JPS61137307A - Gas insulated potential transformer - Google Patents

Abstract

PURPOSE:To prevent entrance of the external air into an exclusive tank even in case a pressure tank is opened, by providing an exclusive tank having a hermetically sealed structure which is resistive to a little pressure difference and valves communicating with internal and external sides and also providing a gas insulated potential transformer. CONSTITUTION:A gas insulated potential transformer 3 is previously filled with insulation gas and is stored under the condition that an automatic valve 7 is closed. At the time of assembling, the transformer 3 is housed together with an exclusive tank 2 within a pressure tank 1. After the assembling of interior, the tank 1 undergoes sealing, vacuum exhaustion and supply of gas. Namely, in the case of vacuum exhaustion, the valve 7 operates and opens depending on a pressure difference between internal and external pressure. Therefore, an excessive pressure difference is not applied on the tank 2. For the supply of gas, the valve 7 operates and opens depending on the pressure difference when the tank 1 is filled with the insulation gas, the insulation gas flows into the tank 2 from the tank 1, not generating an excessive pressure difference. Thereby, the transformer 3 holds initial insulation performance and it is enough for the tank 2 to have the sealed structure which is resistive to an internal and external pressure difference of about 0.3-0.4kg/cm<2>.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a gas-insulated instrument transformer that is housed together with other equipment in a pressure vessel filled with an insulating gas at a predetermined pressure. Concerning means.

[Conventional technology]

Gas insulated instrument transformers (hereinafter referred to as gas FT) are used built into gas insulated switchgear, etc., but conventionally, a dedicated container was not used, but a common pressure container filled with gas to a predetermined pressure was used. It was stored together with other equipment.

[Problem that the invention seeks to solve]

Therefore, if the pressure vessel is opened during assembly or inspection, the gas FT will be exposed to the atmosphere, moisture in the atmosphere will be adsorbed inside the high pressure coil, or fine dust will adhere to the insulating parts. This may cause a decrease in pressure resistance. Furthermore, even after the pressure vessel is filled with insulating gas, the moisture inside the coil of the gas FT evaporates into the insulating gas, increasing the moisture content in the insulating gas, resulting in various negative effects.

[Means for solving problems]

In order to solve these drawbacks, the present invention stores gas FT in a special container equipped with an automatic charging/discharging valve (hereinafter referred to as automatic valve) within the pressure vessel.

Even when the pressure vessel is opened, the insulating gas only flows out from the automatic valve into the pressure vessel in the above-mentioned special vessel, thereby eliminating the risk of outside air entering the special vessel.

〔Example〕

In FIG. 1, reference numeral 1 denotes a pressure vessel which houses various equipment (not shown) and is filled with an insulating gas at a pressure of about 5 atmospheres, and a dedicated vessel 2 is provided inside, in which a gas PT3 is housed.

An automatic valve 7, an example of which is shown in FIG. 2, is attached to the special container 2, which operates when the pressure difference between the inside and outside exceeds a predetermined value.

Reference numeral 4 denotes an insulating plate forming a lid plate of the special container 2, and a high voltage terminal 5 is provided on this plate, and a high voltage is applied from the outside through a connecting conductor 6, and the plate is connected to the high voltage side of the gas FT. Note that by forming the insulating plate 4 so as to be inclined at an appropriate angle, it is possible to prevent the insulating performance from deteriorating due to the adhesion of dust on the surface. Further, 8 is a low-pressure extraction terminal of the gas FT, and 9 is a manual valve for charging and discharging the pressure vessel.

Here, the dedicated container 2 is a container with a sealed structure that can withstand a slight pressure difference between the inside and outside, and when the pressure container 1 is open, even if a pressure difference between the inside and outside occurs due to changes in atmospheric pressure or temperature,
The automatic valve 7 does not operate at this level of pressure difference, and when the pressure difference between the inside and outside reaches a predetermined value that is even larger, the automatic valve 7 operates to allow circulation between the inside and outside.

The gas PT3 is dried and vacuum-processed separately beforehand and stored in a special container 2, and the insulating gas is kept at a pressure slightly higher than atmospheric pressure.
It is filled with pressure such that the automatic valve 7 does not operate, and is stored with the automatic valve 7 closed. During assembly, the gas PT3 is housed in the pressure vessel 1 together with the dedicated vessel 2, and other equipment is also housed therein. After the internal assembly of the pressure vessel 1 is completed, it is sealed, and the pressure vessel 1 is evacuated, filled with gas, etc.

