JP5565236B2 - Vacuum circuit breaker and switchgear - Google Patents

Description

  The present invention relates to a vacuum circuit breaker and a switch gear including the vacuum circuit breaker. More particularly, the present invention relates to a two-point vacuum circuit breaker having two vacuum valves and a switchgear including the two-point vacuum circuit breaker.

  The circuit breaker interrupts a large current at the time of a failure such as a short circuit or a ground fault in a receiving / transforming facility or the like, and is also used for a normal circuit switching operation. Examples of the circuit breaker include an oil circuit breaker, a magnetic circuit breaker, an air circuit breaker, a gas circuit breaker, and a vacuum circuit breaker (VCB). Among these, the vacuum circuit breaker has a contact in a vacuum valve, which is a vacuum vessel, and interrupts a load current by utilizing an arc diffusion action in a vacuum state formed in the vacuum valve. For this reason, the vacuum circuit breaker has features such as no fear of fire, suitable for frequent operation, and easy maintenance and inspection, and is widely adopted in receiving and transforming facilities of 66 kV or less. In vacuum circuit breakers used at high voltages exceeding 24 kV, by molding the outside of the vacuum valve with an insulator, the withstand voltage performance on the outside surface of the vacuum valve is improved, and the size of the device is reduced. Is known. For example, in Patent Document 1, the entire shape of the molded vacuum valve is reduced by integrally molding the fixed conductor of the vacuum valve and both sides of the movable conductor with an insulating layer.

  Further, it is known that the dielectric breakdown voltage in the vacuum gap is proportional to the ½ power of the gap interval. Therefore, in a vacuum valve having a rated voltage exceeding several tens of kV, a very large gap interval is required to ensure the rated pressure resistance performance, so that the vacuum valve is increased in size. On the other hand, a longitudinal magnetic field electrode used in a vacuum valve of relatively high current and high voltage generates an axial magnetic field in the gap between the contacts by a longitudinal magnetic field generation mechanism installed on the electrode, and charges the axial magnetic flux. Capture particles. This prevents arc concentration due to the pinch effect and prevents overheating of the electrode. However, when the gap interval increases, the vertical magnetic flux expands in the radial direction, and the arc may come into contact with members other than the electrodes, which may cause re-ignition. Therefore, it is conceivable to connect a plurality of vacuum valves in series to reduce the possibility of re-ignition and reduce the volume and installation area of the vacuum circuit breaker. However, if a plurality of vacuum valves are linearly arranged in the axial direction, the size of the device cannot be sufficiently reduced. This is because the axial length of the series vacuum circuit breaker, when considering the size of the operating mechanism, is the axial direction of the vacuum circuit breaker that employs a single vacuum valve with a sufficient gap length for withstand voltage performance. This is because the length becomes almost the same as the length of. In view of this, there has been proposed a switchgear that reduces the length of the vacuum circuit breaker in the axial direction by arranging two vacuum valves that are operated close to and away from one direction in parallel (see Patent Document 2). Furthermore, in Patent Document 3, a vacuum circuit breaker adopting a configuration in which a contact pressure spring mechanism is disposed in the vicinity of the movable conductor of the vacuum valve in order to improve the initial breaking speed important for the breaking performance of the vacuum valve. Is proposed.

JP 2001-357661 A JP 2002-152930 A JP-A-5-290690

  However, when the contact pressure spring mechanism is arranged close to the movable conductor, there is a problem that it is difficult to maintain a desired withstand voltage if the vacuum circuit breaker is reduced.

  Further, when two vacuum valves are arranged in parallel, there is a problem that the rated current value is limited because the resistance heat generated in each movable conductor cannot be efficiently radiated.

  Then, an object of this invention is to provide the vacuum circuit breaker and switchgear which can solve the problem mentioned above.

  Another object of the present invention is to reduce the size of the vacuum circuit breaker by increasing the insulation withstand voltage of the contact pressure spring mechanism disposed close to the movable conductor.

  Another object of the present invention is to provide a vacuum circuit breaker and a switch gear having a large rated current value by increasing the heat radiation efficiency of resistance heat generated in the movable conductor of the vacuum valve.

