Comparative Study on Injection Molding and Performance of Glass Fiber-Reinforced PET and PA6 Thermoplastic Insulators

Area of Science:

• Materials Science
• Electrical Engineering
• Polymer Engineering

Background:

• Epoxy resin insulators are standard in ultra-high-voltage gas-insulated switchgear (GIS) and gas-insulated lines (GIL).
• The thermosetting nature of epoxy resin poses environmental challenges due to its non-recyclability.
• Thermoplastic insulators offer a recyclable alternative, addressing sustainability concerns in high-voltage equipment.

Purpose of the Study:

• To evaluate 30% glass fiber-reinforced PET and PA6 as potential thermoplastic alternatives for GIS/GIL insulators.
• To analyze their injection molding behavior, hydraulic pressure performance, and insulation characteristics.
• To provide processing insights and design guidance for thermoplastic insulator applications.

Main Methods:

• Injection molding simulations using Moldflow to optimize processing parameters (melt and mold temperatures).
• Coupled Moldflow-ANSYS simulations to assess hydraulic pressure performance under specified stress criteria.
• COMSOL simulations to analyze electric field distribution and inform insulator geometry optimization for SF₆ GIS/GIL.

Main Results:

• Optimal processing parameters were identified: PET (290°C melt, 120°C mold) and PA6 (250°C melt, 70°C mold).
• PA6 successfully met hydraulic pressure requirements (< 20 MPa insert-contact stress) within specific processing windows.
• PET consistently failed hydraulic pressure tests, with insert-contact stress exceeding the 20 MPa threshold under all conditions.

Conclusions:

• PA6 demonstrates viability as a thermoplastic insulator material for GIS/GIL applications based on its processing and hydraulic performance.
• PET, in its tested configuration, is unsuitable for high-voltage GIS/GIL applications requiring significant hydraulic pressure resistance.
• The study provides critical data for selecting and designing thermoplastic insulators, guiding the transition from traditional epoxy resins.