Power Cable Insulation Resin Composition for Electrical Treeing Suppression
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Solution Overview
Problem
The insulating properties of power cable insulation layers deteriorate due to local electrical treeing caused by foreign matter, leading to premature dielectric breakdown.
Innovation Solution
A resin composition for power cable insulation layers containing polyethylene with controlled methine, methylene, and methyl group ratios, suppressing electrical treeing by ensuring RX ≤ 5, 0.05 ≤ RX, and 0.8 ≤ X/Z ≤ 1.2, and optionally including an inorganic filler to manage space charge accumulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If polyethylene is used as base resin for insulation layer, then the insulation layer can be formed, but local electrical treeing occurs due to foreign matter leading to dielectric breakdown
Solution Approach 1:
The patent changes the chemical composition parameters of polyethylene by controlling the ratio of methine groups to total groups (X/(X+Y+Z)) to be 0.05 or more and less than 0.15, and the ratio of methine to methyl groups (X/Z) to be 0.8 or more and 1.2 or less. These parameter changes suppress electrical treeing initiation and improve insulating reliability without requiring additional additives or complex structures.
2Reliability
If conventional polyethylene composition is used, then manufacturing is simple, but DC breakdown electric field strength is insufficient to suppress dielectric breakdown
Solution Approach 1:
The patent specifies precise compositional parameters: methine group ratio X/(X+Y+Z) between 0.05 and 0.15, and X/Z ratio between 0.8 and 1.2. These parameter ranges achieve DC breakdown electric field strength of 100 kV/mm or more while maintaining manufacturing feasibility through standard polyethylene production processes.
Solution Approach 2:
The patent focuses on controlling the local chemical structure at the molecular level (methine group distribution and ratio) to achieve superior electrical properties. This local quality control at the molecular scale translates to macroscopic improvement in breakdown strength and suppression of electrical treeing.
3Reliability
If space charge accumulates under DC electric field, then insulation performance deteriorates, but adding inorganic filler increases manufacturing complexity
Solution Approach 1:
The patent achieves space charge suppression through intrinsic molecular structure modification of polyethylene (controlling methine group ratios) rather than adding inorganic fillers. This approach eliminates the need for complex composite formulations while achieving the desired electrical performance and space charge management.
Data Source
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AI summary
A resin composition for forming an insulation layer of a power cable contains polyethylene. The polyethylene includes methine groups, and satisfies formula (1): RX≤5 in a 13C nuclear magnetic resonance spectrum. Here, RX satisfies RX={X/(X+Y+Z)}×100, and X, Y, and Z respectively represent an integrated intensity of methine groups, an integrated intensity of methylene groups, and an integrated intensity of methyl groups in the 13C nuclear magnetic resonance spectrum of the polyethylene.