JP4262928B2 - Gas circuit breaker - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a gas circuit breaker that cuts off a current due to a ground fault or a short circuit between lines in order to protect a power transmission system and a distribution system, and particularly uses a gas containing oxygen atoms as an arc extinguishing gas. It relates to a gas circuit breaker.
[0002]
[Prior art]
Currently, a puffer-type gas circuit breaker having a simple structure, high reliability, and excellent breaking performance is widely used as a protective switch for a high-voltage power transmission system of 72 kV or higher. 3 to 6 are sectional views showing an example of a conventional gas circuit breaker. FIG. 3 shows a closed state, FIG. 4 shows an initial state of the opening operation, and FIG. 5 shows a state immediately after completion of the opening operation. FIG. 6 shows a state in which the current reaches the zero point after the opening operation is finished.
[0003]
As shown in the figure, the gas circuit breaker has a first contact portion defined as the fixed contact portion 10 and a second contact portion defined as the movable contact portion 20 disposed opposite to each other. These contact parts 10 and 20 are accommodated in a container (not shown) filled with an arc extinguishing gas. Hereinafter, the positional relationship of the movable contact portion 20 will be described by defining the direction on the fixed contact portion 10 side as the front and the opposite side as the rear.
[0004]
The fixed contact portion 10 is composed of a fixed arc contact 11 and a fixed energization contact 12 arranged around the fixed arc contact 11. A conductor 13 is fixed to the fixed energizing contact 12 and is connected to a lead-out portion of a gas circuit breaker (not shown). On the other hand, the movable contact portion 20 includes a hollow operating rod 21, a flange 22 disposed around the operating rod 21 and connected to the operating rod 21 at the front end portion, a puffer cylinder 23 connected to the rear of the flange 22, A hollow and finger-like movable arc contact 24 connected in front of the flange 22, a movable energizing contact 25 disposed around the movable arc contact 24, an insulating nozzle 26 surrounding the movable arc contact 24, and a puffer The fixed piston 27 is inserted into the cylinder 23. The fixed piston 27 is fixed to the flange 14. An energization portion 28 is fixed to the flange 14 so that contact energization and sliding energization with the puffer cylinder 23 are possible. Further, a conductor 29 is fixed to the flange 14 and is connected to a lead-out portion of a gas circuit breaker (not shown).
[0005]
Of the movable contact portion 20 as described above, the operation rod 21 is configured to reciprocate in the axial direction by a driving device (not shown), and in the middle thereof, the hollow portion and the filling gas. A plurality of communication holes 21a communicating with the atmosphere space are formed. Further, between the movable arc contact 24 and the insulating nozzle 26, the gas compressed in the compression space S <b> 1 inside the puffer cylinder 23 is used as a gas flow, and the arc space S <b> 2 passes through the communication hole 22 a provided in the flange 22. An upstream gas flow path S3 is formed to guide the gas.
[0006]
Further, the fixed piston 27 is formed in a circular flat plate shape, and slides with respect to the outer peripheral surface of the operation rod 21 on the inner peripheral surface thereof, and slides with respect to the inner peripheral surface of the puffer cylinder 23 with the outer peripheral surface thereof. It is configured to move. In this case, the fixed piston 27 is fixed in a container (not shown) by a piston support portion 27a that is integrally provided behind the piston and extends in the axial direction. Then, when the operating rod 21 and the puffer cylinder 23 move integrally with the fixed piston 27 fixed in this manner, the puffer cylinder 23 and the fixed piston 27 move relative to each other. The formed space S1 is compressed. Moreover, in the gas circuit breaker having the above-described configuration, the iron-based parts are often subjected to a phosphate film treatment as a rust-proofing treatment.
[0007]
The energization state at the time of closing of the gas circuit breaker having the above configuration will be described. The current is introduced from the outlet portion on one side of the gas circuit breaker, and enters from the conductor 13 side, for example, and enters the fixed energizing contact 12, the movable energizing contact 25, the flange 22, the puffer cylinder 23, the energizing portion 28, the flange 14, and the conductor. Go out 29 through the outlet on the opposite side of the gas circuit breaker. In this case, each contact surface is usually silver-plated to reduce contact resistance when the component is made of aluminum. That is, the contact surface between the conductor 13 and the fixed energizing contact 12, the contact surface between the fixed energizing contact 12 and the movable energizing contact 25, the contact surface between the movable energizing contact 25 and the flange 22, the flange 22 and the puffer cylinder 23. A contact surface between the puffer cylinder 23 and the energization portion 28, a contact surface between the energization portion 28 and the flange 14, and a contact surface between the flange 14 and the conductor 27. In addition, when the parts are made of copper, they are often not plated.
