JPH0714707A - Arrester for power transmission - Google Patents

Abstract

PURPOSE:To provide an arrester for power transmission in which flashover takes place easily across a series gap upon occurrence of lightning surge to protect the transmission and distribution facility positively without causing dielectric breakdown of the arrester. CONSTITUTION:Nonlinear resistor elements 12 are laminated in a cylindrical dielectric container and connected in parallel with a resistor 19. The resistor 19 normally exhibits lower resistance than that of the element 12 and thereby the bearing voltage of a gap metal 18 increases to effect positive flashover. Upon occurrence of lightning surge, resistance of the resistor 19 increases over that of the element 12 and thereby causes no trouble in the interruption of follow current.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power transmission lightning arrester for preventing a transmission line trip accident caused by an abnormal voltage due to a lightning surge.

[0002]

2. Description of the Related Art Conventionally, a lightning arrester for power transmission has been used to protect power transmission and distribution equipment from an abnormal voltage caused by a lightning surge, which is a high voltage of a power line such as a power line supported by a steel tower of earth potential via an insulator. A lightning arrester and a series gap were connected in series between the electric wire and the tower, and when the lightning surge was applied, the series gap was flashed to escape the lightning surge to the ground potential. A resistance element made of zinc oxide having a non-linear voltage-current characteristic was laminated inside the lightning arrester, and the equivalent circuit of the lightning arrester was as shown in FIG. In the figure, C
Is the capacitance of the resistance element, and R is the non-linear resistance of the non-linear resistance element.

Here, attempts have been made to improve the insulation coordination with the arc horns provided above and below the insulator.
In the lightning arrester disclosed in Japanese Patent No. 154068, a non-linear resistance element is laminated in a pressure resistant container made of a conductive material at an earth potential via an insulating material, and the non-linear resistance element is connected in parallel with the capacitance of the non-linear resistance element. An electrostatic capacity is formed between the device and the pressure vessel, the electrostatic capacity of the entire lightning arrester is increased, and the shared voltage of the series gap is increased to ensure the flashover in the series gap. An equivalent circuit of the lightning arrester in this case is shown in FIG. 6, where C _A is the electrostatic capacitance between the nonlinear resistance element and the pressure resistant container.

However, in the lightning arrester disclosed in Japanese Patent Laid-Open No. 1554068/1994, when a lightning surge is applied, the lower electrode fitting provided on the lower portion (high voltage side) of the non-linear resistance element becomes high in pressure, and the surrounding pressure resistant container is Since it is at the ground potential, the entire voltage is applied to the insulating material between the two, and there is a risk of dielectric breakdown occurring during this period.

Therefore, a new lightning arrester was proposed in Japanese Patent Application No. 4-304217. This is one in which a cylindrical container accommodating a resistance element is formed of an insulating material, and a cylindrical conductive layer having an earth potential is buried in the upper side (low voltage side) of this cylindrical container. Also in this case, an electrostatic capacitance is formed between the resistance element and the conductive layer, and the equivalent circuit of the lightning arrester is as shown in FIG. 6, and the shared voltage of the series gap is increased to ensure the flashover and to prevent the lightning surge. It was possible to reliably protect the power transmission and distribution equipment. Also, an insulation distance can be secured between the conductive layer at ground potential and the high voltage side, and dielectric breakdown can be prevented.

[0006]

However, in the above-mentioned Japanese Patent Application No. 4-304217, the length of the conductive layer in the axial direction cannot be increased so much as to obtain the insulation distance. A sufficient capacitance formed between the device and the device could not be obtained. Therefore, the sharing voltage of the series gap does not become so large, and the certainty of the flashover is impaired.

The present invention has been made in order to solve the above-mentioned problems, and when a lightning surge occurs, a flashover is likely to occur in the series gap, and the power transmission and distribution equipment can be reliably protected. It is an object of the present invention to provide a lightning arrester for power transmission that is capable of being performed and is less likely to cause dielectric breakdown in a lightning arrester.

[0008]

A lightning arrester for power transmission according to the present invention has a non-linear resistance element laminated in a cylindrical container made of an insulating material, and is normally arranged in parallel with the non-linear resistance element. A lightning arrester is configured by connecting a resistor having a resistance value smaller than the resistance value and larger than the resistance value of the element at the time of lightning protection operation.

[0009]

In the present invention, the non-linear resistance element is laminated in the cylindrical container of the lightning arrester, and the resistance is connected in parallel with the element. Since the resistance value of the resistance is smaller than that of the element under normal conditions, The series gap voltage is increased, and the series gap is easily flashed. Since the resistance value of the resistor is larger than that of the element during the lightning protection operation, the continuous current interruption is not adversely affected. In addition, there is no conductive layer,
Dielectric breakdown by lightning arrester is unlikely to occur.

[0010]

Embodiment 1 An embodiment of the present invention will be described below with reference to the drawings. Figure 1
1 is a cross-sectional view of a lightning arrester of a lightning arrester for power transmission according to Embodiment 1, where 1 is a cylindrical container made of an insulating material, 2 and 3 are metal flanges attached to the outer circumference of both ends of the cylindrical container 1, and 4 is a cylindrical shape. It is a polymer fold mounted between the metal flanges 2, 3 on the outer circumference of the container 1. Reference numerals 5 to 8 denote two pressing plates attached to the upper and lower ends of the tubular container 1, respectively, and support pressure release plates 9 and 10 that close the both ends of the tubular container 1, respectively. A lower electrode 11 is placed on the pressing plate 7, a nonlinear resistance element (characteristic element) 12 made of zinc oxide is stacked on the lower electrode 11, and an upper electrode 13 is placed on the nonlinear resistance element 12. A spring 14 is provided between the holding plate 5 and the upper electrode 13.

