Gas-insulated switchgear equipment

Abstract: A gas-insulated switchgear equipment com­ prises a plurality of vertical-type circuit breakers (CB₁, CB₂, CB₃) electrically connected in series, outside led-out devices (5A, 5B) connected to connected portions of series connection of the circuit breakers and at least one main bus bar (1, 7; 20) connected to two of the plurality of circuit breakers (CB₁, CB₃) located both ends of the electrically series connection. In the equipment, the circuit breakers are of a vertical type circuit breaker and are arranged on a substantial straight line and led-out portions (11, 12, 13, 14, 15, 16) for leading out terminals formed in the circuit breakers in a direction perpendicular to a direction of the arrangement of the circuit breakers, and connecting bus bars (3, 4) interconnecting the circuit breakers in series and the outside led-out devices (5A, 5B) are disposed on one side of the circuit breakers and the at least one main bus bar (1, 7; 20) is disposed on the other side of the circuit breakers. Therefore, the fixing area can be reduced and the connection between the at least one main bus bar and the circuit breakers and between the circuit breakers and the outside led-out devices can be easily established.

Description: BACKGROUND OF THE INVENTION Field of the Invention This invention relates generally to gas-insulated switchgear equipment and, more particularly, to a gas-insulated switchgear equipment constituted by connecting a plurality of vertical-type circuit breakers. Description of the Prior Art An example of a conventional gas-insulated switchgear equipment of this type, such as the one shown in Fig. 10 on page 147 of BROWN BOVERI REV. VOL. 4 No. 73 is known. The gas-insulated switchgear equipment is called a one-and-a-half circuit breaker system and in the system, a pair of gas-insulated bus bars are disposed in parallel and three horizontal-type circuit breakers are horizontally disposed on a straight line bridging the pair of bus bars and the circuit breakers are connected in series by connecting bus bars disposed between the circuit breakers. Since this type of gas-insulated switchgear equipment uses connecting bus bars which are disposed between the circuit breakers, a large fixing space for the equipment is needed in a direction of the straight line of the disposition of the circuit breakers. Although the described example of a gas-insulated switchgear equipment is constructed by using horizontal-type circuit breakers, it is also possible to constitute the same gas-insulated switch-gear equipment by using vertical-type circuit breakers. However, this method not only has the above-described problem but also needs to devise a disposition of the bus bars as well as connections between the circuit breakers and between the circuit breakers and the bus bars. In view of these problems, gas-insulated switchgear equipments such as one-and-a-half circuit breaker systems and ring bus system using a plurality of vertical-type circuit breakers have been proposed in Japanese Patent Unexamined Publication Nos. 57-193911, 57-211915 (U.S. counterpart: USP No. 4,503,481), and 59-6706. In these equipments, a pair of main bus bars are disposed parallel to a fixing base and a plurality of vertical-type breakers are disposed at one side of the bus bars generally in parallel to the bus bars and cable heads provided as outside lead-out means are disposed at the other side of the main bus bar which is the remotest from the breakers and gas-insulated connecting bus bars electrically connect between the juxtaposed circuit breakers, between the circuit breakers and the main bus bars and between the circuit breakers and the cable heads. In the gas-insulated switchgear equipment, each of the vertical-type circuit breakers has lead-out portions extending from its breaking section on its one side facing the main bus bars. Therefore, there is no element on the other side of each of the circuit breakers. This is advantageous in terms of inspection and maintenance of the circuit breakers. However, the equipment has disadvantages in that the connecting structure using the connecting bus bars becomes complex and the fixing area to fix the equipment becomes large taking connecting operations into consideration. A gas-insulated switchgear equipment with the features included in the first part of each of claims 1 and 2 is disclosed in FR-A-2 569 499. SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a gas-insulated switchgear equipment capable of disposing the circuit breakers closer to each other and reducing the fixing area thereof. It is another object of the present invention to provide a gas-insulated switchgear equipment in which electrical connections between the circuit breakers and between the breakers and the main bus bars are easily established. These objects are met by the switchgear equipments defined in claims 1 and 2. