Patent Application
20130161289
The present invention relates to a gas circuit breaker which interrupts a large current during the occurrence of a fault such as a short-circuit, a load current, and an energization current in normal time by blowing arc extinguishing gas.
In a known gas circuit breaker, in order to effectively interrupt a large current by a small operating force, the gas circuit breaker includes: a heating chamber which enhances the pressure of insulating gas using the heat of an arc; and a pair of cylinder and piston (mechanical puffer) which enhances the pressure of insulating gas by reducing a volume by a mechanical operating force. The heating chamber is a space disposed so as to surround an arc chamber between a contact tulip and an opening and closing pin with an operating axis of the opening and closing pin as a center line, and the heating chamber communicates with the arc chamber by blowing slits. During an interruption operation, pressure in the heating chamber rises by heat which is radiated passing through the blowing slits from an arc generated between the contact tulip and the opening and closing pin. Furthermore, a material constituting the blowing slits becomes evaporation gas by the heat of the arc; and accordingly, a pressure rise in the heating chamber is enhanced. The pressure rise is assisted by the supply of the insulating gas, which is compressed by the piston operating simultaneously with a contact opening operation of the opening and closing pin, to the heating chamber through a blowing path.
For example, in a known circuit breaker disclosed in Patent Document 1, in the case of crossing a next current zero point after a high pressure is generated in a heating chamber, insulating gas in the heating chamber flows from blowing slits to a discharge port provided on the opposite side of a pressure chamber with respect to an arc chamber via the arc chamber and the pressure chamber; and at the same time, the insulating gas flows into other discharge chamber on the opening and closing pin side via the arc chamber. Accordingly, a gas flow inevitably intersects with an arc and gas ionized in an intersection range is sufficiently removed; and therefore, an arc is not generated after crossing the current zero point and arc extinguishing is completed.
Furthermore, for example, in a known gas circuit breaker disclosed in Patent Document 2, in order to absorb a slight amount of moisture contained in arc extinguishing gas in the gas circuit breaker and a gas molecule formed by decomposition by an arc, an adsorbent of a porous body is laid or stored at a path where interrupting gas moves or a portion where the interrupting gas remains.
Further, for example, in a gas circuit breaker disclosed in Patent Document 3, a hydrogen absorbing alloy member is disposed in a flow path from a mechanical puffer to an arc chamber; hydrogen gas is discharged from the hydrogen absorbing alloy member overheated by an arc during a contact opening operation and the arc is cooled; and after completion of the contact opening operation, the temperature of the hydrogen absorbing alloy member decreases and the hydrogen gas is recovered again.
However, in the known circuit breaker of Patent Document 1, heated gas flows out from the arc chamber to other discharge chamber, the heated gas including: a hydrogen ion generated by evaporation of the blowing slits by the heat of the arc and a hydrogen ion generated by decomposition of a slight amount of moisture contained in the insulating gas by the arc; and a fluorine ion generated by decomposition of insulating gas by the arc when the insulating gas is gas containing fluorine. As the temperature of the heated gas decreases, the hydrogen ion combines with the fluorine ion to form hydrogen fluoride. The hydrogen fluoride has a predisposition to make an insulator corrode extremely; and therefore, a problem exists in that an insulating body, which supports a structural object to which a high voltage is applied, causes deterioration of insulation by absorbing the hydrogen fluoride.
Furthermore, heated gas flows out from the arc chamber to other discharge chamber, the heated gas including: a hydrogen ion generated by evaporation of the blowing slits by the heat of the arc and a hydrogen ion generated by decomposition of a slight amount of moisture contained in the insulating gas by the arc; and an oxygen ion generated by decomposition of insulating gas by the arc when the insulating gas is gas containing oxygen. As the temperature of the heated gas decreases, the hydrogen ion combines with the oxygen ion to form water. Water has a predisposition to make insulation deteriorate; and therefore, problems exist in that not only water makes the insulating gas lower its own insulation performance, but also water causes deterioration of insulation by attachment of water to an insulating body, which supports an structural object to which a high voltage is applied, or by adhesion of water to the insulating body.
Furthermore, in the gas circuit breaker of Patent Document 2, the porous body, which is disposed to absorb the slight amount of moisture contained in the arc extinguishing gas and the gas molecule formed by decomposition by the arc, is disposed at a location where a temperature is relatively low and the porous body cannot be brought into directly contact with high temperature heated gas; and therefore, a problem exists in that the temporal efficiency of adsorption is bad.
