JP2547295B2 - Suspended lightning arrester device for power lines - Google Patents

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 transmission line, the lightning surge current 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 that can be prevented in advance.

[0002]

2. Description of the Related Art As a conventional suspension type lightning arrester device for a power transmission line, the applicant of the present application has proposed a device disclosed in Japanese Patent Application Laid-Open No. 3-62423. This lightning arrester device suspends and connects a plurality of suspension type lightning arrestors 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 protection function. A plurality of insulators are connected and suspended in series, and the suspension insulator at the lowermost end supports a transmission line through a lower suspension metal fitting. Further, the uppermost suspension insulator and the lower suspension metal fitting support the discharge electrodes on the ground side and the charging side, and form a predetermined air discharge gap between the discharge electrodes. Furthermore, a voltage is applied to the cap portion of the suspension type lightning arrestor.
In addition to accommodating a resistance element having a non-linear current characteristic, the resistance element is sealed by upper and lower cap electrodes, and the cap metal fitting of the suspension type lightning arrester has no lightning protection function due to deterioration of the resistance element. To prevent the burnout of the surface of the insulator body of the suspended type lightning protection insulator by guiding its arc to the outside of the lightning protection insulator when the continuity breakdown is caused by the continuous current based on the operating voltage (normal ground voltage) following the lightning surge current. Arc guide is attached.

In the suspension type lightning arrester device constructed as described above, 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 similarly to 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 when the resistance element becomes conductive due to deterioration or unexpected lightning strike, the follow-up current following the lightning surge current can be surely suppressed and cut off.

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 If the resistance value is reduced 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 suspension insulators connected. 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 arrestor device is polluted The required value of equivalent salt deposition density on the polluted surface of the insulator body, that is, the required pollution degree, does not cause flashover at normal operating voltage in transmission lines or substations It is required to be able to insulate.

In the prior art, when the required pollution degree of the insulator main body increases, it is necessary to increase the creepage insulation leakage distance for both the lightning arrestor and the standard suspension insulator. As a result, the resulting 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 limiting device based on the lightning surge current. When applied to the lightning protection device, it is required that the lightning protection insulator or the entire lightning protection device can be insulated without flashover by the limiting voltage and the operating voltage.

Further, it is 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

In addition, depending on 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 (one 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 a lightning surge current enters in a deteriorated state of the resistance element In a state where the resistance element deteriorates due to long-term use or is damaged or deteriorated by a lightning stroke exceeding the designed resistance of the resistance element, a lightning arrester device is installed. If an AC ground fault or short circuit current flows and the circuit breaker trips, 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. It is also 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 is a defective insulation body, the switching surge voltage,
It is necessary to insulate the operating voltage. Therefore, the number of connected standard suspension insulators is increased, and as a result, a gap type lightning arrester device with a long insulator connection length is configured, 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.

The object of the present invention is to provide the above-mentioned conventional case to
The electrical characteristics required for
A lightning arrester for a transmission line that can be added and that can be easily applied to an existing transmission line supporting insulator device by suppressing the connection length of a suspension insulator string that does not have a lightning protection function without increasing the size of the suspension type lightning arrestor. It is to provide 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 connected to each other via lead wires or not. Electrically connected, a plurality of suspension insulators having no 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 a transmission line which is attached and has an air discharge gap between both discharge electrodes , the connection length of a plurality of suspension insulators without the lightning protection function is almost increased.
No, and instead of the suspension insulator, a means of using a salt-resistant suspension insulator having a pollution withstand voltage characteristic of about 1.3 times that of a standard suspension insulator is used.

[0015]

According to the present invention , instead of a plurality of suspension insulators having no lightning protection function, a salt-resistant suspension insulator having a pollution withstand voltage characteristic of about 1.3 times that of a standard suspension insulator is used. Therefore, the creepage insulation leakage distance can be secured even when the surface of the insulator string is contaminated, without substantially increasing the connection length of the suspension string. For this reason, in the polluted state of the suspension insulator series, when the resistance value 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 above the design value, and a ground fault occurs due to the follow-up current due to the operating voltage. Is prevented.

Further, according to the present invention, since the connecting length of the suspension insulator series does not become long, the lightning protection insulator 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 EMBODIMENTS 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 bottommost suspension type lightning arrester 5, and a lower horn is connected to the bottommost 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 a surface flashover of a lightning arrestor series and a salt-resistant suspension pendulum series, and also as a discharge electrode on the power-supply side. The lower arc horn 12 is attached.

