DISCONNECTOR FOR HIGH-VOLTAGE OVERHEAD LINES

Abstract: A disconnector for high-voltage overhead power lines, whose particularity consists of the fact that it comprises: a sealed enclosure which contains a dielectric fluid and inside which a plurality of fixed contacts and a plurality of moving contacts are accommodated, said moving contacts being able to mutually couple/uncouple with respect to the corresponding fixed contacts; an actuation rod which is connected to said moving contacts and lies longitudinally within said enclosure; said moving contacts being moved on a plane which is perpendicular to the longitudinal axis of the enclosure by means of a rotary motion of said actuation rod; a remote-controlled motorized actuation unit which is operatively connected to said actuation rod; and supporting means for installation on a pylon of a high-voltage overhead power line.

Description: DISCONNECTOR FOR HIGH- VOLTAGE OVERHEAD LINES DESCRIPTION The present invention relates to a disconnector, particularly for high-voltage overhead power lines. Disconnectors are generally used in substations for the transmission and/or distribution of electric power. It is known from the art that electric power substations comprise a series of primary components, for example circuit breakers, disconnectors and power transformers, which are mutually connected in an appropriate way according to a given electrical layout. The substation is furthermore provided with a series of secondary components, constituted by protection devices and control systems, in order to ensure correct electrical operation of the system and avoid dangerous damage. Owing to the large number of primary and secondary components required, even for the provision of a minimal configuration, known types of substation are not entirely satisfactory in practical use, mainly due to the dimensions required in terms of ground occupation. One possible solution to the problem of dimensions is to install the disconnector on a pylon of the line instead of on the ground. Switching for disconnection is then performed manually, by virtue of appropriate mechanical transmissions at the base of the pylon. Although this solution adequately meets the requirements in terms of ground occupation, it is not fully satisfactory from the point of view of switching ease and accuracy. Furthermore, the fact can not be ignored that it is not possible to remotely control switching for disconnection and coordinate it with the other switching operations performed by the various units of the substation. The aim of the present invention is to provide a disconnector, particularly for i high-voltage overhead power lines, which limits the dimensions required in terms of ground occupation. Within the scope of this aim, an object of the present invention is to provide a disconnector, particularly for high-voltage overhead power lines, which can be remotely controlled. Another object of the present invention is to provide a disconnector, particularly for high-voltage overhead power lines, which has a reduced number of components. Another object of the present invention is to provide a disconnector, particularly for high-voltage overhead power lines, which does not require frequent maintenance. Another object of the present invention is to provide a disconnector, particularly for high-voltage overhead power lines, which is highly reliable, relatively easy to manufacture and at competitive costs. This aim, these objects and others which will become apparent hereinafter are achieved by a disconnector for high-voltage overhead power lines, characterized in that it comprises: ~ a sealed enclosure which contains a dielectric fluid and inside which a plurality of fixed contacts and a plurality of moving contacts are accommodated, said moving contacts being able to mutually couple/uncouple with respect to the corresponding fixed contacts; ~ an actuation rod which is connected to said moving contacts and lies longitudinally within said enclosure; ~ said moving contacts being moved on a plane which is perpendicular to the longitudinal axis of the enclosure by means of a rotary motion of said actuation rod; ~ a remote-controlled motorized actuation unit which is operatively connected to said actuation rod; and ~ supporting means for installation on a pylon of a high-voltage overhead power line. In this manner, one has the advantage of providing a disconnector which does not entail an increase in occupied area and at the same time allows remote control of switching for disconnection. Further characteristics and advantages of the disconnector according to the invention will become apparent from the description of preferred but not exclusive embodiments, illustrated only by way of non-limitative example in the accompanying drawings, wherein: Figure 1 is a sectional view of a disconnector according to the invention; Figure 2 is a view of a first possible way of installing the disconnector according to the invention; and Figure 3 is a view of a second possible way of installing the disconnector according to the invention. With reference to Figure 1, the disconnector, particularly for high-voltage overhead power lines, according to the invention, generally designated by the reference numeral 1, comprises a sealed enclosure 10 which contains a dielectric insulation fluid, for example SF 6 . In the embodiment of Figure 1 , three fixed contacts 11, 12 and 13 are arranged inside the enclosure 10. The fixed contacts 11 and 12 are electrically connected, by means of through insulators 51 and 52, to one of the phases of the overhead power line (not shown). The fixed contact 13 is electrically connected, by means of a bushing 53, to an element of the substation, for example a pole of a circuit breaker. The embodiment of Figure 1 has an additional fixed contact 14 which is grounded. The enclosure 10 furthermore comprises an actuation rod 15 which lies longitudinally inside it. The moving contacts 21, 22, 23 and 24 are arranged on the rod 15 and can be coupled/uncoupled with respect to the corresponding fixed contacts 11, 12, 13 and 14. The movement of the moving contacts and their coupling/uncoupling with respect to the corresponding fixed contacts occurs on a plane which is perpendicular to the longitudinal axis of the enclosure by virtue of the rotation of the actuation rod 15. A motorized actuation unit 30 produces the rotary motion of the rod 15. The disconnector according to the invention furthermore comprises supporting means, constituted for example by brackets 40, for installation on a pylon of an overhead power line. Preferably, electric field shields 61 and 62 are arranged at the ends of the actuation rod 15. The motorized actuation unit 30 can be constituted by a conventional electric motor which is controlled appropriately. Advantageously, it is constituted by a rotary servomotor; this solution in fact allows higher precision and accuracy in switching, since the servomotor allows better control of the speed and positioning of the elements connected thereto. A first possible way of installing the disconnector according to the invention on a pylon 70 of a high-voltage power line is illustrated with reference to Figure 2. This embodiment provides for the installation of a disconnector 1 according to the invention for each phase of the line. In this case, conductors 71, 72 and 73 are arranged on a substantially vertical plane; three disconnectors 1 are installed on the pylon 70 at each conductor and at different elevations with respect to the ground. The line is protected by an earth wire 74. A second possible way of installing the disconnector according to the invention on a pylon 80 of a high- voltage power line is illustrated with reference to Figure 3. In this embodiment, a single disconnector 1 according to the invention is installed. In this case, the three conductors lie on a same substantially horizontal plane and the figure illustrates only one conductor 81. A single disconnector 1, which has an enclosure 10 as described above and the respective actuation unit for each phase, is installed on the pylon 80 at said conductors. The line is protected by an earth wire 84. In practice it has been found that the disconnector for high-voltage overhead power lines according to the invention fully achieves the intended aim and objects, since it does not require space at ground level. In the proposed embodiments, the disconnector according to the invention can be remotely controlled by virtue of the remote control of the motorized actuation unit. The number of mechanical components subjected to wear is furthermore reduced, with a consequent reduced need for maintenance. The disconnector for high-voltage overhead power lines thus conceived is susceptible of numerous modifications and variations, all of which are within the scope of the inventive concept; all the details may furthermore be replaced with other technically equivalent elements. In practice, the materials used, so long as they are compatible with the specific use, as well as the dimensions, may be any according to the requirements and the state of the art.