Furthermore, in the gas circuit breaker of Patent Document 3, although the hydrogen absorbing alloy member is disposed for the purpose of arc cooling, adsorbed hydrogen is discharged during the contact opening operation; and therefore, the hydrogen absorbing alloy member has a function that rather increases than decreases hydrogen during the contact opening operation. Further, the arrangement locations of the hydrogen absorbing alloy member are the puffer chamber, the flow path from the puffer chamber to the arc chamber, and the arc chamber; and accordingly, hydrogen in heated gas containing a hydrogen component formed by decomposition in the arc chamber cannot be absorbed and it is difficult to prevent the hydrogen compound from diffusing outside an arc extinguishing chamber. Thus, a problem exists in that deterioration of insulation is caused.
In addition, the direction of the contact opening operation of an opening and closing pin is opposite to a direction for pressing to the direction of a compression operation of a piston; and therefore, a problem exists in that an operation mechanism, which operates the opening and closing pin and the piston, is complicated.
The present invention has been made to solve the problems described above, and an object of the present invention is to provide a gas circuit breaker which suppresses deterioration of insulation caused by a product that is formed by decomposition of arc extinguishing gas by an arc during a contact opening operation, and in which an operation mechanism is simple and a reduction in size is achieved.
In order to solve the above-described problems, the present invention provides a gas circuit breaker including: a fixed electrode; a movable electrode capable of being connected to and disconnected from the fixed electrode; an arc chamber in which an arc generated when the movable electrode is separated from the fixed electrode is formed; a pressure chamber in which arc extinguishing gas to be sent to the arc chamber is stored; a nozzle which guides the arc extinguishing gas from the pressure chamber to the arc chamber; and a hydrogen absorbent which is disposed in a flow path of heated gas discharged from the arc chamber during the generation of the arc.
According to a gas circuit breaker of the present invention, heated gas exhausted from an arc chamber comes into contact with a hydrogen absorbent and accordingly hydrogen and a hydrogen ion contained in the heated gas are adsorbed and reduced, whereby the formation of hydrogen compounds such as hydrogen fluoride that deteriorates an insulation material and water that lowers insulation can be suppressed and deterioration of insulation can be suppressed.
Hereinafter, gas circuit breakers according to embodiments of the present invention will be described with reference to
In the gas circuit breaker shown in
In
A mechanical puffer 13 electrically connected to the first conductor 2a in
The puffer piston 15 is inserted in the mechanical puffer cylinder 14 and a space surrounded by the mechanical puffer cylinder 14 and the puffer piston 15 constitutes the mechanical puffer chamber 16.
A configuration is made such that the puffer piston 15 is fastened to an operating rod 21 connected to the movable electrode 11; and a contact opening operation of the movable electrode 11 and the fixed electrode 12 and an operation of drawing the puffer piston 15 from the mechanical puffer cylinder 14 can be performed at the same time by only driving the movable electrode 11 to the contact opening direction, and the operation mechanism 4 can be of a simple configuration. Further, an object to be driven is the movable electrode 11 and the puffer piston 15; and accordingly, a reduction in weight can be achieved and the operating force of the operating device 5 can be reduced.
The puffer piston 15 is drawn; and accordingly, the volume of the inside of the mechanical puffer chamber 16 is reduced to compress gas therein and its pressure rises.
The heat puffer chamber 20 is connected to the mechanical puffer cylinder 14 by the plurality of pipes 22. The check valve 23 that stops a flow from the heat puffer chamber 20 to the mechanical puffer cylinder 14 is provided on each of the plurality of pipes 22 on the mechanical puffer cylinder 14 side of the pipe 22.
The arc chamber 24 is an arc generation space defined by leading end portions 12t of the contact fingers 12f constituting the fixed electrode 12 and a leading end portion lit of the movable electrode 11, and is surrounded by the annular heat puffer chamber 20 from the circumferential direction of the direction the above-mentioned operation. The wall surface on the inner circumferential side of the heat puffer chamber 20 is constituted by a nozzle 25 and a guide 26 and a section of the heat puffer chamber 20 is a wedge shape; and the ring shaped blow port 27 is provided on the guide 26 positioned at this wedge apex. The outer circumference of the heat puffer chamber 20 is constituted by a tube shaped outer circumferential wall 19; and the maximum dimension of the arc extinguishing device 1 is defined by the diameter of the outer circumferential wall 19.
