JPH0251072A - Inspection of loaded power for voltage non-linear resistor - Google Patents

Abstract

PURPOSE:To achieve a selection to satisfy a guarantee value by prescribing an amount of energy and a current waveform in a square wave impulse current test to prevent internal deterioration in a voltage non-linear resistor. CONSTITUTION:When making a selection to determine whether a voltage non- linear resistor mainly composed of zinc oxide meets a guarantee value or not, first a limit guarantee value in a square wave impulse current test is converted into energy. Then, a square wave impulse having energy equivalent to 110-160% as much as the energy converted is applied to the voltage non-linear resistor in a current waveform exceeding by 0.5ms. This test is performed twice: those resistors broken and having an abnormal waveform are screened out as reject. Thus, the energy and the current waveform are prescribed, thereby enabling selection to satisfy the guarantee value without internal deterioration in resistors.

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a voltage application inspection method for determining whether a voltage nonlinear resistor used in a lightning arrester, etc. satisfies a guaranteed value. .

(Prior art) Bi2O2, 5bJs, 5io with zinc oxide as the main component
2゜Co, 0. It is widely known that resistors containing small amounts of additives such as , MnOz, etc. exhibit excellent voltage nonlinearity, and are used in lightning arresters and the like by taking advantage of this property.

Since this voltage nonlinear resistor must satisfy a guaranteed value at the time of shipment, conventionally, a square wave impulse current test or the like is performed for each loft such as each granulation or each firing to determine whether the resistor has passed or not.

If this test for each loft is performed on all the resistors, even if they pass, some resistors will deteriorate due to the test and will not meet the guaranteed value, and tests that involve destruction of the resistor, such as limit capacity tests. Therefore, the resistor was extracted and used as a representative of each loft for inspection.

(Problem to be Solved by the Invention) However, in the manufacturing of voltage nonlinear resistors, variations in manufacturing conditions can lead to large variations even in products with the same loft, and there is a problem that sufficient quality cannot be ensured by sampling tests. there were. Therefore, it has been desired to establish an inspection method that can perform guarantee tests on all resistors without leaving any deterioration.

The purpose of the present invention is to solve the above-mentioned problems, and to provide a voltage application testing method for voltage nonlinear resistors that can reliably guarantee the guaranteed limit value without leaving any internal deterioration even if there are fluctuations in manufacturing conditions. This is what we are trying to provide.

(Means for Solving the Problems) The voltage non-linear resistor voltage testing method of the present invention uses a square wave impulse current to determine whether or not the guaranteed value of a voltage non-linear resistor containing zinc oxide as a main component is acceptable. Convert the guaranteed limit value of the test into energy, and calculate 11 for that energy.
It is characterized by applying energy of 0% to 160% in a current waveform of 0.5 ms or more for selection.

(Function) In the above configuration, we have newly discovered that by specifying the energy amount and current waveform in the square wave impulse current test, it is possible to select a resistor that satisfies the guaranteed value without internal deterioration. .

Even with the above-mentioned square wave impulse current test within the scope of the present invention, damage may remain in the resistor if the number of tests exceeds 5, and screening takes time and is not practical. The number of tests for one resistor is 1 to 5.
It is preferable that it is twice.

In addition, when implementing the voltage testing method of the present invention, if the electrode of the device used is smaller than the electrode of the resistor, the current will concentrate locally and damage will remain on the resistor. It is preferable that the electrode is the same as or larger than the electrode of the resistor.

(Example) First, a method for manufacturing a voltage nonlinear resistor, which is a target of the electrification testing method of the present invention, will be described. To obtain a voltage nonlinear resistor whose main component is zinc oxide, first, a raw material for zinc oxide adjusted to a predetermined particle size, bismuth oxide, cobalt oxide, manganese oxide, antimony oxide, chromium oxide, and oxide adjusted to a predetermined particle size are used. A predetermined amount of additives such as silicon, nickel oxide, boron oxide, silver oxide, etc. are mixed. In this case, silver nitrate or boric acid may be used instead of silver oxide or boron oxide. Preferably, bismuth borosilicate glass containing silver is used. At this time, a predetermined amount of polyvinyl alcohol aqueous solution or the like is added to these raw material powders. Preferably, a predetermined amount of aluminum nitrate solution is added as a source of aluminum oxide. This mixing operation preferably uses an emulsifying machine.

