JPH04303520A - Lightning insulator device - Google Patents

Abstract

PURPOSE:To prevent the damage to a resistance element and also enabling the quick return of a system through resetting a breaker by surely making flashover in a protective gap between arcing horns when thunderbolt surge current, exceeding the maximum allowable discharge current of the resistance element built in a lightning insulator, is infiltrated. CONSTITUTION:Setting is made so as to make the flashover of an air protection gap length L between charge and earth sides arcing horns 13 and 14 by current, slightly lower than the maximum allowable discharge current Imax, decided with a resistance element housed in the fitting tube part 24 of a lightning insulator string 7, and so as not to make the flashover below a rated discharge current Ir decided by the resistance element of the lightning insulator string 7.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] This invention is designed to quickly discharge a normal lightning surge current to the ground when it flows through a power transmission line.
A lightning arrester device that can prevent ground faults by suppressing and interrupting the subsequent follow-on current, and can prevent damage to the resistive element built into the lightning arrester in the event that an abnormal lightning surge current that exceeds expectations flows. It is related to.

0002

[Prior Art] Conventionally, a lightning arrester having a resistance element with non-linear voltage-current characteristics is interposed between a grounding side and a power supply side, and a power supply side metal fitting and a grounding side metal fitting of the lightning arrester insulator are provided. In a lightning insulator device in which arcing horns on the energizing side and the grounding side are provided between the arcing horns on the energizing side and the grounding side to prevent creepage flashover of the lightning arrester, an air protection gap between the arcing horns on the energizing side and the grounding side is provided. The length of the lightning arrester was set to be long enough to prevent flashover between both arcing horns even if the maximum allowable discharge current flows through the lightning arrester.

0003

[Problem to be Solved by the Invention] Therefore, in conventional lightning arrester devices, when an unexpectedly abnormal lightning surge current flows through the lightning arrester, the resistance element is destroyed due to conduction, and the expensive lightning arrester must be replaced. There was a problem with becoming. The purpose of this invention is that when a lightning surge current that exceeds the maximum permissible discharge current of the resistive element built into the lightning arrester insulates, the limiting voltage ensures flashover in the protective gap between the arcing horns, thereby preventing damage to the resistive element. It is an object of the present invention to provide a lightning arrester device that can prevent such problems and also enable quick recovery of the system by re-closing the circuit breaker.

0004

[Means for Solving the Problems] In order to achieve the above object, the present invention interposes a lightning arrester having a resistance element with non-linear voltage-current characteristics between the ground side and the energized side, and In the lightning arrester device, arc horns on the charging side and the grounding side are provided between the charging side metal fitting and the grounding side metal fitting of the lightning arrester to prevent creeping flashover of the lightning arrester. The air protection gap length between the arcing horns on the ground side is flashed over at a current slightly lower than the maximum allowable discharge current determined by the resistive element of the lightning arrester, and the rated discharge is determined by the resistive element of the lightning arrester. It is set so that flashover does not occur below the current.

[0005]

[Operation] According to the present invention, a lightning surge current that is less than the maximum allowable discharge current of the resistor element flows through the resistor element of the lightning arrester and is discharged to the ground, and the subsequent current that occurs is suppressed and interrupted by restoring the resistance value of the resistor element. Ground fault accidents are prevented. Further, if a lightning surge current exceeding the maximum allowable discharge current of the resistor element flows, flashover occurs in the protective gap between the arc horns, so the resistor element is not destroyed. Flashover in this protection gap causes a ground fault, which is immediately retransmitted after the substation circuit breaker is tripped.

[0006]

[Example] An example embodying this invention is shown below in Figure 1.
〜Explained based on FIG. 6. As shown in FIG. 1, a connecting yoke 3 is horizontally supported on a support arm 1 of a steel tower via an upper hanging metal fitting 2. At the left end of the connecting yoke 3 is a suspension insulator chain 5 formed by connecting a plurality of ordinary suspension insulators 4 in series.
is suspended, and a suspension type lightning arrester chain 7 made up of a plurality of suspended type lightning arrester insulators 6 connected in series is suspended from the right end. A lower connecting yoke 8 is horizontally connected between the lower ends of both insulator chains 5 and 7, and a power transmission line 10 is supported on the connecting yoke 8 via a lower hanging metal fitting 9.

