JPS5850401B2 - Lightning arrester - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a lightning arrester in which a discharge gap is provided in parallel with a portion of a non-linear resistor.

Recently, ZnO, which has very good nonlinearity compared to conventional SiC, has been developed.
A series resistor has been developed that can be used to realize a surge arrester without a series gap (hereinafter referred to as a gapless surge arrester).

This new ZnO-based non-linear resistor is usually a conventional SiC
It is generally formed into a disk shape and stacked to form a lightning arrester.

An example of the current-voltage characteristics of this ZnO-based nonlinear resistor is shown in FIG.

The voltage axis in FIG. 1 is graduated with a value of 1 when the current is 1 mA.

In order to construct a gapless lightning arrester, nonlinear resistors must be stacked so that the nonlinear resistors are not destroyed by the current that flows when the rated voltage of the arrester is constantly applied.

This current value is, for example, around 1 r mA j.

When the stacking of nonlinear resistors is determined in this way, the limiting voltage for the lightning surge discharge current and the switching surge discharge current is uniquely determined from the current-voltage characteristics as shown in FIG.

Therefore, in order to lower this limiting voltage, a discharge gap 2 is connected in parallel with a portion 1a of the non-linear resistor 1 as shown in the electrical circuit diagram of FIG. It is considered that when the voltage rises above this level, the discharge gap is caused to discharge and a part of the non-linear resistance element is short-circuited.

FIG. 3 shows a specific example thereof.

FIG. 3 shows one unit of a lightning arrester, and the lightning arrester is constructed by stacking these units according to the rated voltage.

In the figure, 1 is a nonlinear resistor formed by stacking nonlinear resistance elements, 2 is a discharge gap device, 3 is a metal connection plate, and 4
5 is a connection lead plate, and 5 is an insulating plate.

Now, when a surge current flows through the series gapless arrester equipped with the discharge gap device 2 connected in parallel and the discharge gap device 2 discharges due to the voltage of the non-linear resistor 1a in the parallel section, the non-linear resistor 2 in the parallel section 1a is short-circuited, and no current flows through the non-linear resistor 1a in the parallel section.

Therefore, the energy of the surge is consumed by the non-linear resistor of the non-parallel portion 1b after the discharge of the parallel gap.

The discharge capacity of a non-linear resistor is generally proportional to its cross-sectional area.

Therefore, for the above reasons, it is clear that it is not necessary to make the non-linear resistor 1a in parallel with the discharge gap device 2 and the non-linear resistor 1b in the non-parallel part the same cross-sectional area as shown in FIG. .

Therefore, by reducing the cross-sectional area of the non-linear resistor 1a in the parallel portion, the material of the non-linear resistor can be saved and the size of the lightning arrester can also be reduced.

Therefore, as shown in FIGS. 4 and 5, a lightning arrester has been considered in which a non-linear resistor 1a having a smaller cross-sectional area than the non-linear resistor 1b in the non-parallel portion is arranged in parallel with a gap device 2. There is.

However, the gap device 2, which is required to have good following and breaking characteristics, is required to have excellent insulation recovery characteristics after arc extinction.

However, in the above configuration, the size of the space around the gap device 2 is limited by the non-linear resistor 1 arranged in parallel, so there is a problem that it is difficult to satisfy the required characteristics.

The present invention has been made with attention to the above points, and an object of the present invention is to provide a lightning arrester with parallel gears that has good follow-up and break characteristics and excellent insulation recovery characteristics.

This invention will be explained based on the drawings.

In Fig. 6, 1 is a non-linear resistor constructed by stacking non-linear resistive elements mainly composed of metal oxides, 2 is a discharge gap device, 3 is a metal connection plate, 4 is a connection lead plate, and 5 is an edge. The edge plate is shown.

FIG. 6 shows a non-linear resistor 1 in parallel with a discharge gap device 2.
The cross-sectional area of a is made smaller than the cross-sectional area of the non-linear resistor 1b in the non-parallel portion, and the discharge gap device 2 and the non-linear resistor 1 are
are stacked in series.

Compared to the one shown in FIG. 3, the cross section of the non-linear resistor 1a in parallel with the discharge gap device 2 is smaller, which not only saves material but also reduces the cross-sectional area of the edge plate 5 to the non-linear resistor 1b.
Since the cross-sectional area of the connecting lead plate 4 can be arranged closer to the central axis, the storage container can be made smaller accordingly.

Furthermore, since the gap device 2 is not placed in parallel with the non-linear resistor 1a in the parallel section, it is possible to prevent deterioration of follow current and breaking characteristics, and it is also expected that the insulation recovery characteristics after arc extinguishment will be improved. can.

In the series gapless lightning arrester with a discharge gap device configured as described above, when a surge current flows and the voltage of the nonlinear resistor 1 exceeds a set value, the discharge gap device 2 discharges.

After the parallel discharge gap device discharges, the non-linear resistor 1a in the parallel portion is short-circuited, so the surge energy is consumed in the non-linear resistor 1b in the non-parallel portion.

Therefore, the discharge withstand capacity of the non-linear resistor 1a in the parallel portion may be smaller than that of the non-linear resistor 1b in the non-parallel portion, and the thickness may also be smaller.

Furthermore, the discharge gap device 2 is connected to the non-linear resistor 1 in the parallel section.
Since the structure is not arranged in parallel with a, the following flow and breaking characteristics are also good, and the edge recovery characteristics after arc extinction can also be improved.

As described above, the present invention can provide a lightning arrester with parallel gears that has good follow-up and break characteristics and excellent insulation recovery characteristics.

[Brief explanation of drawings]

Figure 1 is a diagram showing the current-voltage characteristics of a ZnO-based nonlinear resistor, Figure 2 is an electrical circuit diagram of a gapless arrester with a parallel gear knob, Figure 3 is a configuration diagram of a conventional device of this type, and Figure 4 is a diagram showing the current-voltage characteristics of a ZnO-based nonlinear resistor.
5 is a block diagram of a lightning arrester in which a discharge gap device and a non-linear resistor in a parallel section are arranged side by side, and FIG. 6 is a block diagram of a lightning arrester according to an embodiment of the present invention. 1...Non-linear resistor, 2...Discharge gap device, 3...Metal connection plate, 4...
Connection lead plate, 5... Insulation plate.

Claims (1)

[Claims] 1 Non-linear resistance elements mainly composed of metal oxides are stacked to form a first non-linear resistor and a second non-linear resistor, connected in series, and connected in parallel to the second non-linear resistor. In a lightning arrester formed by connecting a gap device, the cross-sectional area of the second non-linear resistor is smaller than the cross-sectional area of the first non-linear resistor, and the second non-linear resistor and the gap device are connected to each other. An insulating plate having a smaller cross-sectional area than the first non-linear resistor is inserted between them, and the first non-linear resistor, the second non-linear resistor, and the gap are arranged in a stacked manner. lightning arrester.