JP2556055B2 - Hot wire insulation diagnostic device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention continuously monitors the degree of deterioration of insulation without stopping the operation of production equipment, and determines the degree of deterioration of electrical equipment and the remaining life of a live line. The present invention relates to an insulation diagnostic device.

[Conventional technology]

The insulation of electrical equipment deteriorates due to heat, discharge, and other factors, eventually leading to dielectric breakdown. Therefore, in order to maintain the reliability of the electric machine and the reliability of the equipment equipped with the electric machine, the insulation diagnosis is often performed by regularly stopping the operation as a part of prevention and maintenance.

However, in the conventional insulation diagnostic methods such as direct current test method, alternating current test method, dielectric loss tangent test method, partial discharge test method and the like, only the test voltage up to the rated voltage of the device under test can be applied. Therefore, changes in the obtained characteristics are small. Moreover, since the test result is affected by the environmental conditions at the time of the test, particularly the humidity, it is only empirically inferring the deterioration state without being able to stably cope with the insulation deterioration. In addition, since the operation of the equipment is stopped and the measurement is performed, it is not possible to continuously monitor the deterioration status.

In order to solve these problems, electrodes are installed on the surface of the insulating layer of high-voltage equipment, and partial discharge pulses as a precursor phenomenon of dielectric breakdown, a method of continuously detecting without stopping the operation of the equipment, There has been proposed a method of embedding an ultrasonic oscillator in an insulating layer and continuously detecting insulation deterioration by ultrasonic flaw detection.

[Problems to be solved by the invention]

However, in these methods, a conductive material is placed on the surface of the insulating layer, or a conductive material is embedded inside the insulating layer to take out the leads, which may adversely affect the insulation. Moreover, the countermeasure against insulation deterioration is still insufficient.

Further, a method of continuously detecting the leakage current flowing through the ground line has been proposed, but it is above the operating voltage of the device and its change is small.

As described above, the conventional method includes various problems such as the operation of the device under test has to be stopped, and the actual insulation deterioration cannot be dealt with.

SUMMARY OF THE INVENTION It is an object of the present invention to solve these problems and to provide a hot wire insulation diagnostic apparatus that can perform repair and update processing for maintenance of electric devices and the like with high reliability in a database.

[Means for solving problems]

In order to achieve the object, the hot wire insulation diagnostic device of the present invention has a photodetection probe provided with an optical fiber for illumination and an optical fiber for receiving light provided inside or around an insulating layer, and a standard connected to the photodetection probe. A light source, a photoelectric conversion element which is connected to the light receiving optical fiber and receives reflected light from a surface to be measured corresponding to a wavelength of standard light, and a colorimetric operation section to which an output of the photoelectric conversion element is input. The system, a function generator that stores the relationship between the previously obtained color change and the degree of deterioration of the insulating layer, an output from the function generator, and an output from the colorimetric calculator of the color measurement system. Based on the above, the deterioration degree / remaining life calculation section for calculating the deterioration degree and remaining life of the insulating layer, and an alarm for generating a predetermined signal based on the calculation result of the deterioration degree / remaining life by the deterioration degree / remaining life calculation section・ Includes display And wherein the are.

[Action]

Insulation deterioration of electrical equipment is mainly caused by heat deterioration. In general, the change in the chemical structure amount due to the thermal deterioration of the insulating layer follows the chemical reaction kinetics, and the change in the color of the insulating material is uniquely determined by the chemical structure amount.

Therefore, if the change in the chemical structure amount X of the insulating material due to thermal deterioration follows the chemical reaction kinetics, the chemical structure amount X is represented by the following equation (1).

Here, t is the deterioration time, A is the frequency factor, ΔE is the activation energy, R is the gas constant, T is the absolute temperature of deterioration, and g (X) is a function representing the reaction mechanism.

Assuming that the deterioration of the insulating material progresses from time 0 to t and the chemical structure amount changes from X ₀ to X, the following expression (2) is obtained by integrating the expression (1).

The integration on the right side of this equation (2) is called the conversion time θ because it has a dimension of time.

Therefore, the equation (2) can be rewritten as follows.

On the other hand, in the deterioration region where the function g (X) representing the reaction mechanism and the frequency factor A are constant, even if the deterioration occurs under various temperature conditions, if the conversion time θ is equal, the change in the chemical structure amount X is also equal, The following expression (5) is established.

θ = f (X) (5) Further, if the value that quantitatively represents the color of the insulating material, that is, the colorimetric value P is uniquely determined by the chemical structure, P = h (X) (6) ), The following equation (7) is established between the conversion time θ and the color specification value P.

θ = f {h ⁻¹ (P)} (7) Therefore, by measuring the change in the colorimetric value P of the insulating material, the converted time θ that is a measure of the degree of thermal deterioration can be obtained. Furthermore, when the conversion time at the life point of the same insulation configuration obtained in advance is θ _e , the difference Δθ from the conversion time θ obtained from the color change is the conversion time corresponding to the remaining life. That is, this remaining life Δθ is expressed by the following equation (8).

As seen from this equation (8), the remaining life is obtained as a function of temperature and time. Therefore, if the temperature condition after time t is determined, the remaining life time Δt (= t _e −t) can be obtained.

〔Example〕

In the following, by embedding the light detection probe in the insulating layer of the rotating machine insulating wire ring, the present invention will be described with reference to an example of a live line insulation diagnostic device due to a color change due to thermal deterioration of the resin impregnated in the insulating layer. This will be specifically described.

FIG. 1 is a schematic diagram of a hot-line insulation diagnostic apparatus of this embodiment, and FIG. 2 is a sectional view taken along line I-I thereof.

