change of the resistance value of the metal wiring 31b when exposed to a specific gas is α×ΔRmax_b or more when the maximum value of the time rate of change of the resistance value of the metal wiring 31b when exposed to a specific gas is ΔRmax_b. α is predetermined, for example, 0.1.

[0026] FIG. 6 is a diagram showing the correlation between the surface resistivity of the insulator and the resistance value of the metal wirings 31a, 31b when the insulator and metal wirings 31a, 31b to be diagnosed are exposed to a specific gas. FIG. 6 shows the correlation when the thickness or type of metal of the metal wirings 31a, 31b is set so that the corrosion rate of the metal wiring 31b caused by the specific gas is slower than the corrosion rate of the metal wiring 31a caused by the specific gas. As shown in FIG. 6, the range of the surface resistivity of the insulator that correlates with the resistance value of the metal wiring 31b (1×10 8 ~1×10 11 Ω / □) is the range of surface resistivity of the insulator that correlates with the resistance value of the metal wiring 31a (1×10 11 ~1×10 15 Ω / □).

[0027] 7 is a diagram showing the correlation between the surface resistivity of the insulator and the combined resistance value of the metal wirings 31a and 31b when a specific gas is exposed to the insulator and the metal wirings 31a and 31b connected in parallel. The correlation shown in FIG. 7 is calculated from the correlation between the surface resistivity of the insulator and the resistance values ​​of the metal wirings 31a and 31b shown in FIG. 6. As shown in FIG. 7, there is a correlation between the combined resistance value of the metal wirings 31a and 31b connected in parallel and the surface resistivity of the insulator. By utilizing this correlation, the surface resistivity of the insulator can be estimated from the resistance value of the insulation degradation sensor 10 (i.e., the combined resistance value of the metal wirings 31a and 31b).

[0028] In order to improve the accuracy of estimating the surface resistivity of the insulator, it is preferable that the correlation coefficient between the combined resistance value of the parallel-connected metal wirings 31a and 31b and the surface resistivity of the insulator is 0.5 or more. Therefore, the thickness, metal type, width, length, etc. of the metal wirings 31a and 31b are adjusted according to the insulator to be diagnosed so that the correlation coefficient becomes 0.5 or more.

[0029] In the technology disclosed in Patent Document 1, a single metal wiring is used. For example, when the metal wiring 31a is used as the single metal wiring, the range of the surface resistivity of the insulator that correlates with the resistance value of the metal wiring is 1×10 11 ~1×10 15 Ω / □ (see Figure 6). Therefore, the possible range of the surface resistivity of the insulator is also 1×10 11 ~1×10 15 In addition, when the metal wiring is broken, the resistance value changes suddenly, which may result in an erroneous diagnosis.

[0030] In this embodiment, metal wirings 31a and 31b are used that are connected in parallel and have different corrosion rates caused by a specific gas. For example, the corrosion rate of the metal wiring 31b caused by a specific gas is slower than the corrosion rate of the metal wiring 31a caused by a specific gas. Therefore, the range of the surface resistivity of the insulator that correlates with the combined resistance value of the metal wirings 31a and 31b is 1×10 7 ~1×10 15The resistance value is Ω / □, which is wider than the range of the surface resistivity of the insulator that correlates with the resistance value of the metal wiring 31a or the metal wiring 31b. This allows the surface resistivity of the insulator to be estimated with high accuracy over a wider range. Even if the metal wiring 31a is broken, the combined resistance value does not change suddenly. This prevents erroneous diagnosis.

[0031] Fig. 8 is a block diagram showing a schematic configuration of degradation diagnosis device 100 that executes the degradation diagnosis method according to embodiment 1. As shown in Fig. 8, degradation diagnosis device 100 is realized in the form of a control board whose operation is controlled by a program recorded on a recording medium such as a ROM (Read Only Memory). However, the control board is one example of the realization of degradation diagnosis device 100, and the hardware configuration of degradation diagnosis device 100 is not limited to the configuration shown in Fig. 8.

[0032] Degradation diagnosis device 100 includes insulation degradation sensor 10 , measurement unit 20 , input unit 101 , storage unit 102 , control unit 103 , and output unit 104 .

[0033] The measurement unit 20 measures a combined resistance value of a plurality of metal wirings connected in parallel in the insulation degradation sensor 10. Specifically, the measurement unit 20 measures a resistance value between the lead wires 34_1, 34_2 shown in Fig. 4 as a combined resistance value of the metal wirings 31a, 31b connected in parallel. The measurement unit 20 is constituted by, for example, a tester, and measures the combined resistance value by applying a predetermined voltage (for example, 100 V) between the lead wires 34_1, 34_2.

