JPS604202A - Zinc oxide type arrester element - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] Is this invention improved? Introduction to zinc oxide type lightning arrester elements.

Conventional "L pressure"
! The custom-made IL flow is shown as shown in Figure 7.The special feature of this element is rc', which has a voltage that is different from current ii'i P'! , Regular vs. 1110
Reduce leakage fFL flow ■a when voltage is applied, and 71'
jj'+3fi, element when rc energized"・Makenma 1: I-
In order to reduce the pressure (hereinafter referred to as “limitation”),
Improvements have been made mainly by devising the &Jl configuration of the elements.

In addition, arresters using the above-mentioned elements are sometimes used by removing the gap used in conventional lightning arresters. In this case, the current ■a in FIG. 1 always flows through the element.

FIG. 2 conceptually shows the change over time in the leakage current flowing through the element when a current is constantly applied. C shows a pattern in which the leakage current increases and eventually destroys the element, while D shows a stable pattern in which the leakage current does not increase in response to voltage application. Conventionally, efforts have been made to obtain a stable pattern D mainly through reheating treatment. - It is believed that the reheating treatment causes changes in the internal groove structure of the device, especially in the bismuth oxide crystal phase (for example, JP-A-Sho Sθ-/, 370941
No. 1 Publication, 1Machikai Showa λ-33 Yu9s Publication, JP-A Showa Sλ
-g') A9! Publication No. R, but no data directly indicating this is stated).

Is bismuth oxide a microscopic element? 1IlC'? Shojo oxidation 111
．． A grain boundary layer is formed between the lead grains, and the voltage i of the device is
nn can be considered as a constituent phase that plays an important role in flow surface linearity characteristics. Therefore, how to manufacture and control bismuth oxide is extremely important to the characteristics of the device.When the crystal phase of bismuth oxide is gamma (γ) phase, the above Charging characteristics and lightning distribution
17. The subsequent device characteristics are stable. However, cB'
The leakage current Ia shown in the figure increases with the growth of the γ phase, and also has the drawback that the ratio of the starting voltage to the limiting 1-likelihood voltage (hereinafter referred to as the limiting voltage ratio) increases, deteriorating the maintenance characteristics. there were.

This invention was made in order to eliminate the drawbacks of the conventional ones as described above, and the crystal phase of bismuth oxide in the zinc oxide type lightning arrester element contains the γ phase, and the entire bismuth oxide is in the γ phase. By controlling the current to be 2o-go % when It is intended to.

The present invention is a zinc oxide type lightning arrester element containing at least bismuth oxide as an additive, in which θ~go% of the crystal phase of the bismuth oxide is gamma bismuth oxide.

γB :L20. Although additives, firing and its atmospheric conditions, reheating, etc. may be factors in obtaining , reheating will be selected as a factor in the explanation of the embodiments of the present invention. 2 The present invention will be described below based on examples.

Examples Zinc oxide (ZnO) is the main component, and additives include o, i~λ mol bismuth oxide (B12o3), T7-f-mo', / (5t)203) oxide, cobalt oxide (CoO), and oxide. Manganese (MnO), chromium oxide (cr20s), silicon oxide (Si02), and boric acid (H2BO3) of 0.0θ/~θ, 0/molti, respectively.
, Aluminum Nitrate 1 (A4 (NO3) 73゜qH20
), and after pulverizing, mixing, granulating, and molding them/2
It was fired at 00°C.

These samples (size Sθφ×25) are llj (, −
The electrodes were reheated at 700° C. for a holding time of λ hours, and the limiting voltage ratio, leakage current, and charging characteristics were examined.

FIG. 3 shows the change in limiting voltage ratio due to reheating.

ll! The limiting voltage ratio becomes the minimum during the reheating treatment at rθ to SOO°C, and becomes a very large value at 7θO°C.

Figure 3 shows the change in leakage current due to reheating.

As the measurement conditions, the ambient temperature of the device was set to θ° C., and the voltage generated between the device electrodes (hereinafter referred to as starting voltage) when a current of /mA was passed through the device with an applied voltage of 70 was selected. When the reheating temperature is 5o-soo℃, the leakage current is minimum, 70θ℃
That would be a huge price increase.

Figure S shows the change in charging characteristics due to reheating.

Here, the charging characteristics mean that the ambient temperature of the element is maintained at 73θ℃,
It refers to the leakage current characteristics of an element when three applied voltages are applied: left (curve E), SS (curve F), and go (curve G) of the starting voltage. FIG. 5 Ratio of I40 I40/I+(
(hereinafter referred to as leakage current ratio). If this value is smaller than 80 or close to i and o, it means that the leakage current does not increase, and it can be said that the charging characteristics are stable.

When the applied voltage is small, as shown by curve E in FIG. 5, it is stable regardless of the reheating process.

However, if the applied voltage is increased (curve 'rG),
Without reheating, the leakage current ratio cannot be maintained at a value close to 0. Under the condition that the applied voltage is g0% of the starting voltage, which is important for the device, as shown in curve G, when the reheating treatment force is in the range of Sθ0−AOO℃, the leakage current Mf, the ratio (ma/, is close to θ, and in this case it can be said that the element charging characteristics are stable.