Next, deaeration is performed under reduced pressure, preferably at a vacuum level of 200 wHg or less, to obtain a mixed slurry. Here, the water content of the mixed slurry is 30
~35-t%, and the viscosity of the mixed slurry is 100%.
Preferably, it is ±50 cp. Next, the obtained mixed slurry was supplied to a spray drying device, and the average particle size was 50 to 150 μm.
Preferably, the diameter is 80 to 120 μm and the water content is 0.5 to 2.
Owt%, more preferably 0.9 to 1.5 wt% of the granulated powder is granulated. Next, the obtained granulated powder is molded into a predetermined shape under a molding pressure of 800 to 1000 kg/am'' in a molding process.
It is fired under the conditions of 800-1000°C2 holding time 1-5 hours at 0-70°C/hr. In addition, before calcining, the molded body is heated at a temperature raising/lowering rate of 10 to 100°C/hr for 400 to 400°C.
It is preferable to remove the binder by scattering at 600° C. for a holding time of 1 to 10 hours.

Next, an insulating coating layer is formed on the side surface of the calcined body. As the insulating coating layer, Biz(h, 5bzO3Z
An oxide paste made by adding ethyl cellulose, butyl calpitol, n-butyl acetate, etc. as an organic binder to a predetermined amount of nO+S 10□, etc.
Coat the side surface of the calcined body to a thickness of m. Next, this is heated to a temperature of 1000 to 1300°C at a temperature increase/decrease rate of 20 to 60°C/hr.
Main firing is preferably performed at 1050 to 1250°C for 3 to 7 hours. In addition, a glass paste prepared by adding ethyl cellulose, butyl calpitol, vinegar Mn butyl, etc. as an organic binder to glass powder was applied on the insulating coating layer.
Apply to a thickness of 0 to 300 μm and heat up and cool down at a rate of 5 in air.
It is preferable to form the glass layer by heat treatment under the conditions of 0 to 200°C/hr, 400 to 800°C holding time for 0.5 to 2 hours.

After that, both end faces of the obtained voltage nonlinear resistor were bonded to SiC,
Af□03. Polish with a polishing agent equivalent to #400 to #2000, such as diamond, using water or oil as the polishing liquid. Next, after cleaning the polished surfaces, metallicon electrodes made of aluminum metallicon or the like are provided on the entire surface of both polished end surfaces by, for example, thermal spraying to obtain a voltage nonlinear resistor.

Hereinafter, the results of actually implementing a voltage application testing method within the scope of the present invention and outside the scope of the present invention on a voltage nonlinear resistor will be explained.

A voltage nonlinear resistor with a diameter of 47 mm and a thickness of 22.5 mm and a voltage nonlinear resistor with a diameter of 47 mm and a thickness of 20 m were prepared using the method described above.
A voltage nonlinear resistor of m was prepared. Table 1 shows the guaranteed limit value, average breakdown value, and varistor voltage representing the energy of the prepared resistor. In Table 1, the varistor voltage (VlffiA/H) indicates the limiting voltage per unit length when 1 mA of direct current is applied to the resistor. Further, each energy indicates a 20-time withstand capacity based on the JEC203 square wave impulse current test.

Table 1 Impulse current was applied twice to the prepared voltage nonlinear resistor with the applied energy and waveform shown in Table 2, and those with broken resistors and abnormal waveforms were rejected. It was selected as A square wave impulse current test was performed on the resistors that passed the screening, and the percentage of resistors that passed when a guaranteed limit value of current was applied 20 times was determined. The results are shown in Table 2. In Table 2, the length of the waveform is the time from the start to the end of current application.

Table 2 From the results in Table 2, those selected by implementing the inspection method of the present invention, that is, 1 of the guaranteed value converted into energy.
Voltage nonlinear resistors that were screened with 10% to 160% energy using a current waveform of 0.5 ms or more passed the subsequent square wave impulse current test 100%, demonstrating that the screening was performed accurately. It can be seen that those selected by implementing an inspection method outside the scope of the present invention may be destroyed by the subsequent square wave impulse current test.

Regarding other characteristics such as lightning surge resistance, the voltage nonlinear resistors selected by the square wave current impulse test within the scope of the present invention are good, whereas the voltage nonlinear resistors selected by the square wave current impulse test outside the scope of the present invention are good. In some cases, the selected voltage nonlinear resistors were destroyed by subsequent impulse tests.

Furthermore, for the resistors subjected to the square wave current impulse test within the scope of the present invention, there was no adverse effect on the results of the life test, limited voltage test, VImA change rate test before and after impulse application, etc.

(Effects of the Invention) As is clear from the above explanation, according to the voltage application testing method for voltage nonlinear resistors of the present invention, by specifying the energy amount and current waveform in the square wave impulse current test, voltage It is possible to select a linear resistor that satisfies guaranteed values without internal deterioration.

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Claims (1)

[Claims] 1. When determining whether the guaranteed value of a voltage nonlinear resistor whose main component is zinc oxide is acceptable, the guaranteed limit value of the square wave impulse current test is converted to energy, and the value is 110% to 160% of that energy. energy of 0.5ms
A voltage application inspection method for a voltage nonlinear resistor characterized by applying and selecting the current waveform as described above.