Large-carrying-capacity and environmentally-friendly direct current cable used for fixed laying

Abstract

The invention discloses a large-carrying-capacity and environmentally-friendly direct current cable used for fixed laying. The direct current cable disclosed by the invention comprises a round compacted stranded copper conductor positioned at the axis of the cable, wherein an EPDM (ethylene-propylene-diene monomer) rubber insulating layer is extruded outside the round compacted stranded copper conductor in a wrapping manner; and a copper strip wrapping protection layer, a low-smoke halogen-free flame-retardant belting and a low-smoke halogen-free flame-retardant environmentally-friendly over sheath are sequentially arranged outside the EPDM rubber insulating layer. According to the invention, based on the improvements on the structure and used material of the cable, the direct current cable, which can be used for fixed laying for a long time, meets the requirement of large carrying capacity and accords with the environmentally-friendly requirement, can be provided for direct current use occasions; the space charge generation phenomenon caused by external lightning stroke and overvoltage and the water branch generation phenomenon in cross-linked polyethylene, which commonly exist when the cross-linked polyethylene insulation alternating current cable is used for direct current transmission in the prior art, can be avoided; and the service life of the cable is greatly prolonged, and the safe reliability of the cable is greatly improved.

Description

[0001] technical field [0002] The invention belongs to the field of power cables, in particular to an environment-friendly DC cable for fixed laying with high carrying capacity. The product is suitable for underground railways, iron and steel, chemical industry, electric power, petroleum, metallurgy and other places where high-power DC motors are used. Background technique [0003] DC transmission has the advantages of large transmission capacity, low cost, less line energy loss, less line interference, stable line voltage distribution, and easier control of power and current regulation. Direct current has been used more and more at present, such as: used for long-distance high-power transmission; contacting AC systems with different frequencies or the same frequency but not synchronous operation; used as a connection line between network interconnection and regional systems (easy to control , without increasing the short-circuit capacity); use submarine cables to transmit...

AI Technical Summary

Problems solved by technology

However, XLPE insulated cables have been used for DC transmission for a long time, and space charges will accumulate due to external lightning strikes and overvoltages, causing the polarity reversal tests of cables to often fail to meet the requirements.

At the same time, the electric field of the DC cable is mainly concentrated on the insulating surface. Under the influence of the electric field, cross-linked polyethylene is easy to produce water branches, which reduces the service life of the cable. At the same time, DC cables are mostly used in subways, locomotives, chemicals, and oil exploration. In other occasions, the cables are required to be flame-retardant, low-smoke, halogen-free, and free of harmful components.

However, there are no DC cables meeting these conditions on the market at present

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