High-Throughput Compatibility Screening of Materials for SF₆-Alternative Insulation

Area of Science:

• Materials Science
• Environmental Science
• Electrical Engineering

Background:

• Sulfur hexafluoride (SF6) is a potent greenhouse gas used in gas-insulated equipment (GIE).
• Developing SF6 alternatives with lower global warming potentials (GWPs) is crucial for environmental sustainability.
• Ensuring material compatibility is essential for the safe and reliable operation of GIE with new gas mixtures.

Purpose of the Study:

• To conduct a high-throughput screening of common GIE materials for compatibility with C4F7N/CO2 gas mixtures.
• To identify the primary causes of material incompatibility with SF6 alternatives.
• To propose and validate mitigation strategies for enhancing material compatibility.

Main Methods:

• Periodic monitoring of insulation performance of C4F7N/CO2 gas mixtures during thermal aging with various GIE materials.
• Identification of incompatible materials and subsequent mechanism studies.
• Development and validation of mitigation strategies targeting material acidity.

Main Results:

• Material acidity was identified as the primary cause of incompatibility between C4F7N/CO2 mixtures and GIE materials.
• The study screened tens of materials including desiccants, rubber, plastics, composites, ceramics, and metals.
• Validated mitigation strategies were developed to address material acidity issues.

Conclusions:

• Material acidity is a critical factor in the compatibility of C4F7N/CO2 gas mixtures with GIE.
• The findings provide essential insights for selecting and designing materials for future eco-friendly GIE.
• The study offers validated mitigation strategies for overcoming material incompatibility challenges with SF6 alternatives.