JPS6326780Y2 - - Google Patents

Description

[Detailed description of the invention] The present invention uses optical means to detect temperature changes in the characteristic elements of a lightning arrester, which is formed by housing characteristic elements consisting of non-linear resistors mainly composed of metal oxides in a container, from outside the container. Relating to lightning arresters that can be monitored by.

Conventional lightning arresters have adopted SiC-based characteristics, but because the nonlinearity was insufficient, it was not possible to create a lightning arrester without a series gap.

However, in recent years, non-linear resistors with excellent non-linear characteristics that are mainly composed of metal oxides such as lead oxide have been developed, and it has become possible to realize lightning arresters without a series gap. On the other hand, the role played by the nonlinear resistor becomes extremely important compared to conventional characteristic elements. For example, if a characteristic element deteriorates, the leakage current increases, leading to a rise in temperature, which may eventually lead to thermal runaway of the nonlinear resistor.

Therefore, it is desirable to periodically check the performance of the nonlinear resistor to understand its characteristics. By the way, the first method for checking the temperature characteristics of a lightning arrester is
As shown in the figure, a characteristic element 7 in which non-linear resistor elements 1 are stacked is housed together with an insulating gas 2 in a grounded tank 4 whose one opening is sealed with an insulating spacer 3. Then, a thermocouple 5 made of copper or constantan, for example, is attached to the lowest part b on the grounding side of the characteristic element 7, and this is connected to a thermometer 6 outside the grounding tank 4 to measure the surface temperature of the nonlinear resistor element 1. Measure.

However, since there is a capacitance between the characteristic element 7 and the ground tank 4, and this capacitance cannot be ignored compared to the capacitance of the characteristic element 7, the constant operating voltage of the commercial frequency is as shown in Figure 2. As shown in the figure, if the vertical axis is the potential and the horizontal axis is the position from position a to position b at the top of the characteristic element, the potential distribution will be as shown in curve A for the upper nonlinear resistor element. Because it is biased,
A difference occurs in potential sharing, and deterioration due to constant power application occurs unevenly. For this reason, the leakage current always increases only in the upper part, causing a rise in temperature. In this way, the conventional temperature measurement method can only measure the surface temperature of the nonlinear resistor element at the bottom, and the characteristic element 7
Since the overall deterioration characteristics could not be grasped, there was a risk that the determination of life deterioration would lack accuracy.

The present invention has been made in consideration of the above points, and its purpose is to provide a lightning arrester in which deterioration of the entire characteristic element can be determined from the outside in a energized state.

Hereinafter, the present invention will be described with reference to an embodiment shown in the drawings in which the same parts as in FIG. 1 are denoted by the same reference numerals.
As shown in FIG. 3, a characteristic element 7 in which nonlinear resistor elements 1 are laminated is grounded with an insulating gas 2 such as sulfur hexafluoride (SF ₆ ) gas, and the opening thereof is sealed with an insulating spacer 3. Housed in a tank 4, one end of the characteristic element 7 is connected to a conductor 3a that passes through the insulating spacer 3 and connects to other equipment, and the other end is connected to the grounded tank 4. A transparent member 8 capable of optical measurement is provided in a part of the grounded tank 4, and an infrared temperature measuring device 9 is installed in this transparent member 8.
This transparent member 8 is a transparent organic glass lens such as methacrylic resin, or a glass lens coated with a transparent anti-corrosion paint.

Next, the effect of the configuration of the present invention will be explained. As described above, the unevenness of the potential distribution of the characteristic element 7 causes an uneven temperature rise in the nonlinear resistor element 1, and this temperature rise causes infrared rays to be emitted. By passing this infrared ray through the transparent member 8 and measuring it with an infrared temperature measuring device 9 provided outside, the temperature rise of the characteristic element 7 can be ascertained. Therefore, even if the characteristic element 7 has a non-uniform temperature distribution, life deterioration can be accurately determined. If a system is installed to detect by some means when the temperature measured by the infrared temperature measuring device 9 reaches the dangerous temperature of the nonlinear resistor element 1, destruction of such a lightning arrester without a gap can be avoided. This can be prevented.

A description will be given of another embodiment of the present invention shown in FIG. 4, in which parts that are the same as those in FIG. 3 or have the same functions are given the same reference numerals. A cylindrical capacitor 11 for improving potential distribution is installed surrounding the characteristic element 7 in which the non-linear resistor elements 1 are laminated. Transparent members 8 are provided at several locations on this cylindrical capacitor 11, and optical fiber members 10 for transmitting infrared rays are airtightly led out from the grounded tank 4 from the transparent members 8.
By connecting this optical fiber member 10 to the infrared temperature measuring device 9, the temperature rise of the characteristic element 7 can be measured and life deterioration can be accurately determined, similarly to the present invention.

As explained above, according to the present invention, by accurately measuring the temperature distribution of the characteristic elements from the outside of the grounded tank, the degree of deterioration of the characteristic elements can be accurately determined, and the destruction of the characteristic elements can be prevented. Therefore, it is possible to provide a lightning arrester that can be maintained accurately and reliably.

[Brief explanation of the drawing]

Fig. 1 is a longitudinal cross-sectional view showing a conventional lightning arrester, Fig. 2 is a characteristic line diagram showing the potential distribution of characteristic elements of the lightning arrester,
FIG. 3 is a longitudinal cross-sectional view showing the lightning arrester of the present invention, and FIG. 4 is a longitudinal cross-sectional view showing another embodiment of the present invention. 1...Non-linear resistor element, 2...Insulating gas, 3
... Insulating spacer, 4 ... Grounding tank, 8 ... Transparent member, 9 ... Infrared temperature measuring device, 10 ... Optical fiber member, 11 ... Capacitor.

Claims (1)

[Claims for Utility Model Registration] (1) A characteristic element consisting of a plurality of laminated non-linear resistor elements mainly composed of metal oxides is hermetically stored in a grounded tank together with an insulating gas, and the outer wall of this grounded tank is sealed. A lightning arrester characterized in that the temperature of the characteristic element is measured by optical means. (2) Install a transparent member in a part of the grounded tank to make it airtight.
The lightning arrester according to claim 1, wherein an infrared temperature measuring device is installed through the transparent member.