  In order to achieve the above object, a vacuum circuit breaker according to the present invention has a fixed conductor having a pair of contacts at one end, which form a contact that can be separated from each other, and a contact disposed opposite to the contact at one end. Two vacuum valves each having a movable conductor provided, a common conductor electrically connected to the movable conductors of the two vacuum valves, an operation mechanism for operating the contact and separation of the vacuum valve, and the movable conductor are connected to each other. A contact pressure spring mechanism disposed close to the connection between the movable operation shaft and the movable conductor of the movable operation shaft, a bottom surface disposed close to the two vacuum valves, a common conductor, and contact addition And a conductive box having a side surface surrounding the pressure spring mechanism, the two vacuum valves, and the conductive box being molded with an insulator.

  Furthermore, it is preferable that the vacuum circuit breaker according to the present invention further includes a heat transfer member that transfers heat between the common conductor and the conductive box.

  In the vacuum circuit breaker and the switch gear according to the present invention, the vacuum circuit breaker and the switchgear have a bottom surface portion disposed adjacent to the movable side cover plate of the two vacuum valves, and a side surface portion surrounding the common conductor and the contact pressure spring mechanism. Since the conductive box is provided, the vacuum circuit breaker can be reduced.

It is a figure which shows the single wire connection of an example of the switchgear which concerns on this invention. It is a figure which shows the cross section of an example of the switchgear which concerns on this invention. It is a figure which shows the cross section of an example of the vacuum circuit breaker which concerns on this invention. It is a figure which shows an example of a series of opening-and-closing operation | movement of the vacuum circuit breaker which concerns on this invention. It is a figure which shows an example of a series of opening-and-closing operation | movement of the vacuum circuit breaker which concerns on this invention. It is a figure which shows an example of a series of opening-and-closing operation | movement of the vacuum circuit breaker which concerns on this invention. It is a figure which shows an example of a series of opening-and-closing operation | movement of the vacuum circuit breaker which concerns on this invention. It is a figure which shows an example of a series of opening-and-closing operation | movement of the vacuum circuit breaker which concerns on this invention. It is a figure which shows an example of a series of opening-and-closing operation | movement of the vacuum circuit breaker which concerns on this invention. FIG. 4 is a perspective plan view of the vacuum circuit breaker from the direction of arrow A shown in FIG. 3. FIG. 4 is a perspective plan view of another example of the vacuum circuit breaker from the direction of arrow A shown in FIG. 3. It is a figure which shows the cross section of the other example of the vacuum circuit breaker which concerns on this invention. It is a figure which shows the cross section of the other example of the vacuum circuit breaker which concerns on this invention. It is a figure which shows the cross section of the other example of the vacuum circuit breaker which concerns on this invention. It is a figure which shows the cross section of the other example of the vacuum circuit breaker which concerns on this invention. It is a figure which shows the cross section of the other example of the vacuum circuit breaker which concerns on this invention. It is a figure which shows the cross section of the other example of the vacuum circuit breaker which concerns on this invention. FIG. 18 is a perspective plan view from the direction of arrow A shown in FIG. 17. It is a figure which shows the cross section of the other example of the vacuum circuit breaker which concerns on this invention. It is a figure which shows the cross section of the other example of the vacuum circuit breaker which concerns on this invention. It is a figure which shows the cross section of the other example of the vacuum circuit breaker which concerns on this invention. It is a figure which shows the cross section of the other example of the switchgear which concerns on this invention.

  Hereinafter, a switchgear and a vacuum circuit breaker according to the present invention will be described in detail with reference to the accompanying drawings. In each drawing, components having the same or similar functions are denoted by the same or similar reference numerals. Therefore, a component having the same or similar function as the component described above may not be described again.

  An example of the switchgear according to the present invention will be described with reference to FIGS. 1 and 2. FIG. 1 is a single-line diagram showing the switch gear 1. In FIG. 1, the switch gear 1 is connected to a high-voltage or extra-high-voltage transmission / distribution line by a cable head 15 (hereinafter referred to as “CHD” (Cable Head)), and a lightning arrester 14 (hereinafter referred to as “LA” (Lightning Arrester)). Line side earthing switch 13 (hereinafter referred to as “LES” (Line side Earthing Switch)), load side disconnector 11a, and line side disconnector 11b (hereinafter referred to as “DS” (Disconnecting Switch)), grounding Switches 12a and 12b (hereinafter referred to as “ES” (Earthing Switch)) and circuit breaker 10 (hereinafter referred to as “CB” (Circuit Breaker)). Connected to the CHD is a high-voltage electric circuit such as a transmission / distribution line for supplying commercial power. On the other hand, a load circuit or the like is connected to the DS 11a via a bus (BUS) 16 and a main transformer (not shown). The CB 10 cuts off the electrical connection between the load circuit and the power transmission and distribution line when the instrument transformer detects an abnormal current or an abnormal voltage that occurs when a failure such as a short circuit or a ground fault occurs. The CB 10 is also used for a constant opening / closing operation of the load circuit. The DS 11 is opened / closed when inspecting electrical equipment for receiving / transforming equipment such as the switch gear 1 and transmission / distribution lines, and is not used for opening / closing the load current. The LES 13 is closed when checking the CHD 15 and the transmission / distribution line connected to the CHD 15. The ES 12 is closed when checking the CB 10 and the load circuit equipment. The LA 14 protects an electrical device such as the CB 10 from a transient abnormal voltage. LA14 is typically applied in a gapless form using zinc oxide (ZnO).