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a schematic plan view of a gas-insulated switchgear equipment of an embodiment of the present invention; Fig. 2 is a right side view of the gas-insulated switchgear equipment shown in Fig. 1; Fig. 3 is a sectional side view taken along the line III - III of Fig. 1; Fig. 4 is a connection diagram of the gas-insulated switchgear equipment shown in Fig. 1; Fig. 5 is a sectional side view taken along the line V - V of Fig. 1; Fig. 6 is an enlarged schematic cross-sectional view of an essential portion shown in Fig. 5; Fig. 7 is a sectional side view of another embodiment of the structure shown in Fig. 5; Fig. 8 is a schematic plan view of a gas-insulated switchgear equipment of another embodiment of the present invention; Fig. 9 is a left side view of the gas-insulated switchgear equipment shown in Fig. 8; and Fig. 10 is a connection diagram of the gas-insulated switchgear shown in Fig. 8. DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described hereinafter with reference to the accompanying drawings. A circuit shown in Fig. 4 is called a one-and-a-half circuit breaker system to which a gas-insulated switchgear equipment according to the present invention is applied. Three circuit breakers CB₁, CB₂, CB₃ having at their opposite sides disconnecting switches DS₁₁ and DS₁₂, DS₂₁ and DS₂₂, DS₃₁ and DS₃₂ are placed on a fixing base and electrically connected in series. Outside lead-out means 5A and 5B such as cable heads are led out from points between the disconnecting switches. The three circuit breakers CB₁, CB₂, and CB₃ connected in series are connected between main bus bars 1 and 7. A gas-insulated switchgear equipment based on the circuit arrangement is constituted as shown in Fig. 1. The circuit breakers CB₁, CB₂, and CB₃ are of a vertical type and include breaking units adapted for three or one phase disposed in a grounding tank in which insulating gas is filled. The circuit breakers CB₁, CB₂, and CB₃ are disposed on a straight line. Lead-out portions 11, 13, 14, and 15 of terminals and connecting bus bars 3, 4, which are used to electrically interconnect the circuit breakers as indicated by broken lines in Fig. 1, are provided at one side of the circuit breakers CB₁, CB₂, and CB₃. In more detail, as shown in Figs. 1 to 3, the circuit breaker CB₁ has a lead-out portion 11 provided at an upper portion thereof that leads out an upper terminal of the breaking unit to the one side, and the adjacent circuit breaker CB₂ has a lead-out portion 13 provided at an upper portion thereof and another lead-out portion 14 provided at a lower portion thereof which lead upper and lower terminals of the breaking unit to the one side, respectively. A connecting bus bar 4 interconnecting the lead-out portions 11, 13 is also disposed at the one side. The circuit breaker CB₃ has, as shown in Figs. 1 to 3, a lead-out portion 15 at a lower portion thereof which leads a lower terminal of the breaking unit to the one side. A connecting bus bar 3 interconnecting the lead-out portions 14, 15 is also disposed at the one side. A lower terminal of the breaking unit of the circuit breaker CB₁ is led by a lead-out portion 12 provided at a lower portion of the circuit breaker to the other side of the circuit breaker and is connected to a main bus bar 1 extending in a direction of the arrangement of the circuit breakers. Similarly, as can be understood from Figs. 1 to 3, an upper terminal of the breaking unit of the circuit breaker CB₃ is led by a lead-out portion 16 extending from the other side of the circuit breaker and is connected to a main bus bar 7 which extends above and generally in parallel with the main bus bar 1. In the embodiment, as