Arc horns 11 are provided at both upper and lower ends of the suspended insulator chain 5 to capture creeping flashover of the insulator chain.
, 12 are supported. Further, arc horns 13 and 14 forming a parallel protection gap G are supported at both upper and lower ends of the suspended lightning arrester series 7. As shown in FIG. 3, the suspended lightning arrester 6 includes an insulator body 21 and a cap metal fitting 2 that is fitted and fixed to a head integrally formed at the upper center of the insulator body 21.
2, a pin fitting 23 fitted and fixed inside the head, and a voltage housed in a mounting cylinder 24 integrally formed on the insulator body 21.
The resistance element 25 has non-linear current characteristics. Cap electrodes 26 and 27 are fitted to both upper and lower ends of the mounting cylinder 24, and both cap electrodes 26 and 27 are electrically connected to the cap metal fitting 22 and the pin metal fitting 23 by lead wires 28 and 29. .

The maximum allowable discharge current Imax due to the resistance element 25 of each lightning arrester chain 7 constructed as described above is as follows:
Although different for each voltage class, the rated discharge current Ir and maximum allowable discharge current I of the lightning arrester chain 7 used for a specific voltage class
max can be confirmed theoretically or experimentally. In the lightning arrester device configured as described above, when a lightning surge current flows through the power transmission line 10, the current is slightly lower than the maximum allowable discharge current Imax (Imax - Δ
I) If it is below, it flows to the lightning arrester chain 7 side and is discharged from the support arm 1 of the steel tower to the earth, and subsequent current caused by the operating voltage is suppressed by restoring the resistance value of the resistance element 25. Also, the lightning surge current is equal to the current (Imax −Δ
If it is above I), it flows to the protection gap G side, and damage to the resistance element 25 of the lightning arrester chain 7 is prevented.

By the way, FIG. 4 shows the relationship between the lightning surge discharge current and the cumulative probability of a lightning accident at a line voltage of 66 KV to 77 KV. According to this graph, for example, lightning arrester series 7
The cumulative probability of an accident due to a lightning current when the discharge current exceeds the rated discharge current Ir (17 KA) is 90%, which accounts for the majority, and the maximum allowable discharge current I increases the possibility of damage to the resistive element 25.
It can be seen that almost no accidents occur when the lightning current exceeds max (65 KA).

Therefore, this maximum allowable discharge current Imax
and the rated discharge current Ir, and the arc horns 13, 14.
The relationship between the protection gap length L and the protection gap length L will be explained below. FIG. 5 shows the ratio of the rated discharge current Ir and maximum allowable discharge current Imax to the corresponding limiting voltages Vr and Vmax of the lightning arrester chain 7. According to this graph, if the limit voltage Vr of the rated discharge current Ir is 1, the maximum allowable discharge current Imax
The ratio of the limiting voltage Vmax is set to 1.3 or more.

Limiting voltage Vr near the rated discharge current Ir
The reason why flashover does not occur in the protection gap G and ground faults caused by lightning strikes on the power transmission line can be prevented will be explained below. For example, in the case where the line voltage is 66 KV, the limiting voltage Vmax when operating at the maximum allowable discharge current Imax of the lightning protection insulator device is 350 KV, and at the same time, the limiting voltage Vr when operating at the rated discharge current Ir is Vmax.
Since it is less than 1/1.3 of (350KV), 269K
V or less, and as shown in FIG. 6, flashover does not occur in the parallel protection gap G, thus making it possible to prevent a lightning strike accident.

[0012] Furthermore, the parallel protection gap length L that has a probability of 50% flashover with respect to the limit voltage Vmax (350 KV) is 500 mm;
Since it is set to 410 which is 0%, the flashover probability at Vmax can be increased to 99% or more. On the other hand, the parallel protection gap length L that has a 50% probability of flashover for the limited voltage Vr (269 KV) up to the rated discharge current Ir, which accounts for the majority of lightning strikes, is 3.
70 mm, and the set parallel protection gap length L (41
0 mm) corresponds to 111% of that value, so the flashover probability with respect to the limit voltage Vr is 0.1% or less, and lightning strikes can be substantially prevented.

