LDPE-PP Cable Insulation Blend for Low-Conductivity HVDC Operation
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Solution Overview
Problem
High voltage direct current (HVDC) cables face challenges with thermal runaway due to high electrical conductivity of insulation materials, which generates excessive heat and deteriorates mechanical properties, especially at increased voltages, and existing crosslinking processes are cumbersome and costly due to the need for degassing volatile by-products.
Innovation Solution
A polymer composition comprising low density polyethylene (LDPE), polypropylene (PP), and a compatibilizer, which offers remarkably low electrical conductivity and improved thermomechanical performance, eliminating the need for crosslinking agents and subsequent degassing procedures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If crosslinking agents are used to improve heat and deformation resistance, then mechanical strength and creep properties are improved, but volatile decomposition products are generated requiring time and energy consuming degassing procedures
Solution Approach 1:
The invention extracts and eliminates the crosslinking agent from the polymer composition, achieving the desired mechanical strength through a blend of polyethylene and polypropylene with compatibilizer, thereby removing the source of volatile decomposition products and the need for degassing procedures
Solution Approach 2:
The invention changes the chemical composition parameters by using a specific blend ratio of polyethylene and polypropylene (60:40 to 80:20) with compatibilizer content (0.1-5 wt%), achieving improved mechanical properties without crosslinking agents
2Reliability
If insulation material with low electrical conductivity is used to prevent thermal runaway, then safety is improved, but manufacturing complexity increases due to need for crosslinking and degassing
Solution Approach 1:
The invention removes crosslinking agents and degassing steps from the manufacturing process by using a simple thermoplastic polymer blend, achieving low electrical conductivity and thermal safety without increasing manufacturing complexity
Solution Approach 2:
The invention achieves low electrical conductivity through specific polymer blend composition and ratios, eliminating the need for crosslinking while maintaining thermal safety
3Power
If higher voltages are applied to increase power transmission, then energy capacity is improved, but heat generation increases proportionally leading to thermal runaway
Solution Approach 1:
The invention changes the electrical conductivity parameter of the insulation material through polymer blend composition, achieving sufficiently low conductivity to limit leakage current and heat generation even at high voltages, preventing thermal runaway while maintaining high power transmission capability
Data Source
AI summary
The invention provides a polymer composition comprising a low density polyethylene (LDPE); polypropylene (PP) and a compatibiliser. The invention also relates to cables comprising said polymer composition and the use of the polymer composition in the manufacture of an insulation layer of cable.