The pressure chamber 28 is a space surrounded by a protective cover 29 and the partition wall 30, the protective cover 29 being a conical side surface shape provided in order to prevent heated gas from flowing in from the slits each between the contact fingers 12f of the fixed electrode 12; and the pressure chamber 28 communicates with the arc chamber 24 by the opening portion 12a surrounded by the leading end portions of the fixed electrode 12. Further, the pressure chamber 28 is a conically shaped space provided between the partition wall 30 and the heat puffer chamber 20 using a conical space in which the inner circumferential side of the annular heat puffer chamber 20 is recessed, and the inner surface of the partition wall 30 facing the opening portion 12a is wider than the opening portion 12a. A reduction in size in the longitudinal direction of the arc extinguishing device 1 is achieved by such a configuration. The exhaust port 31 is provided in the partition wall 30, and the heated gas remained in the pressure chamber 28 is exhausted from the exhaust port 31.
The hydrogen absorbents 32a, 32b, and 32c, which absorb a hydrogen atom, a hydrogen ion or hydrogen molecule (hereinafter, named generically as hydrogen) and a hydrogen compound, are disposed at the position surrounding the movable electrode 11 and the inner surface of the partition wall 30 facing the opening portion 12a of the pressure chamber 28. The hydrogen absorbents 32a, 32b, and 32c are a metal such as palladium (Pd), titanium (Ti), zirconium (Zr), magnesium (Mg), and nickel (Ni). These hydrogen absorbents 32a, 32b, and 32c have performance that absorbs hydrogen equal to or larger than their own volume. Furthermore, the hydrogen absorbents 32a, 32b, and 32c absorb hydrogen most efficiently at about from 200° C. to 1500° C. On the other hand, a melting point is about 2000° C.; and therefore, the arrangement of the hydrogen absorbents placed at the position at temperature equal to or lower than the melting point is preferable.
The guide 26 may use a material that easily evaporates by the heat of an arc for the purpose of increasing the pressure of the heat puffer chamber 20. At this time, in the case where the material is made of an insulator of an organic compound such as a substance containing hydrogen H, for example, polyacetal (POM), acrylic resin (PMMA), polyethylene (PE), urea resin (UF), and melamine resin, hydrogen is generated when such material is decomposed by the heat of the arc. Furthermore, moisture contained slightly in insulation arc extinguishing gas is also decomposed by the arc and hydrogen is generated.
For example, in the case where gas containing fluorine F is used for the insulation arc extinguishing gas like SF6 gas, as the generated hydrogen H is cooled and its temperature decreases, the hydrogen combines with fluorine F to form hydrogen fluoride HF, the fluorine F being generated by decomposition of the arc extinguishing gas by an arc. This hydrogen fluoride HF is extremely high in corrosiveness; and the hydrogen fluoride HF deteriorates an insulator or the like for use at a place where the arc extinguishing device 1 is supported, and lowers dielectric strength. However, the hydrogen absorbents 32a, 32b, and 32c are provided; and accordingly, the generation of HF can be suppressed by absorbing hydrogen before lowering to a temperature at which HF is formed, and an effect that prevents deterioration of insulation can be obtained. Furthermore, in the case where gas containing oxygen O such as CO2 is used for the arc extinguishing gas, oxygen O combines with hydrogen H to form water H2O. When water is generated, insulation deteriorates; however, the generation of water can be suppressed by the hydrogen absorbents 32a, 32b, and 32c by absorbing hydrogen before lowering to a temperature at which water is formed; and deterioration of insulation can be prevented. Further, as shown in
Next, a current interruption operation of the arc extinguishing device 1 of the gas circuit breaker according to Embodiment 1 of the present invention will be described. First, when a contact opening command is given to the gas circuit breaker in a close contact state, the operating device 5 starts up to drive the movable electrode 11 (to the left side in
An alternating current repeats a maximum value and a zero value of the current for every half cycle; and therefore, a current value of the arc is also small in a period of time when the current reduces from the maximum value to the zero value, especially near the zero value, and an amount of generated heat is also small. Therefore, in this time domain, the pressure of the heat puffer chamber 20 is higher than that of the arc chamber 24, and the arc extinguishing gas is blown from the heat puffer chamber 20 to the arc through the blow port 27. Further, at a time when the pressure in the mechanical puffer chamber 16 is higher than that in the heat puffer chamber 20, the check valve 23 opens and the arc extinguishing gas in the mechanical puffer chamber 16 flows into the heat puffer chamber 20 through the pipes 22; and therefore, the flow of the arc extinguishing gas blown from the heat puffer chamber 20 to the arc through the blow port 25 is enhanced.