The salt-resistant suspension insulator 6 having no lightning protection function is fitted and fixed to an insulator main body 13 having a high fold portion 13a as shown in FIG. 2 and a head formed in the central portion of the insulator main body 13. The cap fitting 14 and the pin fitting 15 fitted and fixed to the inside of the head are provided.

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 body 21 by cement, and a pin metal fitting 23 is fitted and fixed to the inside of the head by cement. Inside the plurality of mounting cylinders 21a formed integrally with the cap portion of the insulator body 21, for example, a resistance element 24 made of a material whose main characteristic is zinc oxide and having a non-linear voltage-current characteristic is housed. 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.

In the event that the resistance element 24 of the suspension type lightning arrestor 5 cannot be interrupted by the deterioration of the follow-up current due to deterioration or the like and becomes conductive, the arc is guided to the outside and An 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 as to face the lower cap electrode 26 of the lowermost lightning arrester 5 with a predetermined gap in the mounted state. In addition, the arc guide 27 includes an intermediate arc horn 3 as a ground side discharge electrode.
0 is cantilevered 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. And, the cap metal fitting 14 of the suspension insulator 6 located at the uppermost part 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 member 3, the clevis link 4 and the hanging member 2 to the support arm 1 of the steel tower, and then discharged 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 and prevents a ground fault.

If the resistance element 24 housed in the cap portion of the lightning protection insulator 5 is deteriorated due to long-term use and a lightning surge current intrudes and the subsequent current flowing therethrough cannot be suppressed and cut off, 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 is finally caused between the upper arc horn 11 and the intermediate arc horn 30, and the creeping flashover of the lightning protection insulator series 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.

[0028] Also, almost without the hematopoiesis extension of the insulator coupling number in case, it is decided to satisfy the requirements insulation function in salt-type suspension insulator 6. More specifically,
In this embodiment, the lightning arrestor 5 has a porcelain design having the same level of pollution withstand voltage as a standard suspension insulator, and the salt-resistant suspension insulator 6 does not have a lightning protection function. Compared with the creepage leakage distance of the insulator, the creepage insulation leakage distance of the entire 6 suspension suspension insulators is lengthened by using about 1.3 times . And salt-resistant suspension insulator 6
Is used as 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 number of connected standard suspension insulators corresponding to the above cases and cases when only the standard suspension insulators are used, obtained 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 that occurs 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:
In the contamination categories (a) to (f), "5, 6, 7, 8,
In contrast to the "9,10" pieces, in this embodiment, in the same stain classification (a) to (f), "6, 7, 8, 9, 10, 1"
It can be seen that all the cases 1 to 3 can be dealt with by increasing the number of "1".

FIG. 5 shows changes in the fouling state of the standard suspension insulator and the salt-resistant suspension insulator and the fouling withstand voltage characteristics. 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 pollution 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 a stain withstand voltage characteristic of about 1.3 times that of the standard suspension insulator is used, It is possible to approach the required number of insulators to be connected in the existing suspension insulator device, and therefore, it 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 to each other 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 iron tower is embodied, but it should be embodied as a tension resistant steel tower.

[0042]

As described above in detail, the present invention hardly increases the connection length of a plurality of suspension insulators having no lightning protection function ,
Further, instead of the suspension insulator, a salt-resistant suspension insulator having a pollution withstand voltage characteristic of about 1.3 times that of the standard suspension insulator is used, so that it is required in the above-mentioned cases.
Satisfying all the electrical characteristics and connecting the number of suspension insulators
It is sufficient to increase the number by one, and there is an effect that it can be easily applied to an existing transmission line support insulator device while suppressing the insulator length and weight .

[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 the 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 a 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)

(57) [Claims] 1. A suspension type lightning arrester 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 arrester series. A plurality of suspension insulators without lightning protection function 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 power transmission line, the connection length of a plurality of suspension insulators without the lightning protection function is almost
A transmission line characterized by using a salt-resistant suspension insulator which does not increase and has a pollution withstand voltage characteristic of about 1.3 times that of a standard suspension insulator in place of the suspension insulator. Suspended lightning arrester device.