JPH04154068A - Lightning arrester - Google Patents

Abstract

PURPOSE:To surely obtain a flash short in a series gap of a lightning surge by using a conductive material in a pressure vessel to increase electrostatic capacity of an arrester. CONSTITUTION:A current limiting element 2 and electrode members 3, 4 are stored in a cylindrical pressure vessel 1, and a cavity part in the inside is charged with an organic insulator 8 while coating an external wall surface of the pressure vessel 1 with an organic insulator 7. The pressure vessel 1 is formed of conductive material and connected to an upper part electrode metal fixture 5. That is, share voltage ratio of an arrester to a series gap, when lightning surge voltage is applied, is determined by electrostatic capacity ratio of capacitance C1 of the arrester to capacitance C2 of the series gap, and the capacitance C1 of the arrester is increased by large capacitance C10 between the conductive pressure vessel and the lower electrode member, to obtain C1 C2. In this way, when the lightning surge voltage V1 is applied, most of the voltage V1 is applied to the series gap by obtaining a relation where V1approx.=0, and a flash short can surely be generated.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a lightning arrester installed to protect power transmission and distribution equipment from abnormal voltages caused by lightning surges.

(Prior Art) FIGS. 3 and 4 are both vertical cross-sectional views of the basic structure of a conventional lightning arrester having a current limiting element.

The lightning arrester shown in Fig. 3 has an interior formed by a cylindrical voltage-resistant insulation capacity (rlHx) made of FRP, etc., and an upper electrode fitting (5) and a lower electrode fitting (6) connected above and below by screwing, etc. Upper electrode plate (3) and lower electrode plate (4) are placed in the space.
), springs (3), and other electrode members are housed and fixed, the outer wall surface of the pressure-resistant container (11) is coated with an insulating coating (7) made of an organic insulator, and the internal void is filled with an organic insulator (8). ) It has a similar structure.

The lightning arrester shown in FIG. 4 uses an insulator (I2) instead of the above-mentioned voltage-resistant insulating container (II), and an upper electrode fitting (5) and a lower electrode are connected above and below the insulator (12) by screwing or the like. An upper electrode plate (3), a lower electrode plate (4) and a slot are placed in the internal space formed by the metal fittings (8).

Of course, a pressure relief structure is added to these basic structures as a safety measure in the event of a surge arrester failure.

(Problems to be Solved) FIG. 5(A) is an explanatory diagram of the main parts of the above-mentioned lightning arrester installation example, and FIG. 5(B) is a circuit configuration diagram of a lightning arrester including the lightning arrester shown in the above figure.

An overhead power transmission/distribution line (2G) is suspended from the support arm (21) of the steel tower by a support insulator (22), and arcing horns (23) are attached to the upper and lower ends of the support insulator (22). There is. A lightning arrester (24) is installed in parallel with the support insulator (23).
) is installed, and a series gap (27) is provided between the lower end of the support insulator (23) and the lower end of the lightning arrester (24). The distance of this series gap (27) is
It is set based on the relationship: arcing horn gap distance> series gap distance> opening/closing surge flashover voltage distance.

When such a lightning arrester is operating normally, the tower receives an electric shock (2
8) After receiving the support arm (21) and power transmission/distribution line (2B)
The voltage rises rapidly, but the arcing horn (23)
The series gap (27) flashes before the flash occurs, causing a lightning surge current to flow through the arrester (24). At the transmission voltage after the peak surge voltage, the characteristics of the current limiting element built into the lightning arrester (24) restore the insulation and prevent power outage accidents.

In this way, in order to quickly flash the series gap (27) to prevent flash between the arcing horns (23) of the support insulator (22) when the lightning surge voltage (1) is applied, the arcing horn (23) potential gradient V3 (V
/CI), the potential gradient Ya between the series gap (27)
(V/c+s) must be high, but the voltage sharing ratio between the arrester (24) and the series gap (27) when lightning surge voltage is applied is the ratio between the capacitance C1 of the arrester (24) and the series gap (27). It is determined by the capacitance ratio of capacitance C2.