shown in Fig. 1, a disconnecting switch DS₁₁ for the circuit breaker CB₁ is provided within the main bus bar 1 and a disconnecting switch DS₁₂ is provided within the connecting bus bar 4. A disconnecting switch DS₂₁ for the circuit breaker CB₂ is provided within the connecting bus bar 4, and a disconnecting switch DS₂₂ is provided within the connecting bus bar 3. A disconnecting switch DS₃₁ for the circuit breaker CB₃ is provided within the connecting bus bar 3 and the disconnecting switch DS₃₂ is provided within the main bus bar 7 extending at a higher level. As shown in Figs. 1 and 2, outside lead-out devices 5A and 5B are connected to side portions of the connecting bus bars 3 and 4. Each of the outside lead-out devices 5A and 5B that extends downward comprises a casing, a connecting conductor disposed in the casing, and an insulated terminal while establishing gas-insulation. That is, the outside lead-out device 5A is connected to a side portion of the connecting bus bar 4 interconnecting the circuit breakers CB₁ and CB₂ and the outside lead-out device 5B is connected to a side portion of the connecting bus bar 3 interconnecting the circuit breakers CB₂ and CB₃, and these devices are disposed such that they extend downward from their connecting portions. Accordingly, the outside lead-out device 5A is connected between the disconnecting switches DS₁₂ and DS₂₁ in the connecting bus bar 4. Similarly, the outside lead-out device 5B is connected between the disconnecting switches DS₂₂ and DS₃₁ in the connecting bus bar 3. The circuit arrangement shown in Fig. 4 is thus embodied. It should be noted here that the lead-out portions 11, 13, 14, 15 and the connecting bus bars 3, 4 used to establish electrical connection between the circuit breakers CB₁, CB₂, CB₃ are not placed on portions of the circuit breakers facing each other. With the construction, it is possible to reduce a distance between, for example, the circuit breakes CB₁, CB₂ to an extent of an axial length of the connecting bus bar 4 inclusive the disconnecting switches DS₁₂, DS₂₁. In this embodiment, as three circuit breakers CB₁, CB₂, CB₃ are arranged on the straight line and are electrically connected in series, two connecting bus bars 3, 4 are required. However, as the lead-out portions 11, 13 respectively provided at the upper portion of the circuit breakers CB₁, CB₂ are interconnected by the connecting bus bar 3 and the lead-out portions 14, 15 respectively provided at the lower portion of the circuit breakers CB₂, CB₃ are interconnected by the connecting bus bar 4, it is possible to dispose the two connecting bus bars 3, 4 substantially parallel with each other with a linear structure, so that the structure thereof can be made simple. In this construction, the positions of connections between the circuit breakers and the outside lead-out devices 5A and 5B and the heights of the devices are different from each other, and the connecting position of the outside lead-out device 5B connected to the connecting bus bar 3 coincides with a level of the lead-out portion 15 leading out the lower terminal of the circuit breaker CB₃, as shown in Figs. 2, 3, 5. In a case where the outside lead-out device 5B is a cable head, the height does not become a disadvange by structuring the cable head as illustrated in Fig. 6. That is, internal conductors 9, which are provided within the connecting bus bar 3 are led through a connecting portion 17a formed in a portion of a cable head casing 17 and are turned upward along a side of cable heads 6 and are connected to upper terminals of the cable heads 6. Since conductors 8 turned upward face insulators of the cable heads 6, they can be disposed within the cable head casing 17 without increasing a diameter of the casing 17 while a suitable degree of insulation from the cable head casing 17 is maintained. Therefore, with the use of the cable heads, it is possible for the outside lead-out devices 5A, 5B to have identical appearances except for the positions of the portions connected to the connecting bus bars 3, 4. In order to make the outside lead-out device 5A connected to the connecting bus bar 4 and the outside lead-out device 5B connected to the connecting bus bar 3 have the same height, an arrangement, for example as shown in Fig. 7, may be adapted in which an