JPH05314842A - Suspension type lightning protection insulator device for transmission line - Google Patents

Abstract

PURPOSE:To facilitate application to existing transmission line supporting insulator device by reducing the link number of suspension insulators having no lightning protection function, and restraining the string length of the insulators. CONSTITUTION:Plural suspension type lightning protection insulators 5 are linkedly suspended in series with a supporting arm 1 of an iron tower, and also plural anti-pollution type suspension insulators 6 are linkedly suspended in series to the lowermost end lightning protection insulator 5, to support transmission line L with the lowermost end part of the insulator 6. Intermediate arcing horns 30, also used for an earthing side dischage electrode, are fitted to a cap fitting 14 of the uppermost part suspension insulator 6, and also a lower part arcing horn 12, also used for a charging side discharge electrode, is supported with the lower part of the lowermost end suspension insulator 6, to form a given aerial discharge gap G between both the horns 30 and 12. A suspension insulator, having a characteristic possessing a pollution withstand voltage characteristic of 1.3 or more times compared with that of a standard suspension insulator, is used for the suspension insulator 5.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a ground fault accident in which when a lightning surge current enters a power transmission line, it is quickly discharged to the ground, and a continuous current based on an operating voltage generated thereafter is suppressed and cut off. The present invention relates to a suspension type lightning arrester device for a transmission line, which can be prevented in advance.

[0002]

2. Description of the Related Art As a conventional suspension type lightning arrester device for a transmission line, the applicant of the present invention has proposed a device disclosed in Japanese Patent Laid-Open No. 62423/1993. This lightning arrester device suspends a plurality of suspension type lightning arrestors connected in series to a support arm of a steel tower via an upper hanging metal fitting, and suspends the lightning arrestor at the lowermost end without a lightning arrester function. A plurality of insulators are connected and suspended in series, and the suspension insulator at the lowermost end supports a power transmission line through a lower suspension metal fitting. Further, the uppermost suspension insulator and the lower suspension metal fitting support discharge electrodes on the ground side and the charging side, and a predetermined air discharge gap is formed between the discharge electrodes. Further, a voltage is applied to the cap portion of the suspension type lightning arrestor.
In addition to accommodating a resistive element having a non-linear current characteristic, the resistive element is sealed by upper and lower cap electrodes, and the cap metal fitting of the suspension type lightning arrestor has no lightning protection function due to deterioration of the resistive element. To prevent the burnout of the surface of the insulator body of the suspended type lightning protection insulator by guiding the arc to the outside of the lightning protection insulator when the continuity is broken by the continuous current based on the operating voltage (normal ground voltage) following the lightning surge current. The arc guide of is attached.

In the suspension type lightning arrester device thus constructed, since the air discharge gap is mechanically fixed to the suspension insulator string, the gap can be dealt with by the movement of the insulator device or the power transmission line. The change in length is small,
It has the advantages of having stable discharge characteristics and also having a wire load supporting function as in the conventional standard insulator device.

[0004]

In the above-mentioned lightning protection insulator device, even if the entire insulator connection length is the same as the entire connection length of the suspension insulator series using only standard suspension insulators, the resistance element is It has been considered that the current following the lightning surge current can be surely suppressed and cut off when the resistance element is brought into a conductive state due to deterioration or unexpected lightning strike.

However, in the above-mentioned conventional lightning protection insulator device,
Since a standard suspension insulator was used as a suspension insulator without a lightning protection function, when the surface of the insulator body of the standard suspension insulator is contaminated and moistened by contaminants containing salt, the resistance element of the arrester insulator series is If the resistance value has decreased due to deterioration,
There is a high probability that the insulator surface will flash over due to the operating voltage of the transmission line or the healthy phase rising voltage at the time of one-line ground fault, that is, the pollution withstand voltage characteristics of the suspension insulator series will be insufficient, thus increasing the number of connected suspension insulators. It turned out to be necessary. For this reason, the insulator connection length of the entire lightning protection insulator device becomes long, and a new problem arises in that it is difficult to apply it to an existing transmission line support insulator device.

