Patent ID: 12199413

DESCRIPTION OF EMBODIMENT

Hereinafter, a gas insulation apparatus according to an embodiment will be described with reference to the drawings.

In order to resolve the foregoing problems, various research and tests have been performed. Consequently, it has been confirmed that a concentration of HF, CO, or O3in an insulation gas can be sufficiently reduced and a life span and reliability of a gas insulation apparatus using an insulation gas having CO2and O2as main components can be secured in long-term use by using a removal material constituted of an adsorbent or a catalyst manifesting selective adsorption action depending on a polarity and catalytic action. The present invention is based on this knowledge.

First Embodiment

A first embodiment will be described usingFIG.1. A gas insulation apparatus according to the present embodiment is a puffer-type gas insulation breaker.FIG.1is a partial schematic cross-sectional view of the gas insulation apparatus (gas insulation breaker) according to the present embodiment.

As illustrated inFIG.1, an insulation gas2fills the inside of a sealed container1constituted of a ground metal, a porcelain tube, or the like. Inside the sealed container1, a fixed contact portion31and a movable contact portion41are disposed so as to face each other, and a fixed arc contactor32and a movable arc contactor42are respectively provided in the fixed contact portion31and the movable contact portion41. A high-voltage portion is constituted of the fixed contact portion31and the movable contact portion41. An O-ring or the like is disposed at a sealing location of the sealed container1, thereby forming an airtight structure.

The arc contactors32and42are in a contact conduction state during normal operation, and they separate from each other and generate an arc7in a space between both the contactors32and42due to relative movement during breaking operation. Moreover, a gas flow generation means for spraying the insulation gas2(arc-extinguishing gas) to the arc7is installed on the movable contact portion41side.

Here, as the gas flow generation means, a piston43, a cylinder44, and an insulation nozzle45are provided. In addition, a metal exhaust cylinder33through which a hot gas flow8can pass is attached to the fixed contact portion31side. An exhaust rod46through which the hot gas flow8can pass is provided on the movable contact portion41side so as to lead to the movable arc contactor42. A grease for reducing friction is applied to sliding portions of the piston43and the cylinder44.

Regarding an insulation gas which fills the inside of the sealed container1and also functions as an arc-extinguishing gas, a gas having CO2and O2as main components is used. 50% or more by volume % of CO2is included, and O2is included within a range not exceeding 50% by volume %. Specifically, a mixed gas of CO2(70%) and O2(30%) can be presented as an example.

In addition, even when a gas having a larger molecular size than CO2is mixed into the insulation gas for the purpose of improving a dielectric strength, the effects of the present embodiment can be achieved. Examples of the mixed gas include compounds containing fluorine and iodine, such as hydrofluoromonoether, perfluoroketone, hydrofluoroolefin, perfluoronitrile, or trifluoroiodomethane.

Inside the sealed container1, a removal material6having a function of reducing the concentrations of HF, CO, and O3in the insulation gas is installed. The removal material6is held inside the sealed container1by a case5. An effect of more actively reducing the concentrations of HF, CO, and O3can be achieved by disposing the removal material6on a flow channel of the arc-extinguishing gas on an exit side of the exhaust cylinder33.

The removal material6reduces the concentrations of HF, CO, and O3in the insulation gas by adsorbing, oxidizing, or reducing these substances. For example, regarding the removal material6, a synthetic zeolite in which a mole ratio of silica/alumina is 5 or higher (which may hereinafter be referred to as a high silica synthetic zeolite), a synthetic zeolite having protons (H) as positive ions (which may hereinafter be referred to as a proton exchange synthetic zeolite), and a metal oxide can be presented as examples. In addition, the removal material6may be a combination of two or more kinds of a high silica synthetic zeolite, a proton exchange synthetic zeolite, and a metal oxide.

Moreover, the removal material6may be a combination of materials other than a high silica synthetic zeolite, a proton exchange synthetic zeolite, and a metal oxide. For example, a mixture of a material having a removal performance with respect to HF, a material having a removal performance with respect to CO, and a material having a removal performance with respect to O3may be used as the removal material6according to the present embodiment.

Regarding a high silica synthetic zeolite, for example, a high silica zeolite having a pore size of 4.9 Å and having protons as positive ions can be presented as an example. In addition, regarding a proton exchange synthetic zeolite, for example, a zeolite having a pore size of 4.9 Å can be presented as an example. Moreover, regarding a metal oxide, CuO, CO3O4, and MnO2can be presented as examples.

Regarding a zeolite, generally, it is known that the strength and reaction activity as a solid acid increase as the mole ratio of alumina (Al2O3) to silica (SiO2) becomes high. When a high silica zeolite having a silica/alumina ratio is 5 or higher is used as the removal material6, the removal material6manifests catalytic action of oxidizing CO into CO2as a solid acid. In addition, the speed of O3changing to O2due to self-reaction is accelerated. HF is physically adsorbed into the pores due to an intermolecular force (Van der Waals force) generated depending on the polarity of the zeolite. Accordingly, due to the high silica synthetic zeolite, three kinds of undesired substances, such as HF, CO, and O3, can be effectively adsorbed, oxidized, and reduced.

