JPH0417223A - Lightning insulator device - Google Patents

Abstract

PURPOSE:To reinput power and simplify the construction by connecting a fuse element operated by a fault ground current to the inside of an insulating cylinder equipped with a discharge electrode and also filling the cylinder with dielectric reaction material which makes the fuse element into an insulator through operation of a fuse. CONSTITUTION:A fuse element 19 operated by a fault ground current is connected to the inside of an insulating cylindrical body 13 equipped with a fitting 14 to install the lightning insulator 6 of a discharge electrode body 8 and the discharge electrode 15 opposed to a discharge electrode 12, and also the dielectric reaction material 20 is filled, which makes the fuse element 19 into an insulator by operation of the fuse element 19. When the fuse element 19 is evaporated and molten through its operation by a fault ground current, therefore, it becomes an insulator through reaction to dielectric reaction material and further the insulating cylindrical body 13 becomes dielectric in addition to a discharge gap G, so that the discharge gap is electrically expanded and an insulation level increases. It is thereby possible to reinput a breaker and simplify the construction.

Description

[Detailed Description of the Invention] [Field of Industrial Application] This invention discharges lightning surge current to the ground when it flows through a power transmission line, and limits and interrupts the following current to prevent a permanent ground fault. The present invention relates to a lightning arrester device for preventing electrical discharge, particularly to a lightning arrester device having a discharge gap.

[Conventional technology]

In a conventional lightning arrester device with a discharge cap, when the lightning arrester element is damaged due to an unexpected lightning strike and becomes conductive, the discharge gap length can be increased (thus increasing the insulation level). Various devices that can be reloaded have been proposed.For example, Japanese Patent Application Laid-Open No. 63-1661
As shown in Japanese Patent No. 14, there was a device configured to sense a faulty ground fault current and mechanically rotate and slide a discharge electrode to enlarge a discharge gap.

[Problem to be solved by the invention]

However, especially in low-voltage systems, the faulty ground fault current has only a small amount of energy, so rotating and sliding the discharge electrode requires energy amplification means, which makes the drive mechanism complicated. At the same time, there was a risk that the device would lack reliability in operating normally for a long period of time after being installed on the steel tower.

The purpose of this invention is to electrically expand the discharge gap when the current limiting element built into the lightning arrester deteriorates or breaks and becomes conductive, increasing the insulation level and preventing the circuit breaker from breaking. It is an object of the present invention to provide a lightning arrester device which is capable of being reloaded, has a simple structure, and is reliable even for long-term use.

[Means to solve the problem]

In order to solve the conventional problems, the present invention provides a discharge electrode body 8.
A mounting bracket 14 to be attached to the lightning arrester 6 and the discharge electrode 1
A fuse element 19 activated by a fault earth fault current is connected within an insulating cylinder 13 provided with a discharge electrode 15 facing the discharge electrode 15, and an insulation reaction occurs in which the fuse element 19 becomes an insulator due to the operation of the fuse element 19. This is because the material 20 was filled.

[Effect]

In this invention, the discharge electrode I2 attached to the energized side of the insulator 2 and the discharge electrode body 8 are disposed facing each other with a discharge gap G, and the discharge electrode body 8 is attached to the lightning arrester 6, so that lightning surges can occur. It is possible to ground the lightning surge current without causing the discharge electrode body 8 to operate in response to the current, and to cut off the subsequent flow of the operating voltage that occurs thereafter.

In addition, when the lightning element built into the lightning arrester is destroyed and becomes conductive due to an unexpected lightning strike or deterioration due to long-term use, the fuse element 19 is activated by the faulty ground current and evaporates and melts. At the same time, it reacts with the insulating reaction material 20 filled in the insulating cylinder 13 to become an insulator, and in addition to the discharge gap G, the length of the insulating cylinder 13 becomes insulating, so the discharge gap is electrically expanded. The insulation level increases significantly. Therefore, the lightning arrester has excellent long-term reliability and excellent insulation recovery characteristics, which prevents re-ignition when the circuit breaker is re-closed, and enables power to be retransmitted.

〔Example〕

Below, examples embodying this invention will be described in the first example. This will be explained based on FIG.

In this embodiment, a case will be described in which a lightning arrester device is attached to only one line of a two-line power transmission line.

As shown in FIG. 1, an insulator 2 made of a suspended insulator is suspended and fixed at the tip of a support arm 1 of a steel tower.

A power transmission line 4 is supported by a wire clamp 5 below the insulator 2 via a connecting fitting 3. Also support arm l
A lightning arrester 6 having a built-in lightning arrester element with non-linear voltage-current characteristics is suspended and fixed in parallel with the insulator 2 on the lower surface of the tip. A discharge electrode body 8 is attached to a power-supplying side electrode fitting 7 provided at the lower end of the lightning arrester 6 with a mounting bolt 9 . Furthermore, arcing rings 10 and 11 are provided on the support arm 1 and the electrode fitting 7 on the power supply side of the lightning arrester 6 to prevent damage to the lightning arrester 6 due to creeping flash. On the other hand, a discharge electrode 12 is attached to the connecting fitting 3 of the insulator 2 with its tip end facing the discharge electrode body 8.

