JPH04351808A - Lightning insulator - Google Patents

Abstract

PURPOSE:To heighten a discharge-resisting amount and stabilize a breaking characteristic of a follow current following a lighetning surge current by instantly transmitting thermal energy of resistance elements generated by the lightning surge current to the insulating bushing side by heat pipes so as to suppress a temperature rise of the resistance element while suppressing its electric resistance even in the case of a lightning surge current invasion at the time of a lightning stroke. CONSTITUTION:Resistance elements 5 having a voltage-current characteristic are built inside of an insulating bushing 9 having an umbrella part 9a and each inner end of heat pipes 10 for transmitting heat generated in the resistance elements 5 to the insulating bushing 9 is inserted between the resistance elements 5 while inserting each other end part of the heat pipes 10 into the umbrella parts 9a of the insulating bushing 9.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] This invention prevents ground faults by discharging lightning surge current to the ground when a lightning strike occurs on a power line, and suppressing the subsequent current based on the operating voltage. This relates to lightning insulators that can provide lightning protection.

0002

[Prior Art] Generally, in a lightning arrester device for a power transmission line, a support insulator consisting of a chain of suspended insulators is suspended from a support arm horizontally supported on the side of a steel tower body via a connecting fitting on the ground side. A power transmission line is supported at the lower end of the support insulator via a connection fitting and a wire clamp on the power supply side. or,
The tower is equipped with a lightning arrester insulator that contains a resistance element with non-linear voltage-current characteristics that allows the lightning surge current to flow and suppresses the follow-on current based on the operating voltage that follows the lightning surge current. has been done. This lightning arrester supports a ground-side discharge electrode that faces the power-supply-side discharge electrode supported by the power-supply-side connection fitting with a predetermined air discharge gap.

0003

[Problems to be Solved by the Invention] In the above-mentioned lightning arrester device, lightning surge current that has entered the power transmission line flashes over the air discharge gap from the discharge electrode on the energized side and flows to the discharge electrode on the ground side. A follow-on current based on the operating voltage that is discharged through the resistance element in the lightning arrester to the tower side is limited by the restoration of the resistance value of the resistance element, and is suppressed and cut off by the air discharge gap, preventing a ground fault. Prevented. When this lightning surge current is handled by a resistance element, the temperature of the resistance element rises due to Joule heat caused by the lightning surge current, and in some cases, the temperature of the resistance element may exceed the allowable temperature that determines the discharge withstand capacity of the resistance element, or even the operating voltage The electrical resistance in the nearby low voltage area drops below the allowable value. In particular, lightning surge currents such as winter lightning, which have a relatively small current value but have a long duration compared to summer lightning, cause the resistive element to process a large amount of energy, resulting in a temperature rise that is higher than that of summer lightning. As a result, the electrical resistance of the resistive element becomes insufficient, and the electrical resistance of the resistive element decreases significantly, causing a deterioration in the follow-on current breaking characteristics. In the worst case, this can lead to a ground fault. For this reason, it is necessary to increase the diameter or length of the resistance element in order to ensure the discharge withstand capacity and to ensure that the follow-on current breaking characteristics function properly. Due to the emphasis, it is difficult to apply it to existing insulator devices.

[0004] Furthermore, in a type of lightning arrester in which an insulating gas is sealed between an insulating jacket and a resistive element, once a lightning surge current enters the resistive element and the temperature rises, the gas acts as if it were a heat insulating material. It exhibits the properties of radial heat transfer, and the internal temperature does not drop easily. Therefore, the electrical resistance of the resistive element remains low, and when the superimposed lightning surge current enters, There was a problem in that the discharge withstand capacity and follow-on current blocking characteristics further deteriorated.

[0005] The purpose of the present invention is to suppress the temperature rise when a lightning surge current flows through a resistance element, thereby improving the discharge withstand capacity, and at the same time suppressing changes in the electrical resistance of the resistance element, thereby achieving stable follow-on current breaking characteristics. The purpose of this invention is to provide a lightning arrester that can exhibit the following effects.

[0006]

[Means for Solving the Problems] In order to achieve the above object, the present invention incorporates a resistance element with non-linear voltage-current characteristics inside an insulating mantle having a cap, and a resistance element having a non-linear voltage-current characteristic is installed at both ends of the insulating mantle. In the lightning arrester having an electrode fitting attached to the portion thereof, one end portion of the heat pipe is inserted into the resistance element, and
The other end is inserted into the cap of the insulating jacket.

[0007]

[Operation] By adopting the above-mentioned means, this invention causes the temperature of the resistance element to rise when a lightning surge current flows through the resistance element built into the lightning arrester during a lightning strike. Thermal energy associated with this temperature rise is transmitted to the outside of the resistance element by the heat pipe and then to the cap of the insulating jacket, and the thermal energy transmitted to the cap is radiated into the air from the surface of the cap. , the temperature rise of the resistance element itself is suppressed, thus reducing the thermal stress generated in the element, improving the discharge withstand capacity, and suppressing the decrease in the electrical resistance of the resistance element, which improves the blocking characteristics of follow-on current following lightning surge current. can be stabilized.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment embodying the present invention will be described below with reference to the drawings. As shown in Fig. 1, electrode fittings 3 and 4 on the grounding side and on the power supply side are fitted and fixed with adhesive 2 to the upper and lower ends of a voltage-resistant insulating cylinder 1 formed in a cylindrical shape from FRP (reinforced plastic) or the like. has been done. The electrode fitting 3 on the ground side is formed with a flange portion 3a for attachment to the steel tower side, and the electrode fitting 4 on the power supply side is formed with a bracket 4a for supporting the discharge electrode. A plurality of resistive elements 5 mainly made of zinc oxide and having non-linear voltage-current characteristics are housed in series inside the voltage-resistant insulating tube 1 . A heat transfer conductor 6 having excellent thermal conductivity is interposed between each of the resistance elements 5. An electrode plate 7 and a spring 8 are interposed between the electrode fitting 3 on the ground side and the resistance element 5, and the resistance element 5 and the heat transfer conductor 6 are pressed against each other to maintain a good thermal and electrical connection state. There is.

