KR20210026744A - Substitute insulation or arc quenching gas of sf6 gas and electrical apparatus - Google Patents

Abstract

The present invention relates to an insulating gas used for electrical insulation or arc extinguishing of an electrical device, and an electrical device using the same to insulate electricity. The insulating gas of the present invention, which can replace SF6 gas, is a mixed gas of F3N, F3N, and CO2, a mixed gas of F3N and O2, and a mixed gas of F3N, CO2, and O2. Thereby, compared to using SF6 gas as the insulating gas, the insulating gas may reduce the greenhouse gas due to the low global warming potential while maintaining the insulation and extinguishing ability.

Description

Insulating gas used for electrical insulation or arc extinguishing by replacing SF6 gas, and electrical equipment using the same {SUBSTITUTE INSULATION OR ARC QUENCHING GAS OF SF6 GAS AND ELECTRICAL APPARATUS}

The present invention relates to an insulating gas used for electrical insulation or arc extinguishing of an electric device and an electric device using the same.

Electrical devices use insulating gas to cut off electricity, and in general, SF ₆ (sulfur hexafluoride) gas is widely used. SF ₆ gas has excellent insulation performance and excellent arc extinguishing properties. However, SF ₆ gas has a global warming index (GWP) of 23,900, which is 23,900 times higher than _{CO 2 (carbon dioxide).} It was designated as a greenhouse gas in the Protocol. Therefore, there was a need for a gas to reduce the use of _{SF 6 gas or to replace it.}

From this, ABB has developed a 2015 SF ₆ gas instead of CO ₂ gas mixture using a circuit breaker (CO ₂ and O ₂ mixture), C ₅ PFK, switchgear applying a mixed gas of CO _2, O _2.

Here, the C ₅ PFK gas has a global warming index of 1 or less, but it is difficult to use alone because it has a boiling point of 27°C, so it was mixed with _{CO 2} , O ₂ , and N _{2 with low boiling points.} The mixing specific gravity must be maintained at 10 mol% or less, and in this case, the boiling point is only about 5℃ at the minimum, and the insulation performance is only 70 mol%, so there is a limitation in use. _{Therefore, the C 5} PFK, CO ₂ and O ₂ mixed gas was used for the ultra-high pressure class, _{and the C 5} PFK, N ₂ and O ₂ mixed gas was used only for the indoor switchgear for the distribution class.

Similarly, ALSTOM developed a switchgear in 2015 using g3 gas, a mixture of _{fluoronitrile gas and CO 2 gas.} Fluoronitrile has more than 150% insulation performance than SF6, but because of its high boiling point (-4.7℃), it uses a method of mixing 80 mol% or more of CO2 with a low boiling point in order to apply it to an actual electric device. In this case, the insulation performance is only 87%.

As described above, when _{a mixed gas of C 5} PFK or g3 gas is used _{, insulation and arc extinguishing performance is lower than that of SF 6} gas, but in combination with design technology, it is possible to manufacture more environmentally friendly devices.

On the other hand, ABB and ALSTOM have patent rights for these insulating gases, so there are restrictions on the use of these gases, and countries around the world are demanding the development of insulating gases that can replace the gases other than SF6.

By inserting the O- ring with the conventional Korea Registered Utility Model Publication No. 20-0357843, the arc, the gas insulated switchgear of the bellows flange tube for sealing the SF ₆ gas in order to prevent the leakage of SF ₆ gas is used in gear SF _{6 It is described about the SF 6} insulating gas shut-off valve that shuts off gas and seals the residual gas.

Korean Patent Laid-Open Publication No. 10-2013-0118461 discloses an ultra-high voltage transformer that reduces the amount _{of SF 6 gas consumption by 50 mol% by using a hybrid insulating gas in which N 2} , CO ₂ , and dry air are mixed in an _{SF 6} gas insulating medium. It has been described for.

Korean Patent Application Publication No. 10-2010-0077747 discloses a gas-insulated switchgear using dry-air instead of _{SF 6 gas filled in the gas-insulated switchgear.}

The above-mentioned prior art, to reduce the gas that is lost to prevent leakage of SF ₆ gas, a mixture of SF ₆ gas and other gas, but to reduce the amount of SF ₆ gas, so it is still using the SF ₆ gas, hazardous warming The influence was still there.

