Salinity adhesion amount estimation method and salinity adhesion amount estimation device

Abstract

To provide a salinity adhesion amount estimation method and a salinity adhesion amount estimation device that can easily and accurately estimate the amount of salt adhesion.SOLUTION: A salinity adhesion amount estimation method includes a dust accumulation amount estimation step of estimating the amount of dust accumulation D in the electrical equipment, and a salinity adhesion amount estimation step of estimating the amount of salinity adhesion by multiplying the estimated accumulation amount D by a predetermined value α. The predetermined value α is a value calculated by α=ΔS / (D2 - D1), where ΔS is the measured amount of salinity adhesion over a predetermined period, D1 is the accumulation amount at the start of the predetermined period, and D2 is the accumulation amount at the end of the predetermined period. The accumulation amount D is calculated by D=-(L*K)-1*log{V / (A*Vcc)}, where V is a voltage corresponding to current flowing in a photodetector due to reflected or transmitted light from a predetermined surface by emitted light of a light-emitting unit when a power supply voltage Vcc is applied to the photodetector, K is a correction coefficient depending on the properties of the dust, L is a constant depending on the amount of light emitted from the light-emitting unit, and A is a constant depending on the detection sensitivity of the photodetector.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention relates to a method and an apparatus for estimating the amount of salt adhered to electrical equipment, electrical facilities, etc.

Background Art

[0002] In electrical equipment, electrical facilities, etc., when dust flies in from the outside and accumulates, the risk of malfunction and insulation degradation of the electrical equipment and electrical facilities increases. In order to ensure the normal operation of these devices and facilities, it is necessary to take measures such as regular cleaning.

[0003] Techniques for evaluating the degree of dust adhesion are known. For example, Patent Document 1 below discloses a method of optically detecting the progress of dust deposition on a reflector or a transmission plate and estimating the amount of dust deposition from the detection result. Further, Patent Document 2 below discloses a method of detecting the occurrence of insulation degradation of a simulated electrode and estimating the amount of salt adhered from the resistance value and relative humidity of the simulated electrode.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] Regarding Patent Document 1, although the amount of dust deposition can be estimated regardless of the properties of the dust, there is a problem that the equivalent salt adhesion density (hereinafter also referred to as the amount of salt adhered), which is used as an index of the contamination of electrical equipment, cannot be estimated. Regarding Patent Document 2, the amount of salt adhered cannot be detected unless the relative humidity rises, that is, there is a problem that, in a low-humidity environment, even if salt adhesion progresses, it cannot be detected in principle.

[0006] Accordingly, an object of the present invention is to provide a salt adhesion amount estimation method and a salt adhesion amount estimation apparatus that can easily and accurately estimate the amount of salt adhering to an electric device.

Means for Solving the Problems

[0007] (1) The salt adhesion amount estimation method according to the first aspect of the present invention includes a dust deposition amount estimation step of estimating the deposition amount D of dust deposited on an electric device, and a salt adhesion amount estimation step of estimating the salt adhesion amount by multiplying the deposition amount D estimated in the dust deposition amount estimation step by a predetermined value α. The predetermined value α is a value calculated by α = ΔS / (D2 - D1), where ΔS is the measured value of the salt adhesion amount in a predetermined period, D1 is the deposition amount at the start of the predetermined period, and D2 is the deposition amount at the end of the predetermined period. The dust deposition amount estimation step is executed using a device including a light emitting unit that irradiates light onto a predetermined surface within the electric device, a light detection unit that detects the light transmitted through the surface or reflected by the surface, and a measurement terminal that generates a voltage corresponding to the current flowing through the light detection unit. In a state where the surface is irradiated with light by the light emitting unit, a measurement step of measuring the voltage generated at the measurement terminal is included. With the voltage measured in the measurement step being V in a state where the power supply voltage Vcc is applied to the light detection unit, a correction coefficient depending on the properties of the dust being K, a constant depending on the light emission amount of the light emitting unit being L, and a constant depending on the detection sensitivity of the light detection unit being A, the deposition amount D is calculated by D = -(L·K) -1 ·log{V / (A·Vcc)}. Thereby, the deposition amount of dust in the electric device can be accurately estimated, and the salt adhesion amount can be easily and accurately estimated.

[0008] (2) In the above (1), the correction coefficient K is set according to the properties of the dust and is a value of 0.5 or more and 3 or less. Thereby, the deposition amount of dust can be estimated more accurately, and the salt adhesion amount can be estimated more accurately.

[0009] (3) In the above (1) or (2), ΔS is determined by measuring the conductivity of an aqueous solution prepared by suspending dust deposited on the surface of a sample placed at the location where the electrical equipment is located in distilled water over a predetermined period, or is determined by converting the amount of chloride ions measured by ion chromatography of the aqueous solution into the amount of sodium chloride. Thereby, the amount of salt adhesion can be estimated with higher accuracy.

[0010] (4) In the above (3), the predetermined period is one year or two years. Thereby, since spring, summer, autumn, and winter are included to the same extent, the amount of salt adhesion can be estimated accurately.