FIG. 2 is a cross-sectional view of the switchgear 1 shown in FIG. The switchgear 1 has a metal container 2 in which an insulating gas such as SF ₆ gas or compressed air is filled. The metal container 2 is grounded via the grounding conductor 5 to the ground. Inside the metal container 2, a main circuit conductor 17 that connects the CHD 15 and the BUS 16 via electrical devices such as CB10, DS11a, and 11b, and grounding devices such as LES13, ES12a, and 12b are disposed. The main circuit conductor 17 and the electric equipment such as the CB 10 arranged inside the metal container 2 are insulated and held in the metal container 2 by an insulating support 18 such as an insulating spacer. DS11a and ES12a are operated by the operation device 3a, DS11b and ES12b are operated by the operation device 3b, and LES13 is operated by the operation device 3c. The CB 10 is operated by the operating device 3d through the circuit breaker operating mechanism 4. Note that each of the electrical devices shown in FIG. 2 is described with only a single phase, but actually, the switch gear 1 is configured with three phases.

  The CB 10 used in the switchgear 1 is a two-point vacuum circuit breaker having a load side vacuum valve 21a and a line side vacuum valve 21b each having a function of cutting off a load current. The load-side vacuum valve 21a and the line-side vacuum valve 21b are arranged so that their movable operation axes are parallel to each other and to the floor surface. These two vacuum valves 21a and 21b are arranged such that the surface including both movable operation axes is perpendicular to the floor surface. In this way, the CB 10 can be configured such that the two vacuum valves 21 a and 21 b are stacked in the vertical direction inside the container 2 of the switch gear 1. The CB 10 operates the circuit breaker operating mechanism 4 with the operating device 3d to simultaneously connect and disconnect the contacts formed inside the load side vacuum valve 21a and the line side vacuum valve 21b. To control the electrical connection.

  An example of the CB according to the present invention will be described with reference to FIGS. FIG. 3 is an enlarged view of the cross section of the CB 10 of FIG. The CB 10 includes a load-side vacuum valve 21a, a line-side vacuum valve 21b, and a common conductor 24 that electrically connects the movable conductors 31a and 31b of the two vacuum valves 21a and 21b. For example, the common conductor 24 can be electrically connected to the movable conductors 31a and 31b by a sliding contact. Each of the load side vacuum valve 21a and the line side vacuum valve 21b has a load side connection terminal 22a and a line side connection terminal 22b connected to the main circuit conductor 17 shown in FIG. When power is supplied to the load circuit (not shown) connected to the BUS 16 of the switch gear 1 via the switch gear 1, the load current is transmitted from the line side connection terminal 22b to the line side vacuum valve 21b, the common conductor. 24 and the load side vacuum valve 21a in this order to flow to the load side connection terminal 22a.

  The CB 10 includes movable operation shafts 26a and 26b connected to the movable conductors 31a and 31b, and a contact pressure spring mechanism 25a disposed close to the end of the movable operation shafts 26a and 26b on the vacuum valve side. And 25b. The movable operating shafts 26a and 26b connect the movable conductors 31a and 31b of the vacuum valve and the circuit breaker operating mechanism 4 shown in FIG. Thereby, based on the command input into the operating device 3d shown in FIG. 1, the circuit breaker operating mechanism 4 contacts and separates the contacts formed inside the two vacuum valves 21a and 21b. The movable operation shafts 26 a and 26 b are formed of an insulating material in order to insulate the movable conductors 31 a and 31 b from the circuit breaker operation mechanism 4. Further, during the opening operation, a large force is instantaneously applied to the movable operation shafts 26a and 26b in order to extinguish arcs generated in the vacuum valves 21a and 21b. For this reason, the movable operation shafts 26a and 26b need to have sufficient robustness to withstand such a force. The contact pressure spring mechanisms 25a and 25b press the contacts formed at the ends of the movable conductors 31a and 31b against the contacts formed at the ends of the fixed conductor when the CB 10 is in the closing state. The energy is accumulated so as to apply a pressing force in the direction. Thereby, even when an electromagnetic force in the opening direction is generated at the contact point due to a large current flowing through the contact point of the CB 10 at the time of a fault such as a ground fault or a short circuit, the CB 10 can maintain the input state.

