JP2000131373A - Insulator contamination detecting sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To downsize an insulator contamination detecting sensor and enable the contamination detection in such condition that a contamination detecting surface is frosted or iced. SOLUTION: Two electrodes 10, 11 are disposed on a contamination detecting surface 9 of an insulation board 2 with a Peltier module 1 provided on the other surface. A d-c current of a polarity for cooling the board is fed from a d-c power source 6 to the Peltier module to dew the detecting surface 9 and then the polarity of the power source is changed to heat the board through the Peltier module, thereby moistening the contamination detecting surface to make contaminants conductive even when the dew is iced. A voltage is applied between the electrodes from the power source 7 to measure the leak current, thereby detecting the contamination degree.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sensor for detecting the degree of contamination on the surface of an insulator used for a transmission and substation equipment.

[0002]

2. Description of the Related Art Insulators used for power transmission and transformation equipment installed outdoors have their surfaces contaminated by the attachment of salt and the like. If condensation occurs on the surface of the insulator due to rainfall or a change in temperature while the surface of the insulator is contaminated, the surface of the insulator becomes conductive and the insulation performance decreases. Therefore, it is necessary to detect and monitor the pollution degree of the insulator.

As a conventional method for detecting the degree of contamination, there is a dew-point type contamination detector. In this method, an electronic cooling element is incorporated in a pilot insulator having the same shape as a real insulator whose contamination degree is to be detected. When detecting the degree of contamination, the pilot insulator is cooled to a temperature equal to or lower than the dew point temperature by the electronic cooling element, and moisture in the air is collected on the insulator surface. Then, the contaminants adhering to the pilot insulator are forcibly wetted and have conductivity. In this state, a measurement voltage is applied to the insulator to measure the leakage resistance.

[0004]

In the above-mentioned conventional method for detecting the degree of contamination of an insulator, the apparatus is large and requires a large power supply. In addition, when the detection is performed at a temperature below the freezing point, frost and icing occur on the stain detection surface, so that the measurement cannot be performed with the stain surface wetted. SUMMARY OF THE INVENTION It is an object of the present invention to reduce the size of an insulator fouling detection sensor and to detect fouling even in a situation where frost or icing occurs on the fouling detection surface.

[0005]

SUMMARY OF THE INVENTION The present invention has been made to achieve the above object. The present invention provides two electrodes disposed on one surface of an insulating substrate, a Peltier module provided in contact with the other surface of the insulating substrate, a power supply for applying a voltage between the two electrodes, and a power supply for applying a voltage between the two electrodes. Means for measuring a leakage current flowing on the surface of the insulating substrate by the applied voltage, a DC power supply for supplying a DC current to the Peltier module, and heating after cooling between the two electrodes,
A switching means for inverting the polarity of the DC current and supplying it to the Peltier module constitutes an insulator fouling detection sensor.

[0006] The insulator fouling detection sensor of the present invention is placed in the same environment as an actual insulator whose fouling degree is to be detected. As a result, the fouling detection surface on which the two electrodes are disposed is fouled to the same extent as the actual insulator. At the time of detecting the degree of contamination, a direct current is supplied to the Peltier module to cool and condense the contamination detection surface on which the two electrodes are arranged. Thereafter, the polarity of the direct current flowing through the Peltier module is reversed to heat the contamination detection surface. By this heating, even if the fouling detection surface is frosted or iced, it can be forcibly brought into a wet state.

In this wet state, an AC voltage is applied between the two electrodes. Then, a leakage current having a value corresponding to the degree of contamination flows on the contamination detection surface. The degree of contamination of the actual insulator is detected by measuring the leakage current by the measuring means.

[0008]

Embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a longitudinal sectional view showing a configuration of an insulator fouling detection sensor to which the present invention is applied. The Peltier module 1 is held on the upper surface of the stain detection board 2 by being sandwiched between the stain detection board 2 and the supply / radiation block 3. The lower surface of the stain detection board 2 is a stain detection surface 9. When the DC current is supplied, the Peltier module 1 cools or heats the contamination detection surface 9 according to the polarity of the DC current. Electrodes 10, 11, and 12 are arranged on the stain detection surface 9.

The stain detection board 2 is held on a conversion box 5 by a support pipe 4. The Peltier module 1 and the electrodes 10 to 12 are connected by a lead wire passing through the support pipe 4.
Connected to terminal 16 in conversion box 5. The lead wires of the electrodes 10 to 12 pass through the core of the current transformer 8 on the way, and
Function as a primary winding. The secondary winding of the current transformer 8 is connected to an external measuring instrument (not shown) through a terminal 16.

A control box 15 is provided, and a DC power supply 6 for the Peltier module 1 and an AC power supply 7 for the electrodes 10 to 12 are provided.
And the controller 14 are stored. Controller 14
Is configured by a microcomputer or the like, performs on / off control of the DC power supply 6 and the AC power supply 7, and controls switching of the polarity of the DC power supply 6. FIG. 2 is a diagram illustrating a configuration of a stain detection surface 9 which is a lower surface of the stain detection substrate 2.

The stain detection surface 9 has three concentric electrodes, an outer electrode 10 and an inner electrode 1 as stain detection electrodes.
1. The intermediate electrode 12 is formed. An AC voltage is supplied from the AC power supply 7 to the outer electrode 10 and the inner electrode 11. The AC power supply 7 is turned on and off under the control of the controller 14. Although the intermediate electrode 12 can be omitted,
It is provided so that the maximum amount of contamination on the contamination detection surface 9 can be detected.