The electrical characteristics required for the suspension type lightning arrester device having the above-mentioned series gap will be examined in the following three cases. (Case) When the insulator surface of the suspension type lightning arrester device is polluted The required value of the equivalent salt deposition density of the polluted surface of the insulator body, that is, the required pollution degree, does not cause flashover at the normal operating voltage in the transmission line or substation It is required to be able to insulate.

In the prior art, when the required pollution becomes large, it is necessary to increase the creepage insulation leakage distance for both the lightning arrestor and the standard suspension insulator. In the lightning arrester, the resistance element is housed in the porcelain cap portion. In addition, the lightning insulator has a large cap diameter and a heavy weight, which makes it difficult to handle during transportation and construction.

(Case) When the lightning surge current enters in the normal state of the resistance element When the lightning strike occurs, the lightning surge current causes the air discharge gap to operate, and the lightning arrester is provided with the lightning surge current limiter voltage and the operating voltage based on the lightning surge current. When applied to the lightning protection device, it is required that the lightning arrester or the entire lightning arrester device can be insulated without flashover by the limiting voltage and the operating voltage.

Further, it is also required that the lightning arrester or the entire lightning arrester device can be insulated without flashover within the time required for the arc of the series gap to extinguish against the operating voltage or the healthy phase rising voltage at the time of one-line ground fault. It

With respect to the conditions of the case, almost all the voltage such as the operating voltage is applied to the lightning protection insulator series.
Since the insulation of the air discharge gap is restored in an extremely short time (1 cycle or less) due to the continuous current interruption capability of the resistance element, the lightning protection insulator is required to have only a short-time insulation property. No such measures for strengthening insulation are required.

(Case) When lightning surge current occurs when the resistance element is deteriorated When the resistance element is deteriorated due to long-term use or is damaged due to a lightning stroke exceeding the designed resistance of the resistance element, the lightning protection device is connected to the AC grounding device. If a circuit breaker trips due to a short circuit or short circuit current, and the circuit breaker is turned on again,
It is required that the switching surge voltage generated at that time can be insulated by a standard suspension insulator series that does not have a lightning protection function. Further, it is required that the standard suspension insulator series can insulate against the operating voltage at the required pollution degree.

That is, since the lightning protection insulator string has a poor insulation, the switching surge voltage,
It is necessary to insulate the operating voltage. For this reason, the number of standard suspension insulators connected is increased, and as a result, a gap type lightning arrester device with a long insulator connection length is constructed, and when it is applied to an existing steel tower (or substation premises). However, there are cases where it is difficult to apply due to restrictions on the length.

An object of the present invention is to solve the above-mentioned conventional problems and to suppress the connecting length of a suspension insulator series having no lightning protection function without increasing the size of the suspension type lightning arrestor and to support the existing transmission line. It is an object of the present invention to provide a lightning arrester device for a power transmission line that can be easily applied to an insulator device.

[0014]

In order to achieve the above-mentioned object, the present invention connects the suspension type lightning arresters in series, and the resistance elements of the respective suspension type lightning arrestors are not connected to each other via lead wires. Electrically connected, a plurality of suspension insulators without a lightning protection function are connected in series at the end of the lightning protection insulator series, and a charging side discharge electrode and a ground side discharge electrode are provided at both ends of this suspension insulator series. In the suspension type lightning arrester device for transmission lines which is attached and has an air discharge gap between both discharge electrodes, the pollution withstand voltage characteristic as a suspension insulator without the lightning protection function is compared to a standard suspension insulator. The measure is to use a salt-resistant suspension insulator having a property of 1.3 times or more.

