JPS63138614A - Arresting insulator - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] Purpose of the Invention (Field of Industrial Application) The present invention provides a method for quickly discharging surge current to the ground when a surge current due to a lightning strike is applied to a power transmission line, and interrupting the subsequent current. This invention relates to a suspended insulator type lightning arrester that prevents ground faults and enables retransmission of power.

(Prior Art) Conventionally, it has been considered to introduce lightning devices into power transmission lines in order to absorb lightning and switching surges and prevent power transmission line ground faults.

However, attaching a lightning arrester having only a lightning arresting function to a power transmission line is undesirable because it complicates the structure of the transmission line tower and the insulator device. For this reason, a suspended insulator type lightning arrester has been proposed, which combines the insulation and wire support functions of a conventional insulator and the lightning arresting function of a lightning arrester. As this lightning arrester, the applicant of the present application has proposed an insulator in which a lightning arrester element having non-linear voltage-current characteristics is attached to a cylindrical portion of the insulator body. A plurality of these lightning arrester insulators are connected in series as shown in FIG. 3 (see the arrangement in the drawing of the present application) and are used as an insulator device for supporting a power transmission line.

In addition, the cross-sectional area of the lightning arrester is 18c+J (element diameter 48φn) when the rated voltage is 140KV or less as a lightning arrester for a substation.
~32cnl (element diameter 64φmm), 32cal (element diameter 64φ dragon) for 280KV or less, and 64CdC element diameter 64φ two parallel for 500KV) are generally used. (Meiden Jiho May 1978 issue 1ffi
(Refer to Table 1, Vol. 142, No. 35, page 35) For transformers, it has the function of absorbing and reducing the level of switching surges generated when circuit breakers open and close. For this reason, for power transmission applications, the function for handling switching surges is not dominant in element design, and the element diameter has been determined from the standpoint of lightning surge handling, and the diameter has generally been reduced. When the line voltage of the transmission line is 66KV, it is 15cd,
For 275KV, it is 20CII! , it is set to about 25c+J in the case of 550KV.

(Problem to be Solved by the Invention) However, in such a conventional device, although the voltage sharing of each lightning arrester in a clean state can be controlled by a shield ring provided on the energized side, the outer surface of the lightning arrester is When soiled and wet, a leakage current that is considerably larger than the current that flows through the element when clean flows through the outer surface of the insulator, causing an imbalance in voltage sharing due to uneven soiling or drying due to the leakage current. . This imbalance cannot be controlled with a shield ring. In particular, since it is not possible to specify which insulators will share the high voltage, countermeasures must be taken for all lightning arrester insulators, and the only way to do this is to increase the overall length of the element. In this case, when dealing with lightning surges, the limiting voltage increases by the increase in the overall length of the element, making it difficult to protect the insulation between the adjacent insulator device or electric wires and the tower body, assuming application to existing equipment.

Structure of the Invention (Means for Solving the Problems) In order to solve the above-mentioned problems, the present invention provides a method for charging a single lightning arrester used when the line voltage of a power transmission line is 187 KV or less in a suspension insulator type lightning arrester. Breaking load 12~21to
n, and the cross-sectional area of the lightning arrester is approximately 30 cI! ! Based on the above, the electrical breakdown load of a single lightning arrester used for 275 KV or less is 21 to 33 tons, the cross-sectional area of the lightning arrester element is approximately 4Qc4 or more, and the electrical breakdown of a single lightning arrester used for 550 KV or less is set as follows. Load 33~5
4 tons, and the cross-sectional area of the lightning arrester is approximately 50c+J.
The above configuration is adopted.

(Function) By adopting the above-mentioned means, the present invention improves the potential sharing under dirty conditions in a pole installation state in which a plurality of lightning arresters are connected in series, and the overall element length of the lightning arrester series is reduced accordingly. Short is fine.

This makes it easy to protect other insulator chains from lightning surges, and it can be applied to existing railway lines.

(Example) An example embodying the present invention will be described below with reference to FIGS. 1 to 3.

As shown in FIG. 3, a large number of suspension insulator-type lightning arresters 3 are connected and suspended in series from a support arm l provided on a steel tower (not shown) via hanging fittings 2, and the lowest end of the lightning arrester 3 is A power transmission line is supported via a hanging metal fitting 4.