[0011] (5) The salt adhesion amount estimation device according to the second aspect of the present invention includes a dust deposition amount estimation unit that estimates the deposition amount D of dust deposited on the electrical equipment, a salt adhesion amount estimation unit that estimates the salt adhesion amount by multiplying the deposition amount D estimated by the dust deposition amount estimation unit by a predetermined value α, an input unit that receives the input of the measured value of the salt adhesion amount over a predetermined period, a light emitting unit that irradiates light onto a predetermined surface within the electrical equipment, a light detection unit that detects the light transmitted through the surface or reflected by the surface, and a measurement terminal that generates a voltage corresponding to the current flowing through the light detection unit. The predetermined value α is a value calculated by setting the input measured value as ΔS, setting the deposition amounts at the start and end of the predetermined period estimated by the dust deposition amount estimation unit as D1 and D2 respectively, and α = ΔS / (D2 - D1). The deposition amount D is calculated by setting the voltage generated at the measurement terminal as V in a state where the power supply voltage Vcc is applied to the light detection unit and the surface is irradiated with light by the light emitting unit, setting the correction coefficient depending on the properties of the dust as K, setting the constant depending on the light emission amount of the light emitting unit as L, and setting the constant depending on the detection sensitivity of the light detection unit as A, and D = -(L·K) -1 ·log{V / (A·Vcc)}. Thereby, the deposition amount of dust in the electrical equipment can be estimated accurately, and the salt adhesion amount can be estimated easily and accurately.

Advantages of the Invention

[0012] According to the present invention, it is possible to provide a salt adhesion amount estimation method and a salt adhesion amount estimation device that can easily and accurately estimate the amount of salt adhering to an electrical device.

Brief Description of the Drawings

[0013]

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Embodiment for Carrying Out the Invention

[0014] In the following embodiments, the same parts are given the same reference numerals. Their names and functions are also the same. Therefore, detailed descriptions thereof will not be repeated.

[0015] (Device Configuration) Referring to FIG. 1, a salt adhesion amount estimation device 100 used for the salt adhesion amount estimation method according to an embodiment of the present invention includes a light emitting unit 102 that emits light, a power supply unit 104 that supplies power to the light emitting unit 102, a light detection unit 106 that detects light, a control unit 108, a storage unit 110, a timer 112, an operation unit 114, a presentation unit 116, a temperature detection unit 118, and a light reflection member 120. The salt adhesion amount estimation device 100 also includes a power supply etc. (not shown) for operating each part.

[0016] The light emitting unit 102, the light detection unit 106, the temperature detection unit 118, and the light reflection member 120 are arranged inside an electrical device such as a switchboard that is the monitoring target for salt adhesion. A sample 130 for measuring the amount of salt adhesion is also arranged inside the same device that is the monitoring target. The sample 130 is a cylindrical container having an opening (for example, a cylindrical petri dish with a diameter of about 90 mm), and dust containing salt can adhere inside the container. The sample 130 is formed of resin, glass, metal, ceramic, or the like. The arrangement locations of the power supply unit 104, the control unit 108, the storage unit 110, the timer 112, the operation unit 114, and the presentation unit 116 are arbitrary and may be arranged inside the device that is the monitoring target or outside the device.

[0017] Referring to FIG. 2, the light emitting unit 102 is, for example, a light emitting diode (hereinafter referred to as an LED (Light Emitting Diode)). For the light emitting unit 102, an LED that emits red light (center frequency 630 nm), for example, can be used. The light emitting unit 102 is not limited to an LED, and any light emitting element that can stably output light of a predetermined intensity in a predetermined direction for a predetermined time (for example, about 1 to several seconds) may be used. The wavelength of the emitted light of the light emitting unit 102 may be any wavelength that can be detected by the light detection unit 106. The emitted light of the light emitting unit 102 is, for example, infrared light, visible light, or ultraviolet light. The power supply unit 104 receives control by the control unit 108 and supplies power for lighting the light emitting unit 102 to the light emitting unit 102.

[0018] The light detection unit 106 is, for example, a phototransistor. The light detection unit 106 is not limited to a phototransistor, and any element that can detect light and output an electrical signal (for example, voltage or current) having a magnitude corresponding to the intensity (light amount) thereof may be used. The light detection unit 106 preferably has the center wavelength of the emitted light of the light emitting unit 102 near the center of the detection sensitivity.

[0019] The light reflecting member 120 is held by the holding member 122, reflects the light irradiated from the light emitting unit 102, and makes it incident on the light detection unit 106. The light reflecting member 120 is formed in an L-shaped cross section, and can accommodate the optical path from the light emitting unit 102 to the light detection unit 106 in a relatively narrow space. Two orthogonal surfaces on the light emitting unit 102 side are mirror surfaces that reflect the light from the light emitting unit 102. For the light reflecting member 120, for example, a BA (Bright Annealing: finish with a surface having a gloss close to a mirror surface) material of stainless steel SUS304 can be used. The surface finish is not limited to BA, and may be electrolytically polished. The light reflecting member 120 only needs to be arranged such that the two reflecting surfaces form an angle of about 90°, and can be formed, for example, by bending a metal plate. The light reflecting member 120 may be formed by joining two planar members having reflecting surfaces so as to be substantially orthogonal. The light emitting unit 102, the light detection unit 106, and the light reflecting member 120 constitute a light detection system.

[0020] The light emitting unit 102 and the light detecting unit 106 can be realized by, for example, a photo-reflector which is an element that houses an LED and a photo-transistor in one package. Thereby, the number of components can be reduced, and the optical detection system can be formed compactly.

