A 500kV and above 500kV AC/DC power cable external terminal

Abstract

500kV and above 500kV AC / DC power cable external terminal, belonging to the technical field of high-voltage crosslinked power cable accessories, The outdoor terminal comprises a sleeve, an upper flange and a lower flange mounted on the sleeve and a connecting fitting mounted on the lower flange, wherein a stress cone is arranged in the sleeve, an epoxy seat located at the top end of the connectingfitting is arranged on the periphery of the stress cone, an insulating oil is arranged between the epoxy seat and the sleeve, and the insulating oil is low-temperature resistant silicone oil; The bottom of the stress cone is provided with a pressure adjusting device. The interfacial pressure between the stress cone and the cable is adjustable, so that the tight adhesion between the stress cone and the epoxy seat and the stress cone and the cable can be ensured, and the flowability of the insulating oil under the low temperature condition can be ensured.

Description

technical field [0001] The invention relates to an outdoor terminal for AC and DC power cables of 500kV and above, belonging to the technical field of high-voltage cross-linked power cable accessories. Background technique [0002] At present, with the construction of large-scale hydropower stations, pumped storage power stations, and UHV power grids, outdoor terminals are increasingly used in power cable transmission systems with voltage levels of 500kV and above. As an important connection between the cable and the overhead line, the reliability of the outdoor terminal directly affects the reliability of the power transmission system. [0003] In the outdoor terminals of power cables of 500kV and above, the commonly used stress cones are generally made of silicone rubber or EPDM rubber, and the insulating filler is generally polyisobutylene oil. If the stress cone is immersed in the insulating filler for a long time, it is easy to cause The aging of the stress cone materi...

AI Technical Summary

Problems solved by technology

[0003] In the outdoor terminals of power cables of 500kV and above, the commonly used stress cones are generally made of silicone rubber or EPDM rubber, and the insulating filler is generally polyisobutylene oil. If the stress cone is immersed in the insulating filler for a long time, it is easy to cause The aging of the stress cone material reduces the electrical performance, and long-term operation is likely to cause insulation damage, posing a safety hazard; most of the filled insulating oil cannot guarantee the fluidity and insulation under low temperature conditions, and product breakdown is prone to occur, which seriously affects the outdoor terminal at low temperature. Electrical performance and safety performance under conditions

[0004] The Chinese invention patent with the application number 201010190801.0 discloses an outdoor terminal for power cables of 500kV and above, which is equipped with a silicon rubber stress cone on the cable and an epoxy sleeve outside the stress cone. Insulating oil is used to isolate the stress cone to avoid rubber infiltration or aging caused by the long-term immersion of the stress cone in the insulating oil. At the same time, a compression device is installed under the stress cone to generate an interface pressure between the stress cone and the cable. The interface pressure makes the stress cone and the cable tight. tightly pressed together, the interface pressure is not adjustable, and the air bubbles between the stress cone and the cable cannot be completely eliminated, and the tight fit between the stress cone and the epoxy sleeve and the stress cone and the cable cannot be guaranteed. The stress relaxation problem between the stress cone and the cable caused by the action of the electric field and thermal field makes the electric field distribution at the cutting point of the cable insulation shield uneven, reducing the power frequency and breakdown strength of the cable

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