JP2984741B2 - Non-contact measurement method and apparatus for the amount of substances adhering to an object surface - Google Patents

Description

Description: FIELD OF THE INVENTION The present invention relates to a method and an apparatus for non-contact measurement of the amount of a substance attached to the surface of an object, and more particularly to a method and apparatus for non-contact measurement of the amount of salt attached to the surface of an insulator. Regarding the device.

(Prior Art) Non-contact remote measurement of the amount of a substance attached to the surface of an object is required in various fields. Especially in the field of power transmission and distribution technology, if the amount of salt attached to the surface of the insulator attached to the transmission line tower increases, there is a danger of flashover, etc., so measure the amount of salt, exceeding the expected amount If it is, it is necessary to take measures such as cleaning the insulator.

For this reason, conventionally, a pilot insulator (for example, Japanese Patent Publication No. Sho 63-2426) having the same shape and surface condition as an actual insulator has been used.
Under the same conditions as the actual insulator, it is common practice to attach it to a power transmission tower or the like and allow it to be naturally exposed, and to estimate the contamination state of the actual insulator from the amount of fouled salt attached to the surface of the pilot insulator. Is being done.

For example, JP-B-61-28306 and JP-B-61-30710 disclose that a pilot insulator attached to a transmission line tower is removed from the tower at an appropriate time and the surface is artificially and uniformly wetted. After that, the electric resistance between the measurement electrodes provided on the pilot insulator was measured in advance, and based on the measurement result, the electric resistance was attached to the surface of the pilot insulator from the previously prepared electric resistance versus adhesion (fouling) salt content relationship curve. The amount of fouled salt is estimated, and the amount of fouled salt attached to the surface of the actually used insulator is further estimated and detected.

(Problems to be Solved by the Invention) As described above, as a device for measuring the electric resistance between the measurement electrodes provided on the pilot insulator, the insulator for mounting and removing the pilot insulator on the power transmission tower is used. There is a problem that a large-scale facility such as a wetting chamber and a water vapor supply device for uniformly wetting the surface of the pilot insulator to be measured is required, and a large space is occupied.

Not only that, when the pilot insulator is removed or wetted, the state of surface contamination (adhesion of salt) of the pilot insulator to be measured changes, and it may not be possible to accurately measure the amount of attached salt.

Also, once the pilot insulator is removed from the power transmission tower and the amount of deposited salt is measured, the state of salt deposition changes due to wetting and the like, so this is attached to the power transmission tower again and the change over time in the deposited salt content is measured. There is also the problem that this is virtually impossible.

An object of the present invention is to solve such a problem and to provide a method and an apparatus for non-contactly measuring the amount of a substance attached to the surface of an object.

Also, a specific object of the present invention is to use a pilot insulator without using a salt, the amount of salt attached to the surface of the actual insulator itself, while the insulator is attached to a power transmission tower, from a distance.
In addition, it is an object of the present invention to provide a non-contact measurement method and an apparatus for measuring the amount of salt attached to the insulator surface, which can be measured even when a high voltage is applied.

In the following description, an example in which the present invention is applied to non-contact measurement of the amount of salt attached to the insulator surface will be described. However, the present invention is not limited to the amount of salt attached to the insulator surface, and is heated and evaporated (sublimated) by laser light irradiation. Naturally, the present invention can be applied to the measurement of the amount of a substance as long as the substance generates light (radiation rays) of a specific wavelength, and the present invention also includes such a method and apparatus for measuring the amount of the substance. Is what you do.

(Means for Solving the Problems) In order to achieve the above object, the present invention provides a method in which a laser beam is directed to a surface of an object and irradiated, and a test substance on the surface of the object is heated and evaporated to obtain the target. A step of generating excitation light having a wavelength specific to the test substance, and an irradiation light amount cumulative value of the laser light necessary for the excitation light to attenuate and disappear, and / or until the excitation light disappears. Detecting the accumulated light quantity of the excitation light, and the relationship between the accumulated irradiation light quantity of the laser light and the amount of the test substance, or / and the accumulated light quantity of the excited light versus the test substance. Determining the amount of the test substance on the surface from the relationship between the amounts.

According to the present invention, there is provided a laser light source for generating a laser beam, means for directing the laser beam to the surface of the object to be focused, and irradiating the laser beam, and a laser beam on the surface of the object to be performed. Means for measuring the intensity of the specific wavelength light generated from the test substance at the irradiation position, and means for determining the cumulative irradiation amount of the laser light required to attenuate the intensity of the specific wavelength light to zero. Based on the obtained cumulative irradiation amount of laser light, means for determining the amount of the test substance that has generated a specific wavelength light on the surface of the test object, or, instead, the intensity of the specific wavelength light is Means for calculating the accumulated light emission of the specific wavelength light until it attenuates to zero, and generates the specific wavelength light on the surface of the test object based on the calculated accumulated light emission of the specific wavelength light And a means for determining the amount of the test substance.

