Extra-high-voltage direct current binodal composite insulator and pressure welding method of hardware fittings and core rods thereof

Abstract

The invention discloses an etra-high-voltage direct current binodal composite insulator, and relates to a composite insulator for a high-voltage power transmission line. The high-voltage direct current binodal composite insulator comprises two single-node composite insulators and a middle connecting piece, each single-node composite insulator comprises a core rod, an umbrella skirt and two hardware fittings, each hardware fitting comprises a connecting ring and a pressure welding tube used for being connected with the core rod in a sleeved mode, the closed ends of the pressure welding tubes are connected with the connecting rings, the pressure welding tubes are provided with pressure welding parts, the pressure welding tubes of the two hardware fittings are respectively sleeved and adopt the compression amount of 1.8mm to 1.95mm to be connected at two ends of the core rods in a pressing mode, and the closed ends of the pressure welding tubes carry out pressure welding for eight times towards the other ends of the pressure welding tubes. The hardware fittings of the high-voltage direct current binodal composite insulator have the newly-designed structures, meanwhile a novel pressure welding method is used in pressure welding of the hardware fittings and the core rods, therefore the tensile strength of the high-voltage direct current binodal composite insulator is made to reach more than 1000kN, strict operating conditions are met, and the high-voltage direct current binodal composite insulator stably operates on a power transmission line of an extra-high-voltage class of + / - 1100kv and over + / - 1100kv.

Description

technical field [0001] The invention relates to a composite insulator for a high-voltage transmission line, in particular to a UHV DC double-section composite insulator and a crimping method for a fitting and a mandrel. Background technique [0002] In UHV transmission lines with a voltage level of ±1100kv, there are very high requirements for the electrical performance of insulators. Due to the electrostatic adsorption of UHV DC transmission lines during operation and the absence of arc current zero-crossing, etc., the external insulation of insulators Leakage distance requirements are very strict, and insulators must have a sufficiently long external insulation leakage distance, the length of ±1100kV UHVDC insulators is often more than ten meters long, and the weight of the insulator itself is very heavy. The strength, especially the tensile strength, is also very high, so the insulators used in this voltage level must have high mechanical properties, and the existing insu...

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Problems solved by technology

[0002] In UHV transmission lines with a voltage level of ±1100kv, there are very high requirements for the electrical performance of insulators. Due to the electrostatic adsorption of UHV DC transmission lines during operation and the absence of arc current zero-crossing, etc., the external insulation of insulators Leakage distance requirements are very strict, and insulators must have a sufficiently long external insulation leakage distance, the length of ±1100kV UHVDC insulators is often more than ten meters long, and the weight of the insulator itself is very heavy. The strength, especially the tensile strength, is also very high, so the insulators used in this voltage level must have high mechanical properties, and the existing insulators cannot meet the requirements

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