500kv and above 500kv power cable outdoor terminal

Abstract

The invention relates to a cable accessory in the field of power cable transmission systems, in particular to a 500kV and more power cable outdoor terminal. The terminal comprises a sleeve (1), an insulating agent (2), a stress cone (3), an epoxy sleeve (4) and a spring compression mechanism (5) and further comprises outlet hardware (6), an upper cover board (7), a lower bottom plate (8) and a tail pipe (9). The stress cone (3) is arranged in the sleeve (1). The epoxy sleeve (4) is sleeved outside the stress cone (3). The spring compression mechanism (5) is arranged under the stress cone (3).The stress cone (3) is made of liquid silicon rubber. The terminal disclosed by the invention has the advantages of has steady and reliable performance, high yield, low integrated cost; simple manufacture process, easiness manufacture and low manufacture cost; and more excellent process mouldability and low required forming pressure because before the liquid silicon rubber has lower viscosity andbetter liquidity being vulcanized; and good product quality.

Description

technical field [0001] The invention relates to a cable accessory in the field of power cable transmission system, in particular to an outdoor terminal of a power cable of 500kV or above. Background technique [0002] At present, in power cable transmission systems with voltage levels above 500kV and 500kV, cables are mostly XLPE insulated power cables, and outdoor terminals are used to connect XLPE insulated power cables and overhead lines to realize power transmission. transmission. With the construction of large-scale hydropower stations, pumped storage power stations, and UHV power grids, the use of outdoor terminals is increasing. In the power cable connection system of 500kV and above, outdoor terminals are important connectors. The reliability of outdoor terminals It directly affects the reliability of the transmission system. [0003] In the outdoor terminals of power cables of 500kV and above, the stress cone of the commonly used outdoor terminal is a structural t...

AI Technical Summary

Problems solved by technology

[0004] (1) The quality of the material used to make the stress cone is difficult to control. The material of the stress cone is mainly a terpolymer of ethylene, propylene and non-conjugated dienes. Various additives are added during the kneading process, and the formula is complicated It is difficult to control the quality of the material; the viscosity of the material is high, the molding process is poor, and the yield of the stress cone is only about 60%

[0005] (2) The manufacturing process is complicated, and the molding equipment required to process the stress cone has a large pressure, a large volume, and high product manufacturing costs

Because the viscosity of EPDM rubber after plasticization is very high and its fluidity is poor, it needs tens of megabytes of pressure to inject it into the cavity. During the injection process, the cavity and equipment need to withstand very high pressure. Due to the molding mold The volume is very large, and it requires a special large-scale rubber injection machine with a large tonnage and a large mold to perform rubber injection molding, and the materials used must be injected at one time. Therefore, the production of stress cones for outdoor terminals of power cables with 500kV and above requires rubber injection. The tonnage of the machine must reach more than 1,600 tons, and the single injection of glue must reach more than 80 liters to meet the requirements. Such equipment is large in size and high in equipment cost, and the increase in equipment cost causes the entire production cost to be extremely high.

[0006] (3) Due to the high hardness of EPDM rubber, Shore A60~70, the adhesion to the surface of the cable is poor, resulting in difficulty in product installation and an increase in product failure rate, and the air box of EPDM rubber is aging Post-mechanical properties (aging conditions: 135°C±3°C, 7d), compression set ≤ 15-25%, tensile strength change rate ≤ 20-30%, elongation change rate ≤ 20-30%, material The aging resistance and high temperature resistance are poor, and the product must be operated under the environmental conditions of ≤100°C, the use is limited, and the scope of application is narrow

[0007] Although the existing 500kV and above 500kV power cable outdoor terminals have the above defects, people have been unable to solve this technical problem for a long time

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