  Still referring to FIG. 3, the CB 10 has a conductive box 23. The conductive box 23 surrounds the bottom surface portion of the two vacuum valves 21a and 21b disposed close to the movable side cover plates 36a and 36b, the common conductor 24, and the contact pressure spring mechanisms 25a and 25b. And a side surface portion. The CB 10 can relieve the electric field generated on the surfaces of the contact pressure spring mechanisms 25 a and 25 b and the common conductor 24 by the conductive box 23. Since the contact pressure spring mechanisms 25a and 25b and the common conductor 24 are difficult to take an appropriate shape in terms of electric field in terms of their functions, the distribution of the electric field is uneven in these portions. The electric field becomes stronger and dielectric breakdown is likely to occur. By shielding the portion where such dielectric breakdown is likely to occur with the conductive box 23, the dielectric strength of the CB 10 can be improved.

In the CB 10, the vacuum valves 21 a and 21 b and the conductive box 23 are molded by an insulator 27 formed of an insulating resin material such as an epoxy resin in order to further improve the dielectric strength. In general, an insulating resin material such as an epoxy resin has better dielectric strength than an insulating gas such as SF ₆ gas or compressed air. For this reason, the CB 10 can improve the dielectric strength and can reduce the size of the CB 10 by molding the vacuum valves 21a and 21b and the conductive box 23 with an insulating resin material. When molding with the insulator 27, the conductive box 23 may be any one of a punching metal, a wire mesh, a casting, and a cut product. As a result, the integrity between the insulator 27 and the conductive box 23 is improved, and cracks and cavities due to separation between the conductive mold 23 and the insulating mold material forming the insulator 27 can be prevented. it can. For this reason, partial discharge resistance (corona resistance) performance is improved, and it is possible to improve the life of the apparatus by suppressing deterioration of trees and tracking. In addition, the conductive box 23 may be a combination of punching metal, wire mesh, casting, and a cut product. Furthermore, when a casting and a cut product are used for the conductive box 23, the adhesiveness may be improved by roughening the adhesive surface with sandblasting or the like so as not to cause a decrease in insulation.

  The CB 10 may further include a heat transfer member 29 that transfers the conductive box 23 and the common conductor 24. By conducting the heat transfer connection between the conductive box 23 and the common conductor 24, it is possible to dissipate the resistance heat generated in the movable conductors 31a and 31b and the common conductor 24 of the vacuum valves 21a and 21b. At the contacts of the vacuum valves 21a and 21b, resistance heat is generated by the electrical resistance between the contacts arranged opposite to each other, but the resistance heat generated by the contact of the fixed conductor is connected to the main circuit via the connection terminal 22. Heat is radiated to the conductor 17. However, since the contacts of the movable conductors 31a and 31b are transferred only to the common conductor 24, there is a possibility that the heat dissipation efficiency is deteriorated. Therefore, in the CB 10, the conductive box 23 and the common conductor 24 are connected via the heat transfer member 29 in order to use the conductive box 23 as a heat radiating plate for radiating the resistance heat generated by the contact of the movable conductor. Heat can be transferred. The heat transfer member 29 can be formed of a ceramic member having high thermal conductivity such as aluminum nitride or silicon nitride, or can be formed of metal such as copper or aluminum.

  With reference to FIGS. 4 to 9, the CB 10 making operation and the opening operation will be described. FIG. 4 is a perspective sectional view showing the open state of the CB 10. Unlike FIG. 3, in FIG. 4, the vacuum valve 21a includes a movable conductor 31a, a fixed conductor 32a, a contact 33a formed at one end of the movable conductor 31a, a contact 34a formed at one end of the fixed conductor 32a, and a molding. Components such as bellows 35a are shown. The contact pressure spring mechanism 25a includes a casing 71a, a spring 73a, and a spring fixing portion 75a as constituent elements. Similarly, in FIGS. 4 to 9, components of the vacuum valve 21 b and the contact pressure spring mechanism 25 b are also shown. However, in the closing operation and opening operation of the CB 10, the vacuum valve 21 a and the contact pressure spring mechanism 25 a. Since the vacuum valve 21b and the contact pressure spring mechanism 25b operate in the same manner, only the vacuum valve 21a and the contact pressure spring mechanism 25a are referred to here, and the CB 10 is turned on and opened. The pole operation will be described.