[0021] The control unit 108 is a CPU (Central Processing Unit), and controls the output of the power supply unit 104 to turn on or off the light emitting unit 102. For example, when the control unit 108 outputs a high-level (e.g., 5V) signal to the power supply unit 104, the power supply unit 104 supplies power to the light emitting unit 102. Thereby, the light emitting unit 102 lights up. When the control unit 108 outputs a low-level (e.g., 0V) signal to the power supply unit 104, the power supply unit 104 stops supplying power to the light emitting unit 102. Thereby, the lit light emitting unit 102 turns off.

[0022] Also, the control unit 108 acquires the output signal of the light detecting unit 106 at a predetermined timing. For example, if the light detecting unit 106 has an A / D conversion function, the control unit 108 acquires the digital data output from the light detecting unit 106. If the light detecting unit 106 outputs an analog signal, the control unit 108 samples the input analog signal at a predetermined time interval to generate digital data.

[0023] The storage unit 110 is a volatile or non-volatile memory that stores data input from the control unit 108. The timer 112 outputs information representing the current time in response to a request from the control unit 108. The operation unit 114 is an operating device such as a computer keyboard and a mouse for inputting instructions to the control unit 108. The presentation unit 116 is, for example, a display device such as a liquid crystal display. The presentation unit 116 may include an acoustic device such as a speaker.

[0024] The temperature detection unit 118 is, for example, a temperature sensor (such as a thermistor, a resistance temperature detector, or a thermocouple), and is arranged around the light emitting unit 102 and the light detecting unit 106. The detected value (temperature) of the temperature detection unit 118 is input to the control unit 108.

[0025] In FIG. 1, dust 190 deposited on the horizontal surfaces of the light reflection member 120, the holding member 122, and the sample 130 is shown. That is, the same amount of dust accumulates on the light reflection member 120, the holding member 122, and the sample 130 disposed in the same environment (inside the same electrical equipment). The light emitted from the light emitting unit 102 passes through the dust 190, is then reflected by the horizontal surface of the light reflection member 120, passes through the dust 190 again, is reflected by the vertical surface of the light reflection member 120, returns parallel to the optical axis of the light emitting unit 102, and is detected by the light detection unit 106. The amount of light measured by the light detection unit 106 changes according to the amount of dust 190 deposited on the light reflection member 120. As the deposition amount of the dust 190 increases, the measured value becomes smaller. The accumulation of dust in the equipment increases according to the passage of time since the equipment was installed. Therefore, at a predetermined timing, when the power supply unit 104 is controlled by the control unit 108 to turn on the light emitting unit 102, if the amount of light detected by the light detection unit 106 is measured, the change in the dust accumulation state can be observed. At this time, it is preferable that the control unit 108 performs temperature correction of the detection value of the light detection unit 106 using the detection value of the temperature detection unit 118 as described later.

[0026] An example of an optical detection circuit using an LED for the light emitting section 102 and a phototransistor for the light detection section 106 is shown in FIG. 3. Referring to FIG. 3, the light emitting section 102 includes an LED 140 and a resistor R1 connected in series between terminals 150 and 152. In FIG. 3, the light reflecting member 120 is shown as a flat plate for convenience. The light detection section 106 includes a phototransistor 142, resistors R2 and R3 connected in series between terminals 154 and 156. With terminals 152 and 156 grounded, when a DC voltage is applied from the power supply section 104 between terminals 150 and 152 of the light emitting section 102, the LED 140 emits light. The light detection section 106, when light (the light emitted from the light emitting section 102 reflected by the light reflecting member 120) is incident on the phototransistor 142 with a predetermined DC voltage applied between terminals 154 and 156, the phototransistor 142 turns on and a current flows (a current flows between terminals 154 and 156). The control section 108 measures the voltage generated at the measurement terminal 144 due to the accompanying voltage drop. Since the current value flowing through the phototransistor 142 depends on the amount of light incident on the phototransistor 142, the voltage measured at the measurement terminal 144 represents the amount of light incident on the phototransistor 142. Note that the resistors R1, R2, and R3 may have appropriate resistance values according to the LED 140 and the phototransistor 142.

[0027] (Estimation of dust deposition amount) Using the voltage value measured using the circuit shown in FIG. 3, the dust deposition amount D is calculated by the following equation. D = -(L·K) -1 ·log{V / (A·Vcc)} ···(Equation 1) In Equation 1, Vcc is the power supply voltage applied to operate the phototransistor 142 (the voltage between terminals 154 and 156), and V is the voltage value measured at the measurement terminal 144 with the power supply voltage Vcc applied. K is a correction coefficient considering the properties of the dust, and L and A are constants depending on the light emission amount of the light emitting section (LED 140) used and the detection sensitivity of the light detection section (phototransistor 142) used, respectively.

[0028] The correction coefficient K varies depending on the properties of the dust, and it may generally take values within the range of 0.5 ≤ K ≤ 3. Usually, the correction coefficient K may be 1. By adjusting the correction coefficient K according to the properties of the dust (such as color), the variation in the estimated amount D of dust can be suppressed. For example, in an environment where the reflectivity of the main dust is low (dark-colored), the correction coefficient K is set to, for example, 1.3.

[0029] (Determination of the salt adhesion amount estimation formula) Hereinafter, with reference to FIG. 4, a process for determining an equation for estimating the salt adhesion amount in an electrical device using the salt adhesion amount estimation device 100 of FIG. 1 will be described. The process shown in FIG. 4 is performed by the control unit 108 reading and executing a predetermined program stored in the storage unit 110 in advance. It is assumed that the light emitting unit 102 and the light detection unit 106 constitute the circuit shown in FIG. 3 and are arranged inside the same electrical device (such as a switchboard) (a dark place where external light does not enter) together with the sample 130.