Further, the discharge electrode body 8 includes an insulating cylindrical body I3 and this insulating cylindrical body 1.
It is formed by a mounting bracket 14 provided on one side of 3 and a discharge electrode 15 provided on the other side.

FIG. 2 shows the discharge electrode body 8. In the center of the discharge electrode body 8, an insulating cylinder 13 made of an insulating material such as porcelain or FRP is formed in a cylindrical shape with left and right sides open, and a conductive cap 16.
17, the openings at both ends are covered and hermetically fixed. Inside this insulating cylinder 13, an insulating core 18 made of porcelain and having a star-shaped cross section is placed across the shaft center. A fuse element 19 made of silver wire or silver-plated copper wire is spirally wound around the insulating core 18, and each end is connected to a cap 16, 17, respectively. Note that the fuse element 19 does not operate against lightning surge current.
It is adapted to operate against fault earth fault currents. That is, the amount of heat Q required for the fuse element 19 to evaporate or melt and operate is expressed as Q = i'' r t - (1). Here, r is the electrical resistance of the fuse element 19, and i is the The current flowing through the fuse element 19, t, is the current duration time. Now, the lightning surge current that flows through the lightning arrester due to a normal lightning strike is about 5 KA, and this electrical shock current is processed by the lightning arrester, and the current duration time t is approximately 5 KA. Wave crest length x wave tail length =
It is about 2×20 microseconds. Therefore, the amount of heat Q due to the lightning surge current is approximately 52×20 r=500 r. On the other hand, in a resistive reactor grounding system, the ground fault current is about 0.3 to 0.4 KA, and the switching surge discharge current is about 0.2 to 0.3 KA, and the current duration t
are approximately 0.1 seconds and 0.002 seconds, respectively. Therefore, even in the resistive reactor grounding system, the amount of heat Q due to the fault ground current is (0,3)" XO, lXl0' r = 9000
It is about r. Also, the amount of heat Q due to the switching surge discharge current
is (0,3) 2X0.002xlO' r=18or
It is. Therefore, the amount of heat generated by lightning surge currents and switching surge currents is significantly smaller than the amount of heat generated by ground fault currents, so it does not operate against lightning surge currents and switching surge currents.
Fuse element 1 that operates in response to faulty earth fault current
You can select and install 9.

Silica sand 20 as an insulating reaction material is tightly packed inside the insulating cylinder 13, and when a large current flows, the fuse element 19 evaporates, and the fuse element 19 and the silica sand 20 react to cause an emergency. It is designed to be a highly insulating material.

The outer periphery of the insulating cylindrical body 13 is covered with a rubber material 21 by adhesion or filling, and insulation between the outer periphery of the insulating cylindrical body 13 and the rubber material 21 is ensured. Further, both ends of the rubber material 21 are fastened and fixed by band fittings 22 and 22. Further, a plurality of folds 23 are formed on the outer periphery of the rubber material 21 to prevent creeping flash from occurring.

At the top of both caps 16.17 there is a coordination horn 24.2.
5 are provided facing each other, and when an abnormal voltage occurs after the discharge electrode body 8 is activated, a flashover occurs between the coordination horns 24 and 25 to protect the discharge electrode body 8 from damage.

A mounting bracket 14 is attached to the cap 16 side with screws 26. The mounting bracket 14 is made of a conductive material,
Bolt insertion holes 27, 27 for attaching to the electrode fitting 7 of the lightning arrester 6 with attachment bolts 9 are formed on the negative side thereof. Further, a rod-shaped discharge electrode 15 is attached to the cap 17 side with a screw 28, and faces the discharge electrode 12 attached to the insulator 2 with a discharge gap G therebetween.

Note that the discharge gap G in this embodiment is set to be short enough to prevent flashover with respect to the operating voltage in order to minimize the insulation level against lightning surges. That is, the value is generally about the value of the interval called the abnormality insulation interval, and insulation coordination with the one-sided line or insulator 2 not equipped with a lightning arrester device is sufficiently achieved.

Next, the operation of the lightning arrester equipped with the discharge electrode body 8 as described above will be explained.

The lightning arrester 6 is insulated from the ground by the discharge gap G against the operating voltage.

Now, when a switching surge or a lightning surge is applied to the power transmission line 4 due to the opening/closing of the circuit breaker, the discharge occurs in the discharge cab G with a small insulation level and flows reliably to the lightning arrester 6 side. In FIG. 1, the switching surge current and the lightning surge current flow from the wire clamp 5 to the connecting fitting 3 and the discharge electrode 12, causing the discharge cap G to flash over. At this time, the flashover voltage, especially the lightning surge flashover voltage, is significantly lower than in the past. The support arm 1 then passes through the fuse element 19 of the discharge electrode body 8 and the current limiting element of the lightning arrester 6.
and is discharged to the earth. The subsequent flow of the operating voltage that occurs thereafter is current-limited and cut off by the current-limiting element of the lightning arrester 6, thereby preventing a ground fault. At this time, in the discharge electrode body 8, the second
In the figure, an opening/closing surge or a lightning surge that flashes over the discharge cap G flows from the discharge electrode 15 to the mounting bracket 14 via the fuse element 19. Note that the fuse element I9 is selected to be larger than the lightning surge withstand capacity of the current limiting element in the lightning arrester 6 to which it is installed. Can send surge current to the ground.

