JPS6016105A - Gas leakage repairing method of gas insulated device - 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 Field of the Invention This invention relates to a method for repairing gas wetting of the sheath of gas insulated equipment.

DESCRIPTION OF PRIOR ART Referring to FIG. 1, a gas insulated device is a device in which a conductor 1 is disposed within a sheath 2 via a spacer (not shown), and a space between the conductor 1 and the sheath 2 with a high insulation performance is established. It is filled with a superior gas, such as 5FE (sulfur hexafluoride) gas, and is used in pipelines, aerial power transmission lines, gas-insulated switchgear, etc.

In this gas insulated device, when gas leaks from the sheath 2, the gas-wetted area 3 is repaired by welding. At this time, prior to the welding work, it is necessary to lower the pressure of the insulating gas sealed within the sheath 2 to atmospheric pressure. This is because the pressure of the insulating gas sealed in the sheath 2 is usually 3 to 5 KO/C1G, which is considerably higher than atmospheric pressure, so when the sheath 2 melts during welding, the insulating gas blows out from there, causing gas wetting. This is because the hole 3 will be enlarged. Therefore, conventionally, the pulp 5 which is attached in advance to the opening 4 of the sheath 2 of gas insulated equipment is opened, and the S
F! The gas was collected or released into the atmosphere. After the gas pressure inside the sheath 2 decreased to near atmospheric pressure, the valve 5 was left open. Or as another method, S F until the pressure inside the sheath 2 becomes a vacuum state.
The pressure inside the sheath 2 was brought to atmospheric pressure by letting air flow into the sheath 2 through the sliding door from which the g gas was recovered and the valve 5 which was in an open state. In this manner, with the pressure inside the sheath 2 reaching atmospheric pressure, welding is performed to build up the gas trapping portion 3 to repair the gas leakage. Thereafter, the inside of the sheath 2 is brought into a vacuum state and an insulating gas is filled.

Such conventional gas leak repair methods have the following drawbacks.

First, the first drawback will be explained. The opening 4 in the sheath 2 of gas insulated equipment is generally directed downwardly or laterally. The specific gravity of SFg gas, which is used as a typical insulating gas, is that if it is left in an air layer, the SF and gas inside the sheath 2 will flow out from the opening 4, and the outside air will flow through the opening 4. It flows into the sheath 2. FIG. 2 shows the state of mixture of SF6 gas and air. In the figure, an air layer 6 is located in the upper part, and an SF6 gas layer 7 is located in the lower part.
is located. Needless to say, the presence of air degrades gas insulation performance. Therefore, air flows through sheath 2
It must be eliminated from within. Specifically, it is necessary to evacuate the inside of the sheath 2 after repairing the gas leakage point by welding, but this operation requires a considerable amount of time.

Regarding the point that this long time is required, as described earlier as another method, work such as work to recover SF and gas until the pressure inside the sheath 2 becomes a vacuum state prior to welding. This is also common.

The second drawback is that the loss of insulating gas such as SFs gas is large. This means that if the S F G gas is recovered prior to welding and the pressure inside the sheath 2 is reduced to near atmospheric pressure, the remaining S F G gas equivalent to IKg/CI' will be released into the vacuum after the gas wetting repair. This is because it is released during the pull. Or, even if the SF6 gas is recovered until the pressure inside the sheath 2 becomes a vacuum state prior to welding, the recovery! !
Due to the recovery capacity of Ill, SFs gas cannot be recovered until a high vacuum is achieved. For that reason, a considerable amount of S
This is because the Fs gas remains within the sheath and is also released later.

OBJECTS AND STRUCTURE OF THE INVENTION The present invention has been made to eliminate the above-mentioned drawbacks, and its main purpose is to shorten the time required to restore gas insulated equipment to its normal operating condition, and to It is an object of the present invention to provide a method for repairing gas leaks in gas insulated equipment, which can reduce the loss of insulating gas.

In order to achieve the above-mentioned object, the present invention includes the following steps prior to repairing a gas-wetted part of a sheath of a gas-insulated device by welding.

