Mg(OH)2 Core MgO Shell Filler for DC Cable Insulation
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Solution Overview
Problem
The degradation of DC characteristics in the insulation layer of DC power cables due to long-term water immersion, caused by the conversion of MgO to Mg(OH)2, which reduces the ability to trap space charges and leads to local accumulation and degradation of insulation properties.
Innovation Solution
A resin composition with a core part containing Mg(OH)2 and a covering part of MgO particles, where the volume fraction of Mg(OH)2 is 10-50% and the content of the inorganic filler is 0.1-5 parts by mass per 100 parts of base resin, forming fine irregularities on the surface to delay water-induced conversion and maintain space charge trapping ability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If MgO is added to the resin composition to suppress space charge accumulation, then DC characteristics are improved, but long-term water resistance deteriorates due to conversion to Mg(OH)2
Solution Approach 1:
The inorganic filler is segmented into a core part containing Mg(OH)2 and a covering part containing MgO particles. This segmentation allows the inner core to provide space charge trapping ability while the outer MgO covering protects it from water, preventing conversion and maintaining long-term stability.
Solution Approach 2:
The invention uses a composite inorganic filler structure combining Mg(OH)2 core and MgO shell. This composite material approach allows the filler to simultaneously possess the space charge trapping capability of Mg(OH)2 and the water resistance of MgO, resolving the contradiction between DC characteristics and long-term water resistance.
2Reliability
If MgO is used as inorganic filler to trap space charges, then volume resistivity is improved, but dielectric breakdown strength deteriorates after water immersion
Solution Approach 1:
The segmented structure with Mg(OH)2 core and MgO covering ensures that the Mg(OH)2 responsible for trapping space charges and maintaining volume resistivity is protected from water by the MgO shell, thereby preserving dielectric breakdown strength during long-term water immersion.
Solution Approach 2:
The MgO covering acts as an intermediary protective layer between the Mg(OH)2 core and water. It prevents water from reaching and converting the Mg(OH)2, thereby maintaining both volume resistivity and dielectric breakdown strength over time.
3Reliability
If inorganic filler content is increased to improve space charge trapping, then DC characteristics are enhanced, but manufacturing complexity increases
Solution Approach 1:
The inorganic filler adopts a nested structure where MgO particles are embedded on the surface of the Mg(OH)2 core. This nested configuration allows the filler to achieve effective space charge trapping with optimized composition, reducing the need for excessive filler content and simplifying the overall manufacturing process.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The configuration effectively suppresses degradation in DC characteristics by maintaining space charge trapping efficiency and improving long-term water resistance, ensuring high volume resistivity and dielectric breakdown strength even after prolonged water exposure.
Implementation Method 1
forming fine irregularities on the surface to delay water-induced conversion
Implementation Method 2
a core part containing Mg(OH)2
Implementation Method 3
a covering part containing a plurality of MgO particles provided on an outer periphery of the core part
Data Source
AI summary
A resin composition including a base resin containing polyolefin, and an inorganic filler, wherein the inorganic filler includes: a core part containing Mg(OH)2, and a covering part containing a plurality of MgO particles provided on an outer periphery of the core part, the content of the inorganic filler in the resin composition is 0.1 parts by mass or more and 5 parts by mass or less with respect to 100 parts by mass of the base resin; and a volume fraction of Mg(OH)2 in one particle of the inorganic filler is 10% or more and less than 50%.