After completing the above electrical test, the central part of the element was cut out.1. X-ray diffraction measurements were carried out on the powder obtained by pulverizing it through a j00 mesh screen G) until it reached iM.

FIG. 6 shows the powder X-ray diffraction paddle turn of the device before reheating, and FIG. 7 shows the powder X-ray diffraction pattern of the device after the reheating treatment at 00°C.

The diffraction peaks that appeared in Figures 6 and 7 (well, ZnO
, Zn7Sb20,2. Zn, 5i04 and Bi,
It can be identified that it is caused by the substance O. What should also be noted is that when comparing FIG. 6 and FIG. 7, only Bi2O undergoes phase transformation due to reheating. That is,
It is observed that the crystal phase of B i 2.0 before reheating was β phase, but after reheating at 700° C., the crystal phase was transformed to γ phase.

As seen in Figures 6 and 7, the strongest peaks of β-Bi203 and γ-Bi2o overlap at θζ and 2g0, so the peak appearing between θ=3λ and 30 indicates the bismuth oxide produced by reheating. We quantitatively investigated the metamorphosis of

That is, β-Bi203 has a peak due to (gθθ), and γ
-Bi2o3 focuses on the peaks due to (,7,2/), cuts out the entire area that appears above the background on the recording paper on which those peaks were measured, weighs it on a balance, and calculates its weight by peak integration. It is shown in Fig. 3 as equivalent strength. In the figure, curve H corresponds to the peak integrated intensity of β-Bi203 (g00), and curve H corresponds to the peak integrated intensity of β-Bi203 (g00). The peak integrated intensity equivalents of o and (3,21) are shown, respectively.

From Figure 3, approximately 11. y O'C; more β-B1tos
(It can be seen that the transformation to D γ-Bi, 03 begins, and the conversion to r-Bi, 0. is almost completely completed at about 65θ℃. Bismuth oxide is completely transformed into γ-Bi2O3 (!: Has it become?
The ratio of the value equivalent to the peak integrated intensity of r-Bi20s at each heating temperature to the value equivalent to the peak integrated intensity of γ-Bi2O3 at 00°C is shown in FIG. That is, FIG. 9 shows the conversion rate of bismuth oxide to γ phase by reheating treatment.

Comparing and examining the limiting voltage ratio (Figure 3), leakage current (Figure 9), charging characteristics (Figure S), and conversion rate of bismuth oxide to γ phase (Figure 9), it was found that bismuth oxide 20~
When the phase θ is the γ-Bi2O3 phase, it is possible to keep the charging characteristics of the element stable under heavy load conditions without worsening the limiting voltage ratio or leakage current.

In the above example, the optimal amount of 1-Bi2O3 produced was controlled by reheating treatment, but any method that can control the amount of γ-Bi and o3 produced may be used, such as a method of devising the firing atmosphere or the composition of the element. It is also possible.

As described above, according to the present invention, the bismuth oxide in the zinc oxide type lightning arrester element can be controlled so that the crystal phase thereof is the γ phase and the amount thereof is in the ratio of 2θ to gθ of the total bismuth oxide. Therefore, there is an effect that the element charging characteristics can be kept stable under heavy load conditions without deteriorating the limiting voltage ratio and leakage current.

[Brief explanation of drawings]

Figure 1 shows the voltage-current characteristics of a conventional zinc oxide arrester element.
FIG. 2 is a diagram conceptually showing the charging characteristics of the device shown in FIG. 1, FIG. FIG. 3 is a diagram showing changes in leakage current due to reheating of the element according to the example; FIG.
FIG. 6 is a diagram showing the X-ray diffraction pattern of the device according to the example before reheating treatment, FIG. 7 is a diagram showing the xi diffraction pattern of the device according to the example after reheating treatment at 7θθ℃, and FIG. A diagram showing further changes in Bi2O3 peak intensity due to heating,
FIG. 9 is a diagram showing the conversion rate of bismuth oxide to γ phase by reheating treatment. Agent Masuo Oiwa Figure 1 Book Figure 2 Section Electrical opening Figure 4 Figure 5
Degrees) 2θ (degrees) Procedural Amendment ``Spontaneous'' Showa! March 7, 2007, Mr. Yu and the Commissioner of the Japanese Patent Office1, Indication of the case, Patent Application No. 1, No. 2, Title of the invention: Zinc oxide type lightning arrester element 3, To the representative of the person making the amendment, Hitoshi Katayama. (1) Column for detailed explanation of the invention in the specification Details of the amendment (1) In the second page of the specification box, line G, "current" is corrected to "voltage." (2) Same page 10? //line r(Al (No!
)ri,・9H20)-1 as “(Aj, (NO3h・9H
20) Correct to J.

Claims (1)

[Claims] ri containing at least l':"bismuth dioxide as an additive.
T-type 30'! :1 In Takako Raiki, 'i' says that the crystalline phase of bismuth mulberry has a gamma of 1 and is bismuth 2! 7 Q (1' Zinc dioxide type lightning arrester element.