JP2005203132A - Conductive glazed suspension insulator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a conductive glazed suspension insulator without fear of heat runup nor generation of fouling corona, even if it is used for a power line or the like along a coastline of intense staining. <P>SOLUTION: Of the conductive glazed suspension insulator with a semiconductive glaze on the surface, a direct current resistance value of its insulator single body is 150 MΩ to 900 MΩ. With this, heat runup as well as generation of the fouling corona is prevented when an insulation string is stained. Further, it is desirable if corrosion-resistant aluminum alloy plating is applied on a cap metal fitting 3 to improve corrosion resistance to natural corrosion as well as to prevent corrosion due to a direct current component in leak current flowing on the surface of the insulators, and a pin metal fitting 5 is made provided with a zinc sleeve 7 to improve corrosion resistance to natural corrosion as well as to prevent corrosion of a cement boundary part due to leak current flowing on the surface of the insulators. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a conductive insulator having a semi-conductive glaze applied to the surface of the porcelain.

  BACKGROUND ART As shown in Non-Patent Document 1, a conductive insulator suspended in which a tin oxide-based semiconductive glaze is applied to the porcelain surface of the suspended insulator has been known for a long time. Such a conductive insulator has a DC resistance value of 20 to 30 MΩ, and a normal suspension insulator (direct current) in a fouling environment due to the heat generation effect due to Joule heat of the current flowing in the glaze and the pressure equalization effect due to the conductive insulator. As compared with a resistance value of 2000 MΩ or more, the antifouling voltage characteristics and the effect of suppressing local discharge (fouling corona) can be exhibited.

  However, when a conventional insulator chain using a conductive insulator is installed in a highly fouled place where seawater splashes, a phenomenon called heat escape may occur. That is, if the DC resistance value is reduced to, for example, 10 MΩ or less due to the surface of the conductive insulator suspended, the heat generated by the leakage current is generated. If the amount of generated heat is larger than the amount of heat released, the temperature of the insulator surface increases. . Since the contamination occurs unevenly, this phenomenon starts with the most heavily contaminated insulators in the insulators. When the insulator surface is dried due to this temperature rise, the shared voltage of the insulator increases as compared with the shared voltage of other insulators in the insulator series, and the amount of heat generation further increases. As described above, thermal runaway is a phenomenon in which nonuniformity of contamination causes a concentration of a shared voltage to a specific insulator, and the temperature of the insulator rises significantly, resulting in insulator damage.

Therefore, a voltage limit is provided to prevent insulator damage due to such thermal escape, but when an experiment using simulated seawater is performed, a large temperature rise occurs even with an average shared voltage equivalent to ground voltage (about 7 kV / piece). May be observed. For this reason, there is a problem that the conductive fence suspension insulator cannot be installed on the transmission line on the coastline where the splash of seawater is splashed even though it has a feature of excellent anti-fouling voltage characteristics.
"Gaishi", published by the Institute of Electrical Engineers of Japan, June 15, 1983, p. 226

  The present invention solves the above-mentioned conventional problems, and maintains a superior corona suppression effect, and is a novel conductive suspension that does not cause heat escape even when used for a heavily fouled coastline transmission line. It was made to provide an eggplant.

  The present invention was made to solve the above-mentioned problems. In the conductive cage suspended insulator in which the glaze on the surface is semiconductive, the lower limit of the direct current resistance value of the conductive cage suspended insulator is set to 150 MΩ, and the insulator series is damaged. The thermal runaway at the time is prevented, and the upper limit of the direct current resistance value is set to 900 MΩ to prevent the occurrence of fouling corona. In particular, the insulator temperature heated by the leakage current at the time of fouling is preferably maintained at 150 ° C. or lower.

  Caps are also provided to improve corrosion resistance against natural corrosion due to sea salt pollution and industrial pollution, as well as to prevent corrosion due to the DC component in the leakage current flowing through the insulator surface, and to prevent corrosion at the cement boundary due to the DC component in the leakage current. It is preferable to apply corrosion-resistant aluminum alloy plating to the metal fitting and to provide a zinc sleeve on the pin metal fitting.

  In the conductive insulator of the present invention, the DC resistance value of the insulator alone is set to 150 to 900 MΩ, which is much higher than the conventional 20 to 30 MΩ. By setting the lower limit of the DC resistance value to 150 MΩ in this way, the heat generated by the leakage current can be reduced even when the surface is contaminated with salt and the surface is contaminated with salt. Smaller than. For this reason, the rise of the insulator temperature at the time of pollution is also suppressed to 150 degrees C or less, and it does not lead to heat escape. In addition, since the upper limit of the direct current resistance value is set to 900 MΩ, it is possible to prevent the occurrence of fouling corona that causes audible noise, which is excellent in terms of environmental measures.

  Further, as in the third and fourth aspects of the invention, the corrosion resistance against natural corrosion due to sea salt pollution, industrial pollution, etc. is improved by applying a corrosion-resistant aluminum alloy plating to the cap metal or providing a pin with a zinc sleeve. At the same time, it is possible to prevent corrosion due to the direct current component in the leakage current flowing on the insulator surface and corrosion of the cement boundary due to the direct current component in the leakage current, and to extend the service life.