Next, another example of the present invention will be explained in detail with reference to FIG. This embodiment is a suspension type insulator device that supports a power transmission line 10 only by the above-mentioned ordinary suspension insulator chain 5, in which an integral lightning arrester 32 is suspended and supported from the support arm 1 via a mounting adapter 31, and A discharge electrode 33 on the energized side is supported on the lower hanging metal fitting 9, a discharge electrode 34 on the ground side is supported on the lower end of the lightning arrester 32, and a predetermined air discharge gap is formed between both the discharge electrodes 33 and 34. It forms G1. Further, arc rings 35 and 36 on the energizing side and the grounding side are supported at both upper and lower ends of the lightning arrester 32, and the protection gap length L between the rings 35 and 36 is set to the same value as in the above embodiment. The flashover is set to occur at a current slightly lower than the maximum allowable discharge current Imax determined by the resistive element 25 of the lightning arrester 32, and not to occur below the rated discharge current Ir determined by the resistive element 25 of the lightning arrester 32. There is.

In this embodiment, when a lightning surge current enters the power transmission line 10, it is flashed over from the lower hanging metal fitting 9 and the discharge electrode 33 on the charging side to the discharge electrode 34 on the ground side, and the resistance element of the lightning arrester 32 is 25, flows from the mounting adapter 31 to the support arm 1, and is discharged to the ground. Furthermore, when a lightning surge current exceeding the maximum allowable discharge current Imax of the resistive element 25 flows, the current does not flow into the lightning arrester 32, but is flashed over by the protective gap G between both arc rings 35 and 36. , flows from the mounting adapter 31 to the support arm 1 and is discharged to the ground, preventing destruction of the resistive element 25 and eliminating damage to the lightning arrester 32.

It should be noted that the present invention is not limited to the above-mentioned embodiments, and may be embodied by making arbitrary changes without departing from the spirit of the invention, such as forming the arc horns 13 and 14 in a ring shape. can.

[0016]

Effects of the Invention As detailed above, this invention ensures that when a lightning surge current that exceeds the maximum allowable discharge current of the resistive element built into the lightning arrester insulates, flashover occurs in the protective gap between the arcing horns. This has the effect of not only preventing damage to the resistor element but also enabling quick recovery of the system by re-throwing the circuit breaker.

[Brief explanation of drawings]

FIG. 1 is a front view of a lightning arrester device embodying the present invention.

FIG. 2 is a right side view of FIG. 2.

FIG. 3 is a half-longitudinal cross-sectional view showing a suspended lightning arrester.

FIG. 4 is a graph showing the relationship between lightning surge discharge current and lightning accident probability.

FIG. 5 is a graph showing the relationship between discharge current and limiting voltage.

FIG. 6 is a graph showing the relationship between limiting voltage and protection gap length.

FIG. 7 is a front view showing an embodiment of another lightning arrester device of the present invention.

[Explanation of symbols]

6 Suspended lightning arrester, 7 Suspended lightning arrester series, 13
arcing horn forming a protective gap G, 14
Arc horn forming protective gap G, 32 Lightning arrester, 35 Arc ring forming protective gap G, 36 Arc ring forming protective gap G, G
Protection gap, L Protection gap length.

Claims (1)

[Claims] Claim 1: A lightning arrester having a resistance element with non-linear voltage-current characteristics is interposed between the grounding side and the energized side, and the energizing side metal fitting and the grounding side metal fitting of the lightning insulator are interposed. In a lightning insulator device in which arcing horns on the energizing side and the grounding side are provided between them to prevent creepage flashover of the lightning arrester, the air protection gap length between the arcing horns on the energizing side and the grounding side is: The flashover is set to occur at a current slightly lower than the maximum allowable discharge current determined by the resistance element of the lightning arrester, and the flashover is not performed below the rated discharge current determined by the resistance element of the lightning arrester. Lightning arrester device.