JPH06207920A - Pollution detecting method - Google Patents

Abstract

PURPOSE:To correctly measure a leakage current between electrodes in a short time by predicting a saturation value of the leakage current based on a measured value of the leakage current in a relatively early stage after dampening is started and a selected characteristic curve. CONSTITUTION:Switching circuits 3, 4 in the lateral and longitudinal directions connected to each of many electrodes 2 on an insulating plate 1 are sequentially switched, and the selected electrode 2 is connected to a measuring resistance 8. When a current running in the resistance 8 is measured, a leakage current of the selected electrode 2 flows in the circuit, and an electromotine force proportional to the leakage current is generated in the resistance 8. A voltage value at both ends of the resistance is input by an operational device 10. The device 10 which stores characteristic curves of many shapes representing the change of the leakage current due to the ambient humidity after dampening is started selects a characteristic curve corresponding to the measured ambient humidity. The leakage current is measured while the insulating plate 1 is dampened. For instance, when the relative humidity is 65%, the leakage current saturates in about 300 seconds. However, a saturation value of the leakage current is predictable in a relatively short time, e.g. 100 seconds, from the value of the leakage current and the shape of the selected characteristic curve.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pollution detecting method used for grasping the amount of pollution of an insulator device which insulates and supports an overhead power transmission line.

[0002]

2. Description of the Related Art When the surface of an insulator device is polluted by the attached salt, its insulating property deteriorates. Therefore, in order to maintain an overhead power transmission line, it is necessary to always know the amount of contamination of the insulator device. For this reason, a stain detection sensor installed near the insulator device has been conventionally known.

A typical stain detecting sensor of this type is, for example, as disclosed in Japanese Utility Model Laid-Open No. Sho 62-88951, based on the resistance value between electrodes on the insulating plate, the equivalent salt deposition amount on the insulating plate. In this method, the insulating plate is electronically cooled at the time of measurement to cause dew condensation, and the leakage current is measured even when the electrodes are wet.

However, this type of conventional contamination detection sensor is
Since it is necessary to moisten the whole electrode widely distributed on the insulating plate, it is inevitable that a part is excessively moistened, and the leakage current between the electrodes changes and the measurement is performed. The accuracy tended to decrease. Further, if wetting is suppressed to avoid this, insufficient wetting partially occurs, the measurement ends before the leakage current between the electrodes reaches saturation, and there is a tendency that the measurement accuracy also deteriorates.

Therefore, the inventor of the present invention arranges a large number of electrodes 2 on the insulating plate 1 in a matrix form as shown in FIG. We are developing a pollution detection sensor that detects the leakage current between two electrodes and performs this operation between all electrodes and then calculates the equivalent salt deposition amount from the resistance value distribution on the entire insulating plate 1. is there.

However, in the stain detection method using this stain detection sensor, the measurement is finished within a certain time after the start of wetting,
Since the system adopted the measured value for each electrode at that time, the measured value may be the value before the leakage current reaches saturation because it is not sufficiently wet depending on the part on the insulating plate. However, there is a drawback that the detection accuracy is lowered. Also, to prevent this drawback, if each electrode is wetted for a sufficient time, it takes a long time for measurement and it becomes impossible to deal with rapid contamination such as during a typhoon. There is also a problem in that the electronic cooling device is required to be energized for a long time, and the battery for that purpose must be enlarged.

[0007]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems of the prior art and accurately measures the leakage current between a large number of electrodes widely distributed on an insulating plate in a relatively short time. It has been completed in order to provide a stain detection method that can be performed.

[0008]

SUMMARY OF THE INVENTION The present invention, which has been made to solve the above-mentioned problems, is to measure a leakage current by sequentially applying a voltage between a large number of electrodes arranged on an insulating plate to measure the insulating plate. When calculating the equivalent salt deposition amount from the distribution of measured values over the whole, select the characteristic curve that represents the change in leakage current after the start of wetting, and select it with the measured value of leakage current at a relatively early time after the start of wetting. It is characterized in that the saturation value of the leakage current is predicted on the basis of the obtained characteristic curve.

[0009]

In the present invention, the characteristic curve showing the change of the leakage current after the start of wetting draws a specific shape depending on the ambient humidity and the like, and the measured value of the leakage current at a relatively early stage after the start of wetting. And a saturation value is predicted based on this characteristic curve. For this reason, it is not necessary to measure the saturation value of the leak current by performing the wetting for a long time as in the conventional method,
It is possible to accurately know the amount of permeated salt that indicates fouling in a relatively short time. Along with this, it is possible to shorten the time for energizing the electronic cooling device for wetting the insulating plate, so that the battery for that purpose can be downsized.