In
The heated gas flown out to the fixed electrode 12 side is discharged from the opening portion 12a of the fixed electrode 12 to the pressure chamber 28. The heated gas comes into contact with the hydrogen absorbents 32b and 32c disposed in front of the partition wall 30, and hydrogen contained in the heated gas is adsorbed to reduce the amount of hydrogen. The pressure chamber 28 is a conically shaped and relatively wide space enlarging from the opening portion 12a toward the inner surface of the partition wall 30; a flow path formed by the shape of the conical hydrogen absorbent 32b and the cylindrical hydrogen absorbent 32c reduces flow path resistance of a flow from the fixed electrode 12 toward the pressure chamber 28, promptly exhausts the heated gas from the arc chamber 24, and expands the heated gas; and accordingly, the temperature can be lowered to a temperature at which the hydrogen absorbents 32b and 32c can efficiently absorb.
Whereas, the heated gas flown out to the movable electrode 11 side comes into contact with the hydrogen absorbent 32a disposed around the movable electrode 11. Accordingly, hydrogen contained in the heated gas is adsorbed to reduce the amount of hydrogen. The heated gas in which the amount of hydrogen is reduced changes the direction of a flow to a radial direction. The flow path intersects with the plurality of the pipes 22; however, the heated gas from the arc chamber 24 can be exhausted without disturbing the flow by providing a sufficient interval between rows of the pipes. Further, a heat resistant material is used for the pipe 22; and accordingly, the interval between the rows of the pipes can be further enlarged by using pipes each having a narrow diameter and the heated gas can be efficiently exhausted.
In this way, the arc is extinguished by efficiently exhausting the heat between the electrodes to the outside by blowing the arc extinguishing gas to the arc, and the movable electrode 11 is separated from the fixed electrode 12 to a sufficient distance capable of withstanding against a transient recovery voltage to be appeared between the electrodes; and accordingly, insulation recovery between the electrodes is obtained and interruption is completed. More particularly, in the case of a gas circuit breaker to be applied to a high voltage system, the distance between the electrodes necessary for insulation recovery is long because the transient recovery voltage to be appeared just before completion of interruption is high; however, as described above, the heat between the electrodes is efficiently exhausted to the outside; and accordingly, the distance necessary for the insulation recovery can be shortened and it leads to a reduction in size in the longitudinal direction of the arc extinguishing device 1.
Further, the heated gas exhausted from the arc extinguishing chamber 1a to the outside is small in the amount of hydrogen; and therefore, the amount of gas such as hydrogen fluoride that accelerates corrosion and the amount of a hydrogen compound such as water that deteriorates insulation are small. Thus, even when the gas comes into contact with an insulator for use in the insulation supporting body 8 and the like, the generation of deterioration of insulation can be prevented.
As described above, in the gas circuit breaker according to Embodiment 1, heated gas exhausted from the arc chamber is brought into contact with the hydrogen absorbents and accordingly hydrogen and a hydrogen ion contained in the heated gas are adsorbed and reduced; and therefore, the formation of hydrogen compounds such as hydrogen fluoride that deteriorates an insulation material and water that lowers insulation can be suppressed and the deterioration of the insulation can be suppressed. That is, the hydrogen absorbents are provided on the inner surface of the partition wall facing the fixed electrode of the pressure chamber connected to the arc chamber and at the position surrounding the movable electrode; and accordingly, hydrogen, which is contained in the heated gas generated in connection with the arc that is generated during separation of the electrodes is absorbed. Thus, there is a remarkable effect in that there can be obtained a gas circuit breaker in which the generation of corrosion gas that deteriorates the insulation material and the generation of gas such as water (water vapor) that deteriorates insulation can be suppressed, the corrosion gas and the water (water vapor) being formed by combining with hydrogen, can be suppressed; the deterioration of the insulation is suppressed; the operation mechanism is simple; and a reduction in size can be achieved.
In
A potential is applied to the movable electrode 11 through the mechanical puffer cylinder 14 which is electrically connected to a first conductor 2a in
The mechanical puffer cylinder 14 is a cylinder with the operating rod 21 as the central axis. The puffer piston 15 is inserted in the mechanical puffer cylinder 14 and a space surrounded by the mechanical puffer cylinder 14 and the puffer piston 15 constitutes the mechanical puffer chamber 16. The puffer piston 15 is fixed to a structure that supports the arc extinguishing device 1; and when the movable electrode 11 is drive in a contact opening direction, arc extinguishing gas in the mechanical puffer chamber 16 is compressed and its pressure rises.
The heat puffer chamber 20 is disposed in a direction toward the fixed electrode 12 from the mechanical puffer chamber 16 via the partition wall 33. The heat puffer chamber 20 is a space surrounded by a cylindrical outer wall 19 with the operating rod 21 as the central axis. A communication port is formed in the partition wall 33 provided between the mechanical puffer chamber 16 and the heat puffer chamber 20; and the check valve 23 is provided on the partition wall 33 and prevents the arc extinguishing gas from flowing from the heat puffer chamber 20 to the mechanical puffer chamber 16.
