Gas circuit breaker

A gas circuit breaker including a pair of main contacts is openable inside an insulating tank. A pair of arc contacts is arranged on the inner side of the main contacts, and a puffer cylinder has the main contacts and the arc contacts at an end. A puffer chamber is formed inside the puffer cylinder, and a puffer piston is provided on the inner periphery of the puffer cylinder. An insulating nozzle part is mounted on an end of the puffer cylinder to surround the arc contact. The insulating nozzle part includes a split nozzle base part and a split nozzle end part, and the split nozzle base part has a throat part.

TECHNICAL FIELD

The present invention relates to a gas circuit breaker for power having arc extinguishing gas and, more particularly, to a structure of an insulating nozzle configuring a breaker part of the gas circuit breaker.

BACKGROUND ART

In recent years, a gas circuit breaker with enlarged capacity has been developed along with the development of a high-voltage and high-current electric power system. On the other hand, there is an increasing need for cost reduction and space saving by optimization of a breaker part structure, and it is required to ensure excellent breaking performance with further lowered operation force.

Generally, in a moving side breaker part of the gas circuit breaker including a heat puffer type circuit breaker, an insulating nozzle and a moving main contact are provided on a fixed side and a breaker part side more than a puffer cylinder side. The insulating nozzle is provided for the purpose of effectively blowing arc extinguishing gas that is compressed within a puffer cylinder to arc which occurs between a moving arc contact and a fixed arc contact.

As means for improving breaking performance, there is a method of increasing a pressure of arc extinguishing gas within the puffer cylinder by increasing a throat part of the insulating nozzle. In this method, as the circuit breaker is required to break a high-voltage and high-current, a large insulating nozzle becomes necessary.

A gas circuit breaker, in which a nozzle is divided into a first nozzle member including a nozzle throat part and a second nozzle member in an axial direction thereof, and the first nozzle member and the second nozzle member are fixed to a puffer cylinder by a moving conduction contact, is disclosed in PTL 1.

CITATION LIST

Patent Literature

SUMMARY OF INVENTION

Technical Problem

In order to ensure performance of the circuit breaker, since central axes of a fixed side breaker part and a moving side breaker part are necessary to be aligned in a straight line, it is important to confirm a coaxial state of the breaker parts at the time of assembly.

If whether the nozzle throat part on the moving side and the fixed arc contact are present coaxially can be confirmed, it is possible to confirm the coaxial state of the breaker parts with high accuracy.

In the gas circuit breaker disclosed in PTL 1, the first nozzle member is configured to have the nozzle throat part. Thus, since the nozzle throat part is hidden in an end of the first nozzle member, there is a problem that it is difficult to confirm whether the nozzle throat part and the fixed arc contact are present coaxially.

Solution to Problem

The present invention has been made in view of the above problems and the invention provides a gas circuit breaker including: a pair of main contacts being configured of a fixed main contact and a moving main contact and being openable inside a tank filled with arc extinguishing gas; a pair of arc contacts being arranged on the inner side of the main contacts and being configured of a fixed arc contact and a moving arc contact; a puffer cylinder having one of the moving side main contact and the moving arc contact at an end thereof; a puffer chamber being formed inside the puffer cylinder; a puffer piston being provided on the inner periphery of the puffer cylinder; and an insulating nozzle part being mounted on an end of the puffer cylinder to surround the moving arc contact and forming a flow channel to guide the arc extinguishing gas from the puffer chamber to between the arc contacts. The insulating nozzle part includes a split nozzle base part having a portion from a connection part to a puffer cylinder end to a throat part, and a split nozzle end connected thereto.

Advantageous Effects of Invention

The invention having the above-described configuration can provide the gas circuit breaker that can easily confirm the coaxial state of the breaker part with high accuracy at the time of assembly, improves assembling workability, and has excellent breaking performance even in a large insulating nozzle having a long throat part.

DESCRIPTION OF EMBODIMENTS

Hereinafter, embodiments of the invention will be described with reference to the drawings. The following descriptions are merely examples of implementation, and are not intended to limit the contents of the invention to the following detailed embodiments. The invention itself can be implemented in various embodiments in accordance with the contents described in the scope of claims. For example, the invention of the present application can be applied to a two-chamber heat puffer type circuit breaker.