[0010]

The present invention will be described in more detail below with reference to the illustrated embodiments. FIG. 1 is a diagram showing the overall structure of a stain detection sensor. Reference numeral 1 is an insulating plate made of a ceramic material similar to that of an insulator, and 2 is a large number of electrodes arranged in a matrix on the insulating plate 1. . Each electrode 2 is connected to horizontal and vertical switch circuits 3 and 4. Here, analog switches and relay contacts are used as the switch circuits 3 and 4. By sequentially switching these switch circuits 3 and 4, each electrode 2 is selected one after another and electrically connected to the line 5 and the line 6. It is possible to connect.

The lines 5 and 6 are connected to the measuring power source 7 and the measuring resistor 8 and the electrode 2 selected by the switch circuits 3 and 4 by measuring the current flowing through the measuring resistor 8.
The leakage current in the current flows through the circuit and is generated as an electromotive voltage proportional to the leakage current in the measuring resistor 8. The voltage value across the measuring resistor 8 is converted into a digital value by the A / D converter 9 and input to the arithmetic unit 10. A device for moistening the contaminants on the insulating plate 1 such as an electronic cooling device 11 using a solar cell as a power source is attached to the back surface of the insulating plate 1 so that the insulating plate 1 can be wetted. ing.

In the present invention, as shown in the flow sheet of FIG. 2, first, the ambient humidity at the time of measurement is measured. Since the characteristic curve showing the change of the leakage current after the start of wetting depending on the ambient humidity has a specific shape, it is possible to know what characteristic curve is drawn when the ambient humidity is known. For example, in Figure 3, the temperature is 25 ° C.
Is a characteristic curve of leakage current when relative humidity RT is 55%, 65%, and 85% in the case of. The arithmetic unit 10 stores a large number of such characteristic curve shapes, and selects a characteristic curve according to the measured ambient humidity.

Next, the energization of the electronic cooling device 11 is started, and the leakage current is measured while the insulating plate 1 is moistened and a number of electrode pairs are sequentially energized. For example, when the relative humidity is 65%, it takes about 300 seconds until the leakage current reaches the saturation value as shown in FIG. However, in the present invention, the saturation value of the leakage current is predicted from the leakage current value and the shape of the selected characteristic curve at a relatively early time after the start of wetting, for example, at the time of 100 seconds. This operation is performed for all the electrode pairs, and the obtained predicted values are statistically averaged to calculate the contamination amount.

For this reason, it is not necessary to carry out wetting until saturation is reached over a long period of time as in the conventional case, and the amount of pollution can be known very accurately in a relatively short period of time. Further, since the time for energizing the electronic cooling device can be shortened, it is possible to miniaturize the solar cell or the like serving as a power source.

In the flow of FIG. 2, leak currents are measured for all electrode pairs, but when saturation is not reached by predicting leak current values and ambient humidity measured within a certain set time. Alternatively, when there is almost no change in the measured value, the predicted value can be cancelled, and the contamination amount can be evaluated using only the other predicted values. If this method is adopted, it is possible to reduce the variation in the predicted value due to non-uniformity of wetting, and it becomes possible to make an evaluation based on only the ideal predicted value in a sufficiently wet state.

[0016]

As described above, according to the method of the present invention, the leakage current between a large number of electrodes widely distributed on the insulating plate can be accurately measured in a relatively short time, and the typhoon It can cope with rapid soiling such as time. Further, since the time for energizing the electronic cooling device or the like can be shortened, it is possible to miniaturize the solar cell or the like serving as a power source. Therefore, the present invention has an extremely large contribution to industrial development as a stain detection method that solves the conventional problems.

[Brief description of drawings]

FIG. 1 is a plan view showing a pollution measuring device.

FIG. 2 is a flow sheet of an example of the present invention.

FIG. 3 is a graph showing a characteristic curve of leakage current.

[Explanation of symbols]

 1 insulating plate 2 electrode

Claims (1)

[Claims] 1. When the voltage is sequentially applied between a large number of electrodes arranged on an insulating plate to measure the current and the equivalent salt deposition amount is calculated from the distribution of measured values on the entire insulating plate, wetting is started. Select a characteristic curve that represents the change of the leakage current afterwards, and predict the saturation value of the leakage current based on the measured value of the leakage current and the selected characteristic curve at a relatively early time after the start of wetting. A stain detection method characterized by the above.