JPH0574923B2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a lightning arrester that can continue to retransmit power even if an accident occurs in a line lightning arrester installed on a power distribution line or transmission line. be.

[Technical background of the invention and its problems]

In the event that a lightning arrester that is directly grounded to the railway line receives an excessive load such as a direct lightning strike and burns out, resulting in a ground fault or short circuit, it is necessary to be able to continue power transmission by re-energizing the line after the circuit breaker trips. Generally, when a lightning arrester is internally burnt out, not only the creeping surface of the internal elements but also the inner surface of the insulator tube are burnt out or destroyed, causing damage to the line.
The insulation resistance between the ground terminals becomes almost zero, that is, a permanent failure occurs, and unless the faulty arrester is removed from the line, power cannot be retransmitted. In particular, if the work of searching for and removing a faulty arrester is time-consuming, it can sometimes lead to power supply failures for long periods of time.

As a countermeasure against this, for example, in a power distribution surge arrester, a disconnection device 52 is conventionally installed between the surge arrester grounding terminal 50 and the grounding lead wire 51 shown in FIG. By igniting the gunpowder and blowing off the grounding lead wire 51 with the explosive force, the required insulation distance is established between the grounding terminal 50 and the lead wire 51 (or the grounding structure) as shown in Figure 5b, and the accident arrester is installed. removed from electrical circuits,
Methods were being used to enable retransmission. However, this configuration had the following problems.

(1) Dangerous materials such as gunpowder are used for separation,
Because it involves explosions and arcs, it poses a public safety problem, especially when installed on railroad tracks in urban areas.

(2) In heavily polluted areas, the leakage current flowing to the insulator surface increases, but this current inevitably flows into the disconnection device 52, so this heat generation causes the disconnection device 5 to
2 may malfunction.

(3) Depending on the state of the pole installation, it may not be possible to maintain the necessary disconnection distance when the disconnection device 52 operates. It is also susceptible to the influence of outside air (for example, wind pressure, vibration, etc.).

[Purpose of the invention]

It is an object of the present invention to solve these problems and provide an earth arrester equipped with a safe and reliable disconnection device.

[Summary of the invention]

In order to achieve the above object, according to the present invention, an internal element and a fusible conductor connected in series to the internal element are arranged in an insulator pipe, and this fusible conductor instantly melts and melts when the internal element burns out. The gap between the gaps formed later is constructed so that its withstand voltage can withstand the normal operating voltage, and the fusible conductor is further isolated from the chamber containing the internal elements surrounded by an arc-resistant insulating layer. By storing the cutting device indoors, the reliability of the cutting device is improved.

[Embodiments of the invention]

The present invention will be explained below using a most preferred embodiment shown in FIG.

Inside the porcelain insulator tube 1, an insulating tube 4 made of epoxy resin or the like is housed concentrically with the insulator tube 1 to prevent the insulator tube 1 from being broken and scattered due to the uneven heat action of the mark when the lightning arrester burns out. . The inside of this insulating cylinder 4 is divided into upper and lower parts by a partition plate 5 at the middle in the axial direction.
It is isolated into two chambers A and B, and the upper chamber A side has an internal element 2 composed of a non-linear resistance element of a lightning arrester, while the lower chamber B side has a fusible conductor 3 of the required length.
are stored in each. As described above, the partition plate 5 is fixed at a predetermined position in the axially intermediate portion of the insulating cylinder 4, and the internal element 2 and the fusible conductor 3 are electrically connected in series via the partition plate 5. A pressure relief device consisting of a pressure relief plate 7, a pressure relief port 8, an arc guide 9, etc. is provided on one side of the chambers A and B, respectively, to close the upper and lower openings of the porcelain insulator tube 1. The fusible conductor 3 has the characteristic that it does not melt due to regular arrester leakage current and discharge currents such as lightning or switching surges that flow when the arrester is activated, but on the other hand, it melts instantaneously in response to ground fault current or short circuit current that flows during a surge arrester fault. Select the motsuta material and size. In addition, the length is selected so as to ensure an insulating distance sufficient to electrically withstand the voltage (continuous ground voltage) applied at the time of reinsertion in the air gap formed after fusing. The inner surface of the B chamber of the insulating tube 4 containing the fusible conductor 3 is protected by an insulating layer 6 having particularly excellent arc resistance. Insulating materials suitable for this purpose include, for example, Teflon, epoxy resins containing hydrated alumina, or organic materials such as Nomex (trade name);
Inorganic materials such as ordinary porcelain and alumina porcelain, and silicone rubber and the like are used as rubber materials.

The operation of the lightning arrester according to the embodiment of the present invention configured as above will be described below. When a fault current flows due to a flashover of the internal element 2, the fusible conductor 3 instantly melts, and the internal element 2 and the fusible conductor 3 are intertwined to form an arc. The internal pressure in chambers A and B in the insulating cylinder 4 increases due to arc heat, and the respective pressure relief plates 7
operates, and the burnout gas inside moves to the outside via the pressure relief port 8 and the arc guide 9. The released burnout gas has conductivity, so when the pressure is released from the upper and lower arc guides 9, the upper and lower arcs become interconnected external arcs, resulting in a short-circuit condition, so the gas is supplied from the power supply side. After that, the fault current no longer flows inside the arrester through the external arc, so that internal burnout can be minimized.