[0015]

The present invention uses a salt-resistant suspension insulator having a pollution withstand voltage characteristic of 1.3 times or more as compared with a standard suspension insulator as a suspension insulator having no lightning protection function. Even if the surface of the insulator string is contaminated, its creeping insulation leakage distance can be secured without increasing the connection length of. For this reason, in the polluted state of the suspension insulator series, when the resistance value of the resistance element of the lightning insulator series is reduced due to deterioration, etc., even if the operating voltage or the rising voltage of the sound phase at the time of one-line ground fault is applied, The flashover of the line is prevented. In addition, the lightning strike function deteriorates due to a lightning stroke that exceeds the design value, and a ground fault occurs due to the continuous current due to the operating voltage.The creeping flashover of the suspended insulator series due to the switching surge voltage when the circuit is turned on again after the breaker trips Is prevented.

Further, according to the present invention, since the connecting length of the suspension insulator series is not long, the lightning arrester device can be easily applied to the existing transmission line support insulator device without changing the steel tower structure.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be described below with reference to the drawings. As shown in FIG. 1, a suspension metal fitting 2 is connected to a support arm 1 of a steel tower, an upper horn mounting metal fitting 3 and a clevis link 4 are connected in series to the suspension metal fitting 2, and an upper horn mounting metal fitting 3 is further connected. A plurality of suspension type lightning arresters 5 are connected and suspended in series.

A plurality of salt-resistant suspension insulators 6 having no lightning protection function are connected and suspended in series at the lowermost suspension type lightning arrester 5, and a lower horn is attached to the lowermost suspension insulator 6 via a socket clevis 7. The mounting member 8 is connected, and the mounting member 8 supports an electric wire clamp 10 that supports the power transmission line L via a connecting link 9.

The upper horn mounting bracket 3 and the lower horn mounting bracket 8 also serve as an upper arc horn 11 for preventing creeping flashovers of a lightning arrestor series and a salt-resistant suspension pendulum series, and a discharge electrode on the power-supply side. The lower arc horn 12 is attached.

The salt-resistant suspension insulator 6 which does not have the lightning protection function is fitted and fixed to an insulator body 13 having a high fold portion 13a as shown in FIG. 2 and a head formed in the central portion of the insulator body 13. The cap metal fitting 14 and the pin metal fitting 15 fitted and fixed inside the head portion.

Next, the structure of the suspended lightning arrester 5 will be described with reference to FIG. A cap metal fitting 22 is fitted and fixed to the head of the insulator main body 21 by cement, and a pin metal fitting 23 is fitted and fixed to the inside of the head by cement. A resistor element 24 made of, for example, a material whose main characteristic is zinc oxide and whose voltage-current characteristic is non-linear is housed inside a plurality of mounting cylinder portions 21a formed integrally with the cap portion of the insulator main body 21. It is fitted and fixed by the upper cap electrode 25 and the lower cap electrode 26 via an electrode plate or a biasing spring.

If the resistance element 24 of the suspension type lightning arrestor 5 becomes unable to interrupt the follow-up current due to deterioration or the like and becomes conductive due to deterioration or the like, the arc is guided to the outside by the outer periphery of the cap fitting 22. The arc guide 27 for preventing the insulator body 21 from being broken is horizontally fixed. The upper cap electrode 25 and the cap fitting 22 are electrically connected by a lead wire 28, and the lower cap electrode 26 and the pin fitting 23 are electrically connected by a lead wire 29.

As shown in FIG. 1, the arc guide 27 is attached to the cap fitting 14 of the salt-resistant suspension insulator 6 located at the top.
Are fixed by bolts or the like so that they are opposed to the lower cap electrode 26 of the lightning protection insulator 5 on the lowermost side with a predetermined gap in the mounted state. Further, the arc guide 27 has an intermediate arc horn 3 as a discharge electrode on the ground side.
0 is supported in a cantilever manner and faces the lower arc horn 12 with a predetermined air discharge gap G.

