GAS INSULATED ELECTRICAL APPARATUS

Abstract: A gas insulated electrical apparatus wherein a power transformer apparatus (2) and a switchgear device (4) are contained in a single sealed housing (3) filled with a gas insulator, the two devices being electrically connected inside the housing, and the switchgear device (4) being electrically connected to power cables by means of detachable connect­ ing terminals (16, 18).

Description: GAS INSULATED ELECTRICAL APPARATUS This invention relates to gas insulated electrical apparatuses. A gas insulated electrical apparatus is known which comprises a power transformer and switchgear including a circuit breaker, a disconnecting switch, an instrument current transformer, an instrument voltage transformer, a ground switch and the like disposed in separate stationary housings, and with the switchgear electrically connected directly to power cables. This resulted in the dimensions of the ole gas insulated electrical apparatus being large, and complicated the maintenance and inspection of the electrical apparatus. With a view to mitigating the foregoing disadvantages, the present invention provides a gas insulated electrical apparatus including a transformer and switchgear connected to the said transformer arranged within a sealed armour housing filled with an insulating gas, wherein terminals connected to the switchgear are mounted on said sealed housing so as to pass through a wall thereof, and are detachably connectible to connection terminals provided on t.he cables to be connected to the electrical apparatus. The invention will now be described further, by way of example, with reference to the accompanying drawings, in which: Figure l(a) iE a side view showing a prior-art gas insulated electrical apparatus. Figure l(b) is a plan view of the apparatus in Figure 1(a); Figure 2 is a schematic circuit diagram of the apparatus shown in Figures l(a) and l(b); Figure 3(a) is a side view showing an embodiment of a gas insulated electrical apparatus according to this inverl,ion. Figure 3(b) iE a plan view of the apparatus in Figure 3(a); and Figure 4 is a partial sectional side view showing the details of a bushing terminal and a connection terminal for the cable. In Figures l(a) and l(b) and Figure 2, a gas insulated electrical apparatus of two banks is shown. Transformer coils la, lb wound on magnetic cores 2a, 2b are contained in sealed housings 3a, 3b which are filled with an insulating gas such as SF6 gas. Switchgear 4a, 4b are connected betwe@n the transformer coils la, lb and power cables 5a, 5b. The switchgear 4a, 4b comprises circuit breakers, 401a, 401b and disconnecting switches 402a, 402b which function to connect or disconnect the transformer coils la, lb to or from the power cables 5a, 5b; instrument current transformers 403a, 403b which detect the currents flowing through the transformer coils la, 1b; instrument voltage transformers 404a, 404b which detect the voltages applied to the transformer coils la, lb; and ground switches 405a, 405b which earth the transformer coils la, lb. The sealed housings 6a, 6b contain the switchgears 4a, 4b, and are filled with an insulating gas such as SF6 gas. bushings 7a, 7b are mounted on the sealed housings 6a, 6b so as to pass through the walls of the respective housings, and function to connect the ends 501a, 501b of the power cables 5a, 5b to the switchgears 4a, 4b. Cable boxes 8a, 8b are mounted on the sealed housings 6a, 6b. The cable boxes e, 8b function to protect the cable ends 501 a, 501b from dust etc., and also to prevent live parts such as the cable ends 501a, 501b from being physically exposed, in order to prevent electric shock accidents. Bushings 9a, 9b are mounted on the sealed housings 6a, 6b so as to pass through the walls of the housings, while primary bushings lOa, 10b are mounted on the sealed housings 3a, 3b so as to pass through a walls of the latter. Conductors gila, llb are complected between the bushings 9a, 9b and the primary bushings l0a, 10b, to connect the switchgears 4a, 4b to the transformer coils la, lb. Ducts 12a, 12b are constructed of a metal material such as sheet iron, sjd house the conductors lla, llb therein. In addition, these ducts grave the two end parts mounted on the sealed housings 3a, 3b and the sealed housings 6a, 6b, to electrically protect the conductors Ila, 11b etc. from dust etc. and also to prevent live parts such as the conductors lla, llb from being physically exposed, thereby to prevent electric so accidents. Secondary bushings 13a, 13b are mounted on the sealed housings 3a, 3b so as to pass through the walls of the housings, and function to pass electrical power traneformed by the transformer coils la, lb. A circuit breaker 14 is connected between the power cables, 5a, 5b and a power cable 15. Electric power supplied from the power cable 15 to the power cables 5a, 5b through the circuit breaker 14 is applied to the transformer coils la, lb through the switchgears 4a, 4b and is transformed by these transformer coils la, lb. Thereafter, the transformed power is drawn from the secondary bushings 13a, 13b. The prior-art gas insulated electrical apparatus thus constructed necessitates ducts 12a, 12b to hc-:se the conductors lla, llb being the connective conductors between the transformer coils la, lb and that switchgears 4a, 4b; and the primary busings 10 10b and the bushings 9a, 9b which are respectively mounted on the sealed housings 3a, 3b and Åa -ne sealed housings 6a, Cb so as to pass through the walls thereof. This has led to the disadvantage that the apparatus becomes large in size. Noreover, in order to inspect the switchgear 4a, the circuit breaker 14 must be opened. This has led to the drawback that power supply is cut off on the aide of tC switchgear 4b, also. This invention seeks to mitigate the disadvantages of the prior art as stated above, and provides a gas insulated electrical apparatus in which the switchgear 4a or 4b and the transformer coils la or lb are contained in a single sealed housing, and in which the power cables 5a and 5b are detachably connected to the switchgears 4a and 4b. Hereinbelow, an embodiment of this invention will be described with reference to the drawings. Figure 3(a) is a side view showing an embodiment of the gas insulated electrical apparatus according to this invention, while Figure 3(b) is a plan vie corresponding to Figure 3(a). Figure 4 is a partial sectional side view showing the details of a bushing terminal and a line side terminal device. In these figures, portions corresponding to those in Figure l(a) and 1(b) are respectively assigned the sane reference numerals. Referring to Figures ,(a) and 3(b) and Figure 4, sealed housings 3A, 3B respectively contain the two transformer coils la, lb and the switchgears 4a, 4b and are each filled with an insulating gas such as SF6 gas. The bushing terminals 16a, 16b are male in form in the present embodiment. These bushing terminals 16a and 16b are supported by the bushings 7a, 7b and have convey parts at their respective fore ends. Flanges 17a, 17b are formed integrally with the bushings 7a, 7b and are mounted on walls of the sealed housings 3A, 3B. Connecting terminals l8a, l8b on the cable side function to detachably connect the power cables 5a, 5b to the bushing terminals 16a, 16b. As illustrated in Figure 4, the terminals 18a, 18b comprise female form connective terminals 181a, 1818b which are connected to the cable ends 501a, 501b and which are connected to the convex parts at the fore ends of the bushing terminals 16a, 16b with the latter received snugly therein. Busings 183a, 183b serve to mount the connective terminals 181a, 181b on cable boxes l82a, 182b; and cable beds 184a, 184b (Figures 3(a) and 3(b)) which support the power cables 5a, 5b. wheels 19 are mounted on the sealed housing 34, 3B and function to allow the sealed housings to be moved. In the gas insulated electrical apparatus thus constructed, the transformer coil la or 1b and the switchgear 4a or 4b are contained in a single sealed housing 3A or 3B, and the transformer coil la or 1b and the switchgear 4a or 4b are directly connected by means of the conductor lla or llb. Accordingly, the ducts 12a, 12b and the pritary bushings lOa, 10b well as the bushings 9a, 9b as in the prior-art apparatus shown in Figures l(a) and l(b) are not required, and the apparatus can be reduced in overall size. Further, the sealed vessels 3A, 3B are provided with the wheels 19. Therefore, in order to inspect the switchgear 4a, the bushing terminals 16a and the connective terminals 181a maybe separated by moving the sealed vessel 3k to the right as viewed n Figures 3(a) arla 3(b). Thus, the switchgear 4a cam be inspected without opening the circuit breaker 14 shown in Figure 2, and the power supply on the side of the sealed housing 3b reed riot be cut off. Although, in the embodiment illustrated in Figures 3(a) and 3(b), the wheels 19 are mounted on the sealed vessels 3A, 3B, it could equally be the line side connection terminals 18a, l8b that are rendered movable to allow disconnection. As set forth above, the transformer coils and the switchgear are contained in single sealed housing, allowing the apparatus to be made small in size, and the ducts of the prior-art apparatus to be dispensed with, which also brings about the benefit that the apparatus is reduced in cost. Furthermore, the power cables and the switchgears are detachably connected, so that when the gas insulated electrical apparatus is arranged in a plurality of banks, it is possible to disconnect only a desired one or ones of the switchgears from the power cables.