The metal flanges 2 and 3 are provided with pressure relief plates 9 and 1 when the internal pressure of the cylindrical container 1 rises due to an accident.
The emission gaps 15 and 16 are attached so as not to interfere with the flow of the blast emitted by destroying 0, the emission gap 15 is attached to the tower arm 17, and the emission gap 16
A gap metal fitting 18, which is a series gap, is attached to. Reference numeral 19 is a resistor connected in parallel with the non-linear resistance element 12. The resistor 19 does not need to have a linear voltage-current characteristic, but its resistance value is sufficiently smaller than the resistance value of the non-linear resistance element 12 in a steady state (for example, 100 MΩ or less) and conversely large in a lightning protection operation (for example, 1 KΩ or more), which is a value that does not hinder the follow-current interruption after the lightning impulse discharge, and the withstand voltage is sufficient to withstand the terminal voltage of the lightning arrester during the lightning arrester operation.

Next, the operation of the lightning protection device having the above construction will be described. FIG. 2 shows an equivalent circuit of the lightning arrester having the above configuration, where R _A is the resistance of the resistor 19 connected in parallel with the nonlinear resistance element 12. When the resistor 19 is provided in this way, R _A is very small in the state where the gap metal fitting 18 is not discharged, so that R _A shares the voltage in the arrester, and the shared voltage is almost OV.
Becomes Therefore, most of the voltage applied to the lightning arrester is applied to the gap metal fitting 18, so that the gap metal fitting 18 is surely flashed when a lightning surge is applied, and good insulation coordination with the arc horn can be obtained.

When the gap metal fitting 18 is discharged by a lightning impulse, the resistance value of the non-linear resistance element 12 is rapidly reduced to reduce an abnormal voltage, and the continuous current that follows continues to be interrupted by the non-linear resistance element 12 and the gap metal fitting 18. To do.
At this time, the follow current flows not only to the non-linear resistance element 12 but also to the resistor 19, so that the resistance value of the resistor 19 is more than the resistance value of the non-linear resistance element 12 so as not to hinder the follow current interruption. It is necessary to be big. For example, in the case of a 66 KV power transmission line, if it is desired to limit the current flowing through the resistor 19 to 1 A or less in order to cut off the follow current at the maximum voltage of the power system without any problem, 69 KV / 1 A = 69 KΩ to 6 KV
A resistance value of 9 KΩ or more is required for the resistor 19. or,
Since it is not necessary to form the parallel capacitance C _A as in the conventional case, there is no need to form a conductive layer or the like, and there is no problem in insulation from the high voltage side.

Embodiment 2 FIG. 3 is a cross-sectional view of a lightning arrester of a lightning arrester for power transmission according to Embodiment 2, 20 is a conductive rubber coated on the outer periphery of a laminated body of nonlinear resistance elements 12, and a resistor 19 is Not provided. Other configurations are similar to those of the first embodiment. In the second embodiment, the resistance R _A is formed in parallel with the non-linear resistance element 12 by the conductive rubber 20, and the equivalent circuit is as shown in FIG. The resistance value of the conductive rubber 20 satisfies the same condition as that of the resistor 19, and the second embodiment also has the same effect as the first embodiment.

Third Embodiment FIG. 4 is a sectional view of a lightning arrester of a lightning arrester for power transmission according to a third embodiment, in which 21 is a metal flange 2 on the outer periphery of the cylindrical container 1.
3 is a fold made of a conductive rubber provided between the resistors 3, and the resistor 19 is not provided. Other configurations are similar to those of the first embodiment. The pleats 21 are connected in parallel with the laminated body of the non-linear resistance elements 12 via the metal flanges 2 and 3, and the equivalent circuit is as shown in FIG. The resistance value of the fold 21 is the resistance 1
The conditions similar to those of Example 9 are provided, and the effects of Example 3 are similar to those of Example 1.

[0016]

As described above, according to the present invention, the non-linear resistance element is laminated in the cylindrical container of the arrester, and the resistance is connected in parallel with the element. Since the value is smaller than that of the element, the shared voltage of the series gap becomes large, the flash of the series gap is likely to occur when a lightning surge occurs, and the protection of the power transmission and distribution equipment is ensured and the insulation coordination is facilitated. Further, since the resistance value of the resistor is larger than that of the element during the lightning protection operation, the interruption of the follow current does not occur. Further, since there is no portion where the dielectric breakdown between the high voltage side and the ground potential side is likely to occur, the dielectric breakdown is unlikely to occur.

[Brief description of drawings]

FIG. 1 is a sectional view of a lightning arrester of a power transmission lightning arrester according to a first embodiment.

FIG. 2 is an equivalent circuit diagram of a lightning arrester of a power transmission lightning arrester according to a first embodiment.

FIG. 3 is a sectional view of a lightning arrester of a power transmission lightning arrester according to a second embodiment.

FIG. 4 is a cross-sectional view of a lightning arrester of a power transmission lightning arrester according to a third embodiment.

FIG. 5 is an equivalent circuit diagram of a lightning arrester of a conventional power transmission lightning arrester.

FIG. 6 is an equivalent circuit diagram of a lightning arrester of another conventional lightning arrester for power transmission.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Cylindrical container 12 ... Non-linear resistance element 17 ... Tower arm 18 ... Gap metal fitting 19 ... Resistor 20 ... Conductive rubber 21 ... Pleat

Claims (1)

[Claims] 1. A power transmission lightning arrester in which a lightning arrester and a series gap are connected in series between a high voltage potential and a ground potential,
A non-linear resistance element is laminated in a cylindrical container made of an insulating material and has a resistance value which is smaller than the resistance value of the non-linear resistance element in the normal state and smaller than the resistance value of the element during lightning protection operation. A lightning arrester for power transmission, comprising a lightning arrester connected to a resistor.