The degree of burnout while the arc inside the arrester continues will be explained below. Generally, the arc length on the A side of the insulating cylinder 4 in which the internal element 2 is housed is longer than that on the B side, and since the internal element 2 is composed of a plurality of components mainly consisting of organic substances, it is not susceptible to high temperatures. Due to the arc, a large amount of burnout gas is generated, and the creeping surface of the internal elements and the inner surface of the A chamber of the insulating tube 4 are all carbonized and burnt out.
The insulation resistance on the room side has become almost zero. On the other hand, the B chamber side inside the insulating cylinder 4 is a fusible conductor 3.
Since the A and B chambers are completely separated by the partition plate 5, burnout gas from the A chamber side will not enter the B chamber side in the event of an accident. Therefore, the degree of burnout is clearly B.
Symptoms are milder on the room side. In addition, the inner surface of the insulating cylinder 4, which is easily carbonized, is protected by the insulating layer 6 made of the above-mentioned arc-resistant material, and the insulating layer 6 itself exhibits particularly strong resistance to arcs, and the creeping insulation resistance is not so great. Does not decrease. On the other hand, since the porcelain insulator tube 1 is protected by the insulating tube 4, it is constructed so that the arc radiant heat and internal pressure increase in the event of an accident will not directly act on it, so it will not be destroyed or scattered, and it will be able to maintain its original shape even after the accident.

Next, we will explain the effect when the power is turned on again. The arc formed between both terminals of the fusible conductor 3, which was fused by the fault current at the time of the accident, disappears as soon as it transfers to an external arc, and then insulation recovery begins, and then it is reintroduced by the subsequent circuit breaker trip. Insulation is completely restored during the no-voltage period. In this situation, if the circuit voltage is re-ignited to the lightning arrester after the accident, the insulation resistance of the internal element 2 has completely become zero, so all the circuit voltage will be transferred to the insulation tube chamber B side. However, in order to sufficiently withstand this applied voltage, the creeping surface of the arc-resistant insulating layer 6 and the insulation of the air gap formed after the fusible conductor 3 disappears, the power supply can be carried out with the fault arrester removed from the circuit. becomes possible. According to the inventor's experimental results, for example, in a 66kV system circuit, a gap length of 250mm (= length of fusible conductor 3) is required for a 30kA class short circuit accident.
If there is, the re-injection will be successful within 0.35 seconds after the accident trip.

FIGS. 2 to 4 show other different embodiments of the present invention. In these embodiments, members corresponding to those in FIG. 1 are given the same reference numerals as in FIG. 1. In FIG. Give an example. In FIG. 3, an insulating cylinder 4 having an arc-resistant insulating layer 6 is provided only on the fusible conductor 3 side, and the insulating cylinder in the A chamber on the internal element 2 side is omitted. Further, FIG. 4 shows a structure in which a shielding tube 10 made of an arc-resistant material is provided in the air between the fusible conductor 3 and the insulating tube 6. Each of these embodiments can be selected as appropriate depending on the short-circuit capacity of the circuit to which it is applied. As a result, a rational and economical lightning arrester with a disconnection device can be constructed.

〔Effect of the invention〕

As described above, according to the present invention, the disconnection device in the event of a lightning arrester accident can be built into the sealed container of the lightning arrester itself, so there is no need to worry about threatening public safety, and there is no risk of malfunction due to contamination or the influence of external weather conditions. It can be expected to operate safely and with high reliability without any risk factors, and can greatly contribute to the supply reliability of the power transmission and distribution system.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a lightning arrester structure showing one embodiment of the present invention, FIGS. 2, 3, and 4 are sectional views showing other embodiments of the present invention, and FIGS. 5a and 5b are It is a schematic block diagram which shows the conventional lightning arrester with a disconnection device. DESCRIPTION OF SYMBOLS 1... Porcelain insulator tube, 2... Internal element, 3... Fusible conductor, 4... Insulating tube, 5... Partition plate, 6... Arc-resistant insulating layer, 7... Pressure release plate, 8... pressure relief port,
9...Arc guide, 10...Shiyahei tube.

Claims (1)

[Scope of Claims] 1. An internal element composed of a non-linear resistance element and a fusible conductor connected in series with this internal element are housed and arranged in a porcelain insulator tube, and upper and lower openings of the porcelain insulator tube are opened. The fusible conductor is selected so that it will be fused when the internal element burns out, and the withstand voltage between the gaps of the gap formed after the fusion can withstand the normal operating voltage. a second chamber surrounded by an arc-resistant insulator and isolated from the first chamber within the porcelain tube containing the internal element;
A lightning arrester characterized by being housed inside a room. 2 The first chamber and the second chamber include an insulating tube arranged concentrically with the insulator tube within a porcelain insulator tube, and a partition plate that separates the insulating tube provided in the axially intermediate portion of the insulating tube into two chambers. Claim 1 formed by
Lightning arrester as described in section. 3 The first chamber and the second chamber include an arc-resistant insulating tube arranged concentrically with the insulator tube within a porcelain insulator tube, and an arc-resistant insulating tube provided at an axially intermediate portion of the arc-resistant insulating tube. 2. The lightning arrester according to claim 1, wherein the lightning arrester is formed by a partition plate that separates the lightning arrester into two chambers. 4. The lightning arrester according to claim 1, wherein the second chamber is formed by an insulating tube arranged concentrically with the porcelain insulator tube, and a partition plate that closes an opening on one side of the insulating tube.