An insulating jacket 9 having a cap 9a made of EPDM rubber or the like is molded on the outer periphery of the voltage-resistant insulating cylinder 1. The voltage-resistant insulating tube 1 has a plurality of through holes 1a (180 holes in this embodiment) corresponding to the heat transfer conductors 6.
Insertion holes 6a are formed in the heat transfer conductor 6 so as to correspond to the through holes 1a. Before the insulating jacket 9 is molded, the heat pipe 10 is fixed through the through hole 1a and the insertion hole 6a, and the heat pipe is insulated so that the outer part of the heat pipe is buried inside the cap 9a. The mantle body 9 is molded.

A large number of radiation fins 11 are formed in the heat pipe 10 so as to be buried in the cap 9a. As shown in FIG. 2, a circular heat dissipation ring 12 made of metal with excellent heat transfer coefficient is connected to the tip of the heat pipe 10. The heat pipe 10 is a thermal conductive element having an equivalent thermal conductivity of 500 to 1000 times that of a silver rod of the same diameter. As shown in FIG. 3, this heat pipe 10 is made by completely expelling air from the inside of a metal tube 13 to create a vacuum state, and then sealing it with a small amount of working fluid 14 such as water, fluorocarbon, or methanol. A wick 15 is formed on the inner surface of the metal tube 13 to promote boiling, condensation, and capillarity of the working fluid 14.

Since the heat pipe 10 has the above-described structure, when one end of the metal pipe 13 is heated, the working fluid 14 boils at a low temperature because the pressure inside is reduced, and the vapor becomes a pressure liquid and moves at the speed of sound. It moves to the other end, and when it is cooled there, it condenses, releases latent heat, and liquefies, and the condensed liquid flows into the wick 1.
5 and returns to the end of the heating section, becomes boiling steam again and moves to the other end, and the cycle is repeated without any external force. Therefore, compared to the metal solid conduction heat pipe 10,
Extremely large amounts of heat can be transported instantaneously with very small temperature differences.

Next, the operation of the lightning arrester constructed as described above will be explained. Now, in FIG. 1, a lightning surge current due to a lightning strike enters the power-supplying side electrode fitting 4 from the power transmission line side (not shown), flows from the fitting through the resistance element 5 and the heat transfer conductor 6 in order, and reaches the grounding side electrode fitting 3. After that, it flows to a steel tower (not shown) and is discharged to the ground. Further, a follow-on current due to the operating voltage following the lightning surge current is suppressed by restoring the resistance value of the resistance element 5. When processing this lightning surge current, Joule heat is generated in the resistance element 5, but after this thermal energy is transferred from the resistance element 5 to each heat transfer conductor 6, the heat pipe 10 connects the cap of the insulating jacket 9. Part 9
instantaneously transmitted to a. At this time, the heat pipe 10 is connected to the insulation jacket 9 by the heat radiation fins 11 and the heat radiation ring 12.
Heat is efficiently transferred to. Moreover, the cap 9 of the insulating mantle 9
The heat transferred to a is radiated from its surface into the atmosphere. Therefore, the temperature rise of the resistance element 5 is suppressed to a predetermined value,
The discharge withstand capacity is ensured, and a decrease in the electrical resistance of the resistance element 5 is suppressed, and the follow-on current interrupting characteristics are stabilized.

As a result, the design of the resistor element 5 is designed in consideration of the fact that large lightning energy such as winter lightning penetrates the lightning arrester, increasing the temperature of the resistor element 5 and reducing the discharge withstand capacity and electrical resistance. This eliminates the need to increase the diameter and length of the resistance element 5, thereby making the element smaller and lighter, making it easier to manufacture, and reducing the cost of the lightning arrester. Furthermore, it is easy to apply to existing insulator devices.

[0014] When the temperature of the insulating mantle 9 increases, the mantle dries more easily, so that the contamination resistance voltage characteristic along the surface of the mantle 9 improves. Furthermore, the present invention is not limited to the above embodiments, but may be embodied as follows. In the embodiment described above, the heat transfer conductor 6 was interposed between each resistance element 5, but it is possible to provide the heat transfer conductor 6 at a certain interval, or omit this and insert the end of the heat pipe 10 into an insertion hole (not shown) formed in the resistance element 5 itself. omitted). Or electrode fittings 3, 4
Also add a heat pipe.

[0015]

[Effects of the Invention] As described in detail above, even when a lightning surge current enters during a lightning strike, the thermal energy of the resistance element generated by the lightning surge current is instantly transmitted to the insulating jacket side through the heat pipe. Therefore, the temperature rise of the resistance element can be suppressed, the discharge withstand capacity can be improved, and the follow-on current blocking characteristics can be stabilized, and the lightning arrester can be made smaller and lighter.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view showing an embodiment of a lightning arrester according to the present invention.

FIG. 2 is a sectional view taken along the line AA in FIG. 1;

FIG. 3 is a cross-sectional view of a heat pipe.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 voltage-resistant insulation tube, 5 resistance element, 6 heat transfer conductor, 9 insulation jacket, 9a cap, 10 heat pipe.

Claims (1)

[Claims] 1. A lightning arrester in which a resistance element with non-linear voltage-current characteristics is built into an insulating jacket having a shade, and electrode fittings are attached to both ends of the insulating jacket, comprising:
A lightning arrester characterized in that one end of a heat pipe is inserted into the resistance element, and the other end is inserted into a cap of the insulating jacket.