  The distance between the contact 33a of the movable conductor 31a and the contact 34a of the fixed conductor 32a in the open state of the CB 10 is a predetermined separation distance. The electrical connection between the movable conductor 31a of the vacuum valve 21a and the common conductor 24 can be made by a movable contact such as a tulip contact. One end of the spring 73a of the contact pressure spring mechanism 25a is in contact with the casing 71a, and the other end is in contact with the spring fixing portion 75a. The casing 71a of the contact pressure spring mechanism 25a is a member including a surface with which the spring 73a contacts, and is mechanically connected to the movable operation shaft 26a, but is mechanically connected to the movable conductor 31a of the vacuum valve 21a. Not. The spring fixing portion 75a of the contact pressure spring mechanism 25a is mechanically connected to the movable operation shaft 26a on the surface where the spring 73a contacts, and mechanically connected to the movable conductor 31a of the vacuum valve 21a on the opposite surface. Connected. For this reason, as will be described in detail later, the spring 73a is compressed between the casing 71a and the spring fixing portion 75a when the CB 10 is put in, so that the contact 33a of the movable conductor 31a and the fixed conductor A pressing force can be applied to a contact formed between the contact 34a of 32a.

  With reference to FIGS. 5-7, the process of operation | movement of CB10 is demonstrated in order. In FIG. 5, the movable conductor 31a receives a force in the direction of the fixed conductor 32a from the circuit breaker operating mechanism 4, and starts moving in the direction of the fixed conductor 32a. At this time, the extension of the spring 73a of the contact pressure spring mechanism 25a is the same as the extension of the open spring 73a. As shown in FIG. 6, the force continues to be received from the circuit breaker operating mechanism 4 even after the contact 33 a of the movable conductor 31 a and the contact 34 a of the fixed conductor 32 a come into contact with each other. As a result, the casing 71a of the contact pressure spring mechanism 25a moves in the direction of the common conductor 24 while compressing the spring 73a. In the closed state shown in FIG. 7, the spring 73a of the contact pressure spring mechanism 25a is compressed between the casing 71a and the spring fixing portion 75a. In this manner, the spring 73a can apply a desired pressing force that presses the contact 33a of the movable conductor 31a in the direction of the contact 34a of the fixed conductor 32a. The spring 73a applies a pressing force larger than an electromagnetic repulsive force generated by a short circuit current or the like to the contact 33a of the movable conductor 31a, thereby fixing a contact formed between the contact 33a and the contact 34a. be able to. On the contrary, when the pressing force of the spring 73a is smaller than the electromagnetic repulsive force, a gap may be generated between the contacts due to the electromagnetic repulsive force, and an arc may be generated. When the arc is generated, the contact 33a of the movable conductor 31a and the contact 34a of the fixed conductor 32a may be melted or welded. Therefore, in the applied state, it is necessary to always press the contactor 33a with the pressing force of the spring 73a that is larger than the electromagnetic repulsive force generated by the assumed short-circuit current.

  Next, with reference to FIGS. 7 to 9, steps of the opening operation of the CB 10 will be described in order. As described above, FIG. 7 is a diagram showing a state where the CB 10 is put in, and the spring 73a of the contact pressure spring mechanism 25a is compressed. During the opening operation, the movable conductor 31a receives a force in the direction opposite to the fixed conductor 32a from the circuit breaker operation mechanism 4 via the movable operation shaft 26a. As shown in FIG. 8, the contact 33a of the movable conductor 31a and the contact 34a of the fixed conductor 32a are in contact until the housing 71a contacts the spring fixing portion 75a of the contact pressure spring mechanism 25a. to continue. Next, as shown in FIG. 9, the casing 71a of the contact pressure spring mechanism 25a contacts the spring fixing portion 75a, so that the force from the circuit breaker operating mechanism 4 is applied to the movable conductor 31a of the vacuum valve 21a. At this time, the moment of movement that the movable operating shaft 26a and the casing 71a had before colliding with the spring fixing portion 75a is given to the movable conductor 31a, so that the movable conductor 31a opens at a certain initial speed. be able to. In this way, the contact pressure spring mechanism 25 in the CB 10 applies a pressing force in a direction in which the contactor 33 is pressed in the direction of the contactor 34 when the CB10 is turned on, and a certain amount of force is applied to the movable conductor 31a when the contact is opened. The initial speed can be given.