However, in the conventional lightning arrester mentioned above, the upper and lower electrode members are connected by an insulating material, so the capacitance C1 of the lightning arrester is small as shown in the equivalent circuit shown in Figure 2 (b), and the static capacitance of the series gap is small. The ratio with the capacitance C2 is C, :C. Therefore, the potential gradients of v2 and V become close, and the supporting insulator (22)
There is a risk that the side arcing horn (23) will flash. For this reason, the supporting insulator (22) side arcing horn (
23) changes such as widening the interval were necessary. In addition,
In FIG. 2 (0'), Co□ to Co15 are the capacitances of the current limiting elements, and C1l is the extremely small capacitance between the upper and lower electrode members.

(Means for Solving the Problems) The present invention provides a lightning arrester that solves the above-mentioned problems.The present invention is characterized by a lightning arrester in which a current-limiting element is housed in a pressure-resistant container, in which the pressure-resistant container is made of a conductive material. The reason is that the upper electrode fitting is formed and connected to the upper electrode fitting.

(Example) FIG. 1 is a longitudinal sectional view of a specific example of the lightning arrester of the present invention. In the drawings, the same symbols as in FIG. 3 represent the same parts.

In the lightning arrester of the present invention, the pressure vessel (1) is bulged and a portion of the lower end is opened. The above conductive pressure container (
The internal space of 1) includes a current limiting element (2) and an upper electrode plate (3).
), the lower electrode plate (4), the spring (1) and the upper part of the lower electrode fitting (8) are housed and fixed, and a part (6a) of the lower electrode fitting (8) is attached to the conductive pressure vessel ( 1
), and a part of it protrudes to the outside. In this way, the conductive pressure vessel (1) is connected to the current limiting element (
2) and a structure in which a capacitive one-sided electrode is formed that includes a lower electrode member.

The outer wall surface of the conductive pressure vessel (1) is coated with an insulating coating (7) made of an organic insulator, and the internal cavity, including the lower opening of the conductive pressure vessel (1), is coated with an organic insulator (7). 8)
is filled.

(Function) When the above-mentioned lightning arrester of the present invention is arranged as shown in FIG. 5(a), the lightning arrester (
The capacitance C8 of 24) is a large capacitance C□ between the conductive pressure-resistant container and the lower electrode member, as shown in the equivalent circuit shown in FIG. 2(a). CI>CQ. As a result, when the surge voltage vl is applied, v:
= Q, most of V is applied to the series gap, flashing can be achieved reliably, and countermeasures such as increasing the distance between the existing arcing horns on the supporting insulator side are not required.

(Effects of the Invention) As explained above, according to the lightning arrester of the present invention, by increasing the capacitance of the arrester by using a conductive material in the pressure-resistant container, flash faults in the series gap of lightning surges are reduced. become certain. Therefore, there is no need to take measures such as widening the arcing horn spacing on the existing insulator side, and both reliability and economic efficiency are improved, and it is extremely effective when used as lightning arresters for power transmission and distribution lines and power transmission and distribution equipment.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view of a specific example of the lightning arrester of the present invention. 2(A) and 2(III) are equivalent circuit diagrams of the capacitance of the lightning arrester, where FIG. 2(A) shows the lightning arrester of the present invention and FIG. 2(B) shows the conventional lightning arrester. 3 and 4 are longitudinal cross-sectional views of structural examples of conventional lightning arresters. Figure 5 (a) is an explanatory diagram of the main parts of an example of lightning arrester installation;
0) is a circuit configuration diagram of a lightning arrester including a lightning arrester. 1... Conductive pressure vessel, 2... Current limiting element, 3...
Upper electrode plate, 4... Lower electrode plate, 5... Upper electrode fitting, 6... Lower electrode fitting, 7... Insulating coating, 8...
-Filled insulator, 9...spring. equal ward

Claims (1)

[Claims] (1) A voltage-current nonlinear resistance element (current-limiting element) and an electrode member are housed in a cylindrical pressure-resistant container, and the outer wall surface of the pressure-resistant container is covered with an organic insulator, and the internal cavity is covered with an organic insulating material. 1. A lightning arrester filled with an organic insulator, characterized in that the pressure-resistant container is made of a conductive material and is coupled to an upper electrode fitting.