In the lightning arrester device configured as described above, when a lightning surge current enters the power transmission line L, this current flashes the air discharge gap G from the connecting link 9, the lower horn mounting member 8 and the lower arc horn 12. It flows over and flows into the intermediate arc horn 30. Then, the cap metal fitting 14 of the suspension insulator 6 located at the uppermost position from the horn,
The lower cap electrode 26, the resistance element 2 through the pin metal fitting 23 and the lead wire 29 of the suspension type lightning protection insulator 5 located at the lowermost end.
4, the upper cap electrode 25, the lead wire 28, the cap fitting 22, and the resistance element 24 of the lightning protection insulator 5 located immediately above.
Flow through the upper horn mounting bracket 3, the clevis link 4, and the suspension bracket 2 and then to the support arm 1 of the steel tower for discharge to the ground.

On the other hand, the follow-up current based on the operating voltage following the lightning surge current is the air discharge gap G between the lower arc horn 12 and the intermediate arc horn 30, and each resistance element 24.
Restoration of the resistance value of the power supply suppresses and cuts off the ground fault.

If the resistance element 24 housed in the cap portion of the lightning protection insulator 5 deteriorates due to long-term use and a lightning surge current intrudes and the subsequent current flowing therethrough cannot be suppressed and interrupted, the resistance is reduced. The element 24 is conductively broken, the cap electrodes 25 and 26 thereof are separated from the mounting cylinder portion 21a by the high-temperature and high-pressure gas, and an arc is ejected. The arc is generated by the arc guide 27 on the outside of each lightning protection insulator 5. After being guided in one direction, a flashover finally occurs between the upper arc horn 11 and the intermediate arc horn 30, so that a creeping flashover of the lightning protection insulator chain is prevented.

Next, the stain withstand voltage characteristic of the salt-resistant suspension insulator 6 which is an essential part of the present invention will be described. In this embodiment, it was noticed that the lightning protection insulator 5 and the salt-resistant suspension insulator 6 have different functions from each other under the required operating conditions of the three cases described in the section of the prior art. That is, in the case, the lightning protection insulator 5 and the salt-resistant suspension insulator 6 share the respective functions. In order to prevent the lightning protection insulator 5 from increasing in size and weight in the case, the salt-resistant suspension insulator 6 can bear more of the insulation function against the operating voltage.

Further, the required insulation function is satisfied by the salt-resistant suspension insulator 6 without increasing or extending the number of insulators connected in the case. More specifically, in this embodiment, the lightning protection insulator 5 has a porcelain design having a pollution withstand voltage performance equivalent to that of a standard suspension insulator, and the salt-resistant suspension insulator 6 having no lightning protection function is used as the surface leakage of the insulator body 13. Compared to the creepage leakage distance of a standard suspension insulator, the creepage insulation leakage distance of the entire 6 suspension insulators is lengthened by using one that is approximately 1.3 times or more longer. The number of salt-resistant suspension insulators 6 used is the minimum number of connections that can secure the air insulation gap G required for the switching surge voltage. The reason for this setting will be described below.

For example, in a 66 kV transmission line, Table 1 shows the required connection number of standard suspension insulators corresponding to the above cases and cases when only standard suspension insulators are used, for each contamination amount.

In Table 1, (a) to (f), the fouling classification, that is, the salt adhesion density (mg / cm ² ) was 0.01,
The case of 0.03, 0.06, 0.12, 0.25, and 0.50 is shown. Further, as the operating voltage E, the nominal voltage is 66
Since it is kV, the following equation is obtained.

[0031]

[Equation 1] E = 66 × (1 / √3) × (1.2 / 1.1) = 41.6 kV Furthermore, when a one-line ground fault occurs in the transmission line, the abnormal voltage U _LG generated in other healthy phases is The normal phase voltage rise coefficient K at the time of one-line ground fault and the operating voltage E are expressed by the following equation. However, when the nominal voltage ≤154 kV, K = √3.

[0032]

[Formula 2] U _LG = E × K = 41.6 × √3 = 72 kV

[0033]

[Table 1]

On the other hand, in the lightning protection insulator device of the present invention,
Table 2 shows the required number of suspension insulators that can be used in cases 1 to 3 as a result of experiments. The salt-resistant suspension insulator 6 used here has a diameter of 250 mm.