  FIG. 10 is a perspective plan view of the CB 10 from the direction of the arrow A shown in FIG. The conductive box 23 and the insulator 27 included in each of the single-phase CBs 10a, 10b, and 10c have a rounded rectangular shape. Further, the conductive box 23 and the insulator 27 can be formed in an oval shape or a bowl shape. By adopting such a shape with few irregularities, convective heat dissipation of the insulating gas that convects between the CBs 10 can be effectively performed. For this reason, it is possible to improve the energization performance (current capacity) of CB10. Furthermore, as shown in FIG. 11, the conductive box 23 and the insulator 27 can be formed in a substantially iron array shape in which the circular portions at both ends are connected by straight portions. By making the conductive box 23 and the insulator 27 have a substantially iron array shape, the amount of insulating gas that convects between the CBs 10 can be increased. For this reason, the convective heat radiation of the insulating gas can be performed more effectively. Furthermore, by forming the conductive box 23 and the insulator 27 in a substantially iron array shape, the area of the portion where the electric field on the surface of the insulator 27 between the phases is high can be reduced, and the insulation performance can be improved.

  The configuration and function of the CB 10 that is an example of the present invention have been described above. Hereinafter, CB of other examples of the present invention will be described in order with reference to FIGS. FIG. 12 is a diagram showing a CB 101 according to the present invention. In CB101, the conductive box 23 is R-bent at the end of the side surface opposite to the bottom surface. The R bending process is a process of winding an end portion by a drawing process. By subjecting the end portion of the side surface portion to R bending, electric field relaxation and strength can be ensured. Moreover, as shown in FIG. 13, in CB102, the metal wire coil 51 can be arrange | positioned cyclically | annularly near the side part opposite to the bottom face part of the electroconductive box 23. FIG. Furthermore, as shown in FIG. 14, in the CB 103, the metal wire coil 53 can be annularly arranged by connecting to the side surface portion opposite to the bottom surface portion of the conductive box 23. By adopting such a configuration, the partial discharge resistance (corona resistance) performance of the high electric field portion such as the end of the conductive box 23 is improved, and the life of the device is improved by suppressing deterioration of trees and tracking. Can be achieved.

  FIG. 15 is a diagram showing the CB 104 according to the present invention. In the CB 104, a flexible conductor, that is, a flexible conductor is adopted as the common conductor 24. By adopting a flexible conductor as the common conductor 24, a sliding contact (see FIG. 4 and the like) disposed between the movable conductor 31 and the common conductor 24 is unnecessary in the CB 10 shown in FIG. Become. That is, since the common conductor 24 having flexibility is bent as the movable conductor moves, the common conductor 24 can be attached to the movable conductor 31. In CB 104, by attaching the common conductor 24 to the movable conductor 31, the contact area between the common conductor 24 and the movable conductor 31 increases, so that heat conduction between the common conductor 24 and the movable conductor 31 is achieved. The rate is improved. For this reason, in CB104, the resistance heat which arises in the movable conductor 31 of the vacuum valves 21a and 21b can be more efficiently transferred.

  In FIG. 15, when the CB 104 is in the open state, the spring of the contact pressure spring mechanism 25a is compressed to a predetermined elongation. This is because the common conductor 24 and the movable operation shaft 26 are integrally operated by the pressing force of the spring. In order to operate the common conductor 24 and the movable operation shaft 26 integrally, the pressing force stored in the spring of the contact pressure spring mechanism 25a may be larger than the repulsive force of the common conductor 24. desirable. When the pressing force accumulated in the spring of the contact pressure spring mechanism 25a is smaller than the repulsive force of the common conductor 24, the spring of the contact pressure spring mechanism 25a is compressed during the closing operation. In this case, the common conductor 24 and the movable operation shaft 26 cannot move together. In order to prevent such a situation, it is desirable that the pressing force of the spring stored in the contact pressure spring mechanism 25 a is larger than the repulsive force of the common conductor 24.