[0008]
Next, the opening operation of the gas circuit breaker will be described. First, in the initial state in the middle of the opening operation shown in FIG. 3, the rear operating rod 21 is moved, and the movable contact portion 20 including the operating rod 21 is moved integrally. FIG. 4 shows a state after the fixed arc contact 11 and the movable arc contact 24 are separated by such an opening operation. In the arc space S2 between the arc contacts 11 and 24, a large current arc is shown. 30 has occurred.
[0009]
Here, the pressure in the pressure accumulating space S <b> 1 inside the puffer cylinder 23 is increased by a mechanical compression action by relative movement between the puffer cylinder 23 and the fixed piston 27. At this time, the arc space S2 is in a high temperature and high pressure state due to the large current arc 30. For example, when the current of the high-current arc 30 is 50 kA, the temperature easily reaches 10,000 K or more. For this reason, the arc space S2 has a pressure higher than that of the compression space S1, and a gas flow 32a is generated from the internal space of the operating rod 21 to the compression space S1 through the communication hole 21a. That is, a part of the energy of the large current arc 30 is taken into the compression space.
[0010]
Thus, when the opening operation proceeds, the pressure accumulation space S1 inside the puffer cylinder 23 is boosted by a thermal action in addition to a mechanical compression action. When the pressure accumulation space S1 is sufficiently boosted in this way and the opening operation further proceeds as shown in FIG. 5 and the throat portion S4 of the insulating nozzle 26 opens, the movable arc contactor 24 and the insulating nozzle 26 A gas flow 32 b is generated that flows from the gas flow path therebetween toward the fixed arc contact 11. On the other hand, a gas flow 32 c that flows from the hollow portion of the movable arc contact 24 toward the communication hole 21 a provided in the operation rod 21 is also generated. However, at this stage, since the arc space S2 is almost closed by the large-current arc 30 having a large diameter, the gas flows 32b and 32c are only weak flows.
[0011]
Further, when the opening operation proceeds and the current zero point is reached as shown in FIG. 6, the large current arc 30 is attenuated to become the residual arc plasma 31, and the pressure, density, and temperature in the pressure accumulation space S <b> 1 decrease. As a result, the throat portion S4 of the insulating nozzle 26 is sufficiently opened, and strong gas flows 32d and 32e are generated. Accordingly, the gas flows 32d and 32e in these two directions are powerfully and synergistically cooled to extinguish the arc and achieve current interruption.
[0012]
[Problems to be solved by the invention]
In recent years, global environmental problems have been greatly taken up, and gas circuit breakers have been pointed out to be related to global warming problems. In other words, the high warming potential GWP (Global Warming Potentials) of SF6 gas, which has been widely used as an effective arc extinguishing gas for gas circuit breakers, has attracted attention and is related to the prevention of global warming held in December 1997. It was designated as a greenhouse gas at the Kyoto Conference (COP3). At present, since the total amount of SF6 gas used is small compared to CO2 gas, reducing the discharge of SF6 gas is an effective measure.
[0013]
However, while the global warming potential is 1 for CO2 gas, SF6 gas is said to be about 24900, which is much larger, and it is desired to reduce the total amount used. For this reason, the possibility of the gas circuit breaker which reduced the usage-amount of SF6 gas is searched. In such movement, gas containing oxygen atoms, for example, carbon dioxide, air, oxygen, or a mixed gas thereof has been studied as a conventional arc extinguishing gas other than SF6.
[0014]
However, it is known that a gas containing these oxygen atoms generates free oxygen atoms by arc energy. Free oxygen atoms easily react with the metal material to erode the metal material and form a powdered metal oxide. As described above, the parts constituting the contact portion of the gas circuit breaker and the pressure accumulating space are often exposed to the high-temperature gas heated by the arc, and an oxidation reaction may occur. If the oxidation reaction proceeds and the metal material is eroded, there is a problem that the strength of the structural material is reduced or the surface state of the component is changed to make the performance unstable.