In other words, in the case of evacuation, open the manual valve 9 of the pressure vessel,
When the inside is evacuated using a vacuum pump (not shown), the automatic valve 7 of the special container is activated by the pressure difference between the inside and outside, and the valve 7A is activated.
is opened, and the insulating gas inside flows out into the pressure vessel 1. Therefore, the insulating gas in the dedicated container z remains in the pressure container 1 by a pressure difference that operates the automatic valve, but the vacuum is approximately the same, and no excessive pressure difference is applied to the dedicated container.

That is, the gas PT3 has already been evacuated, then stored in a special container and filled with insulating gas, and here, when filling the pressure vessel 1 with gas, the automatic valve 7 operates to keep the pressure difference between the inside and outside within a predetermined value. Make sure that no excessive pressure difference is applied to the special container.

When filling with gas, if the pressure vessel 1 is filled with insulating gas from the manual valve 8, the automatic valve 7 is actuated by the pressure difference to open the valve 7B, and the insulating gas flows from the pressure vessel 1 into the special container 2. It is filled to almost the same pressure as the pressure vessel without creating an excessive pressure difference.

In this way, the dedicated container initially contained the gas FT.

After the pressure vessel is stored and filled with insulating gas, only the insulating gas inside the pressure vessel flows in, and there is no risk of atmospheric air entering, and the internal gas PT3 can completely maintain its original insulating performance.

Here, the change in pressure difference between the inside and outside of the special container 2 caused by fluctuations in atmospheric pressure, etc. during assembly or inspection, that is, when the pressure container 1 is opened, is much lower than 0.1 to 0.2 Kg/C♂. Presumed. Therefore, when storing the gas FT in the dedicated container 2, the pressure difference change amount is 0.2 to 0.3, which is one step higher than the above pressure difference change amount.
Filled with insulating gas at a pressure of Kg/cm2, and equipped with an automatic valve 7
Set the operating pressure of the tore to the same pressure value. Moreover, the special container has a sealed structure that can withstand even higher pressures of 0.3 to 0.4 kg/cm2.

The pressure difference between the inside and outside of the special container 2 during opening of the pressure container 1 is 0.1 to 0.2 K compared to the pressure difference when filling with insulating gas.
g/c+/, automatic valve 7 did not operate during this period, there was no problem with the sealed structure of the special container, and the insulating gas inside was kept as it was when it was originally filled. It will be done. In this way, by providing a special container with an automatic valve and a sealed structure that can withstand slight pressure differences inside the pressure container, and storing the gas FT in this container, it is possible to maintain the original insulation performance without impairing it. can.

Next, another embodiment is shown in FIG.
The inside of the pressure vessel is connected to the manual valve 10 by a pipe 11. That is, the automatic valve 7, which was opened into the pressure vessel 1 in the embodiment shown in FIG. 2, is opened to the atmosphere through the pipe 118 and the manual valve IO.

Here, when evacuation or gas filling, etc., filling and evacuation are performed simultaneously by means such as using the 20 connecting pipe 12 shown by the broken line using the manual valve 9 for the pressure vessel and the manual valve 10 for the special container. The pressure vessel 1 and the dedicated vessel 2 are always maintained at approximately the same pressure. This is how you vacuum or fill with gas.

Perform operations such as degassing, but be sure to close the manual I valve IO for the special container after the operation.

As a result, in FIG. 2, the automatic valve 7 of the dedicated container that opened into the pressure container is closed by the manual valve IO except when charging or exhausting, and if the automatic valve 7 malfunctions, it is completely closed. Even if the pressure vessel is opened in such a case, the risk of outside air entering the dedicated vessel is prevented.

〔Effect of the invention〕

As explained above, according to the present invention, the gas PT, which was conventionally exposed to the atmosphere when the pressure vessel was opened during assembly or inspection, is always kept in an insulating gas in a special container provided in the pressure vessel. In addition, the dedicated container does not require a pressure vessel and can withstand only a small difference in internal and external pressure caused by fluctuations in atmospheric pressure, etc. It has advantages such as a sealed structure.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention, FIG. 2 is a sectional view showing an example of an automatic valve, and FIG. 3 is a sectional view showing another embodiment of the invention. 1...Pressure vessel, 2...Special container, 3...Gas insulated instrument transformer, 7...Automatic valve.

Claims (1)

[Claims] A gas-insulated instrument transformer is installed in a special container that is housed together with other equipment in a pressure container filled with insulating gas, and the special container has a sealed structure that can withstand an internal and external pressure difference of 0.3 to 0.4 Kg/cm^2. A gas-insulated instrument transformer, characterized in that it is filled with the above-mentioned insulating gas and has a valve that communicates with the inside and outside of the dedicated container.