FIG. 1is a schematic view of an inside of a gas circuit breaker configured by using a split nozzle base part2and a split nozzle end part3of the aspect of the present invention. Configurations other than the split nozzle base part2and the split nozzle end part3are the same as configurations of a conventional puffer type gas circuit breaker.

An insulating tank301is filled with arc extinguishing gas such as SF6and a fixed side conductor202and a moving side conductor109are drawn into the insulating tank301.

The fixed side conductor202is electrically connected to a fixed side main circuit conductor201, a fixed arc contact base203, a fixed arc contact204, and a fixed main contact205configuring a fixed side breaker part200. The fixed arc contact204can be removed and mounted from and on the fixed arc contact base203.

The moving side conductor109is electrically connected to a moving side breaker part100via a moving side main circuit conductor103, a sliding contact101, and a puffer cylinder104. A puffer piston110is connected to an inside of the moving side main circuit conductor103. A puffer cylinder support sliding guide107mounted on an outer periphery of the puffer piston110and the sliding contact101mounted on the inner periphery of the moving side main circuit conductor103concentrically support the puffer cylinder104in a sandwich manner. According to the configuration, the puffer cylinder104is movable in an axial direction while maintaining electric connection to the moving side main circuit conductor103.

A through-hole is provided in the center of the puffer piston110, a puffer shaft111passes through the inside thereof, and the puffer shaft111is supported by a puffer shaft support sliding guide108mounted on the inner periphery of the puffer piston110. One end of the puffer shaft111is fixed to the puffer cylinder104and the other end is connected to an insulating rod112. According to the configuration, the moving side breaker part100is operated in the axial direction by an operation unit (not illustrated) connected to the other end of the insulating rod112.

Further, an intermediate portion of the insulating tank301has a side hole302for maintaining a part of the moving side breaker part100and the fixed side breaker part200.

FIG. 2is an enlarged view of the moving side breaker part100inFIG. 1. A moving arc contact105is provided in the center of the end of the puffer cylinder104. On an outer periphery of the moving arc contact105, an insulating cover106, an insulating nozzle part1, and a moving main contact102are respectively concentrically provided so as to surround the outer periphery of the moving arc contact105. Moreover, in general, an end of the moving arc contact105is positioned on the fixed side breaker part200side more than the moving main contact102.

If the moving side breaker part100moves from a state ofFIG. 1to a fixed side ofFIG. 1, first, the moving arc contact105comes into contact with the fixed arc contact204and is electrically connected to the fixed arc contact204. Even thereafter, the operation of the moving side breaker part100continues and finally moves to a position of an inserted state illustrated inFIG. 3. In this position, the moving main contact102is inserted into the inside of the fixed main contact205and the moving side breaker part100and the fixed side breaker part200are electrically and completely connected to each other.

Conversely, if the moving side breaker part100moves from a state ofFIG. 3to a moving side, first, the moving main contact102is separated from the fixed main contact205and then the moving arc contact105is separated from the fixed arc contact204. In this case, if a large current flows through between the moving side breaker part100and the fixed side breaker part200, even if the moving arc contact105and the fixed arc contact204are separated, the current is not interrupted, arc is generated between contacts of the moving arc contact105and the fixed arc contact204, and the current continuously flows.

In the puffer type gas circuit breaker, arc extinguishing gas within the puffer cylinder104is compressed by the puffer piston110by a series of breaking operations, the arc extinguishing gas is blown to the arc, and then the arc is arc-distinguished, and the moving side breaker part100and the fixed side breaker part200are electrically cut-off. High-temperature and high-pressure arc extinguishing gas (hereinafter, referred to as hot gas) flows through the inside of the insulating nozzle part1at the time of a breaking operation.

As illustrated inFIG. 2, the insulating nozzle part1is configured of the split nozzle base part2and the split nozzle end part3, and both are formed of polytetrafluoroethylene (PTFE). Moreover, a material other than PTFE may be used as long as the material is an insulating material excellent in heat resistance and mechanical strength. Furthermore, the insulating material may contain additives such as boron nitride, aluminum oxide, and molybdenum disulfide.