In addition, when protons (H+) are adopted as positive ions of the synthetic zeolite, it can be used as a solid acid and manifests catalytic action of oxidizing CO into CO2. In addition, the speed of O3changing to O2due to self-reaction is accelerated. HF is physically adsorbed into the pores due to an intermolecular force (Van der Waals force) generated depending on the polarity of the zeolite. Accordingly, due to the proton exchange synthetic zeolite, three kinds of undesired substances, such as HF, CO, and O3, can be effectively adsorbed, oxidized, and reduced.

Moreover, metal oxides such as CuO, CO3O4, and MnO2have a function of a catalyst at least within a temperature range of −30° C. to 50° C. Since these metal oxides are oxidation catalysts, they manifest catalytic action of oxidizing CO into CO2. In addition, the speed of O3changing to O2due to self-reaction is accelerated. HF is physically adsorbed on a surface of the catalyst due to an intermolecular force (Van der Waals force) generated depending on the polarity. Accordingly, due to the metal oxide, three kinds of undesired substances, such as HF, CO, and O3, can be effectively adsorbed, oxidized, and reduced.

A metal oxide may be added to a coating material such that an inner surface of the sealed container1is coated therewith, and thus the inner surface of the sealed container1can have a function of a catalyst.

In a breaking process of the gas insulation breaker having the foregoing constitution, when the movable contact portion41operates in the leftward direction inFIG.1, the fixed piston43compresses a puffer chamber47that is an internal space of the cylinder44and raises the pressure therein. Further, the insulation gas2present inside the puffer chamber47becomes a high-pressure gas flow, is guided to the insulation nozzle45, and is strongly sprayed to the arc7generated between the arc contactors32and42. Accordingly, the conductive arc7generated between the arc contactors32and42disappears and a current is blocked.

When O2is mixed into a gas including CO2and an arc is ignited, there is a likelihood that HF, CO, and O3are generated. HF is a gas having corrosiveness particularly with respect to a metal and is noxious with respect to the human body. CO is a toxic gas and degrades the dielectric strength of the insulation gas. O3is also a gas having high reactivity and being poisonous to the human body. In addition, O3causes the O-ring used for the sealed container1retaining the airtight structure or grease applied to the sliding portions of the piston43and the cylinder44to deteriorate. When the removal material6having a function of reducing the concentrations of HF, CO, and O3in the insulation gas is installed inside the sealed container1, these poisonous gases can be adsorbed, oxidized, or reduced, safety can be enhanced, and the life span of the equipment can be lengthened.

Table 1 shows performances of various kinds of removal materials. A removal material1is a proton exchange synthetic zeolite in which the mole ratio of silica/alumina is 5 and the pore size is 4.9 Å. A removal material2is a potassium exchange synthetic zeolite in which the mole ratio of silica/alumina is smaller than 5 and the pore size is 3 Å. A removal material3is a sodium exchange synthetic zeolite in which the mole ratio of silica/alumina is smaller than 5 and the pore size is 9 Å. A removal material4is a lithium exchange synthetic zeolite in which the mole ratio of silica/alumina is smaller than 5 and the pore size is 9 Å. The marks “G” in Table 1 indicate that a sufficient performance can be exhibited when being used in the gas insulation breaker illustrated inFIG.1, and the marks “B” indicate that a sufficient performance cannot be exhibited. In addition, inFIGS.2to5, removal performances of the removal materials1to4are shown in graphs. InFIGS.2to5, the horizontal axis indicates the time, and the vertical axis indicates the concentrations of HF, CO, and O3illustrated inFIG.1, that is, the generated concentration (volume ppm) per 1 MJ of a breaking current energy in the gas insulation breaker. As shown in Table 1 andFIGS.2to5, it is ascertained that the removal material1can exhibit a sufficient effect of reducing the concentration with respect to all of HF, CO, and O3.

TABLE 1HFCOO3Removal material 1GGGRemoval material 2BBBRemoval material 3GBGRemoval material 4GBG

The gas insulation apparatus of the present embodiment includes a gas insulation opening/closing apparatus. A gas insulation opening/closing apparatus includes a breaker, a disconnector, a grounding switch, and a lightning arrestor.

According to at least one embodiment described above, when a removal material is used, a gas insulation apparatus reducing the concentrations of HF, CO, and O3in the insulation gas can be provided. Accordingly, a life span and reliability of a gas insulation apparatus using an insulation gas having CO2and O2as main components can be secured in long-term use, and safety during maintenance can also be secured.

Some embodiments of the present invention have been described, but these embodiments are presented as examples and are not intended to limit the scope of the invention. These embodiments can be performed in various other forms, and various omissions, replacements, and changes can be performed within a range not departing from the gist of the invention. These embodiments and modifications thereof are included in the invention described in the claims and the scope equivalent thereto as they are included in the scope and the gist of the invention.

REFERENCE SIGNS LIST

1Sealed container2Insulation gas6Removal material31Fixed contact portion (high-voltage portion)41Movable contact portion (high-voltage portion)