[0030] It is assumed that the storage unit 110 stores information for specifying the time at which the measurement described later is to be performed (hereinafter referred to as measurement time information), the parameters (K, L, A, and Vcc) of Equation 1, and a message. The measurement time information may be specified according to the timing at which the measurement is to be performed and is arbitrary. For example, when the measurement is to be performed at a predetermined time (including year, month, and day), the measurement time information may be information directly representing the time. When the measurement is to be performed after a predetermined time has elapsed, the measurement time information may be the time interval Δt. The measurement time information is preferably determined according to the deposition rate of the dust, the degree of influence of the dust on the electrical device, etc.

[0031] The message includes a message indicating that a predetermined time has elapsed. The message is, for example, a text or acoustic message. As described later, when a message indicating that a predetermined time has elapsed is presented to the presentation unit 116, an administrator or the like performs the measurement of the salt adhesion amount.

[0032] In step 400, the control unit 108 executes a process of estimating the dust deposition amount. Step 400 is executed, for example, when the light reflection member 120 and the sample 130 are in a clean state where no dust is deposited. Specifically, as a process of estimating the dust deposition amount, the control unit 108 executes the process shown in FIG. 5.

[0033] Referring to FIG. 5, in step 500, the control unit 108 turns on the light emitting unit 102 and measures the voltage V of the measurement terminal 144. To turn on the light emitting unit 102, the control unit 108 outputs a high-level signal to the power supply unit 104 to cause the power supply unit 104 to supply power to the light emitting unit 102. The measured voltage V is stored in the storage unit 110. Step 500 is executed multiple times as described later, but it is sufficient that only the voltage V measured last is stored in the storage unit 110. After the voltage measurement, the control unit 108 turns off the light emitting unit 102, and the control proceeds to step 502. To turn off the light emitting unit 102, the control unit 108 outputs a low-level signal to the power supply unit 104 to stop the power supply to the light emitting unit 102.

[0034] In step 502, the control unit 108 measures the temperature T by the temperature detection unit 118. The measured temperature T is stored in the storage unit 110. Then, the control proceeds to step 504. Note that step 502 is executed multiple times as described later, but it is sufficient that only the temperature measured last is stored in the storage unit 110.

[0035] In step 504, the control unit 108 performs temperature correction on the voltage measured in step 500. If temperature correction is not performed, when the ambient temperature of the light emitting unit 102 and the light detection unit 106 rises, the detection value (voltage) of the light detection unit 106 also tends to rise. Due to the difference in the decrease state of the detection value of the light detection unit 106 caused by dust deposition, the amount of increase in the voltage of the measurement terminal 144 due to the ambient temperature is different. Therefore, if the installation locations and installation environments of the light emitting unit 102 and the light detection unit 106 are different, relative evaluation becomes difficult.

[0036] The amount of change in the detected value (the slope of the graph) due to temperature change is almost constant regardless of the dust deposition state. Therefore, the control unit 108 corrects the voltage V measured in step 500 using the temperature measured in step 502 according to the following equation. V(25) = V(T) × (1 - (T - 25) / C) ···(Equation 2)

[0037] T is the temperature measured in step 502, V(T) is the voltage of the measurement terminal 144 at temperature T, that is, the voltage measured in step 500, and V(25) is the voltage of the measurement terminal 144 at T = 25 (°C). C is a constant, which varies depending on the temperature characteristics of the elements (LED, phototransistor, etc.) used, but a value in the range of usually 50 to 500 can be determined in advance. According to Equation 2, the voltage V(T) measured in step 500 can be converted into the detected value V(25) at T = 25 (°C). The converted value is a value with the influence of the ambient temperature (temperature dependence of the elements used) suppressed. Then, the control proceeds to step 506.

[0038] In step 506, the control unit 108 estimates the dust deposition amount using the above Equation 1. Specifically, the control unit 108 uses the voltage V(25) of the measurement terminal 144 after being corrected in step 504 as the voltage V in Equation 1, and uses the value read from the storage unit 110 as the correction coefficient K in Equation 1, and calculates the dust deposition amount D according to Equation 1. The control unit 108 stores the calculated dust deposition amount D in the storage unit 110. Then, the control returns to the flowchart of FIG. 4 and proceeds to step 402.

[0039] In step 402, the control unit 108 stores the deposition amount D calculated in step 400 (the first executed step 506) in the storage unit 110 as the first deposition amount D1. Then, the control proceeds to step 404.

[0040] In step 404, the control unit 108 determines whether a predetermined time has elapsed. Specifically, the control unit 108 reads measurement time information from the storage unit 110, acquires information representing the current time from the timer 112, and compares them to determine whether the predetermined time has elapsed. The predetermined time is, for example, one year or two years after step 400 is executed. If it is determined that the predetermined time has elapsed, the control proceeds to step 406. Otherwise, step 404 is repeated.

[0041] There may be seasonal variations in the quality and quantity of airborne dust. For example, there may be a large amount of pollen flying in spring. Also, the wind direction changes with the season, and the quality and quantity of airborne dust may vary. Assuming such a case, it is desirable that the period during which the sample 130 is placed is a period that equally includes spring, summer, autumn, and winter, such as one year or two years. Thus, in order to improve the estimation accuracy of the salt adhesion amount, it is preferable that the predetermined time be a period in years, but it may be otherwise.