[0015]
The present invention has been proposed in order to solve the above-described problems. The object of the present invention is to prevent oxidation reaction by subjecting parts exposed to high-temperature gas to an oxidation-resistant surface treatment, thereby suppressing the oxidation reaction. An object of the present invention is to provide a gas circuit breaker that prevents the generation of metal oxides and the erosion of metal materials and stabilizes performance.
[0016]
[Means for Solving the Problems]
In order to achieve the above object, according to the present invention, a first contact portion and a second contact portion are disposed to face each other in a sealed container filled with an arc extinguishing gas, and the first contact portion and The second contact portion is provided with a first arc contact and a second arc contact, respectively, and the first arc contact and the second arc contact are in a contact conduction state during normal operation, and are opened. The gas flow generating means is configured to generate an arc in an arc space defined as a space between the two contacts and to dissipate the arc, while being separated while relatively moving. The means includes at least one pressure accumulating space, at least one pressure raising means for raising the pressure in the pressure accumulating space, at least one upstream gas passage connecting the pressure accumulating space and the arc space, the arc space and the sealed space. And at least one downstream gas flow path that connects a downstream space defined as a space having the same pressure as the internal filling pressure, and the pressure raising means is formed from at least one of a mechanical compression means and a heating pressure raising means. The constructed gas circuit breaker has the following characteristics.
[0017]
The present invention is characterized in that, among the parts exposed to the high-temperature gas generated by the arc, the iron-based metal surface exposed to a high-temperature gas of at least 1000 ° C. is subjected to a phosphate coating treatment or a black dyeing treatment. And
In this invention which has such a structure, it can prevent that an iron-type component is directly exposed to high temperature. For this reason, generation | occurrence | production of a powdery iron-type metal oxide can be prevented, and the gas circuit breaker of the stable performance can be obtained.
[0018]
According to a second aspect of the present invention, in the gas circuit breaker according to the first aspect, the arc-extinguishing gas is any one of carbon dioxide, dry air, oxygen , or a combination of a plurality of types. .
In the invention of claim 2 as described above, a gas circuit breaker that exhibits non-toxic, low ozone depletion coefficient, or zero arc extinguishing gas and exhibits stable performance and excellent environmental friendliness. Can be obtained.
[0020]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an example of an embodiment of a gas circuit breaker according to the present invention will be specifically described with reference to FIGS. 1 and 2. In addition, about the member same as the prior art example shown in FIGS. 3-6, the same code | symbol is attached | subjected and description is abbreviate | omitted.
[0021]
[1. Representative embodiment]
[1-1. Constitution]
This embodiment is a gas circuit breaker to which the inventions of claims 1 and 2 are applied. As shown in FIG. 1, at the initial stage of the opening operation, the high-temperature gas flow 32a generated by the high-current arc 30 reaches the pressure accumulation space S1 through the inside of the insulating rod 21 and the communication hole 21a. Therefore, the oxidation-resistant treatment unit 40 is provided on the inner surface of the operation rod 21, the portion facing the pressure accumulation space S <b> 1 of the operation rod 21, the flange 22, the puffer cylinder 23 and the fixed piston 27. The oxidation-resistant treatment part 40 is formed on a metal surface that is exposed to a high-temperature gas of at least 1000 ° C. or higher among components exposed to a high-temperature gas generated by an arc.
[0022]
Further, as shown in FIG. 2, at the end of the opening operation, a high-temperature gas flow 32b generated by the high-current arc 30 flows from the tip of the insulating nozzle 26 toward the inside of the fixed energizing contact 12, and is also at a high temperature. The gas flow 32 c passes through the inside of the operation rod 21, the communication hole 21 a, and reaches a space surrounded by the fixed piston support portion 27 a and the operation rod 21. Therefore, the oxidation-resistant treatment unit 40 is provided on the inner surface of the fixed energizing contact 12, the outer surface of the operation rod 21, the inner surfaces of the fixed piston 27 and the fixed piston support portion 27 a.