■ Recover or release the insulating gas in the sheath until the gas pressure in the sheath is slightly higher than atmospheric pressure Step 5 - ■ Connect a hose to the opening in the sheath and pass it through the Step of ensuring that the insulating gas is discharged into the atmosphere:■ Soak the hose so that any part from its connection port to its tip is higher than the highest level of the target gas section of the gas insulated equipment. FIG. 3 and FIG. 4 are cross-sectional views showing one implementation state of the gas leak repair method according to the present invention, and FIG. 3 shows the opening 4 of the sheath 2. Shows an example where is facing downward,
FIG. 4 shows an example in which it is oriented laterally. In either example, the following operations are performed prior to repairing the gas leak location in the sheath 2 of the gas insulated equipment by welding.

First, while checking the pressure gauge, the S F s gas in the sheath 2 is collected or released until the pressure in the sheath 2 reaches a pressure (positive pressure) slightly higher than atmospheric pressure. after that,
A hose 8 is connected to the valve 5, and the valve 5 is left open. The hose 8 is held such that any part from the connection port 8a to the tip 8B of the hose 8 is higher than the highest level of the target gas section of the gas insulator. In this case, it is preferable that the tip 8b of the hose 8 is directed upward, but it is not necessary to do so. In other words,
The vicinity of the tip of the hose 8 has an inverted U-shape, so there is no problem even if the tip of the hose 8 is directed downward.

In short, any part of the hose may be higher than the maximum level mentioned above.

In this way, the SFG gas, which has a considerably higher specific gravity than air, is discharged into the atmosphere through the hose 8, so that the pressure inside the sheath 2 becomes approximately the same as the atmospheric pressure.

Therefore, when repairing a gas leak location in the sheath 2, SF6 gas will not be ejected from the repair location. On the other hand, air whose specific gravity is smaller than that of 8F6 gas is in the sheath 2.
Therefore, even after welding, there will be no situation where SFG gas and air are mixed into the sheath 2.

After repairing the gas leakage point by welding, the hose 8 is removed and SFs gas is sealed in the sheath 2 until a specified gas pressure is reached.

Effects of the Invention As described above, according to the present invention, there is no need to recover an insulating gas such as SF5 gas until the pressure inside the sheath reaches a vacuum state prior to welding work, or it is not necessary to perform evacuation after repair. There is no need for a long period of time to restore gas insulated equipment to normal operating conditions. Furthermore, the insulating gas remaining in the sheath during welding can be released and reused, which is advantageous in terms of cost.

Furthermore, since the valve attached to the sheath opening can be left open during welding, the gas pressure inside the sheath will not increase during welding, and gas will not blow out. do not have. Therefore, the workability of gas leak repair can be improved and its reliability can be increased.

[Brief explanation of the drawing]

FIG. 1 is a sectional view schematically showing the structure of a gas insulated device. FIG. 2 is a sectional view showing a state in which air and insulating gas are mixed in the gas insulated device of FIG. 1. 3 and 4 are cross-sectional views showing one implementation state of the gas wet repair method according to the present invention, in which FIG. 3 shows an example in which the opening of the sheath faces downward, and FIG. The figure shows an example facing to the side. In the figure, 2 is a sheath, 3 is a gas wet part, 4 is an opening, 8 is a hose, 8a is a connection port of the hose, and 8b is the tip of the hose. 9- Figure 1 Figure 2 Figure 3

Claims (1)

[Claims] Prior to repairing gas-wetted parts of the sheath of gas insulated equipment by welding, the insulating gas in the sheath is recovered or released until the gas pressure in the sheath reaches a pressure slightly higher than atmospheric pressure. connecting a hose to the opening in the sheath through which the insulating gas in the sheath can be vented to the atmosphere; and connecting the hose from its connection port to its tip. A method for repairing gas insulated equipment due to gas leakage, the method comprising the step of maintaining the gas insulated equipment so that any part thereof is higher than the highest level of the target gas section of the gas insulated equipment.