  FIG. 16 is a diagram showing a CB 105 according to the present invention. In CB105, the function of the sliding contact in CB10 shown in FIG. 3 is substituted by employ | adopting a flexible member for the heat-transfer member 29 instead of the common conductor 24. FIG. As a flexible material employed for the common conductor 24 of the CB 104 shown in FIG. 15 and the heat transfer member 29 of the CB 105 shown in FIG. 16, an oxygen-free copper foil or the like can be used. These copper foils can determine the number of layers to be stacked in consideration of the temperature rise due to the resistance heat generated by the rated current and the short-circuit current and the heat resistance temperature of the insulator 27.

FIG. 17 is a diagram showing the CB 106 according to the present invention. In the CB 106, the radiation fins 61 are arranged on the outer surface of the insulator 27 corresponding to the side surface portion of the conductive box 23. By disposing the radiating fins 61 on the side surface portion of the conductive box 23, the radiating area is increased and the convection cooling performance can be further improved. As a result, the CB 106 can acquire a larger energization capacity. The heat radiating fins 61 can be created by forming protrusions with insulating members at portions corresponding to the side portions of the conductive box 23 of the insulator 27. Further, the heat radiation fins 61 can be formed of an insulating material having a high thermal conductivity such as ceramics. 18 is a perspective plan view of the CB 106 from the direction of arrow A shown in FIG. The radiating fins 61a included in the first single-phase CB 106a of the CB 106 and the radiating fins 61b included in the second single-phase CB 106b are alternately arranged. Similarly, the radiation fins 61b included in the second single-phase CB 106b and the radiation fins 61c included in the third single-phase CB 106c are arranged alternately. By arranging the radiating fins 61 in this manner, the electric field at the tip of the radiating fin can be reduced, and a passage for the insulating gas to convect between each single-phase CB 106a-c is secured. it can. As a result, it is possible to ensure electrical insulation while ensuring a convective heat dissipation effect, and to reduce the size of the CB 106.

  FIG. 19 is a diagram showing a CB 107 according to the present invention. In the CB 107, the common conductor 24 has heat radiating fins 63. By forming the radiation fins 63 on the common conductor 24, it is possible to directly radiate the resistance heat generated in the movable conductors 31a and 31b and the common conductor 24 of the vacuum valves 21a and 21b. The electric field distribution in the vicinity of the heat radiating fins 63 may be non-uniform. However, as with the contact pressure spring mechanism 25 and the like, the heat radiating fins 63 are shielded by the conductive box 23 and thus non-uniform. Generation of electric field distribution can be prevented. The heat radiation fins 63 may be formed not only on the common conductor 24 but also on the heat transfer member 29.

  FIG. 20 is a diagram showing the CB 108 according to the present invention. In the CB 108, the vacuum valves 21a and 21b are molded on the insulator 27 via the insulating layer 28 having elasticity. By disposing the elastic insulating layer 28 between the vacuum valves 21a and 21b and the insulator 27, local strain or stress caused by curing of the insulating resin is concentrated locally. Can be relaxed. For this reason, it can prevent that a crack generate | occur | produces between the vacuum valves 21a and 21b and the insulator 27. FIG.

  FIG. 21 is a diagram showing a CB 109 according to the present invention. The CB 109 can have a sealing member 41 arranged to seal the open end of the insulator 27. The close contact surface between the sealing member 41 and the insulator 27 blocks gas from entering and leaving between the hermetic space 45 formed by the sealing member 41 and the insulator 27 and the outside of the hermetic space 45. The movable operation shaft 26 is connected to the circuit breaker operation mechanism via the operation shaft connection member 42 and the connection operation shaft 43. The connecting operation shaft 43 is sealed by a molded bellows 44 in order to hold the airtight space 45. The CB 109 blocks the gas between the airtight space 45 and the outside of the airtight space 45 by the sealing member 41 or the like, so that the pressure of the airtight space 45 is increased by the insulating gas filled in the metal container 2. The pressure can be different from the pressure. For example, the pressure in the airtight space 45 can be made lower than the pressure of the insulating gas of about 0.3 Mpa filled in the metal container 2 and can be brought close to the vacuum pressure inside the vacuum valves 21a and 21b. . As a result, it is possible to suppress the pressure applied to the molded bellows disposed in the vacuum valves 21a and 21b in order to secure the confidential structure for holding the vacuum. As a result, when the CB 10 has the sealing member 41, the molded bellows need not have a pressure resistant structure against the pressure of the insulating gas filled in the metal container 2. In the CB 109, the sealing member 41 forms an airtight space 45 for each single-phase CB109, but it is also possible to form a common airtight space 45 across the CB109 of all the phases. For example, as shown in FIG. 22, an airtight space 45 can be formed inside the metal container 2 by a member that forms the metal container 2 in which the CB 109 is stored.