On the other hand, it _{was attempted to achieve eco-friendly environment by replacing SF 6} gas with dry air, but there was a problem that the insulation performance of dry air as well as arc extinguishing performance was _{much lower than that of SF 6} gas, so that the insulation function could not be properly performed.

To replace SF ₆ gas, 1) must not be toxic, 2) must have a low global warming potential (GWP), 3) must not destroy ozone, 4) must have a low boiling point, 5) have inertness, 6 ) It has chemical stability, and 7) The cost should be appropriate.

In order to solve the problems of the above-described background art, the present invention is to provide an insulating gas used for environmentally friendly electrical insulation or arc extinguishing while maintaining insulation performance by replacing _{SF 6 gas and having a low global warming index.}

In addition, the present invention is not toxic, does not destroy ozone, has a low boiling point, is inert, is chemically stable, and provides an insulating gas used for electrical insulation or arc extinguishing, which is suitable for cost, and an electric device using the same. There is this.

The present invention for solving the above-described problem is characterized in that it contains _{F 3} N as an insulating gas used for electrical insulation or arc extinguishing in place of the _{SF 6 gas.}

Preferably, the insulating gas is a mixed gas further comprising _{CO 2.}

Preferably, the F ₃ N is 1 to 3 mol%.

Preferably, the mixed gas further includes _{O 2.}

Preferably, the F ₃ N is 1 to 3 mol%, and the O ₂ is 1 to 25 mol%.

An electric device using an insulating gas used for electrical insulation or arc extinguishing in place _{of the SF 6} gas of the present invention for solving the other problems described above is characterized by using an insulating gas containing _{F 3 N.}

Insulating gas used for electrical insulation or arc extinguishing in place _{of the SF 6} gas of the present invention _{and an electric device using the same, compared to SF 6} gas and an electric device using the same, while maintaining the insulation and extinguishing ability, while maintaining the global warming index low SF _{Compared to 6} , it can reduce greenhouse gases.

1 shows the molecular structure _{of F 3} N contained in the insulating gas of the present invention.
2 is a graph showing the Paschen Curve of SF6, g3, and SF6 alternative candidate gases.
3 is a graph showing the global warming index according to the mixing ratio _{of F 3 N.}
4 is a graph showing the carbon monoxide generation rate according to the gas temperature for each oxygen mixing ratio of the insulating gas.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

To replace SF ₆ gas, 1) is not toxic, 2) has a low global warming potential (GWP), 3) does not destroy ozone, 4) has a low boiling point, 5) is inert, and 6) has chemical stability. And 7) must satisfy the condition that the cost must be appropriate.

As a candidate gas that satisfies the above conditions, _{a mixture gas of NF3 (F 3} N), NF ₃ 0 (10 mol%) and CO ₂ (90 mol%), CO ₂ (70.5 mol%) and O ₂ (29.5 mol%) %) A mixed gas was selected, and the boiling point, vapor pressure, and global warming index of these candidate gases are compared with SF6 and g3 as shown in Table 1 below.

Comparison of SF6, g3 gas and SF6 alternative candidate gas gas Boiling point(℃) Vapor pressure [psia@](20℃) GWP SF6 -63.7 334 23,500 g3 -4.7 367 2,400 Mixture CO2 (70.5 mol%) -56.5 - <One O2 (29.5 mol%) -182 - F ₃ N -129 646.6(-39.2℃) 16,100 Mixture NF30 (10 mol%) -89 184.2(-20℃) - CO2 (90 mol%) -56.5 -

Insulating gas to replace the SF ₆ gas in accordance with one embodiment of the present invention, also includes the F ₃ N having the molecular structure of 1 .F ₃ N is the lower boiling point of -129 ℃ and 16,100 low in contrast and SF6 It has a GWP.

In _{order to test the insulation performance of F 3} N, the lighting impulse voltage in IEC 60060-1 was applied and 50% discharge voltage was tested based on the population of 30 times. After the completion of each test, gas collection and electrode cleaning were performed. Here, the 50 mol% discharge voltage refers to a voltage in which half of the shock wave voltage of the standard waveform is repeatedly applied using the old flat electrode and the other half does not flash.

2 is a mixed gas of NF3 (F ₃ N), SF6, g3, NF ₃ 0 (10 mol%) and CO2 (90 mol%), a mixed gas of CO ₂ (70.5 mol%) and O ₂ (29.5 mol%) The Paschen Curve for each gas measured 50% discharge voltage is shown. Here, the Paschen Curve is a graph showing the 50% discharge voltage according to the pressure and the distance between electrodes (old versus flat electrode) in order to check the insulation performance.