[0034] The input unit 101 includes an input device such as a keyboard, a mouse, or a tablet, and a communication port capable of communicating with the measurement unit 20 or an external device. The input unit 101 receives input of data necessary for deterioration diagnosis of the diagnosis target 55 (for example, the mold frames 55a and 55b). For example, a database 70 that specifies the correlation between the resistance value of the insulation deterioration sensor 10 (i.e., the combined resistance value of multiple metal wirings connected in parallel) and the surface resistivity of the polyester insulation when the insulation deterioration sensor 10 and the polyester insulation are exposed to a specific gas is input to the input unit 101 prior to deterioration diagnosis. The database 70 is created in advance based on a preliminary experiment. Alternatively, resistance change data indicating the time change between the resistance value of the insulation deterioration sensor 10 (i.e., the combined resistance value of multiple metal wirings connected in parallel) and the surface resistivity of the polyester insulation when the insulation deterioration sensor 10 and the polyester insulation are exposed to a specific gas may be input to the input unit 101 prior to deterioration diagnosis. The resistance change data is acquired in a preliminary experiment. Furthermore, the input unit 101 receives an input of the combined resistance value measured by the measurement unit 20 .

[0035] The storage unit 102 is a memory device including, for example, a ROM, a RAM (Random Access Memory), and a hard disk. The storage unit 102 stores a program for executing the degradation diagnosis method, a database 70 for calculating the surface resistivity from the combined resistance value, various data input to the input unit 101, and the like.

[0036] The database 70 defines a correlation (see FIG. 7) between the surface resistivity of an insulator and a combined resistance value of a plurality of metal wirings connected in parallel when the insulator and the plurality of metal wirings connected in parallel are exposed to a specific gas. The database 70 is created by an external device and stored in the memory unit 102 via the input unit 101. Alternatively, the database 70 may be created by the control unit 103 based on the resistance change data input to the input unit 101 and stored in the memory unit 102.

[0037] The control unit 103 is realized by, for example, a microprocessor (MPU: Micro-Processing Unit). The control unit 103 reads a program stored in the storage unit 102 and executes a process related to degradation diagnosis according to a procedure described in the program.

[0038] Fig. 9 is a hardware configuration diagram of the main part of the control unit 103 in Fig. 8. Each function of the control unit 103 can be realized by a processing circuit 1. The processing circuit 1 includes at least one processor 1b and at least one memory 1c. The processing circuit 1 may include at least one dedicated hardware 1a together with the processor 1b and the memory 1c, or as a substitute for them.

[0039] When the processing circuit 1 includes a processor 1b and a memory 1c, each function of the degradation diagnosis device 100 is realized by software, firmware, or a combination of software and firmware. At least one of the software and firmware is written as a program. The program is stored in the memory 1c. The processor 1b realizes each function of the degradation diagnosis device 100 by reading and executing the program stored in the memory 1c.

[0040] The processor 1b is also called a CPU (Central Processing Unit), a processing unit, an arithmetic unit, a microprocessor, a microcomputer, or a DSP. The memory 1c is composed of a non-volatile or volatile semiconductor memory such as a RAM, a ROM, a flash memory, an EPROM (Erasable Programmable Read Only Memory), or an EEPROM (Electrically Erasable Programmable Read Only Memory).

[0041] When the processing circuit 1 comprises dedicated hardware 1a, the processing circuit 1 may be realized, for example, by a single circuit, a composite circuit, a programmed processor, a parallel programmed processor, an ASIC (Application Specific Integrated Circuit), an FPGA (Field Programmable Gate Array), or a combination of these.

[0042] Each of the multiple functions of degradation diagnosis device 100 can be realized by processing circuit 1. Alternatively, the multiple functions of degradation diagnosis device 100 can be realized collectively by processing circuit 1. Some of the functions of degradation diagnosis device 100 may be realized by dedicated hardware 1a, and the other parts may be realized by software or firmware. In this way, processing circuit 1 can realize each function of degradation diagnosis device 100 by hardware 1a, software, firmware, or a combination of these.

[0043] 8 outputs the diagnosis result based on the remaining life calculated by the control unit 103 to an external output device 200. The output device 200 may include, for example, a wireless device, a printer, a display, or a combination of these.