[0035]

[Table 2]

As is clear from Tables 1 and 2 above, the number of connected suspension insulators having no conventional lightning protection function is as follows.
In the contamination categories (a) to (f), "5, 6, 7, 8,
In contrast to the “9,10” pieces, in this embodiment, “6,7,8,9,10,1” in the same stain classification (a) to (f).
It can be seen that all the cases 1 to 4 can be dealt with by increasing the number of 1 '.

FIG. 5 shows the change in the fouling state of the standard suspension insulator and the salt-resistant suspension insulator and the fouling withstand voltage characteristic. In the case of a standard suspension insulator and a salt-resistant suspension insulator having a diameter of 250 mm, for example, comparing the withstand voltage characteristics under the same stain condition, the salt-resistant suspension insulator has a withstand voltage characteristic of about 1.3 times that of the standard suspension insulator. I understand.

As is clear from the above analysis results, when the salt-resistant suspension insulator 6 having the pollution withstand voltage characteristic of 1.3 times or more as compared with the standard suspension insulator is used, the existing suspension is used. It is possible to approach the required number of insulators to be connected in the insulator device, and therefore, the insulator device can be easily applied to an existing power transmission line.

In the above embodiment, the transmission line of 66 kV is described, but 154 kV, 275 kV, 500 kV.
Similar results were obtained for each V transmission line.
The present invention is not limited to the above embodiment,
It can also be embodied as follows.

(1) The lead wires 28 and 29 for connecting the resistance elements of the respective suspension type lightning protection insulators are omitted, and an air discharge gap (not shown) is provided between the cap electrodes 25 and 26 of different lightning protection insulators 5. thing.

(2) In the above-mentioned embodiment, the suspension steel tower is embodied, but it should be embodied as a tension resistant steel tower.

[0042]

As described above in detail, the present invention provides a salt-resistant suspension insulator having a pollution withstand voltage characteristic of 1.3 times or more as compared with a standard suspension insulator as a suspension insulator having no lightning protection function. Since it is used, it is not necessary to increase the number of suspension insulators to be connected so much, and there is an effect that it is possible to suppress the continuous length of the insulator and easily apply it to the existing transmission line support insulator device.

[Brief description of drawings]

FIG. 1 is a front view showing an embodiment of a lightning protection insulator device of the present invention.

FIG. 2 is a partially cutaway front view showing only a salt-resistant suspension insulator.

FIG. 3 is a semi-longitudinal sectional view showing a lightning protection insulator.

FIG. 4 is a schematic front view of a lightning protection insulator device.

FIG. 5 is a graph showing the relationship between the salt attachment density of a suspended insulator and the pollution withstand voltage.

[Explanation of symbols]

5 suspension type lightning arrestor, 6 salt-resistant suspension insulator, 11 upper arc horn, 12 lower arc horn which also serves as discharge electrode on the power-supply side, 21 insulator body, 21a mounting cylinder part, 22
Cap fitting, 23 pin fitting, 24 resistance element, 2
8, 29 Lead wires, 30 Intermediate arc horn that also serves as a ground side discharge electrode, G air discharge gap, L power transmission line.

Claims (1)

[Claims] 1. A suspension type lightning arrestor is connected in series, and the resistance elements of each suspension type lightning arrestor are electrically connected to each other via a lead wire or not, and at the end of the lightning arrestor series. A plurality of suspension insulators without lightning protection are connected in series, and a discharge side discharge electrode and a ground side discharge electrode are attached to both ends of this suspension insulator series, and an air discharge gap is formed between both discharge electrodes. In the suspension type lightning arrester device for a transmission line provided with, a salt-resistant suspension insulator having a pollution withstanding characteristic of 1.3 times or more as compared with a standard suspension insulator as the suspension insulator having no lightning protection function. A suspended type lightning arrester device for transmission lines, characterized by being used.