(Operation) According to the present invention, the amount of the substance adhering to the surface of the object can be remotely measured without contact, so that the measurement can be performed safely, quickly, and easily. In addition, since non-contact measurement can be performed, there is little influence or disturbance on the surface state of the test object, and measurement and monitoring of a change with time in the amount of the test substance attached can be performed.

(Embodiment) FIG. 1 is a block diagram showing one embodiment of the present invention.
The pulsed laser light generated from the laser light source 1 intermittently driven by the pulse driving device 15 passes through the beam splitter 10 and is condensed by the collimator 2 to measure the amount of the substance on the surface of the subject 3. Directed to position. Here, it is assumed that the subject is a practical insulator attached to a power transmission tower.

When the actual insulator is the subject, it is preferable to set the laser beam irradiation position to a surface position where salt is most likely to adhere in consideration of the wind direction and the topography. According to a conventional experiment, the measurement point, that is, the laser beam irradiation position is, for example, a leeward portion of a fold formed on the back surface of the insulator and a surface on the center side of the insulator is appropriate.

When a material at that position is heated and evaporated (sublimated) by laser light irradiation, light (radiation radiation) having a wavelength specific to the material is generated by thermal excitation, resonance absorption, multiphoton excitation, plasma-induced excitation, etc. ) Is generated. In the case of salt attached to the insulator surface, light emission due to thermal excitation of Na atoms (Na
D ₁ line = 589.6 nm or D ₂ lines = 589.0nm) occurs.

The emitted light is captured by a telescope 4 and supplied to an optical filter 6 through an aperture 5 for limiting an incident angle. The wavelength selected by the optical filter 6 (in this case, D ₁ line or
The light of D ₂ line) is converted by the photoelectric converter 7 into an electric signal.

On the other hand, light obtained by filtering ambient light or light from the vicinity of the laser light irradiation position by the second optical filter 8 having the same filter characteristics as the optical filter 6 is also electrically converted by the second photoelectric converter 7. Converted to a signal. The output signals of the two photoelectric converters 7 and 9 are supplied to a noise elimination device 11, where noise components included in the output signals of the photoelectric converter 7 are removed.

In practice, the measurement signal of the photoelectric converter 7 is
Is subtracted to remove an error component caused by ambient light. The measurement signal of the photoelectric converter 7 from which noise has been removed is supplied to the zero detector 12.

When the pulsed laser light from the laser light source 1 is repeatedly generated, the attached salt at the laser light irradiation position is gradually evaporated and reduced, so that the light emission due to the thermal excitation of the Na atom also becomes as shown in FIG. When the salt is gradually (exponentially) reduced and substantially all of the attached salt is evaporated, the output signal of the photoelectric converter 7 from which noise has been removed becomes substantially zero.

At this time, the zero detector 12 generates an output, and in response to this, the operation of the pulse driving device 15 is controlled, and the generation of pulsed laser light from the laser light source 1 is stopped.

All the laser light amounts generated so far are accumulated by the laser light amount accumulator 13. In this embodiment, the beam splitter
The laser light divided by 10 is guided to a light quantity detector 18 to be converted into an electric signal, and this is accumulated by a laser light quantity accumulator 13. Instead, the amount of laser light radiated for each pulse may be fixed, and the number of radiated pulses may be integrated to obtain the accumulated value of laser light. Further, the thermal excitation light emission, that is, the output of the noise removing device 11 can be accumulated by the light emission amount accumulator 19.

Thereafter, the output of the accumulator 13 or 19 is supplied to the conversion output device 14. The conversion output device 14 is provided with a conversion curve of the cumulative value of the irradiation laser light amount or the excitation light emission amount which is obtained in advance experimentally or empirically with respect to the salt content (an example of which is shown in FIG. 3). The amount of attached salt can be obtained from the input accumulated value and output. When the amount of attached salt is equal to or more than the predetermined value, an alarm or a cleaning request signal can be generated.

In this case, the irradiation position of the laser beam is not limited to one point, but several points are selected and the above-described measurement is repeatedly performed. Based on these measured values (for example, by taking the average or the maximum value), The amount of adhesion may be obtained.

According to this embodiment, the attached salt on the surface of the actually used insulator attached to the power transmission tower can be directly measured in a non-contact and remote manner in a normal operation state where a high voltage is applied, so that the measurement is safe. Not only can it be carried out quickly and easily, but also the pilot insulator itself is not required, and the number of installation and removal steps, the equipment for wetting, and the number of steps are not required, so that the management cost is significantly reduced.

In addition, since the salt attached state on the surface of the insulator is not substantially disturbed at positions other than the laser irradiation position, the same measurement is performed at a position excluding the previous laser irradiation position (but preferably in the vicinity thereof) at every scheduled period. The effect of facilitating monitoring of the change over time in the fouling (salt attached) state can also be expected.