FIG. 4is a sectional view of a state where the split nozzle base part2and the split nozzle end part3are disassembled from the end of the moving side breaker part100.

The split nozzle base part2has a multi-stage cylinder structure having a passage of arc extinguishing gas on the inside thereof, one end (fixed side end) of the passage of arc extinguishing gas on the inside has a throat part4having an inner diameter greater than an outer diameter of the fixed arc contact204, and the other end (moving side end) has an inner diameter having a space that is capable of housing the moving arc contact.105and the insulating cover106on the inside thereof. Moreover, the throat part4has the minimum diameter of the passage of arc extinguishing gas within the insulating nozzle part1.

On an outer periphery of the end of the split nozzle base part2on the throat part4side, a male screwpart6a, a drop-off prevention part7a, and a tightening jig processing part8are provided.

On the outer periphery of the other end, a male screw part9aand a drop-off prevention part10aare provided. The male screw part9ais screwed into a female screw part9bof the puffer cylinder104, the drop-off prevention part10ais fitted into a drop-off prevention part10bof the puffer cylinder104, and thereby the split nozzle base part2is connected to the puffer cylinder104.

The tightening jig processing part8is configured of a plurality of holes that are, for example, disposed on the same circumference, a tightening jig having pin-shaped protrusion portions hooks into the holes, and the male screw part9ais screwed into the female screw part9b, or torque can be applied in a direction of loosening. Moreover, a shape of the tightening jig processing part8is not limited to the hole and may be a plurality of grooves, and the like arranged radially.

Also, the split nozzle end part3has a multi-stage cylinder structure having a passage of arc extinguishing gas on the inside thereof. One end of the inside has a taper part11of which an inner diameter on the end side is widened.

On the inside of the other end, a female screw part6band a drop-off prevention part7bare provided. The split nozzle end part3is connected to the nozzle base part2by screwing between the female screw part6band a male part6aof the split nozzle base part2, and fitting between the drop-off prevention part7band the drop-off prevention part7aof the split nozzle base part2.

FIG. 5illustrates an enlarged view of a state where the split nozzle base part2and the split nozzle end part3are assembled.

A boundary of the split nozzle base part2and the split nozzle end part3has a fitting part5to prevent entry of hot gas into a screwing part6. Moreover, effects of the fitting part5will be described later and a first gap A between the split nozzle end part3and the split nozzle base part2is not provided in the middle of the throat part4and is provided on the fixed side more than the throat part4. This is because the pressure of arc extinguishing gas is increased in the throat part4having a small area through which gas flows. Thus, since a burden on the strength is large, a distance between the fixed arc contact204and the split nozzle base part2is close and a high electric field is present within the throat part4, turbulence of gas flow occurs by providing a step and the like, and if a region in which a density of arc extinguishing gas is locally lowered occurs, the arc flows through the region and it causes degradation of the performance.

In this embodiment, on the outer periphery of the nozzle end part3on the taper part11side, a guard part12is provided. A tightening jig processing part13is provided in the guard part12. The tightening jig processing part13is configured of a plurality of holes that are, for example, disposed on the same circumference, a tightening jig having pin-shaped protrusion portions hooks into the holes, the male screw part6ais screwed into the female screw part6b, or torque can be applied in a direction of loosening. Moreover, a shape of the tightening jig processing part13is not limited to the hole and may be a plurality of grooves, and the like arranged radially.

According to the structure, the tightening jig is hooked into the tightening jig processing part8of the split nozzle base part2and the tightening jig processing part13of the split nozzle end part3, torque is applied, and thereby the screwing part6is loosened or fastened. Thus, the insulating nozzle part1may be assembled or disassembled into the split nozzle base part2and the split nozzle end part3.

Furthermore, the split nozzle base part2, the split nozzle end part3, and the fixed arc contact204are designed to respectively be a size capable of passing through between the moving main contact102and the fixed main contact205. Thus, it is also possible to remove the split nozzle base part2, the split nozzle end part3, and the fixed arc contact201from the side hole302by splitting of the insulating nozzle part1and removing of the fixed arc contact204from the fixed arc contact base203.