upwardly extending intermediate connecting bus bar 3a is connected at its lower end of the lower lead-out portion 15 of the circuit breaker CB₃ and is connected at its upper end to the outside lead-out device 5B at the same level as the lead-out portions of the circuit breakers CB₁, CB₂. With this construction, the outside lead-out devices 5A, 5B have the same height, so that parts for the devices can be commonly used. The connecting bus bars 3, 4 and the intermediate connecting bus bar 3a which are used to connect the circuit breakers CB₁, CB₂, CB₃ in series so as to construct a plurality of gas-insulated switchgear equipments of the one-and-a-half circuit breaker type, may be of a type having a cylindrical casing in which a connection conductor in a gas-insulation manner is disposed similarly with the well known main bus bars 1, 7, or of other specifically designed types. Figs. 8 to 10 show a gas-insulated switchgear equipment of another embodiment according to the present invention. This embodiment is based on a ring bus bar type of circuit arrangement shown in Fig. 10, in which the circuit breakers CB₁, CB₃ located at both ends of a series connection of three circuit breakers are connected to a main bus bar 20. This embodiment will be described with reference to a Fig. 8 and Fig. 9. In this embodiment, components identical to those of the first embodiment are indicated by the same reference characters and descriptions for the same constructions are omitted. This embodiment will be described with respect to points of difference from the first embodiment. As can be also understood from comparison between the circuit shown in Fig. 4 and the circuit shown in Fig. 10, the connection between the circuit breakers CB₁ and CB₂ and the connection between the circuit breakers CB₂ and CB₃ are the same as the circuit shown in Fig. 4 and only the connection between the circuit breakers CB₁ and CB₃ is different. That is, as shown in Figs. 8 and 9, a lead-out portion 12 which leads out a lower terminal of the circuit breaker CB₁ in an opposite side to the connecting bus bar 4 side is connected to a portion of a main bus bar 20 which extends downward from the main bus bar 20 so that it is generally L-shaped, while a lead-out portion 16 which leads out an upper terminal of the circuit breaker CB₃ in an opposite side to the connecting bus bar 3 side is connected to the main bus bar 20 which extends at a higher level in a direction of an arrangement of the circuit brakers, thus constituting a gas-insulated switchgear equipment corresponding to the ring bus bar system shown in Fig. 10. The main bus bar 20 may be disposed so as to extend at a lower level. In this construction also, the circuit breakers CB₁, CB₂, and CB₃ are arranged on a straight line and the main bus bar 20 is disposed at one side of the arrangement of the circuit breakers and extends in the direction of the arrangement, and the connecting bus bars 3, 4 and the outside lead-out devices 5A, 5B are disposed on the other side similarly with the first embodiment. Therefore, the circuit breakers can be disposed closer to each other in the direction of the arrangement, so that a total fixing space can be reduced. As can be understood from the above-described embodiments, the present invention can be applied to a gas-insulated switchgear system in which a plurality of gas-insulated switchgear equipments are provided in each of which a plurality of circuit breakers are arranged on a straight line and one or two main bus bars extending in the direction of the arrangement and the circuit breakers and the main bus bar or bars are interconnected. As described above, a plurality of vertical-type circuit breakers are closely arranged on a substantially straight line and connecting bus bars interconnecting the circuit breakers and outside lead-out devices are provided on one side of the arrangement of the circuit breakers and one or more main bus bars extend on the other side of the arrangement. Therefore, no connecting bus bars exist between opposite portions of the circuit breakers as in the case of conventional systems, so that a plurality of gas-insulated switchgear equipments can be closely disposed, thereby reducing the installation space. Also, the electrical connection among the elements can be easily established.

