JPH06318505A - Sorting method for zinc oxide element - Google Patents

Abstract

PURPOSE:To provide a sorting method for a good zinc oxide element by electrifying the zinc oxide element, measuring the distribution of generated heat of the zinc oxide element at the time of electrifying making it a sorting standard for the zinc oxide element that the ratio of the maximum value to the minimum value of the temperature increase in each part of the zinc oxide element is within a predetermined value. CONSTITUTION:A metallikon electrode 2 is provided in both end surfaces of a zinc oxide element 1, and a black coating is applied to one side, and a radiation thermometer 4 is arranged in the opposite side thereto. The zinc oxide element 1 is electrified from a high voltage power supply part 5, and the temperature distribution of the electrode surface is measured by the radiation thermometer 4 and at the same time the temperature of the element is increased by continuously electrifying it. Thereby, the sorting of the good zinc oxide element 1 is performed by making it a sorting standard whether the ratio of the maximum value to the minimum value of the temperature increase in each part of the zinc oxide element 1 is within a standard value or not. Thereby, a fine sorting method for the good zinc oxide element 1 can be realized.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for selecting a zinc oxide element used for a power arrester.

[0002]

2. Description of the Related Art A zinc oxide element is selected by conducting a constant current value (eg, a switching impulse current) determined by the element diameter and electrically inspecting the element for damage. In general, in the case of injecting energy into a zinc oxide element to destroy it, in many cases, mechanical destruction such as cracks and cracks occurs before electrical destruction and then electrical destruction. Due to the difference in the current waveform to be applied, mechanical breakdown and electrical breakdown may occur almost at the same time. In a special case, mechanical breakdown may occur, but electrical breakdown may not be achieved. In other words, it can be understood that a good zinc oxide element cannot be reliably selected only by checking the presence or absence of electrical breakdown.

Destruction of a zinc oxide element occurs from a weak portion in mechanical and electrical terms, that is, a point where current concentration occurs due to nonuniform current in each portion in the element. That is, the element can be selected by accurately measuring the current distribution in each part in the element.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an improved and improved method for selecting zinc oxide elements.

[0005]

To achieve the above object, the present invention energizes a zinc oxide element, measures the heat generation distribution of the zinc oxide element during energization, and determines the maximum and minimum values of temperature rise in each part of the element. It is characterized in that the selection standard of the zinc oxide element is that the ratio with the ratio is within a predetermined value.

[0006]

By adopting the selection criterion that the ratio of the maximum value of temperature rise to the minimum value is within a predetermined value, it is possible to perform more detailed selection of zinc oxide elements that cannot be selected by only the electrical breakdown detection method.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to the drawings. In the drawing, metallikon electrodes 2 are provided on both end surfaces of a zinc oxide element 1, and a black coating 3 is applied on at least one surface,
Radial thermometer 4 is arranged on the opposite surface side. The zinc oxide element 1 is energized from the high-voltage power supply unit 5, and while the radiation type thermometer 4 measures the temperature distribution on the electrode surface, energization is continued to raise the element temperature. In this way, a good element is selected based on whether or not the ratio between the maximum value and the minimum value of the temperature rise of each part of the zinc oxide element is within the reference value as a selection criterion.
Examples of temperature measuring methods include a method using a thermocouple and a method using a thermo label.

[0008]

As described above, according to the present invention, it is possible to perform fine and fine selection of elements.

[Brief description of drawings]

FIG. 1 is an illustrative view of a zinc oxide element selection method using a radiation thermometer which is an embodiment of the present invention.

[Explanation of symbols]

 1 ... Zinc oxide element 2 ... Metallicon electrode 3 ... Black coating 4 ... Radiation thermometer 5 ... High voltage power supply

Claims (2)

[Claims] 1. The zinc oxide element is energized, the heat generation distribution of the zinc oxide element during energization is measured, and it is confirmed that the ratio of the maximum temperature rise and the minimum temperature rise of each part of the element is within a predetermined value. A method for selecting a zinc oxide element, characterized in that it is used as a selection criterion. 2. The zinc oxide element selection method according to claim 1, wherein the heat generation distribution is measured using a radiation thermometer.