FIG. 6illustrates an outline of a confirming operation of a coaxial state of the breaker part using the nozzle having the split structure.

In the breaker part, it is important that the fixed side breaker part200and the moving side breaker part100are aligned coaxially and if the axes are not aligned, it causes degradation of the performance or failures such as breakage.

The moving side breaker part100is not connected to the split nozzle end part3and the throat part4of the split nozzle base part2is in a state of being disposed in the end of the moving side breaker part100. In this case, it is preferable that connection between the moving side breaker part100and the operation unit is cut-off, and the moving side breaker part100is in a state of arbitrarily moving.

A coaxial state confirming jig303is mounted on the end of the fixed arc contact204of the fixed side breaker part200. The jig303is, for example, a split structure, a fixed side jig303ahas a hole through which the fixed arc contact204is inserted in one end thereof and a cylindrical structure having a screwing part for connecting to a moving side jig303bin the other end thereof.

The moving side jig303bhas a screwing part for connecting to the fixed side jig303ain one end thereof and has a cylindrical part for inserting into the throat part4of the split nozzle base part2in the other end thereof. In addition, the fixed side jig303aand the moving side jig303brespectively have lengths capable of passing through between the fixed arc contact204and the split nozzle base part2in a state where the moving side breaker part100is opened on the breaking side. It is preferable that a material of the jig303is a resin material, for example, nylon and the like that has no possibility to damage the fixed arc contact204and the split nozzle base part2.

First, in a state where the moving side breaker part100is opened on the breaking side, the fixed side jig303apasses through the fixed arc contact204. Next, the moving side jig303bis screwed into the fixed side jig303aand connected to each other.

In this state, the jig303or the moving side breaker part100is operated, the end of the moving side jig303bis inserted into the throat part4, and conditions of fitting are confirmed. Thus, at is possible to confirm the coaxial state of the breaker part from the side hole302of the insulating tank301, that is, from the side surfaces of the fixed side contact200and the moving side breaker part100. Furthermore, it is possible to grasp a size of a displacement of the breaker part even by feeling when operating the jig303. Thus, it is possible to easily perform fine adjustment of an assembled state.

In the above-described method, since the coaxial state of the fixed arc contact204and the throat part4can be confirmed with high accuracy, improvement of the breaking performance can be expected. Moreover, if the coaxial state of the breaker part is shifted, for example, an entire position of the fixed side breaker part200is adjusted, but details of an adjusting method will not be described in the embodiment because a suitable method is varied by the structure of the circuit breaker.

Moreover, although not illustrated, as the confirming method of the coaxial state, instead of the split nozzle base part2, a method, in which confirmation of the coaxial state is performed using a dummy nozzle having the throat part4that is short and has an inner diameter close to the diameter of the fixed arc contact204, and then the dummy nozzle is replaced by the split nozzle base part2, is also effective.

After the coaxial state of the breaker part is confirmed by the above-described steps, the split nozzle end part3is used by assembling on the split nozzle base part2.

As described above, it is possible to adjust the coaxial state of the breaker part with high accuracy by using the method of the embodiment even in the nozzle of which the throat part4is longer and larger than the insulating nozzle of the conventional circuit breaker. Thus, it is possible to provide the gas circuit breaker having excellent breaking performance and reliably.

Next, an effect of the configuration of the embodiment having the fitting part5will be described with reference toFIG. 5. The fitting part5has the first gap A that is opened in the axial direction, a corner D, a second gap B that is opened in the radial direction, a corner B, and a third gap C that is opened in the axial direction.

Since the PTFE forming the insulating nozzle1is liable to expand by an increase in temperature, absorption of moisture, and the like, if the first gap A or the third gap C that is opened in the axial direction is eliminated by the expansion of the insulating nozzle part1, the split nozzle end part3receives a force in a direction that causes the split nozzle end part3to drop off to the fixed side breaker part200side. Thus, the first gap A and the third gap C have dimensions anticipating a margin of the expansion of the PTFE.