(Modification) In the above embodiment, the laser beam irradiation is continued until substantially all of the attached salt is evaporated, but the number of times of generation of the pulsed laser beam and the emission intensity due to the thermal excitation of Na atoms are reduced. Has a relationship as shown in FIG. 2, and since this relationship can be known in advance, the amount of laser beam irradiation and the number of times required until substantially all of the attached salt is evaporated using this relationship. It is also possible to estimate the laser light amount or the cumulative value of the laser light amount or the thermal excitation light emission directly from the attenuated state of the thermal excitation light emission intensity.

In the above embodiment, the independent optical filter 8 and the photoelectric converter 9 are provided for removing noise.
If the related parts 11 are configured as shown in FIG. 4, they can be omitted and the configuration can be simplified.

In FIG. 4, the output of the photoelectric converter 7 is supplied to the noise removing device 11A via the changeover switch 16. The pulse driving device 15 intermittently drives the laser light source device 1 to generate a pulsed laser beam, and in synchronization with this, a changeover switch
16 is alternately switched between the terminal S side and the N side.

If the changeover switch 16 is connected to the terminal S during the period of generation of laser light, and connected to the terminal N during the pause of laser light, the terminal S emits light by thermal excitation of Na atoms and the surroundings. The signal corresponding to the sum of the light (that is, the noise light)
Further, since a signal depending only on the ambient light is generated at the terminal N, a noise-removed signal similar to that described above with reference to FIG. .

In the above, the example in which the present invention is applied to the measurement of the amount of salt attached to the insulator has been described. However, it is clear that the present invention can be applied to other substances as long as they generate thermally excited light emission. Will.

(Effects of the Invention) As is clear from the above description, according to the present invention, the amount of the substance adhering to the surface of the object can be remotely measured without contact, so that the measurement can be performed safely, quickly, and easily. Can be performed. In addition, since non-contact measurement can be performed, there is little influence or disturbance on the surface state of the test object, and measurement and monitoring of a change with time in the amount of the test substance attached can be performed.

In particular, when the present invention is applied to a practically used insulator attached to a transmission line tower or the like, in a normal operation state where a high voltage is applied, it is possible to directly and remotely measure the salt attached to the surface without contact. Not only can the measurement be performed safely, quickly and easily, but also the pilot insulator itself is not required, and there is no need for installation and removal, as well as equipment for wetting, so the management cost is significantly reduced. Is done.

[Brief description of the drawings]

FIG. 1 is a block diagram showing one embodiment of the present invention. FIG. 2 is a graph showing an example of the relationship between the amount of thermal excitation light emission (intensity) and the number of pulsed laser beam irradiations when the substance to be measured is a salt. FIG. 3 is a graph showing an example of the relationship between the cumulative value of the irradiation laser beam and the amount of the substance to be measured (salt). FIG. 4 is a block diagram showing a main part of another embodiment of the present invention. 1 ... laser light source, 2 ... collimator, 3 ... subject,
4 ... telescope, 5 ... aperture, 6, 8 ... optical filter, 7, 9 ... photoelectric converter, 10 ... beam splitter, 11, 11A ... noise removal device, 12 ... zero detector, 13
…… Laser light amount accumulator, 14 …… Conversion output device, 15 …… Pulse drive device, 18 …… Light amount detector, 19 …… Emission amount accumulator

Continuation of the front page (56) References JP-A-60-179633 (JP, A) Shinichiro Fujiyoshi, "Development of Laser Salt Observation System", Laser Research, Japan Society of Laser Science, Vol. 20, No. 12, Issued December 29, 1992, pp. 955-962 (58) Fields surveyed (Int. Cl. ⁶ , DB name) G01N 21/62-21/74

Claims (2)

(57) [Claims] 1. A laser light source for generating laser light, means for directing and irradiating the laser light to the surface of a test object, and means for generating the laser light from a test substance at a laser light irradiation position on the surface of the test object Means for measuring the intensity of the specified wavelength light, means for calculating the accumulated light emission amount of the specific wavelength light until the intensity of the specific wavelength light is attenuated to zero, and accumulation of the obtained specific wavelength light. Means for determining the amount of the test substance which has generated light of a specific wavelength on the surface of the test object based on the amount of light emission. 2. A method of irradiating a laser beam directed to a surface of an object to heat and evaporate a test substance on the surface of the object,
A step of generating an excitation light emission having a wavelength specific to the test substance; anda step of detecting a cumulative light intensity value of the excitation light emission generated before the excitation light emission is attenuated and disappeared. Obtaining a quantity of the test substance on the surface from the relationship between the cumulative light quantity of the excitation light emission and the quantity of the test substance.