+/-660 kv direct-current composite insulator

Abstract

The invention discloses a + / -660 kV direct-current composite insulator which comprises an annular metal connecting piece located at the end, a sealing ring, an epoxy resin glass fiber stick, a sheath and grading rings. The annular metal connecting piece is connected with the grading ring at the grounding end. The grading ring at the grounding end is connected with the front end of the epoxy resin glass fiber stick through the sealing ring. The outer surface of the epoxy resin glass fiber stick is wrapped by the sheath. Umbrella skirts of three specifications are arranged on the sheath. The tail end of the epoxy resin glass fiber stick is connected with the grading ring at the high-voltage end. According to the + / -660 kV direct-current composite insulator, the structural mode of one large umbrella and two small umbrellas of an extra-large umbrella with arranged flowers is adopted, the creepage distance is effectively increased on the basis of an existing structural height, the electric field distribution of the surface of the + / -660 kV direct-current composite insulator is improved, the local field intensity is reduced, partial discharge is restrained, meanwhile, ice and snow bridge connection can be blocked due to the structure, and the + / -660 kV direct-current composite insulator has the good ice, snow and lightning prevention capacity.

Description

technical field [0001] The invention relates to the field of overhead transmission lines, in particular to a ±660kV DC composite insulator. Background technique [0002] As an important part of transmission lines, insulators play an important role in ensuring the safe operation of power systems. Composite insulators not only have hydrophobic performance, hydrophobic migration performance, small equivalent diameter and good anti-pollution flashover performance, but also have the characteristics of high strength, light weight, unbreakable, convenient transportation, easy operation and maintenance, etc. It is widely used in transmission lines, and it has also begun to be used in batches or even in new AC and DC projects with a voltage level of 500kV and above. However, due to the zero-crossing problem of DC, the DC pollution flashover characteristics of composite insulators are very different from the AC pollution flashover characteristics. At the same time, due to the electro...

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Problems solved by technology

However, due to the zero-crossing problem of DC, the DC pollution flashover characteristics of composite insulators are very different from the AC pollution flashover characteristics. At the same time, due to the electrostatic adsorption of DC voltage, the pollution on the DC outer insulation surface is faster and dirtier under the same conditions. Seriously, the test conclusions of AC composite insulators should not be directly applied to the design of composite insulators for DC transmission lines. The ±660kV DC composite insulators that have been put into operation adopt the structure of large-small-small umbrellas, and different degrees of partial discharge have occurred , which seriously threatens the operation safety of ±660kV DC transmission lines

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