Claims: A gas-insulated switchgear equipment comprising a set of three vertical-type circuit breakers (CB₁, CB₂, CB₃) arranged along a substantially straight line on a fixing base and electrically connected in series between two main bus bars (1, 7), each circuit breaker (CB₁, CB₂, CB₃) having lead-out portions (11...16) extending from its upper and lower portions in a direction perpendicular to said straight line for leading out the circuit breaker terminals, wherein lead-out portions (11, 13) formed on one pair of adjacent circuit breakers (CB₁, CB₂) are interconnected by a first connecting bus bar (4) and lead-out portions (14, 15) formed on the other pair of adjacent circuit breakers (CB₂, CB₃) are interconnected by a second connecting bus bar (3), with outside lead-out devices (5A, 5B) being connected to side portions of the respective first and second connecting bus bars (4, 3), wherein said connecting bus bars (4, 3) and said outside lead-out devices (5A, 5B) are disposed on one side and said main bus bars (1, 7) are disposed on the other side of said set of circuit breakers (CB₁, CB₂, CB₃), characterized in that said main bus bars (1, 7) extend parallel to said straight line and include a lower main bus bar (1) connected to a lower lead-out portion (12) formed on the circuit breaker (CB₁) located at one end of said series connection and an upper main bus bar (7) connected to an upper lead-out portion (16) formed on the circuit breaker (CB₃) located at the other end of said series connection, and that said first connecting bus bar (4) is an upper bus bar connected to upper lead-out portions (11, 13) of said one pair of adjacent circuit breakers (CB₁, CB₂ ), and said second connecting bus bar (3) is a lower bus bar connected to lower lead-out portions (14, 15) of said other pair of adjacent circuit breakers (CB₂, CB₃). A gas-insulated switchgear equipment comprising a set of three vertical-type circuit breakers (CB₁, CB₂, CB₃) arranged along a substantially straight line on a fixing base and electrically connected in series with one end of the series connection being connected to a main bus bar (20), each circuit breaker (CB₁, CB₂, CB₃) having lead-out portions (11...16) extending from its upper and lower portions in a direction perpendicular to said straight line for leading out the circuit breaker terminals, wherein lead-out portions (11, 13) formed on one pair of adjacent circuit breakers (CB₁, CB₂) are interconnected by a first connecting bus bar (4) and lead-out portions (14, 15) formed on the other pair of adjacent circuit breakers (CB₂, CB₃) are interconnected by a second connecting bus bar (3), with outside lead-out devices (5A, 5B) being connected to side portions of the respective first and second connecting bus bars (4, 3), wherein said connecting bus bars (4, 3) and said outside lead-out devices (5A, 5B) are disposed on one side and said main bus bars (1, 7) are disposed on the other side of said set of circuit breakers (CB₁, CB₂, CB₃), characterized in that said main bus bar (20) extends parallel to said straight line and is connected to a lower lead-out portion (12) formed on the circuit breaker (CB₁) located at one end of said series connection and to an upper lead-out portion (16) formed on the circuit breaker (CB₃) located at the other end of said series connection, and that said first connecting bus bar (4) is an upper bus bar connected to upper lead-out portions (11, 13) of said one pair of adjacent circuit breakers (CB₁, CB₂ ), and said second connecting bus bar (3) is a lower bus bar connected to lower lead-out portions (14, 15) of said other pair of adjacent circuit breakers (CB₂, CB₃). The switchgear equipment of claim 1 or 2, wherein the outside lead-out device (5B) connected to said lower connecting bus bar (3) has a cable head (6) disposed in a vertical-type cable head casing (17) which also houses a vertical conductor (8) electrically connecting said lower connecting bus bar (3) to said cable head (6). The switchgear equipment of claim 1 or 2, wherein said lower connecting bus bar (3) is connected to its outside lead-out device (5B) via an upwardly extending intermediate connecting bus bar (3a). The switch-gear apparatus of any of claims 1 to 4, wherein disconnecting switches (DS₁₁, DS₁₂, DS₂₁, DS₂₂, DS₃₁, DS₃₂), which electrically connect said circuit breakers (CB₁, CB₂, CB₃) to said main and connecting bus bars (1, 3, 4, 7, 20), are disposed within the containers of the respective main and connecting bus bars.

Inventors: TSUBAKI TOHRU, TSUBAKI, TOHRU
Applicants: HITACHI LTD, HITACHI, LTD.
Application year: 1988
Main classification: H02B13
IPC codes: H02B13, H02B5