[0044] Fig. 10 is a block diagram showing the functional configuration of the control unit shown in Fig. 8. As shown in Fig. 10, the control unit 103 includes an estimation unit 72, a relational equation creation unit 73, a life calculation unit 74, and a remaining life calculation unit 75. The estimation unit 72 estimates the surface resistivity of the diagnosis object. The relational equation creation unit 73 creates a relational equation between the number of years of use of the diagnosis object and the surface resistivity of the diagnosis object. The life calculation unit 74 calculates the life of the diagnosis object. The remaining life calculation unit 75 calculates the remaining life of the diagnosis object.

[0045] The estimation unit 72 compares the combined resistance value measured by the measurement unit 20 after the insulation degradation sensor 10 is placed around the diagnosis target with the database 70, and estimates the surface resistivity of the diagnosis target. That is, the estimation unit 72 executes the process of step S4 in FIG. 2.

[0046] The relational equation creating unit 73 creates a relational equation between the years of use of the diagnostic object and the surface resistivity of the diagnostic object by connecting a point corresponding to the estimated surface resistivity of the diagnostic object and a point corresponding to the surface resistivity of the diagnostic object whose years of use are 0 (new or unused). That is, the relational equation creating unit 73 executes the process of step S5 in FIG. 2.

[0047] The lifespan calculation unit 74 calculates the lifespan of the diagnostic object in years, based on the relational equation created by the relational equation creation unit 73 and a predetermined threshold value. That is, the lifespan calculation unit 74 executes the process of step S6 in FIG.

[0048] Remaining life calculation unit 75 calculates the remaining life by subtracting the number of years of use of the diagnostic object at the timing of measuring the combined resistance value of insulation degradation sensor 10 or at the timing of arranging insulation degradation sensor 10 from the number of years of life calculated by life calculation unit 74. That is, remaining life calculation unit 75 executes the process of step S7 in FIG. 2.

[0049] As described above, according to the degradation diagnostic method or degradation diagnostic device of the first embodiment, the corrosion rates of the metal wirings 31a, 31b caused by the specific gas are different from each other. Therefore, the range of the surface resistivity of the insulator correlated with the combined resistance value of the metal wirings 31a, 31b is widened. This allows the surface resistivity of the insulator to be estimated with high accuracy over a wider range. As a result, the period during which the degradation of an electrical device including an insulator (e.g., switchgear 49) can be diagnosed with high accuracy is extended.

[0050] Embodiment 2 In the first embodiment, the thickness or the type of metal of the metal wirings 31a, 31b is set in advance so that the corrosion rates of the metal wirings 31a, 31b caused by the specific gas are different from each other. However, one of the metal wirings 31a, 31b may be covered with a coating film so that the corrosion rates of the metal wirings 31a, 31b caused by the specific gas are different from each other.

[0051] Fig. 11 is a schematic diagram of an insulation deterioration sensor according to embodiment 2. The insulation deterioration sensor shown in Fig. 11 differs from the insulation deterioration sensor shown in Fig. 3 in that the metal wiring 31b is covered with a coating film 40. The coating film 40 is formed by applying a coating agent onto the metal wiring 31b.

[0052] Examples of coating agents that can be used include, but are not limited to, polyurethane-based, silicone-based, and silica-based coating agents.

[0053] The specific gas that affects the deterioration of the insulator permeates (penetrates) the coating film 40. Therefore, the metal wiring 31b is corroded by the specific gas. However, there is no change in the resistance value of the metal wiring 31b until the specific gas permeates the coating film 40 and reaches the metal wiring 31b. In other words, the period until the specific gas permeates the coating film 40 and reaches the metal wiring 31b is a dead period of the metal wiring 31b. As a result, even if the thickness and type of metal of the metal wirings 31a and 31b are the same, the corrosion rate of the metal wiring 31b is suppressed compared to the metal wiring 31a on which the coating film 40 is not formed.

[0054] Fig. 12 is a diagram showing the relationship between the exposure time and the resistance value of the metal wiring according to the second embodiment when the metal wiring is exposed to a specific gas. Fig. 12 shows graphs 45a, 45b, and 47, with the horizontal axis representing the exposure time and the vertical axis representing the resistance value. Graph 45a shows the change in the resistance value of the metal wiring 31a between the electrode pads 33a_1 and 33a_2. Graph 45b shows the change in the resistance value of the metal wiring 31b between the electrode pads 33b_1 and 33b_2. Graph 47 shows the change in the resistance value between the lead wires 34_1 and 34_2, i.e., the combined resistance value of the metal wirings 31a and 31b connected in parallel.