The insulator fouling detection sensor is disposed in the vicinity of an actual insulator for detecting fouling. As a result, the insulator contamination detection sensor is placed in the same environment as the actual insulator. The contaminated material 13 containing salt and the like carried by the wind and the like adheres to the surface of the actual insulator and also accumulates on the contamination detection surface 9 of the contamination detection substrate 2. In this example, since the contamination detection surface 9 is formed on the lower surface, it simulates the state of contamination of the lower surface of the actual insulator.

The operation of the insulator fouling detection sensor when detecting fouling will be described with reference to FIG. First, the controller 14
During the predetermined time t _P, to operate the DC power supply 6. At this time, the polarity of the DC power supply 6 is switched to the direction in which the Peltier module 1 cools the stain detection board 2. This cooling causes dew condensation on the fouling detection surface 9 and moistens the fouling detection surface 9. If the temperature is below freezing, or if the cooling period is too long and there is overcooling, icing or frosting occurs on the stain detection surface 9 and a wet state cannot be obtained.

Thereafter, the controller 14 controls the DC power source 6
Switch the polarity of. The Peltier module 1 heats the stain detection board 2 by supplying DC currents having different polarities. This heating causes icing on the stain detection surface 9,
When frost is formed, the frost is melted and the stain detection surface 9 is wetted to make it conductive. This heating is performed for a short time of about one minute, and deterioration of the electrodes 10 to 12 due to the heating is minimized.

Next, the controller 14 turns on the AC power supply 7 while keeping the DC power supply 6 on after a predetermined time t _C has elapsed after the start of heating and the frost or ice has melted. As a result, an AC voltage is applied between the outer electrode 10 and the inner electrode 11, and a leakage current flows through the stain detection surface 9 in a wet state. This leakage current is detected by the current transformer 8. Although the voltage value of the AC power supply 7 is constant, the value of the leakage current is a value corresponding to the contamination state of the contamination detection surface 9. Therefore, by measuring the leakage current detected by the current transformer 8 with a measuring device, the contamination state of the contamination detection surface 9 can be known. Since the contamination state of the contamination detection surface 9 is almost the same as the contamination state of the actual insulator, the contamination state of the actual insulator can be inferred.

After the measurement by the measuring instrument is completed, the controller 14 turns off the DC power supply 6 and the AC power supply 7 to
Stops the detection of insulator contamination at the time. Thereafter, for a predetermined period t
_The above detection operation is repeated for each _T. FIG. 4 is a diagram for explaining the reason why the intermediate electrode 12 is provided. The intermediate electrode 12 fixes the potential at an intermediate position between the outer electrode 10 and the inner electrode 11. The stain detection surface 9 is not always uniformly stained, and the stained portions 17 and 18 may be unevenly present. In this case, between the outer electrode 10 and the inner electrode 11,
Since there is a portion with low contamination and high resistance, only a small leakage current flows despite the presence of the contamination portion.

When the potential at the intermediate position is fixed by the intermediate electrode 12, a route is formed between the outer electrode 10 and the inner electrode 11 through the soiled portions 17, 18 as shown. That is, by providing the intermediate electrode 12, the maximum amount of contamination on the contamination detection surface 9 can be measured. In addition, the intermediate electrode 1
By providing not only one but also a plurality of 2, the maximum contamination amount can be measured more reliably.

FIGS. 5 and 6 are views showing modified examples of the stain detection electrode. The electrodes 10 to 12 for detecting contamination are not limited to concentric circles, but may have other shapes. In the example shown in FIG. 5, the outer electrode 10, the inner electrode 11, and the intermediate electrode 12 each have a square shape. In the example shown in FIG. 6, each of the electrodes 10 to 12 has a square shape as a whole, and then the electrodes are formed in a wave shape.
This diffuses the potential gradient in the vicinity of each of the electrodes 10 to 12, and can prevent the electrodes from being consumed and deteriorated due to a sudden change in the potential gradient.

[0019]

According to the present invention, the insulator fouling detection sensor can be downsized. Further, even in a situation where frost or icing occurs on the stain detection surface, the stain can be detected.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of an insulator fouling detection sensor according to an embodiment of the present invention.

FIG. 2 is a view showing a stain detection surface of the stain detection board in FIG. 1;

FIG. 3 is a time chart for explaining the operation of the insulator contamination detection sensor of FIGS.

FIG. 4 is a view for explaining the reason for providing an intermediate electrode in FIG. 2;

FIG. 5 is a view showing a modification of the electrode for detecting contamination in FIG. 2 (part 1).

FIG. 6 is a diagram showing a modification of the electrode for detecting contamination in FIG. 2 (part 2).

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Peltier module 2 ... Contamination detection board 3 ... Supply / radiation block 4 ... Support pipe 5 ... Conversion box 6 ... DC power supply 7 ... AC power supply 8 ... Current transformer 9 ... Contamination detection surface 10 ... Outer electrode 11 ... Inner electrode 12 ... intermediate electrode electrode 13 ... dirt 14: controller 15 ... control box 16 ... terminal 17,18 ... dirty part

Continued on the front page F term (reference) 2G015 AA20 BA02 CA04 CA05 CA06 2G028 AA01 AA03 BB05 CG03 DH02 HM05 HN09 KQ02 2G060 AA09 AA20 AE07 AE40 AF03 AF07 AG06 AG10 EA07 EB07 HA02 HE03 5G331 BC01 BC04 BC09 BC14

Claims (1)

[Claims] 1. two electrodes disposed on one surface of an insulating substrate; a Peltier module provided in contact with the other surface of the insulating substrate; a power supply for applying a voltage between the two electrodes; Means for measuring a leakage current flowing on the surface of the insulating substrate by a voltage applied between the electrodes, a DC power supply for supplying a DC current to the Peltier module, and heating after cooling between the two electrodes, Switching means for inverting the polarity of the DC current and supplying the DC current to the Peltier module.