In this live line insulation diagnostic device, the photodetection probe 4 is set on the main insulating layer 3 between the conductor 1 and the protective insulating layer 2 and then impregnated with epoxy resin. Then, the illumination optical fiber 5 of the light detection probe 4 is connected to the standard light source 6, the light receiving optical fiber 7 is connected to the photoelectric conversion element 8, and the output of the photoelectric conversion element 8 is input to the colorimetric calculation unit 9. Further, the output from the function generator 10 and the output from the colorimetric calculator 9 that store the color change and the degree of deterioration of the insulating layer that have been obtained in advance are input to the deterioration / remaining life calculator 11 and the deterioration is calculated. Degree / remaining life calculator
The output of 11 is connected to the alarm / display unit 12.

In the hot-wire insulation diagnostic device having this configuration, when the temperature of the wire ring rises due to the operation of the equipment, the epoxy resin with which the main insulating layer 3 is impregnated changes color. This discolored state is the standard light source 6
The light can be detected by irradiating the main insulating layer 3 with light from the illuminating optical fiber 5 and receiving the reflected light on the photoelectric conversion element 8 via the light receiving optical fiber 7.

FIG. 3 shows the color change due to the deterioration of the epoxy resin impregnated in the main insulating layer 3 with respect to the color of the undegraded epoxy resin in the (L ^* , a ^* , b ^* ) color system (ΔE ^* ab). It is represented by. In the figure, ○ is 180 ℃, ● is 200
Values are shown when they are deteriorated at each temperature.

As is clear from FIG. 3, the color difference ΔE ^* ab increases as the epoxy resin deteriorates. Then, between the conversion time θ, which is a measure of deterioration, and the color, the above equation (7)
Since there is a unique relationship as indicated by, the conversion time θ that is a measure of deterioration can be obtained based on this color change.

Furthermore, the conversion time θ _e at the life point with the same insulation configuration
Is calculated, the conversion time Δθ (= θ
_e- θ) is obtained, and if the temperature conditions thereafter are determined, equation (8)
The time Δt (t _e −t) of the remaining life can be calculated. For example, if the color difference ΔE ^* ab after operating for a predetermined time is 26, the conversion time θ of deterioration from the curve A in FIG.
Is 1.2 × 10 ^-8 seconds.

In addition, the insulated wires with the same insulation structure have a heat resistant life of 155 ° C.
^Assuming that it is 4 × 10 ⁻⁴ hours, the converted time θ _{e at} the life point is 2.1 × 10 ⁻⁸ seconds from the equation (3). The activation energy ΔE for deterioration at this time is 31 kcal / mol.
Therefore, the conversion time Δθ (θ _e −θ) of the remaining life is 9 ×
^Assuming that the equipment is operated at 155 ° C for 10 ^-9 seconds, the remaining life time Δt = (t _e -t) is 1.
It will be 7 × 10 ⁴ hours.

The deterioration degree / remaining life calculation unit 11 performs such calculation, sends the result to the alarm / display unit 12, and generates a signal notifying the deterioration state of the insulating layer. Therefore, the worker
The state of the insulating layer can be grasped by this signal.

Since the optical fiber for the photodetection probe 4 is an insulator, the insulating property is not deteriorated by embedding the optical fiber in the main insulating layer 3. The light detection probe 4 can also be attached to the outer periphery of the insulating layer, and the color system other than the (L ^* , a ^* , b ^* ) color system described above can be used as the color system. It is also possible to directly use the reflected light amount of.

Furthermore, the hot-wire insulation diagnosis apparatus of the present invention can be applied to heat deterioration diagnosis of materials used for insulation other than electric equipment insulation.

〔The invention's effect〕

As described above, according to the hot-line insulation diagnostic device of the present invention, from the change in the color of the insulating layer measured by the photodetection probe embedded in the insulating layer or attached to the outer periphery of the insulating layer, the deterioration of the insulating layer The deterioration conversion time, which is direct information, can be obtained, and the deterioration degree can be continuously taken out as an electric signal without stopping the operation of the device. Therefore, it is possible to perform repairs and updates in maintenance in the database with high reliability and in a timely manner.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing a hot-line insulation diagnostic apparatus according to an embodiment of the present invention, FIG. 2 is a sectional view taken along the line II of FIG. 1, and FIG. 3 is a color difference ΔE ^* ab and a conversion time θ. It is a graph which shows the relationship of. 1: Conductor, 2: Protective insulation layer 3: Main insulation layer, 4: Photo-detection probe 5: Optical fiber for illumination, 6: Standard light source 7: Optical fiber for light reception, 8: Photoelectric conversion element 9: Colorimetric calculator, 10: Function generation part 11: Deterioration degree / remaining life calculation part, 12: Alarm / display part

Claims (1)

(57) [Claims] 1. A photodetection probe provided with an optical fiber for illumination and an optical fiber for receiving light provided inside or around an insulating layer, a standard light source connected to the photodetecting probe, and a standard light connected to the optical fiber for receiving light. Of the photoelectric conversion element that receives the reflected light from the surface to be measured corresponding to the wavelength of, the colorimetric system consisting of the colorimetric calculation unit to which the output of the photoelectric conversion element is input, and the change of the color obtained in advance A function generator that stores the relationship with the degree of deterioration of the insulating layer, and the degree of deterioration and remaining life of the insulating layer based on the output from the function generator and the output from the colorimetric calculator of the colorimetric system. And a warning / display unit for generating a predetermined signal based on the calculation result of the deterioration degree / remaining life by the deterioration degree / remaining life calculation unit. Live line insulation diagnostic device