As shown in FIG. 1, an insulator body 5 constituting the lightning arrester 3
A cylindrical portion 5a, a fold portion 5b formed annularly and concentrically on the inner surface of the cylindrical portion 5a, and further, a cylindrical portion 5a.
It is integrally molded with a capped cylindrical head 5c integrally formed at the upper center of the head. Further, a cap fitting 7 is fixed to the outer periphery of the head 5c with cement 6, and an engagement recess 7a is formed in the cap fitting 7 so that it can engage the bottle fitting 8 of the MM insulator 3 directly above it. I have to. The upper part of the pin fitting 8 is fixed inside the head 5c with cement 6,
The lower end is engaged with the engagement recess 7a of the cap fitting 7 of the lightning arrester 3 directly below. In this way, a plurality of lightning arresters 3 are connected in series.

As shown in FIGS. 1 and 2, the cylindrical portion 5a has a plurality of cylindrical mounting holes 9 (four in this embodiment) at equal intervals and parallel to the pin fittings 8. It is formed to penetrate through 5a.

Each of the mounting holes 9 is provided with a plurality of cylindrical materials (in this example, 2 ([1i1) Lightning arrester elements 10 are inserted in series and fixed with adhesive using an insulating airtight sealant 11 made of glass, resin, rubber, or the like.

At both upper and lower ends of the mounting hole 9, sealing lids 12 and 13 made of inorganic material such as porcelain or glass that are weather resistant for outdoor use are adhesively fixed with the airtight sealant 11. The hermetic sealant 11 and the sealing lid 12 and 13 protect the lightning arrester 1.
It is designed to prevent deterioration of 0. Furthermore, an upper electrode 14 and a lower electrode 15 having a planar circular shape are interposed between the lightning arrester element 10 and the sealing lid 12.13, and the outer periphery of the upper electrode 14 and the lower electrode 15 are arranged on the outer periphery of the sealing lid 12.13. Lead portions 14a and 15a are integrally bent and led out through cutout recesses 12a and 13a.

The lead portion 14a is connected to the cap metal fitting 7,
The lead portion 15a is connected to the pin fitting 8 via a lead wire 16.

A ring-shaped electrode 18 is adhered and fixed to the upper surface of the cylindrical portion 5a using metallicon so as to electrically connect the respective lead portions 14a with each other with low inductance. Further, a ring-shaped electrode 19 for electrically connecting each lead portion 15a is fixed to the horizontal portion of each lead portion 15a by soldering or crimping.

By the way, the unbalance of the voltage sharing of the a lightning insulator chain under the dirty 1i condition is ideally 1.0 as shown in Figure 4.
However, based on the existing tower clearance and the clearance of the insulator device, the total length of the insulator chain elements is restricted to a certain value or less due to voltage limitations when dealing with lightning surges. This means that when lightning protection insulators are used on existing lines, the voltage imbalance will inevitably be suppressed, resulting in a voltage difference of 1.5% for equal distribution.
The degree is the upper limit. The imbalance of shared voltages under contaminated conditions can last for several hours, which is different from the abnormal voltage that lasts for about two seconds when designing a lightning arrester.

The above numerical values are empirical values because they are based on natural phenomena. One way to achieve the goal of reducing this unbalance by 1.5 times or less is to increase the cross-sectional area of the lightning arrester 10, as shown in Figure 4, and increase the element current when an unbalance of shared voltage occurs. As a result, it is necessary to generate a voltage drop in other insulators to suppress an increase in unbalance.

Here, with reference to FIG. 5, the specific numerical value of the cross-sectional area of the lightning arrester 10 is exemplified as follows when the line voltage of the power transmission line is classified into three levels and the applied breakdown load is illustrated.

First, when the line voltage of the power transmission line is 187 KV or less, the applied breakdown load of the lightning arrester alone is set to 12 to 21 Lon, and the cross-sectional area of the lightning arrester element 10 is set to approximately 30 cnl.

Similarly, when the line voltage is 275 KV or less, the applied breakdown load of the lightning arrester alone is 21 to 33 tons, and the M lightning element 1
The cross-sectional area of 0 is approximately 40 C1l+.

Similarly, when the line voltage is 550 KV or less, the breakdown load applied to the lightning arrester alone is 33 to 54 tons, and the lightning arrester 1
The cross-sectional area of 0 is approximately 50 cut.