Claims: CLINS 1. A gas insulated electrical apparatus including a transformer and switchgear connected to the said transformer arranged within a sealed armour housing filled with an insulating as, wherein terminals connected to the switchgear are mounted on said sealed housing so as to pass through a wall thereof, and are detachably connectible to connection terminals provided on the cables to be connected to the electrical apparatus. 2. A gas insulated electrical apparatus as claimed in claim 1, wherein at least one of said sealed housing and the connection terminals provided on the cables is constructed so as to be movable, electrical contact between te e terminals being made and broken by noving said sealed housing and the cable connection terminals towards and away fro each other, respectively. 3. A gas insulated electrical apparatus as claimed in claim 1 or 2, wherein said bushing terminals connected to said switchgear are male in form, while said connective terminals of said line side terminal device are female in form. 4. A gas insulated electrical apparatus as claimed in claim 3, wherein said each bushing terminal connected to said switchgear is formed unitarily with a bushing having a flange mounted on the sealed ho@sing wall. rv. A gas insulated electrical apparatus as claimed in claim 3, wherein said connection terminals on the cables are mounted on a cable box by means of bushings which receive the respective bushing terminals connected to said switchgear.

Inventors: INA, TERUO
Applicants: MITSUBISHI DENKI KABUSHIKI KAISHA
Application year: 1981
Main classification: H01F27
IPC codes: H02B13, H01F27