| Title of Invention | "SWITCHGEAR FOR A POWER STATION GENERATOR" |
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| Abstract | 1/ Switchgear between a power station generator (1) and a transformer (5) of a medium voltage or high voltage network, said switchgear comprising a generator circuit breaker (3) connected between the generator (1) and the transformer (5), together with a disconnector (4) connected between the generator circuit breaker (3) and the transformer (5), the disconnector (4) having a fixed pole (4E) connected to a moving contact (4F) movable relative to said fixed pole to open (4B) or to close (4A) the disconnector, or to connect the fixed pole to a ground terminal (4G), said switchgear being characterized in that the fixed pole (4E) of the disconnector is connected to the transformer (5). |
| Full Text | SWITCHGEAR FOR A POWER STATION GENERATOR AND A TRANSFORMER, WITH A THREE-POSITION DISCONNECTOR CONNECTED TO THE TRANSFORMER •The invention relates to switchgear between a power station generator an,d a transformer of a medium voltage or high voltage network. The ewitchgear comprises a generator circuit breaker connected between the generator and the transformer, together with a disconnector connected between the generator circuit breaker and the transformer, the disconnector having a fixed pole connected to a moving contact movable relative to said fixed pole to open or to close the disconnector, or to connect the fixed pole to a ground terminal. In known manner, such a generator circuit breaker is opened to interrupt the electrical circuit that connects the generator to the transformer, and that is in general three-phase. The disconnector, which has no interrupting capability, is subsequently opened to make it absolutely safe to work on the circuit breaker which is isolated. In Document EP A 0 567 773 A2, the disconnector has a fixed pole which is connected to the generator circuit breaker. In order to make it possible to work on the transformer, provision is made to dispose an additional ground disconnector for discharging the transformer after it has been isolated from the generator by opening the circuit breaker and subsequently opening the disconnector, and from the medium voltage or high voltage network by opening a network circuit breaker. An object of the invention is to provide switchgear that is simplified, in particular with respect to the additional ground disconnector. The basic idea of the invention is to dispose a single disconnector which includes a grounding capability and which is connected to the transformer. To this end, the invention provides switchgear between a power station generator and a transformer of a medium voltage or high voltage network, said switchgear comprising a generator circuit breaker connected between the generator and the transformer, together with a disconnector connected between the generator circuit breaker and the transformer, the disconnector having a fixed pole connected to a moving contact movable relative to said fixed pole to open or to close the disconnector, or to connect the fixed pole to a ground terminal, said switchgear being characterized in that the fixed pole of the disconnector is connected to the transformer. In order to work on the transformer, the generator circuit breaker is opened, and then the disconnector is opened. A network circuit breaker connected between the transformer and the network is then opened, and, finally, the fixed pole of the disconnector is connected to the ground terminal via the moving contact to discharge the transformer. In the invention, it is possible to interconnect, to isolate, and to ground the cransformer by using a single disconnector included in the switchgear. Other characteristics and advantages of the invention appear on reading the following description of an embodiment of the invention given with reference to the drawing, in which: the sole figure is a block diagram of switchgear of the invention. As shown in the sole figure, a power station generator 1 is connected to a transformer 5 of a medium voltage and high voltage network via switchgear which includes a generator circuit breaker 3. The power station generator is of the gas turbine type or of the combined gas and steam turbine type, and it includes sets of busbars, each of which is constituted by three circuit-breaker has a closed position referenced 3A and an open position referenced 3B. A disconnector 4 is connected between the generator circuit breaker 3 and the transformer 5. A fixed pole 4E of the disconnector is connected to a moving contact 4F which is displaced into an open first position referenced 4B to open the disconnector, or into a closed second position 4A to close said disconnector. The moving contact is displaced into a third position referenced 4C to connect the fixed pole to a ground terminal 4G. In the invention, the pole 4E of the disconnector of the switchgear is connected to the transformer 5. Under operating conditions, the generator circuit breaker 3 and the disconnector 4 are closed. Prior to starting any work on the transformer 5, e.g. for maintenance purposes, the generator circuit breaker 3 is opened, the disconnector 4 is subsequently opened, and a network circuit breaker (not shown in the sole figure) is then opened. The transformer is isolated. To discharge it, the fixed pole 4E of the disconnector is connected to the ground terminal 4G via the moving contact 4F. CLAIMS 1/ Switchgear between a power station generator (1) and a transformer (5) of a medium voltage or high voltage network, said awitchgear comprising a generator circuit breaker (3) connected between the generator (1) and the transformer (5), together with a disconnector (4) connected between the generator circuit breaker (3) and the transformer (5), the disconnector (4) having a fixed pole (4E) connected to a moving contact (4F) movable relative to said fixed pole to open (4B) or to close (4A) the disconnector, or to connect the fixed pole to a ground terminal (4G), said switchgear being characterized in that the fixed pole (4E) of the disconnector is connected to the transformer (5). 2. Switchgear substantially as herein described with reference to the accompanying drawings. |
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3509-del-1998-correspondence-others.pdf
3509-del-1998-correspondence-po.pdf
3509-del-1998-description (complete).pdf
3509-del-1998-petition-138.pdf
| Patent Number | 220133 | |||||||||
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| Indian Patent Application Number | 3509/DEL/1998 | |||||||||
| PG Journal Number | 28/2008 | |||||||||
| Publication Date | 11-Jul-2008 | |||||||||
| Grant Date | 15-May-2008 | |||||||||
| Date of Filing | 23-Nov-1998 | |||||||||
| Name of Patentee | AREVA T&D SA. | |||||||||
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| PCT International Classification Number | H01H 33/02 | |||||||||
| PCT International Application Number | N/A | |||||||||
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