Next, the operation of the lightning arrester constructed as described above will be explained.

When an excessive voltage due to a lightning surge is applied to the power transmission line, the current flows through the suspension fitting 4 to the pin fitting 8 of the lowest lightning arrester 3, leading to the lead wire 1G - lead part 15a - lower electrode. 15-Lightning arrester element 1o-Upper electrode 14-Lead portion 14a
- transmitted to the cap fitting 7; Thereafter, the cap metal fitting 7 is transmitted to the pin metal fitting 8 of the lightning arrester 3 directly above it. Similarly, the signal is transmitted to a plurality of lightning arresters 3 connected in series, and is transmitted from the cap fitting 7 of the uppermost lightning arrester 3 to the hanging fitting 2.
, and is grounded to the earth via the support arm 1.

At this time, the lightning arrester element 10 built into the insulator body 5 quickly reduces its resistance value due to its characteristics and discharges the large current caused by the lightning surge. Further, in response to a follow-on current following the lightning surge, the lightning arrester element 1o immediately restores its resistance value and restores insulation, so the follow-on discharge is suppressed and interrupted, and the electrical line returns to normal.

Now, in the embodiment of the present invention, the difference portion 5a of the lightning arrester 3
On the other hand, since a lightning arrester element 10 with a cross-sectional area approximately twice that of the conventional value is used, the element current can be increased when the shared voltage is unbalanced, and thereby an increase in unbalance can be suppressed.
Since the capacitance also increases, the overall length of the element can be set the same as before. Therefore, when connected in series as a power transmission line support insulator device to form a series of lightning arresters, it is possible to prevent the appropriate length of the lightning arrester from increasing.
It is easy to emphasize insulation from adjacent insulator devices or tower bodies, and can be easily applied to existing power transmission lines.

Note that the present invention is not limited to the above embodiments,
It may be specified as follows.

(1) Two, three, or five or more lightning arrester elements 10 are arranged at equal angles.

(2) Any one of the ring-shaped electrodes 18 and 19 may be omitted. Also, both ring-shaped electrodes 18 and 19 are omitted.

Effects of the Invention As detailed above, the present invention increases the element cross-sectional area of a single lightning arrester compared to the conventional one, thereby reducing the connection between the energized side and the grounding side both when clean and when contaminated. Since the potential sharing can be averaged and an increase in the appropriate length of the insulator can be prevented, it has the effect of being easily compatible with existing power transmission lines.

[Brief explanation of the drawing]

FIG. 1 is a partial half-longitudinal sectional view of a lightning arrester showing an embodiment of the present invention, FIG. 2 is a sectional view taken along the line A-A in FIG. 1, and FIG. 3 is a front view showing the usage state of the lightning arrester. Figure 4 shows J I SC3
A magnification for the cross-sectional area of the lightning arrester specified in 810;
FIG. 5 is a graph showing the relationship between the variation in potential distribution and the line voltage of the power transmission line and the cross-sectional area of the lightning protection element. 3... Lightning arrester, 5... Insulator body, 5a... Differential part, 5c... Head, 7... Cap fitting, 8... Bottle fitting, 9... Mounting hole, 10 ... Lightning arrester, 11.
...Airtight sealant, 12.13...Sealing lid, 14 (15
)...Top (bottom) electrode.

Claims (1)

[Scope of Claims] 1. A cap fitting (7) is fixed to the capped cylindrical head (5c) formed at the upper center of the cap portion (5a) of the insulator body (5), and the head (5c) is fixed. A pin fitting (8) is fitted and fixed inside the cap, a lightning arrester (10) with non-linear voltage-current characteristics is attached to the cap (5a), and the upper end of the lightning arrester (10) and An upper electrode (14) and a lower electrode (1
5), the lightning arrester used when the line voltage of the power transmission line is 187 KV or less, has a breakdown load of 12 to 21 tons, and the cross-sectional area of the lightning arrester (10) is approximately 30 cm^2 or more. Similarly, the applied breakdown load of a single lightning arrester used for 275 KV or less is 21 to 33 tons, and the lightning arrester element (10
) has a cross-sectional area of approximately 40 cm^2 or more, and the same 550
The breakdown load of a single lightning arrester used for KV or less is 3.
3 to 54 tons, and the lightning arrester element (10) has a cross-sectional area of approximately 50 cm^2 or more.