[0042] In step 406, the control unit 108 reads a message indicating that the predetermined time has elapsed from the storage unit 110 and presents it to the presentation unit 116. If the message is text, the control unit 108 displays it on the display device, and if it is audio, it plays it from the speaker. Thereafter, the control proceeds to step 408.

[0043] When a message indicating that a predetermined time has elapsed is presented on the presentation unit 116, an administrator or the like knows that it is time to measure the salt adhesion amount of the sample 130 being placed. In response to this, the administrator or the like collects the sample 130 placed in the device and measures its salt adhesion amount. For example, a certain amount of distilled water is poured into the sample 130 to wash away the deposits, generating a suspended aqueous solution, and the conductivity of the aqueous solution is measured. The salt adhesion amount means the equivalent salt adhesion density and represents the amount of sodium chloride (table salt) showing the same value as the conductivity of water due to actual contaminants. The salt adhesion amount (equivalent salt adhesion density) is calculated from the measured conductivity. Note that the method for obtaining the salt adhesion amount of the sample 130 is not limited to the method of measuring the conductivity of the aqueous solution. Ion chromatography may be performed on the aqueous solution to measure the amount of chloride ions, and the obtained amount of chloride ions may be converted into the amount of sodium chloride to specify the salt adhesion amount.

[0044] In step 408, the control unit 108 executes a process of estimating the dust deposition amount in the same manner as in step 400. That is, the control unit 108 executes steps 500 to 506 shown in FIG. 5. Thereafter, the control proceeds to step 410.

[0045] In step 410, the control unit 108 stores the deposition amount D calculated in step 408 (step 506 executed the second time) in the storage unit 110 as the second deposition amount D2. Thereafter, the control proceeds to step 412.

[0046] In step 412, the control unit 108 determines whether the salt adhesion amount of the sample 130 has been input. Specifically, the control unit 108 displays on the presentation unit 116 a screen for receiving the input of the salt adhesion amount of the sample 130 from the operation unit 114. When the salt adhesion amount of the sample 130 obtained by measurement as described above is input via the operation unit 114, the control proceeds to step 414. Otherwise, step 412 is repeated, and the control unit 108 waits for the input of the salt adhesion amount of the sample 130.

[0047] In step 414, the control unit 108 determines an estimation formula for the salt adhesion amount. Specifically, the control unit 108 reads the first deposition amount D1 and the second deposition amount D2 from the storage unit 110, and calculates the coefficient α by α = ΔS / (D2 - D1) using the salt adhesion amount ΔS obtained in step 412, D1, and D2. Thereby, as an estimation formula for the salt adhesion amount S corresponding to the deposition amount D of the dust, S = α×D is determined. The control unit 108 stores the calculated coefficient α in the storage unit 110. Thereafter, this program ends.

[0048] As described above, regarding the electrical equipment in which the salt adhesion amount estimation device 100 and the sample 130 are arranged, after the estimation formula for the salt adhesion amount is determined, the salt adhesion amount estimation device 100 can monitor the salt adhesion amount in the electrical equipment as described later using the determined estimation formula. If the environment where the electrical equipment is installed changes and the type of dust or the deposition state of the dust changes, the process shown in FIG. 4 is executed again, and a new estimation formula for the salt adhesion amount is determined.

[0049] (Monitoring of salt adhesion amount) With reference to FIG. 6, the process of monitoring the salt adhesion amount in the electrical equipment, that is, the process of estimating the salt adhesion amount, using the salt adhesion amount estimation device 100 of FIG. 1 will be described. The process shown in FIG. 6 is performed by the control unit 108 reading and executing a predetermined program stored in the storage unit 110 in advance. Inside the electrical equipment (such as a switchboard) to be monitored (a dark place where external light does not enter), the light emitting unit 102 and the light detection unit 106 are arranged, but the sample 130 is not arranged. It is assumed that the amount of salt contained in the dust is generally constant as the property of the deposited dust, and the salt adhesion amount is proportional to the deposition amount of the dust.

[0050] As described above, the parameters (K, L, A, Vcc, and α) are stored in the memory unit 110. Also, it is assumed that the memory unit 110 stores information for specifying the time to execute the estimation process described later (hereinafter referred to as estimation time information). The estimation time information may be specified according to the timing at which the estimation is performed, is arbitrary, and may be set in the same manner as the above-described measurement time information.

[0051] In step 600, the control unit 108 determines whether to estimate the salt adhesion amount. Specifically, the control unit 108 reads the estimation time information from the memory unit 110, acquires information representing the current time from the timer 112, and compares them to determine whether it is the timing to execute the estimation process. If it is determined to estimate the salt adhesion amount, the control proceeds to step 602. Otherwise, the control proceeds to step 608.

[0052] In step 602, the control unit 108 executes a process of estimating the dust deposition amount in the same manner as in step 400. That is, the control unit 108 executes steps 500 to 506 shown in FIG. 5. After that, the control proceeds to step 604.

[0053] In step 604, the control unit 108 estimates the corresponding salt adhesion amount from the deposition amount D calculated in step 602 (step 506). Specifically, the control unit 108 reads the coefficient α from the memory unit 110, and calculates the salt adhesion amount S (estimated value) corresponding to the deposition amount D calculated in step 602 by S = α × D. After that, the control proceeds to step 606.