On the other hand, the second gap B has a dimension smaller than that of the first gap A or the third gap C. If the second gap B and the corner D do not exist, when the first gap A is directly connected to the corner E, there is a concern that some of high-pressure hot gas passing through the inside of the insulating nozzle part1flows into the first gap A and enters the screwing part6via the corner E.

If some of the PTFE that is dissolved and carbonized in the arc at the time of breaking is mixed with hot gas and enters the screwing part6, carbide accumulates in the screwing part. In addition, hot gas is stagnated in the screwing part6and thereby the PTFE of the surface of the screwing part6is heated and may be carbonized. If carbide is accumulated in the screwing part6, there is a concern that the insulating performance of the insulating nozzle part1is lowered.

As the embodiment, if the second gap B and the corner exist, the flow channel area of hot gas is rapidly narrowed in the second gap B. Thus, it is possible to minimize a hot gas amount that reaches the screwing part6. Thus, since accumulation of carbide in the screwing part6is suppressed by providing the fitting part5, it is possible to maintain the insulating performance of the insulating nozzle part1for a long period of time. Moreover, it is preferable that a dimension of a diameter of the second gap B is, for example, approximately 0.5 mm to 1.5 mm.

Furthermore, since a force is applied to the split nozzle end part to the outside by an internal pressure received from hot gas, stress is concentrated on the corner E, it causes failures such as breakage. Also for the stress received from the hot gas, since the stress is dispersed in the corner D and the corner E, it is excellent in strength.

Moreover, as an example illustrated inFIG. 9, the fitting part5may be a structure in which a corner F is provided between the second gap B and the corner E, and directions of concave and convex are reversed, and it is possible to achieve the same effects as those of the above description.

The guard part12of the split nozzle end part3has an outer diameter, for example, equal to or greater than 2.5 times the inner diameter of the throat part4. Thus, a torque load is easily available when connecting or disassembling the split nozzle end part3and the split nozzle base part2, and a function of preventing hot gas ejected from the insulating nozzle part1from flowing into the moving main contact102side is provided. Therefore, it is possible to prevent adverse effects on the insulating performance.

If the insulating nozzle part1is an integral structure, technical difficulty of an integral molding or processing with high accuracy of the insulating nozzle part1is increased. Thus, in the integral structure, although the size of the guard part12is restricted, it is easy to manufacture the guard part12by increasing the diameter thereof and it is easy to configure to prevent hot gas from flowing into the moving main contact102side by making the insulating nozzle part1be the split structure.

FIGS. 7 and 8illustrate an example in which an extending slit part50is provided in the taper part11of the split nozzle end3, that is, on the inner side of the split nozzle end part3in the axial direction of the split nozzle end part3. It is possible to give a change in a cross section shape of the flow channel of hot gas immediately after the fixed arc contact204passes through the throat part4at the time of the breaking operation by providing the extending slit part50in the taper part11.

As a result, it is possible to be a design to increase a degree of freedom with respect to a change in the flow of arc extinguishing gas. For example, when hot gas reaches the taper part11after passing through the throat part4, since a cross section area of the flow channel is different in a portion in which the slit part50exists and a portion in which the slit part50does not exist, a difference occurs in ease of flow of hot gas. Therefore, since the flow of hot gas is disturbed after passing through the throat part4, a layer in which particularly high-temperature gas is gathered and a layer in which relatively low-temperature gas is gathered in hot gas are agitated, and cooling of the high-temperature gas is promoted. Thus, it is possible to expect improvement of the breaking performance.

Moreover, a structure in which the slit is partially provided in the flow channel of hot gas and complicated flow is aimed for can be also possible in the conventional structure, but according to the structure of the embodiment, since only the split nozzle end3can be manufactured separately, there is an advantage that the slit part50can be relatively easily processed with high accuracy.

The above description is an example and the slit part50is not limited to a groove having a uniform depth as illustrated inFIGS. 7 and 8, and a complicated shape thereof can also be easily processed by making the insulating nozzle part1be the split structure. In some cases, there is an advantage that the range of selection of a nozzle design is widened such that the split nozzle base part2and the split nozzle end part3are made of different materials or by a different blending of additives.

REFERENCE SIGNS LIST