  FIG. 1 is a cross-sectional view showing a conductive hanging suspension according to the present invention. Its dimensions and basic shape are the same as those of a normal suspended insulator. 1 is a porcelain insulator body having a number of ribs 2 on its lower surface, 3 is a cap fitting attached to its head with cement 4, 5 Is a pin fitting attached to the center portion thereof with cement 6. The surface of the porcelain insulator body 1 is decorated, but the conductive insulator of the present invention uses a glaze as a semiconductive additive, and the DC resistance of the insulator alone is 150 MΩ which is much higher than that of a conventional conductive insulator. It is characterized by a point of about 900 MΩ.

  In the present invention, the lower limit of the DC resistance value of the single insulator is set to 150 MΩ for the following reason. The present inventors conducted an energization test while spraying simulated seawater corresponding to seawater components on a large number of conductive insulators to determine the relationship between insulator temperature rise and insulator damage. As a result, it has been found that the rib 2 is most easily damaged by the temperature rise.

  As a result of increasing the test voltage stepwise to increase the leakage current and investigating the relationship with the rib 2 breakage while increasing the insulator temperature, as shown in FIG. It was confirmed that damage occurred. In more detail, considering the heat conduction time of the porcelain, the rib will not break if it is within 130 ° C x 4 minutes, and the shade (insulator body) will break if it is within 140 ° C x 12 minutes. Absent.

  Next, the ambient temperature was subtracted from the insulator surface temperature to determine the temperature rise, and the relationship with the DC resistance value was experimentally determined. The result is shown in FIG. When the regression equation is obtained from the experimental results, it is as shown in equation A in FIG. 3, and when 1σ is added, it becomes as in equation B.

  As a result, if the temperature rise is 110K (because the ambient temperature is 40 ° C., the insulator surface temperature is 150 ° C.) or less, there is no risk of breakage, and the temperature rise where the formula B representing the approximate expression + 1σ is the limit temperature It can be seen that the DC resistance value at the point where the line crosses the 110K line is 147 MΩ.

  In other words, if the lower limit of the DC resistance value of a single insulator is set to 150 MΩ, the rise in the insulator temperature due to leakage current will be suppressed below the breakage limit even under severe fouling conditions in which simulated seawater is sprayed on the insulator series. And can prevent damage to the insulator due to thermal escape.

  Thus, if the direct current resistance value of the insulator is increased, the risk of thermal escape can be prevented. However, when the DC resistance value of the insulator alone is increased, a fouling corona occurs near the normal insulator. Using several types of conductive insulators with varying DC resistance values, the occurrence of fouling corona was measured with a leakage current oscillogram, and if it was 900 MΩ, there was almost no fouling corona, but if it exceeded 1000 MΩ, It was confirmed that fouling corona was observed.

  For the above reasons, in the present invention, the lower limit of the direct current resistance value of the conductive insulators is set to 150 MΩ to prevent thermal escape when the insulators are damaged, and the upper limit of the DC resistance value is set to 900 MΩ to generate a fouling corona. Prevented.

  The cap metal fitting 4 shown in FIG. 1 is made of cast iron. However, the cap metal fitting 4 is subjected to corrosion-resistant aluminum alloy plating to improve corrosion resistance against natural corrosion and prevent corrosion due to leakage current flowing through the insulator surface. It is preferable. In addition, as shown in FIG. 1, a zinc sleeve 7 is provided around the pin fitting 5 that is more susceptible to current corrosion than iron, improving corrosion resistance against natural corrosion and preventing corrosion at the cement boundary due to leakage current flowing through the insulator surface. It is preferable to do. If measures against corrosion due to such leakage currents are taken, the service life of the conductive insulators of the present invention can be extended.

  As described above, the conductive insulator of the present invention has a DC resistance lower limit of 150 MΩ and an upper limit of 900 MΩ, so that it can be used as a transmission line for severely damaged coastlines while maintaining the corona suppression effect. This achieves the effect that there is no risk of thermal escape even when used.

It is sectional drawing which shows embodiment of this invention. It is a graph which shows the relationship between the surface temperature of an insulator and a failure | damage. It is a graph which shows the relationship between the DC resistance value of a single insulator, and a temperature rise.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Porcelain insulator main body 2 Rib 3 Cap metal fittings 4 Cement 5 Pin metal fittings 6 Cement 7 Zinc sleeve

Claims (4)

  For conductive insulators with semi-conductive glaze on the surface, the lower limit of the direct current resistance of the conductive insulator is 150 MΩ to prevent thermal escape when the insulator chain is damaged, and the upper limit of the direct current resistance value. A conductive cage suspension insulator characterized in that the occurrence of fouling corona was prevented by setting 900 MΩ.   2. The conductive insulator suspension according to claim 1, wherein an insulator temperature heated by a leakage current at the time of fouling is maintained at 150 ° C. or lower.   The conductive metal suspension insulator according to claim 1 or 2, wherein the cap metal fitting is subjected to corrosion-resistant aluminum alloy plating to improve corrosion resistance against natural corrosion and to prevent corrosion due to leakage current flowing through the insulator surface.   The conductive metal suspension according to any one of claims 1 to 3, wherein a zinc sleeve is provided on the pin fitting to improve corrosion resistance against natural corrosion and to prevent corrosion of the cement boundary due to leakage current flowing through the insulator surface. insulator.

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