Next, if the current limiting element built into the lightning arrester 6 is damaged or deteriorated due to a lightning surge that exceeds expectations, it becomes conductive and cannot block the follow-on current following a lightning strike. . At this time, an AC overcurrent flows through the fuse element 19 of the discharge electrode body 8 to the support arm l of the steel tower. The energy due to the AC overcurrent at this time is much larger than the energy due to switching surges or lightning surges, so it exceeds the AC overcurrent withstand capacity of the fuse element 19.
The fuse element 19 is activated and evaporates. The steam of this fuse element 19 is transferred to the silica sand 20 filled around it.
As it melts, it diffuses and penetrates, changing into a highly resistive material that has insulating properties.

Therefore, as the discharge electrode body 8 operates, an insulator is interposed between the lengths of the insulating cylinders 13, and the insulation level increases significantly. That is, the discharge gap length has been electrically expanded, so that it can sufficiently withstand switching surge voltages, prevents flashover from occurring in the discharge gap G when the circuit breaker is turned on again, and enables power to be retransmitted.

Note that pleats 23 are formed in the rubber material 21, and the discharge electrode 1
2 and the mounting bracket 14, the insulation strength therebetween is also sufficient, and the coordination horns 24, 25 prevent damage to the discharge electrode body 8.

In addition, in this embodiment, the discharge gap G is set to be shorter than the abnormality insulation interval that does not cause flashover with respect to the operating voltage, and the insulation level is low, so that the lightning protection has excellent insulation coordination characteristics with the insulator 2 side. It can be an insulator device. Furthermore, since this lightning arrester is installed on a two-line electrical line where only one circuit is equipped with a lightning arrester, the electrical line has excellent insulation coordination characteristics with lines that are not equipped with a lightning arrester. I can do it.

In addition to the embodiments described above, the present invention can also be embodied as follows.

(1) Although this embodiment describes a lightning arrester using a suspended insulator, the present invention can also be applied to a lightning arrester using a tension insulator.

(2) Although this embodiment shows an example in which the discharge electrode body 8 is attached to the lightning arrester 6 side, it may also be attached to the connecting fitting 3 on the insulator 2 side, or it may be attached directly to the power transmission line 1. You may wear it.

(3) In this embodiment, an example was shown in which one discharge electrode body 8 was installed, but a plurality of discharge electrode bodies 8 were connected in series,
It is also possible to configure a suitable discharge gap G.

〔Effect of the invention〕

As described in detail above, the present invention connects a fuse element activated by a fault earth fault current within an insulating cylinder in which a discharge electrode body is provided with a mounting bracket for attaching it to a lightning arrester and a discharge electrode facing the discharge electrode. At the same time, if the lightning arrester built into the lightning arrester deteriorates or is damaged due to the operation of the fuse element and is filled with an insulating reactive material that uses the fuse element as an insulator, it can be prevented by mechanical means. By increasing the insulation level without causing damage, it is possible to provide a lightning arrester device that allows the power to be turned on again, has a simple structure, and is reliable even for long-term use.

[Brief explanation of drawings]

1.2 shows an embodiment of the present invention, FIG. 1 is a front view of a lightning arrester device, and FIG. 2 is a sectional view of a discharge electrode body. 2... Insulator, 6... Lightning arrester, 7... Electrode fitting, 8... Discharge electrode body, 12... Discharge electrode, 13...
...Insulating cylinder, 19...Fuse element, 20.
...Insulating reactive material, G...Discharge cap Patent applicant Nippon Insulator Co., Ltd. Representative Patent attorney Hironobu Onda (and one other person)

Claims (1)

[Scope of Claims] 1. An insulator (2) that insulates and supports a power transmission line, and a lightning arrester (6) that includes a built-in lightning arrester element with nonlinear voltage-current characteristics.
are installed in parallel on the steel tower, a discharge electrode body (8) is attached to the energized side electrode fitting (7) of the lightning arrester (6), and a discharge electrode (8) is attached to the energized side of the insulator (2). 12) and the discharge electrode body (8), in which the discharge electrode body (8) is provided with a mounting bracket (14) to be attached to the lightning arrester (6). A fuse element (19) activated by a fault earth fault current is connected within an insulating cylinder (13) provided with a discharge electrode (15) opposite to the discharge electrode (12), and the fuse element (19) A lightning arrester device characterized in that the fuse element (19) is filled with an insulating reaction material (20) that becomes an insulator when activated.