In this case, when the component exposed to the high-temperature gas is an iron-based metal, the oxidation-resistant processing unit 40 is formed by subjecting the surface of the iron-based metal to a phosphate coating process or a black dyeing process. Yes. In the present embodiment, the arc extinguishing gas is one of carbon dioxide, dry air, oxygen , or a combination of gases.
[0023]
[1-2. Effect]
The operation of the present embodiment having the above-described configuration is as follows. Since the parts exposed to the high temperature gas flows 32a, 32b and 32c generated during the opening operation are protected by the oxidation resistant treatment unit 40, even when a gas containing oxygen atoms is used as the arc extinguishing gas, There is no oxidation reaction between the component surface and free oxygen atoms, and no powdered metal oxide is generated. In addition, erosion of the metal material can be prevented. Thereby, the gas circuit breaker of the stable performance can be obtained. Moreover, in the present embodiment, a non-toxic, low ozone depletion coefficient, or zero arc extinguishing gas is used, so that a gas circuit breaker that exhibits stable performance and excellent environmental harmony can be obtained. it can.
[0025]
【The invention's effect】
As described above, according to the present invention, by subjecting parts exposed to high-temperature gas to an oxidation-resistant surface treatment, the oxidation reaction is suppressed to prevent generation of powdered metal oxide and corrosion of the metal material. Thus, a gas circuit breaker whose performance is stabilized can be obtained.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of an exemplary embodiment according to the present invention, showing the initial state of the opening operation.
FIG. 2 is a cross-sectional view of the present embodiment, showing a state at the end of the opening operation.
FIG. 3 is a cross-sectional view of a conventional gas circuit breaker, showing a closed state.
FIG. 4 is a cross-sectional view of a conventional gas circuit breaker, showing the initial state of the opening operation.
FIG. 5 is a cross-sectional view of a conventional gas circuit breaker, showing a state immediately after completion of the opening operation.
FIG. 6 is a cross-sectional view of a conventional gas circuit breaker, showing a state where a current zero point is reached after completion of the opening operation.
[Explanation of symbols]
10: Fixed contact part (first contact part)
DESCRIPTION OF SYMBOLS 11 ... Fixed arc contact 12 ... Fixed electricity supply contact 13 ... Conductor 14 ... Flange 20 ... Movable contact part (2nd contact part)
21 ... Operating rod 21a ... Communication hole 22 ... Flange 22a ... Communication hole 23 ... Puffer cylinder 24 ... Moving arc contact 25 ... Moving energizing contact 26 ... Insulating nozzle 27 ... Fixed piston 27a ... Supporting portion 28 ... Energizing portion 29 ... Conductor 30 ... High-current arc 31 ... Residual arc plasma 32a-32e ... Gas flow 40 ... Oxidation resistant part S1 ... Accumulated space S2 ... Arc space S3 ... Upstream gas flow path S4 ... Throat part

Claims (2)

A first contact portion and a second contact portion are disposed opposite to each other in an airtight container filled with an arc extinguishing gas containing oxygen atoms, and the first contact portion and the second contact portion are respectively A first arc contact and a second arc contact are provided, and the first arc contact and the second arc contact are in a contact conduction state during normal operation and are separated while moving relatively during an opening operation. And a gas flow generating means configured to generate an arc in an arc space defined as a space between the two contacts and extinguishing the arc, wherein the gas flow generating means includes at least one pressure accumulating space and , At least one pressure increasing means for increasing the pressure in the pressure accumulating space, at least one upstream gas passage connecting the pressure accumulating space and the arc space, and the same pressure as the filling pressure in the arc space and the sealed container. Connecting the downstream space defined as between is composed of at least one of the downstream gas passage, the pressure increasing device in the gas circuit breaker, which is composed of at least one means of mechanical compression means or heating boost means,
Among the parts exposed to the high-temperature gas generated by the arc , a gas barrier is characterized in that a phosphate coating or blackening treatment is applied to an iron-based metal surface exposed to a high-temperature gas of at least 1000 ° C. vessel. 2. The gas circuit breaker according to claim 1, wherein the arc extinguishing gas is one of carbon dioxide, dry air, and oxygen , or a combination of a plurality of types.

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