Siloxane-Based Nanoporous Polymer Insulating Dielectrics With High Electrical Strength and Low Permittivity for Future Ultrahigh Voltage Pipeline Transmission

Abstract

The operating gas-insulated transmission line (GIL) equipment is typically associated with some challenges, such as high insulation failure rate, severe greenhouse effect, and large space occupation. Thus, compact and environmentally friendly GIL equipment with high electrical performance is particularly desired for ultra-high voltage (UHV) pipeline transmission equipment. Nanocomposite technology, as a conventional method for improving the electrical performance of insulating materials, such as epoxy resin (EP), which is the base material used in basin-type insulators in GIL, has been proven nonviable because of the limited increases in the dielectric properties. Inspired by the singularity phenomenon recently reported that nanostructures inhibit electron multiplication transport in gas to enhance the breakdown field strength of dielectric, a siloxane-based nanoporous polymer insulating dielectric (SNPID) with nanoscale pore structure was developed, with high breakdown field strength 1111.34% greater than the surface flashover field strength of basin-type insulators in GIL. Specifically, the SNPID exhibits excellent dielectric properties, with low dielectric loss and a permittivity value of <2, which is significantly lower than those of existing insulating materials. Finally, to demonstrate the application prospects of the SNPID in a GIL, a SNPID filling-type GIL scaling model was designed, with an insulation level of 358.09% higher than that of basin-type insulators in GIL, which could significantly reduce greenhouse gas sulfur hexafluoride (SF <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">6</sub> ) emissions by markedly decreasing the pipeline volume. This discovery provides a new gas-solid composite insulation form based on super-insulating material with high breakdown field strength and low permittivity for improving the insulation of UHV pipeline transmission equipment in response to the greenhouse effect.