JPS6130710B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for controlling an appropriate amount of moisture in wet-type insulator stain measurement.

BACKGROUND ART Accidents in which insulators used in power transmission lines, etc. are naturally contaminated by sea salt and the like and cause flashing are widespread, and preventive measures have become important in the power supply. In order to take preventive measures, it is important to understand the amount or state of contamination of the insulator. However, it is difficult to directly measure the amount of contamination on actually used insulators, so a common method is to estimate the amount of contamination on a pilot insulator that has been exposed to nature under the same conditions as the actually used insulator. It is true.

Conventional methods for measuring contaminants attached to pilot insulators include washing the contaminants from the underside of the insulator with a brush or measuring the amount of contaminants, or artificially moistening the insulator with contaminants still attached to the insulator and measuring its conductivity. There are methods to measure soiling by taking advantage of the fact that the degree of soiling differs depending on the amount of soiling. The latter method is
Since the measurement is performed while the soiled matter remains on the pilot insulator without being washed away, it is possible to measure changes in the degree of fouling over time, which is advantageous in terms of pollution control, and also has the advantage of being able to perform automatic measurement and remote measurement.

In stain measurement using this wet method, moisture is applied to the underside of the pilot insulator using methods such as steam, spray, or mist, and the amount of contamination is detected by moistening the soiled material and measuring the conductivity between electrodes provided on the underside of the insulator. However, if the degree of infiltration is low, the conductivity cannot be measured because the contaminants will not dissolve, and if it is too high, water droplets will drip from the bottom of the insulator, and the contaminants will fall with the water droplets, making accurate measurements impossible. Therefore, the moisture level must be appropriate. In the past, methods such as relying on the intuition of the measurer to determine the degree of humidity or keeping the total amount of moisture deposited constant were used;
Since the appropriate humidity level changes depending on the humidity and degree of contamination, it has been difficult to obtain an accurate moisture level.

It is an object of the present invention to provide a method that can solve these conventional problems and optimally control the amount of wetting.

To explain the present invention below, when an electrolyte and conductive contaminants are moistened with water, the conductivity generally tends to increase as the wetting progresses. FIG. 1 illustrates this relationship. As wetting further progresses, the conductivity takes on a nearly constant value,
There is a proportional relationship between this value and the amount of adhered contaminants. The principle of measurement is to measure the amount of attached contaminants based on this relationship. However, in a state before this conductivity reaches a nearly constant value, that is, when the amount of wetness is small, the measured values will vary, which is undesirable.
Furthermore, if the degree of humidity is further increased, it becomes over-humidified, resulting in dripping of contaminants. That is, it is desirable to wet the conductivity with an appropriate amount ranging from a wet amount that makes the conductivity substantially constant to a degree that does not cause dripping, and then perform the measurement. FIG. 2 shows the relationship between the amount of adhered moisture (the amount of vapor in the case of wetting by steam) and the conductivity. 1 is when the insulator surface is moist to some extent, and 2 is when it is dry.
In this way, proper wetting varies depending on the wetness state of the insulator surface before wetting starts. For example, if the amount of adhering moisture is supplied in accordance with case 2, in case 1 there is a risk of contaminants dripping due to overwetting. Combined with case 2, the amount of wetting is insufficient and cannot be used as a measurement value, making it extremely difficult to achieve appropriate wetting according to various conditions. However, when we look at the change in conductivity with respect to the amount of adhered moisture, the change becomes smaller as it approaches proper moisture, and this trend is the same regardless of the wet state of the insulator before wetting begins. The present invention utilizes this to control the amount of wetting. That is, the amount or rate of change in the conductivity of the soiled material as the wetting progresses is detected, and when the change becomes less than a certain value, it is determined that proper wetting has been achieved, and the amount of wetting is controlled. Second
In the figure, 1' and 2' indicate changes in the rate of change in cases of 1 and 2, respectively. Due to this principle, it is possible to control the humidity to be appropriate according to the amount of contamination without being affected by the wet state of the insulator before measurement, the amount of contamination, or other factors.

FIG. 3 is a block diagram showing an embodiment for automating the control method of the present invention.
is an electrical resistance detector. This converts electrical resistance into voltage. 5 is a starting comparator; when the electrode becomes wet and the attached contaminants begin to dissolve, the electrical resistance gradually increases and the output voltage of the detector 4 increases, but when the output exceeds a certain value This is to activate the control circuit after the temperature is reached. 7 shows the starting voltage setting device. Reference numeral 6 denotes a timing pulse generator which generates a verification pulse Pc with a pulse width of 10 msec once every several tens of seconds, and a sampling pulse Ps of several msec generated when the pulse ends.
This method attempts to control the amount of moisture by capturing changes in voltage due to the time difference in pulse periods. A memory 9 stores the output voltage of the detector 4 using sampling pulses. Thereafter, the differential amplifier 10 amplifies the difference between the output voltages of the detector 4 and the memory 9, and the comparator 11 compares the difference with a specified value determined by the amount of change controlled. Numeral 12 is a multiplier which activates the control circuit and stops the steam generator 13 on condition that the amount of change has reached a specified value. 8 indicates the specified value setting device. With this control circuit, further adhesion of moisture can be stopped when the dissolution of the adhered contaminants is completed or almost completed, and it is possible to prevent contaminants from dripping due to excessive moisture, such as when it is wet from the beginning.

As described above, the present invention not only makes it possible to control the amount of moisture on the lower surface of the insulator, which has not been done in the past, but also makes it possible to reduce the amount of moisture necessary to dissolve the adhered contaminants to the amount of contaminants. Since it can be supplied according to the requirements, it plays a very large role in improving the performance of measuring the amount of insulator contamination.

[Brief explanation of the drawing]

Figure 1 is a graph showing the relationship between wetness and conductivity.
FIG. 2 is a graph showing changes in conductivity and the rate of change in conductivity with changes in the amount of adhering moisture, and FIG. 3 is a block diagram showing an example of automating the method of the present invention.

Claims (1)

[Claims] 1 An electrode for measuring the amount of contamination is placed on the underside of the pilot insulator, and when measuring the amount of contaminants adhering to the underside of the insulator, water vapor, etc. is attached to the underside of the insulator, and the moisture is used to moisten the insulator. In wet insulator stain measurement, which takes advantage of the fact that the amount of contaminants applied is expressed as the conductivity between the electrodes, the conductivity between the electrodes is sequentially detected from the start of wetting, and the conductivity between the electrodes is sequentially detected. A method for controlling an appropriate amount of wetting, characterized by stopping a wetting operation when a rate of change in conductivity falls below a predetermined value.