  The invention has been described in detail with particular reference to certain preferred embodiments of the invention. However, it will be understood that changes and modifications can be made within the scope of the invention. It should also be understood that the various figures provided in the disclosure of the present invention are intended to illustrate the present invention and are not intended to show an appropriate scale.

DESCRIPTION OF SYMBOLS 1 Switch gear 2 Metal container 3 Operator 4 Circuit breaker operating mechanism 5 Grounding conductor 10 Circuit breaker 11 Disconnector 12 Ground switch 13 Line side ground switch 14 Lightning arrester 15 Cable head 21 Vacuum valve 22 Connection terminal 23 Conductive box 24 Common conductor 25 Contact pressure spring mechanism 26 Movable operating shaft 27 Insulator 28 Insulating layer 29 Heat transfer member 31 Movable conductor 32 Fixed conductor 33 Movable conductor contact 34 Fixed conductor contact 35 Molded bellows 41 Sealing member 45 Airtight space 101 , 102, 103, 104, 105, 106, 107, 108, 109 Circuit breaker

Claims (17)

Two vacuum valves each having a fixed conductor having a contact at one end and a movable conductor having a contact disposed at one end facing the contact;
A common conductor electrically connected to the movable conductor of the two vacuum valves;
An operation mechanism for operating contact and separation of the vacuum valve, a movable operation shaft for connecting between the movable conductor,
A contact pressure spring mechanism disposed in proximity to the connecting portion of the movable operating shaft with the movable conductor;
A conductive box having a bottom surface portion disposed close to the two vacuum valves, a side surface portion surrounding the common conductor, and the contact pressure spring mechanism;
And the two vacuum valves and the conductive box are molded with an insulator ,
The switchgear vacuum shut-off characterized in that the lateral cross-sectional shape of the side surface portion of the conductive box and the insulator that molds the side surface portion is a substantially iron array type in which circular portions at both ends are connected by straight portions. vessel.   The vacuum circuit breaker according to claim 1, further comprising a heat transfer member that transfers heat between the common conductor and the conductive box. The vacuum circuit breaker according to claim 2 , wherein the heat transfer member is a flexible conductor. The said common conductor or the said heat-transfer member is a vacuum circuit breaker as described in any one of Claim 2 or 3 which has a radiation fin. The conductive box includes one of a punching metal, a wire mesh, a casting, and a cut product, or a combination thereof, and a part or all of the conductive box is molded on the insulator. The vacuum circuit breaker as described in any one of Claims 1-4 . Opposite end portion and the bottom portion of the side surface portion of said conductive box is R bent, is connected to the annular metal wire coil, or claims 1 to 5 annular metal wire coil is arranged in the vicinity The vacuum circuit breaker as described in any one of these. The vacuum circuit breaker according to any one of claims 1 to 6 , wherein the movable conductor of the two vacuum valves and the common conductor are connected via a sliding contact. The vacuum breaker according to any one of claims 1 to 7 , wherein the common conductor is a flexible conductor. The vacuum circuit breaker according to any one of claims 1 to 8 , wherein an insulating layer having elasticity is disposed between the vacuum valve and the insulator. The vacuum circuit breaker according to any one of claims 2 to 9 wherein at least a portion the radiating fins of the outer surface for molding the conductive box of the insulator is disposed. The vacuum circuit breaker as described in any one of Claims 1-10 arrange | positioned so that the movable operation axis | shaft of a vacuum valve may be mutually parallel and it may become parallel with respect to a ground plane. A switchgear comprising a container in which three sets of vacuum circuit breakers according to any one of claims 1 to 11 are housed to form three phases and which is filled with an insulating gas. The switchgear according to claim 12 , wherein an airtight space is formed by disposing a sealing member at an open end of an insulator that molds the two vacuum valves and the conductive box. The switchgear according to claim 13 , wherein the pressure in the airtight space is different from the pressure outside the airtight space. A switchgear in which the vacuum circuit breaker according to claim 10 is housed and the radiating fins are alternately arranged. A switchgear, wherein three sets of vacuum circuit breakers according to claim 11 are housed to form three phases, and the floor height of the vacuum valve of each phase is the same. A switchgear comprising three sets of vacuum circuit breakers according to claim 11 to form three phases, and a plane formed including the shafts of two vacuum valves of each phase is perpendicular to the floor surface.

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