[0054] In step 606, the control unit 108 presents the estimated value of the salt adhesion amount calculated in step 606 to the presentation unit 116. After that, the control proceeds to step 608. The administrator or the like can look at the presented salt adhesion amount S and determine whether maintenance such as removal of dirt due to salt adhesion and replacement of parts is necessary for the electrical equipment to be monitored.

[0055] In step 608, the control unit 108 determines whether an end instruction has been received. If an end instruction has been received, this program ends. Otherwise, the control returns to step 600 and the above processing is repeated. The end instruction is performed, for example, by an operation of the operation unit 114 or an operation of turning off the power of the salinity adhesion amount estimation device 100.

[0056] As described above, the salinity adhesion amount in the electrical equipment can be monitored at a predetermined timing. That is, the salinity adhesion amount (estimated value) can be calculated and presented, and an administrator or the like can determine whether maintenance of the electrical equipment is necessary by looking at the presented salinity adhesion amount S. Therefore, maintenance such as removal of dirt and replacement of parts can be executed as necessary.

[0057] In the above, the case where the estimation formula of the salinity adhesion amount is determined (that is, the coefficient α is determined) by executing the process shown in FIG. 4 once in the environment where the electrical equipment is arranged has been described, but it is not limited to this. For example, the process shown in FIG. 4 may be executed a plurality of times for the electrical equipment arranged in the same environment, and a plurality of coefficients α may be calculated. As the estimation formula of the salinity adhesion amount S, an average value α of the plurality of coefficients α AV is used, and the estimation accuracy of the salinity adhesion amount can be improved by using the formula S = α AV ×D.

[0058] In the above, in Equation 2, the reference temperature is set to 25°C, but it is not limited to this. If the reference temperature is T1, Equation 2 becomes V(T1) = V(T) × (1 - (T - T1) / C). Note that this constant C has a value different from the constant C in Equation 2.

[0059] In the above description, the case where the light reflection member 120 having an L-shaped cross section is used and the light emitting unit 102, the light detection unit 106, and the light reflection member 120 are arranged as shown in FIG. 2 has been described. However, the configuration and arrangement of the light detection system are not limited to this. In FIG. 2, the positions of the light emitting unit 102 and the light detection unit 106 may be interchanged. Further, the light detection system may be configured as shown in FIG. 7. In FIG. 7, instead of the light reflection member 120 having an L-shaped cross section, a flat light reflection member 124 is used. Instead of arranging the light reflection member 124 inside the electric device, a predetermined surface (a surface where dust can accumulate) of the electric device may be used as the light reflection member 124. That is, any configuration may be used as long as light is irradiated from the light emitting unit 102 onto a predetermined surface inside the electric device and the reflected light is detected by the light detection unit 106.

[0060] (Modification example) In the above description, the configuration in which dust is deposited on the light reflection member and the light detected by the reflection plate after passing through the dust 190 is detected by the light detection unit 106 has been described. However, the present invention is not limited to this. Dust may be deposited on the light transmission member. For example, as shown in FIG. 8, a configuration in which light from the light emitting unit 102 passes through the dust 190 and then the light is detected by the light detection unit 106 may be used. Referring to FIG. 8, the salt adhesion amount estimation device 160 is configured in the same manner as the salt adhesion amount estimation device 100, except that the light detection system is different. That is, a flat light transmission member 200 is disposed between the light emitting unit 102 and the light detection unit 106. Specifically, referring to FIG. 9, the light transmission member 200 is held by a flat holding member 212 around it, and the holding member 212 is supported on a flat portion 216 of an electric device or the like by, for example, a plurality of columnar support members 214. If there is a predetermined light transmissive surface (a surface where dust can accumulate) inside the electric device, instead of arranging the light transmission member 200, that surface may be used as the light transmission member 200. That is, any configuration may be used as long as light is irradiated from the light emitting unit 102 onto a predetermined light transmissive surface inside the electric device and the transmitted light is detected by the light detection unit 106.

[0061] The light detection system may have a configuration as shown in FIG. 10. The emitted light from the light emitting unit 102 passes through the light transmitting member 230 and the dust 190, and then is reflected by the light reflecting member 232 and detected by the light detection unit 106. Further, an arrangement in which the positions of the light emitting unit 102 and the light detection unit 106 in FIG. 9 or FIG. 10 are interchanged may also be adopted.

[0062] Even if the same type of elements (e.g., LEDs) are used for the light emitting unit 102, their characteristics vary from element to element. The same applies to the light detection unit 106. Even if the same type of elements (e.g., photo transistors) are used, their characteristics vary from element to element. Therefore, even if the amount of dust deposition is the same, the detected values vary. It is preferable to suppress the influence of variations (characteristic variations) of the elements used. For this purpose, referring to FIG. 11, the circuit of the light detection system is composed of the light emitting unit 300 and the light detection unit 106. The configuration shown in FIG. 11 is obtained by adding a variable resistor 302 to the configuration shown in FIG. 3.

[0063] The variable resistor 302 is an element whose resistance value can be adjusted, called, for example, a 3-terminal potentiometer, a volume, etc. One end of the variable resistor 302 is connected to the resistor R1, and the other end is connected to the terminal 152. Thus, when a constant voltage is applied to the terminals 150 and 152, if the resistance value of the variable resistor 302 changes, the current value flowing through the LED 140 changes, and the light emission intensity of the LED 140 changes.