The nozzle 25 is provided in a direction toward the fixed electrode 12 from the heat puffer chamber 20; and the arc extinguishing gas is guided from the heat puffer chamber 20 into the arc chamber 24 that is a space between the movable electrode 11 and the fixed electrode 12 via a space between the nozzle 25 and the guide 26 disposed so as to surround the movable electrode 11. In the case where a material containing a hydrogen atom is used for the whole or a part of the nozzle 25 and the guide 26, the nozzle 25 and the guide 26 are evaporated by the heat of the arc; and accordingly, the hydrogen atom and a hydrogen ion are contained in the arc extinguishing gas and heated gas.
The heated gas generated from the inside of the arc chamber 24 passes through the inside of the cylindrically shaped operating rod 21 from the movable electrode 11; and the heated gas is exhausted from the opening 34 to an outside space, the opening 34 being opened on the side surface of the operating rod 21 at the end portion located on the opposite side of the operating rod 21 with respect to the movable electrode 11. The hydrogen absorbent 35b is disposed near the opening 34 in a manner surrounding the opening 34. The heated gas exhausted from the operating rod 21 impinges on the hydrogen absorbent 35b; and accordingly, hydrogen is reduced.
Whereas, the heated gas discharged from the arc chamber 24 toward the fixed electrode 12 passes through the inside of the cylindrically shaped cooling tube 36 placed in the same axis as the fixed electrode 12 and is exhausted to the outside of an arc extinguishing chamber 1a that is a region where the arc extinguishing device 1 is disposed. The hydrogen absorbents 35a and 35c are disposed in the direction of a heated gas flow path. In
In this way, the hydrogen absorbents 35a, 35b, and 35c are disposed at the flow path of the heated gas and accordingly the amount of the hydrogen contained in the heated gas is reduced; and the formation of hydrogen fluoride and water, each of which is a hydrogen compound, can be suppressed. Thus, an effect can be obtained in that deterioration of insulation of insulators is prevented.
Incidentally, this example shows an example in which the heat puffer 18 is provided; however, as shown in
Furthermore, there is shown an example in which a material containing a hydrogen atom is used for the whole or a part of the nozzle 25 and the guide 26; however, as shown in
As described above, in the gas circuit breaker according to Embodiment 2, as in Embodiment 1, heated gas exhausted from the arc chamber is brought into contact with the hydrogen absorbents and accordingly hydrogen and a hydrogen ion contained in the heated gas are adsorbed and reduced; and therefore, the formation of hydrogen compounds such as hydrogen fluoride that deteriorates an insulation material and water that lowers insulation can be suppressed and the deterioration of the insulation can be suppressed. That is, the hydrogen absorbents are provided on the side surface of the opening of the operating rod, on the inside or the termination end portion of the cooling tube coaxially disposed with the fixed electrode, and on the inner surface of the cooling tube; and accordingly, hydrogen, which is contained in the heated gas generated in connection with the arc that is generated during separation of the electrodes is absorbed. Thus, there is a remarkable effect in that there can be obtained a gas circuit breaker in which the generation of corrosion gas that deteriorates the insulation material and the generation of gas such as water (water vapor) that deteriorates insulation can be suppressed, the corrosion gas and the water (water vapor) being formed by combining with hydrogen, can be suppressed; the deterioration of the insulation is suppressed; the operation mechanism is simple; and a reduction in size can be achieved.
In the gas circuit breaker shown in
In the gas circuit breaker of Embodiment 3 shown in
As described above, in the gas circuit breaker according to Embodiment 3, the hydrogen absorbents are also disposed at portions such as a housing inner wall of the gas circuit breaker, the portions coming into contact with the heated gas. Accordingly, heated gas exhausted from the arc extinguishing device is brought into contact with the hydrogen absorbents; and accordingly, hydrogen and a hydrogen ion contained in the heated gas are adsorbed and reduced. Thus, together with the effects in Embodiment 1 and Embodiment 2, there is a remarkable effect in that the formation of hydrogen compounds such as hydrogen fluoride that deteriorates an insulation material and water that lowers insulation can be suppressed; and deterioration of the insulation can be suppressed.
Incidentally, in the present invention, the respective embodiments can be freely combined and appropriately changed or omitted within the scope of the present invention.
Incidentally, the same reference numerals as those shown in the drawings represent the same or corresponding elements.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2010-272234 | Dec 2010 | JP | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/JP2011/075416 | 11/4/2011 | WO | 00 | 3/1/2013 |