According to this, it can be seen that F ₃ N has an insulation performance of 111% compared to SF6 and 129% compared to g3 gas. In addition, it can be confirmed that the insulation performance is superior to other candidate gases.

Therefore _{, it can be seen that F 3} N is a suitable gas to replace SF6 gas in terms of performance, environment, and convenience in use compared to SF6.

Meanwhile, the insulating gas replacing the SF6 gas according to another embodiment of the present invention may be used by mixing _{F 3 N and at least one of CO 2} and O ₂ as a carrier gas. This can further reduce the global warming index.

3 shows GWP according to the mixing ratio of the mixed gas of _{F 3} N and CO ₂ and the mixed gas of F ₃ N and O _2. According to FIG. 3, when _{the mixing ratio of F 3} N is about 65 mol% or less, it can be seen that the GWP corresponds to 50% of the GWP of SF6 (23,500). Here, the method of calculating the GWP was in accordance with Regulation (EU) NO 517/2014.

Meanwhile, KEPCO stipulates that the general purchase standard for eco-friendly gas insulated switchgear of 72.5kV or higher is GWP of 500 or less for fluorine-based mixed gas. In order to meet these standards, the value of GWP must be reduced, and for this purpose, _{the mixing ratio of F 3} N is preferably 1 to 3 mol%, and more preferably 1 to 2 mol%.

4 is a graph showing an analysis of a carbon monoxide generation rate according to gas temperature for each oxygen mixing ratio of a composite insulating gas by calculating a plasma composition. Here, F ₃ N was set to 3 mol%, CO ₂ was set to (97-N) mol%, O ₂ was set to N mol%, and the values of N were set to 0, 10, 20, 30, 40, 50.

According to FIG. 4, it _{can be seen that when O 2} is mixed and used as a carrier gas, it is effective in reducing carbon monoxide. However, O ₂ has a lower dielectric strength than _{CO 2 , so O 2} The mixing ratio is preferably mixed at 1 to 25 mol%, more preferably 2 to 15 mol%, particularly 2 to 10 mol%.

Table 2 below shows the calculated value of GWP according to the mixing ratio (mol%) of _{F 3} N, CO ₂ and O _2.

F ₃ Value calculated GWP according to the mixing ratio (mol%) of N, CO ₂ and O ₂ F ₃ N O ₂ CO ₂ GWP Mixed gas 1 3 10 87 787 Gas mixture 2 2 11 87 528.31

According to the table above, it can be seen that when the mixing ratio of _{O 2 is increased from 10 mol% to 1 mol% while the CO 2} mixing ratio is fixed at 87 mol%, the GWP value decreases by 33%. The corresponding electric device is an electric device that insulates electricity or extinguishes an arc by an insulating gas, and can insulate electricity or extinguish an arc by using the insulating gas of the above-described embodiment.

_{This replaces the SF 6} gas mainly used in electrical equipment with _{F 3} N alone, _{a mixed gas of F 3} N and CO ₂ , a mixed gas of F ₃ N and O ₂ , and a mixed gas of F ₃ N, CO ₂ and O ₂ By doing so, _{while maintaining the insulating performance compared to using the SF 6} gas as the insulating gas, the global warming index is low, and the harmful effect on the environment can be reduced.

In the above, specific embodiments of the present invention have been described with reference to the drawings, but it will be apparent that the scope of the present invention extends to modifications or equivalents based on the technical idea described in the claims.

Claims (6)

As an insulating gas used for electrical insulation or arc extinguishing of electrical devices,
Insulating gas comprising F _{3 N} The method according to claim 1,
The insulating gas is an insulating gas, characterized in that the mixed gas further containing _{CO 2} The method according to claim 2,
The F ₃ N is an insulating gas, characterized in that 1 ~ 3 mol% The method according to claim 2,
The mixed gas is an insulating gas, characterized in that it further _{comprises O 2} The method of claim 4,
The F ₃ N is 1 ~ 3 mol%, the O ₂ is an insulating gas, characterized in that 1 ~ 25 mol% In an electric device that insulates electricity or extinguishes an arc by an insulating gas,
An electric device characterized by using the insulating gas of any one of claims 1 to 5

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