[0064] Therefore, for each salt adhesion amount estimation device, for example, in a state where no dust is deposited on the light reflecting member 120, the variable resistor 302 is adjusted in advance so that the voltage detected from the measurement terminal 144 becomes a predetermined value when the light emitting unit 300 emits light. Thereby, the influence of variations (characteristic variations) of the elements used as the light emitting unit 300 and the light detection unit 106 can be suppressed.

[0065] In order to suppress the influence of variations in elements (variations in characteristics), it is sufficient to provide an adjustment element in at least one of the light-emitting unit and the light-detection unit, and it is not limited to the circuit shown in FIG. 11. For example, in the circuit shown in FIG. 3, the resistor R3 may be replaced with a variable resistor. On-site, for the variable resistor, for example, a 3-terminal potentiometer may be used, and its adjustment terminal (the terminal where the contact position to the resistive member changes) may be used as the measurement terminal 144. Thereby, even if the amount of light irradiated to the phototransistor 142 is the same, the voltage detected by the measurement terminal 144 can be changed. Therefore, by adjusting the resistance value of the variable resistor, the influence of variations in each element on the detection value (voltage of the measurement terminal 144) of the light-detection unit can be suppressed with respect to the LED 140 and the phototransistor 142.

[0066] Also, as a circuit similar to FIG. 11, in the circuit shown in FIG. 11, the resistor R3 may be replaced with a variable resistor as described above. By adjusting two variable resistors, the influence of variations in each element on the detection value (voltage of the measurement terminal 144) of the light-detection unit can be suppressed with respect to the LED 140 and the phototransistor 142.

[0067] Furthermore, the circuit of the light-detection system is not limited to the circuits shown in FIGS. 3 and 11 and circuits similar thereto. That is, the light-detection unit is not limited to a configuration in which the phototransistor 142 and two resistors are directly connected (resistors R2 and R3 in FIG. 3 and resistors R2 and variable resistor 302 in FIG. 11). Any configuration that includes the phototransistor 142 and at least one resistor and can detect a change in the current value flowing through the phototransistor 142 as a change in the voltage drop due to the resistor is acceptable. Depending on the deposition amount of the dust 190, the amount of light received by the phototransistor 142 changes, and a change in the current value flowing through the phototransistor 142 corresponding to the change in the amount of light can be detected as a change in the voltage drop.

[0068] In the above description, the case where the sample for estimating the salt adhesion amount is arranged simultaneously with the arrangement of the salt adhesion amount estimating device and the initial dust deposition amount is zero has been described, but the present invention is not limited thereto. The arrangement of the salt adhesion amount estimating device and the arrangement of the sample for estimating the salt adhesion amount do not necessarily have to be simultaneous. The sample for estimating the salt adhesion amount may be arranged after the salt adhesion amount estimating device is arranged. In that case, the dust deposition amounts before and after the arrangement of the sample for estimating the salt adhesion amount are estimated, and the dust deposition amount during the arrangement period of the sample for estimating the salt adhesion amount can be calculated from the difference therebetween. Therefore, conversion to the salt adhesion amount is possible.

[0069] The configuration for detecting the dust deposition amount in the electrical equipment is not limited to the above. Any device capable of estimating the dust deposition amount may be used. After arranging a sample in the electrical equipment, if an apparatus having a function of estimating the dust deposition amount is used to obtain the estimated values of the dust deposition amounts at the start and end of a predetermined period, the coefficient α for estimating the salt adhesion amount can be calculated by α = ΔS / (D2 - D1) using those estimated values D1 and D2 and the measured value ΔS of the salt adhesion amount in the predetermined period.

Example

[0070] The experimental results are shown below to demonstrate the effectiveness of the present invention. The salt adhesion amount estimating device 100 and the sample 130 having the configuration shown in FIG. 1 were arranged in a switchboard installed outdoors, and an experiment was conducted for about one year from June 12, 2021 to June 17, 2022. The arranged light reflection member 120 and sample 130 were in a clean state without dust deposition. After arranging them, the light emitting unit 102 was turned on every 10 minutes to measure the voltage of the measurement terminal 144. The results are shown in FIG. 12. In FIG. 12, the vertical axis represents the measured voltage, that is, the relative value of the voltage (generated voltage) generated at the measurement terminal 144 by the phototransistor 142 included in the light detection unit 106, and the horizontal axis represents the time (month / day).

[0071] From the graph in Fig. 12, it can be seen that the generated voltage shows a downward trend in the long term. The generated voltage has decreased from 0.9 at the initial stage (June 17, 2021) to 0.66 180 days later (December 19, 2021) as indicated by the arrow. By observing the dust deposition situation in the experimental target equipment (distribution board), it was confirmed that this long-term downward trend is due to dust deposition.

[0072] Fig. 13 is a graph showing the relationship between the generated voltage and the dust deposition amount of the salt deposition amount estimation device used in the experiment. In Fig. 13, the vertical axis is the same as in Fig. 12, and the horizontal axis is the dust deposition amount (mg / cm 2 ). The arrow shown in Fig. 13 indicates the dust deposition amount calculated by the above formula 1 180 days later (refer to December 19, 2021 in Fig. 12), and the value was 0.45 mg / cm 2 . Using this value, with the correction coefficient K = 1 in the above formula 1, the parameters L, A, and Vcc were determined. Specifically, the power supply voltage Vcc used in the experiment was 5V, and as the values of the parameters, L = 0.3125 and A = 0.18 were obtained. Applying these values to K, L, A, and Vcc in formula 1 and using formula 1, the values (estimated values) calculated from each generated voltage in Fig. 12 are the dust deposition amounts shown in Fig. 13.