[0055] Since the corrosion rate of metal wiring 31b is slower than that of metal wiring 31a, the range 46a of exposure time in which the resistance value of metal wiring 31a changes when the insulation deterioration sensor of embodiment 2 is exposed to a specific gas and the range 46b of exposure time in which the resistance value of metal wiring 31b changes when the metal wiring 31b is exposed to a specific gas have regions that do not overlap with each other.

[0056] The position of the range 46b depends on the length of the dead period of the metal wiring 31b. The length of the dead period of the metal wiring 31b depends on the thickness of the coating film 40. Therefore, the thickness of the coating film 40 may be adjusted so that the range 46a and the range 46b do not overlap each other. This broadens the range of the surface resistivity of the insulator that correlates with the combined resistance value of the metal wirings 31a and 31b.

[0057] By forming the coating film 40, contact between the metal wiring 31b and an object (e.g., a person, dust, etc.) that may cause detection failure is prevented. As a result, occurrence of a phenomenon such as unintentional cutting of a part of the metal wiring 31b is suppressed.

[0058] The metal wiring 31a may also be covered with the coating film 40. This prevents contact between the metal wiring 31a and an object that may cause detection failure. In this case, the thickness of the coating film 40 covering the metal wiring 31a may be set to be thinner than the thickness of the coating film 40 covering the metal wiring 31b. This makes the corrosion rate of the metal wiring 31b slower than the corrosion rate of the metal wiring 31a.

[0059] Embodiment 3 In the first and second embodiments, an insulation deterioration sensor is used in which two metal wires 31a, 31b are connected in parallel. However, the number of metal wires connected in parallel is not limited to two, and may be three or more. By using more metal wires, it is possible to take into account multiple items that affect the insulation performance of the insulator, and deterioration diagnosis that is more suited to the environment becomes possible.

[0060] For example, the insulation deterioration sensor may include another metal wiring connected in parallel to the metal wirings 31a and 31b. The range of exposure time during which the resistance value of the other metal wiring changes when the other metal wiring is exposed to a specific gas has an area that does not overlap with the ranges 36a and 36b corresponding to the metal wirings 31a and 31b.

[0061] In the explanation of the first to third embodiments, a switchgear is used as an example of an electric device, but the electric device is not limited to a switchgear. If an insulator is used for insulation between the current-carrying parts of the electric device and the ground or between the phases, and the deterioration of the insulation performance of the insulator is diagnosed, the same effect as that of the first to third embodiments can be obtained in the configuration.

[0062] Examples of electrical equipment include high-voltage electrical equipment such as switchgear, power distribution equipment, transformers, control gear such as motor control centers, generators, electric motors, or power supplies for power supply (e.g., AC power supplies, DC power supplies, or rectifiers).

[0063] The above-described embodiment may be implemented in various other forms by making omissions, substitutions, or modifications without departing from the contents of the disclosure. The embodiments in which omissions, substitutions, or modifications are made are also included in the scope and contents of the disclosure, and are included in the scope of the claims and the scope equivalent to the contents thereof.

[0064] The embodiments disclosed herein are intended to be combined as appropriate within the scope of non-inconsistency. The embodiments disclosed herein should be considered to be illustrative and not restrictive in all respects. The scope of the present disclosure is defined by the claims, not the above description, and is intended to include all modifications within the scope and meaning equivalent to the claims. [Explanation of symbols]

[0065] 1 processing circuit, 1a hardware, 1b processor, 1c memory, 10 insulation deterioration sensor, 20 measurement unit, 31a, 31b metal wiring, 32 insulating substrate, 33a_1, 33a_2, 33b_1, 33b-2 electrode pad, 34_1, 34_2 lead wire, 40 coating film, 49 switch gear, 50a, 50b circuit breaker, 51a, 51b operation mechanism, 52 horizontal busbar, 53a, 53b, 54a, 54b connecting conductor, 55 diagnosis target, 55a, 55b mold frame, 56 busbar support plate, 57a, 57b cable, 58 insulator, 61a, 61b bogie, 70 database, 72 estimation unit, 73 relational equation creation unit, 74 life calculation unit, 75 remaining life calculation unit, 100 Deterioration diagnosis device, 101 input section, 102 memory section, 103 control section, 104 output section, 200 output device.