Claims: CLAIMS 1. A disconnector for high- voltage overhead power lines, characterized in that it comprises: ~ a sealed enclosure which contains a dielectric fluid and inside which a plurality of fixed contacts and a plurality of moving contacts are accommodated, said moving contacts being able to mutually couple/uncouple with respect to the corresponding fixed contacts; ~ an actuation rod which is connected to said moving contacts and lies longitudinally within said enclosure; — said moving contacts being moved on a plane which is perpendicular to the longitudinal axis of the enclosure by means of a rotary motion of said actuation rod; ~ a remote-controlled motorized actuation unit which is operatively connected to said actuation rod; and — supporting means for installation on a pylon of a high-voltage overhead power line. 2. The disconnector according to claim 1, characterized in that the sealed enclosure accommodates a first fixed contact, a second fixed contact and a third fixed contact and corresponding first, second and third moving contacts, the first and second fixed contacts being electrically connected to said overhead power line by means of a first bushing and a second bushing, the third fixed contact being electrically connected to an element of a substation by virtue of a third bushing. 3. The disconnector according to claim 2, characterized in that said enclosure accommodates a fourth fixed contact and a corresponding fourth moving contact, said fourth fixed contact being grounded. 4. The disconnector according to one or more of the preceding claims, characterized in that electric field shields are arranged at the ends of said actuation rod. 5. The disconnector according to one or more of the preceding claims, characterized in that said motorized actuation unit is constituted by a rotary servomotor. 6. A high-voltage overhead power line, characterized in that it comprises, for each phase of said line, a disconnector according to one or more of the preceding claims. 7. The high- voltage overhead power line, characterized in that it comprises a single disconnector according to one or more of claims 1 to 5. 8. A high-voltage substation, characterized in that it comprises a disconnector according to one or more of claims 1 to 5.

Inventors: PIAZZA COSTANTE, PIAZZA, COSTANTE
Applicants: ABB RICERCA SPA, PIAZZA COSTANTE, PIAZZA, COSTANTE
Application year: 2000
Main classification: H01H31
IPC codes: H02B5, H02B13