[0073] Assuming that the salt deposition amount of the sample after being placed for 180 days as described above was 0.006 mg / cm 2 , the result of converting the dust deposition amount to the salt deposition amount is shown in Fig. 14. In Fig. 14, the vertical axis is the same as in Fig. 12, and the horizontal axis is the salt deposition amount (mg / cm 2 ). The coefficient α (= 0.006 (mg / cm 2 ) / 0.45 (mg / cm 2 )) is approximately 0.013, and using this, the salt deposition amount S was calculated from the dust deposition amount D shown in Fig. 13 by S = α × D. The graph in Fig. 14 shows the change in the salt deposition amount S (calculated value) with respect to the generated voltage corresponding to the dust deposition amount D. The arrow shown in Fig. 14 indicates the salt deposition amount 180 days later (refer to December 19, 2021 in Fig. 12), and the value was 0.006 mg / cm 2That is. According to the graph of FIG. 14, for example, when the generated voltage of the salt adhesion amount estimation device drops to 0.53, it can be estimated that the salt adhesion amount has progressed to 0.01 mg / cm 2 and when it drops to 0.31, it can be estimated that it has progressed to 0.02 mg / cm 2 .

[0074] As described above, the present invention has been described by explaining the embodiments. However, the above-described embodiments are examples, and the present invention is not limited to only the above-described embodiments. The scope of the present invention is shown by each claim of the claims, taking into consideration the description in the detailed description of the invention, and includes all modifications within the meaning and scope equivalent to the language described therein.

Explanation of Reference Numerals

[0075] 100, 160 Salt adhesion amount estimation device 102, 300 Light emitting unit 104 Power supply unit 106 Light detection unit 108 Control unit 110 Storage unit 112 Timer 114 Operation unit 116 Presentation unit 118 Temperature detection unit 120, 124, 232 Light reflection member 122, 212 Holding member 130 Sample 140 LED 142 Phototransistor 144 Measurement terminal 150, 152, 154, 156 Terminal 190 Dust 200, 230 Light transmission member 214 Support member 216 Flat portion 302 Variable resistor R1, R2, R3 Resistor

Claims

1. A dust deposition amount estimation step of estimating a dust deposition amount D deposited on an electric device, and a salt adhesion amount estimation step of estimating a salt adhesion amount by multiplying the deposition amount D estimated in the dust deposition amount estimation step by a predetermined value α, wherein the predetermined value α is a value calculated by α = ΔS / (D2 - D1), where ΔS is a measured value of the salt adhesion amount in a predetermined period, D1 is the deposition amount at the start of the predetermined period, and D2 is the deposition amount at the end of the predetermined period, and the dust deposition amount estimation step is executed using a device including a light emitting unit that irradiates light onto a predetermined surface within the electric device, a light detection unit that detects the light transmitted through the surface or the light reflected by the surface, and a measurement terminal that generates a voltage corresponding to the current flowing through the light detection unit, and a measurement step of measuring the voltage generated at the measurement terminal in a state where the surface is irradiated with light by the light emitting unit. With the power supply voltage Vcc applied to the light detection unit, let the voltage measured in the measurement step be V, the correction coefficient depending on the properties of the dust be K, the constant depending on the light emission amount of the light emitting unit be L, and the constant depending on the detection sensitivity of the light detection unit be A. Then, the deposition amount D is calculated as D = -(L·K) －１ ·log{V / (A·Vcc)}, and a method for estimating the salt adhesion amount including a calculation step.

2. The correction coefficient K is set according to the properties of the dust, and is a value of 0.5 or more and 3 or less. The salt adhesion amount estimation method according to Claim 1.

3. ΔS is specified by measuring the conductivity of an aqueous solution prepared by suspending the dust deposited on the surface of a sample placed at the location where the electric device is located in distilled water during the predetermined period, or is specified by converting the amount of chloride ions measured by ion chromatography of the aqueous solution into the amount of sodium chloride. The salt adhesion amount estimation method according to Claim 1 or Claim 2.

4. The predetermined period is one year or two years. The salt adhesion amount estimation method according to Claim 3.

5. A dust deposition amount estimation unit that estimates a dust deposition amount D deposited on an electric device, a salt adhesion amount estimation unit that estimates a salt adhesion amount by multiplying the deposition amount D estimated by the dust deposition amount estimation unit by a predetermined value α, an input unit that receives an input of a measured value of the salt adhesion amount in a predetermined period, a light emitting unit that irradiates light onto a predetermined surface within the electric device, a light detection unit that detects the light transmitted through the surface or the light reflected by the surface, and a measurement terminal that generates a voltage corresponding to the current flowing through the light detection unit. The predetermined value α is a value calculated by α = ΔS / (D2 - D1), where the input measurement value is ΔS, the deposition amount at the start of the predetermined period estimated by the dust deposition amount estimation unit is D1, and the deposition amount at the end of the predetermined period is D2. The deposition amount D is calculated as D = -(L·K)·log{V / (A·Vcc)}, where V is the voltage generated at the measurement terminal in a state where the power supply voltage Vcc is applied to the light detection unit and the surface is irradiated with light by the light emitting unit, K is a correction coefficient depending on the properties of the dust, L is a constant depending on the light emission amount of the light emitting unit, and A is a constant depending on the detection sensitivity of the light detection unit. －１ A salt adhesion amount estimation device calculated by

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