Claims

1. A degradation diagnosis method for diagnosing degradation of an electrical device including an insulator, comprising: The method further comprises a step of arranging an insulation deterioration sensor around the insulator, the insulation deterioration sensor including a plurality of metal wirings connected in parallel that corrode when exposed to a specific gas, the plurality of metal wirings including a first metal wiring and a second metal wiring that have different corrosion rates when the insulation deterioration sensor is exposed to the specific gas, and the deterioration diagnosis method further comprises: creating a database in advance that defines a first correlation between a combined resistance value of the insulation degradation sensor and a surface resistivity of the insulation material when the insulation material and the insulation degradation sensor are both exposed to the specific gas; Measuring a combined resistance value of the insulation deterioration sensors at a measurement timing; estimating a surface resistivity of the insulator at the measurement timing using the combined resistance value at the measurement timing and the database; creating a relational expression that represents a second correlation between the usage time of the electrical equipment and the surface resistivity of the insulator from the usage time of the electrical equipment at the measurement timing, the estimated surface resistivity of the insulator, and the surface resistivity of the insulator when the electrical equipment is unused; calculating a lifetime of the electrical device corresponding to a reference surface resistivity at which the insulator loses its insulating performance in the relational expression; and calculating a remaining life time of the electrical equipment by subtracting from the life time the usage time of the electrical equipment at the measurement timing or the usage time of the electrical equipment at the timing when the insulation deterioration sensor is placed around the insulator.

2. 2. The degradation diagnosis method according to claim 1, wherein when the insulation degradation sensor is exposed to the specific gas, a first range of exposure time in which the resistance value of the first metal wiring changes and a second range of exposure time in which the resistance value of the second metal wiring changes have regions that do not overlap with each other.

3. The degradation diagnosis method according to claim 2 , wherein the first range does not overlap with the second range.

4. The degradation diagnosis method according to claim 1 , wherein the correlation coefficient of the first correlation is 0.5 or more.

5. 4. The degradation diagnosis method according to claim 1, wherein at least one of the first metal wiring and the second metal wiring is covered with a coating film that is permeable to the specific gas.

6. The degradation diagnosis method according to claim 1 , wherein the electrical equipment includes at least one of a switch gear, a power distribution device, a transformer, a control gear, a generator, an electric motor, and a power supply device for power supply.

7. A degradation diagnosis device for diagnosing degradation of an electrical device including an insulator, comprising: The deterioration diagnosis device further includes an insulation deterioration sensor having a plurality of metal wirings connected in parallel, the plurality of metal wirings being corroded by exposure to a specific gas, the plurality of metal wirings including a first metal wiring and a second metal wiring that have different corrosion progression rates when the insulation deterioration sensor is exposed to the specific gas, a database that defines a first correlation between a combined resistance value of the insulation degradation sensor and a surface resistivity of the insulation material when the insulation material and the insulation degradation sensor are both exposed to the specific gas; A measurement unit that measures a combined resistance value of the insulation deterioration sensor at a measurement timing; an estimation unit that estimates a surface resistivity of the insulator at the measurement timing by using the combined resistance value at the measurement timing and the database; a relational equation creating unit that creates a relational equation that represents a second correlation between the usage time of the electrical device and the surface resistivity of the insulator, based on the usage time of the electrical device at the measurement timing, the estimated surface resistivity of the insulator, and the surface resistivity of the insulator when the electrical device is unused; a life calculation unit that calculates a life time of the electrical device corresponding to a reference surface resistivity when the insulator loses its insulating performance in the relational expression; a remaining life calculation unit that calculates a remaining life of the electrical equipment by subtracting from the lifetime a usage time of the electrical equipment at the measurement timing or a usage time of the electrical equipment at a timing when the insulation degradation sensor is disposed around the insulator.

8. 8. The degradation diagnosis device according to claim 7, wherein when the insulation degradation sensor is exposed to the specific gas, a first range of exposure time in which the resistance value of the first metal wiring changes and a second range of exposure time in which the resistance value of the second metal wiring changes have regions that do not overlap with each other.

9. The degradation diagnosis device according to claim 8 , wherein the first range does not overlap with the second range.

10. 10. The degradation diagnosis device according to claim 7, wherein a correlation coefficient of the first correlation is equal to or greater than 0.

5.

11. 10. The degradation diagnosis device according to claim 7, wherein at least one of the first metal wiring and the second metal wiring is covered with a coating film that is permeable to the specific gas.

12. 10. The deterioration diagnosis device according to claim 7, wherein the electrical equipment includes at least one of a switch gear, a power distribution device, a transformer, a control gear, a generator, an electric motor, and a power supply device for power supply.

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