Insulating crosslinking polyethylene for winding cable

Abstract

The invention relates to insulating crosslinking polyethylene for a winding cable, which is characterized by comprising the following components by weight portion: 100 portions of low density polyethylene (LDPE), 35 to 55 portions of ethylene-vinyl acetate copolymer (EVA), 30 to 45 portions of polyisobutylene (PISOB) or butyl rubber (iiR), and 1.5 to 2.2 portions of peroxide cross-linking agent; and the insulating crosslinking polyethylene is prepared from the components through crosslinking. The insulating crosslinking polyethylene not only keeps the excellent electric property of the crosslinking polyethylene, in particular to the low electric loss of the crosslinking polyethylene, but also improves the softness of the crosslinking polyethylene, can satisfy the requirements on winding and inserting the winding cable, and improves the low temperature resistance of an insulating material. The insulating crosslinking polyethylene is not cracked by low-temperature impact at a temperature of 50 DEG C below zero in a test, can satisfy the mounting of cables in an environment at a temperature of not less than 25 DEG C below zero, and has the bending times of more than 1,000 to 1,100 times (according to the test condition of GB / T12706.2-2002), thus the insulating crosslinking polyethylene is particularly suitable for the insulation of winding wires of a high-voltage motor or a transformer for wind power generation and hydroelectric power generation.

Description

technical field [0001] The invention relates to a winding cable insulating material, in particular to a winding cable insulation cross-linked polyethylene which not only has the softness of rubber, but also has the mechanical and electrical properties of cross-linked polyethylene, especially low power loss. Background technique [0002] Medium and high voltage winding cables are required to have a certain degree of flexibility in order to meet the requirements of winding and embedding, so the insulation is basically made of rubber such as ethylene propylene rubber (EPR). Propylene rubber is the main material for insulation; the medium voltage winding cable disclosed in Chinese patent CN1652261 is composed of 70-90% EPDM rubber and 10-30% EVA for insulation. Although rubber insulation has good flexibility, the four major electrical parameters of rubber such as EPR (dielectric strength E kp , insulation resistance ρ v , dielectric constant ε and dielectric loss tangent tgδ) ...

AI Technical Summary

Problems solved by technology

The above-mentioned cross-linked polyethylene spears are softly modified, and the modified substances used will lead to an increase in the dielectric constant (ε) and dielectric loss tangent (tgδ), resulting in an increase in transmission power loss

For example, EVA must be increased to have a significant softening effect, and the tgδ of EVA is 0.003-0.02, which is dozens to 200 times higher than that of PE and XLPE; EPR makes the four major electrical properties of XLPE drop significantly; silicone rubber ( The ε and tgδ of SiR) are 3.3 and 0.3-0.8 respectively, which are likely to increase the dielectric constant (ε) and dielectric loss tangent (tgδ) of the modified XLPE, and it is difficult to meet the XLPE insulation requirements for medium and high voltages. Therefore, the above Softening modification can only be used in low battery state

Therefore, the prior art only uses rubber to modify XLPE, only considers softness, and does not consider the satisfaction of electrical properties, especially the electrical loss under high voltage

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