The surface voltage resistance of insulating materials is closely related to their surface electrical parameters, such as surface resistance, leakage current, surface electric field distribution, and surface charge dissipation rate. The electrical performance parameters mentioned above are directly affected by the physical morphology, chemical composition, and other characteristic parameters of the material surface. For example, the roughness of the insulating surface will change the electron creepage distance, and the chemical composition of the insulating surface will change the trap energy level distribution. Therefore, surface treatment of insulation can change its surface physicochemical properties without affecting the performance of the insulation body, in order to optimize and regulate the electrical properties of the insulation surface. At present, the main methods for modifying insulation surfaces include physical polishing, surface coating, vacuum fluorination, electron beam irradiation, low-temperature plasma, etc. Compared with other methods, atmospheric pressure low-temperature plasma technology, as a cross disciplinary research direction in the field of discharge plasma and high-voltage insulation, has unique advantages in surface treatment and modification improvement of insulation materials. Under the excitation of a power source, neutral gas molecules are ionized to form a large number of active particles, such as Ar*(11.5~11.7eV)、He*(19.8~20.6eV)、N2+(X)(15.63eV) And its energy is higher than the chemical bond energy on the surface of typical insulation materials (C-H: 4.29eV; C-O: 3.0eV). Therefore, when plasma acts on the material surface, it can open the chemical bonds on the material surface and simultaneously trigger physical and chemical reactions, achieving modification effects at the nanometer to micrometer level without affecting the material's intrinsic properties. Specifically, by changing the parameters of the working gas, reaction medium, driving power supply, reactor, etc., the distribution of plasma active particles and the physical and chemical reaction processes induced by them can be adjusted, and the microstructure, chemical composition, and macroscopic dielectric properties of the material surface can be controlled, thereby achieving optimization and improvement of the electrical properties of the insulation surface. Compared with other methods, plasma technology has significant advantages: in terms of treatment effect, it can trigger physical and chemical reactions such as etching, activation, cross-linking, and deposition at the micro nano scale on the insulation surface, achieving an improvement in the comprehensive performance of the insulation surface; In terms of processing efficiency, plasma contains a large number of high-energy active particles, and minute level processing can change surface physicochemical properties, regulate surface properties, and facilitate large-scale insulation treatment; In terms of environmental friendliness, plasma technology is a typical dry process that uses air and inert gases as working gases, effectively avoiding environmental problems such as chemical reagent residue and harmful byproduct emissions.

Research on Plasma Modified Insulation Performance and Application

Plasma can change the micro physical and chemical properties of insulating materials through multi-level surface reactions, which in turn can alter the macro electrical properties of insulating surfaces. By establishing appropriate reaction conditions, plasma treatment can effectively improve the weather resistance and electrical resistance of insulation surfaces, and has also made new progress in damaged insulation repair, nanocomposite insulation synthesis, and metal electrode modification.

Surface hydrophilicity/hydrophobicity

Outdoor insulation materials are directly exposed to harsh working environments such as rainfall, condensation, and moisture intrusion. Therefore, external insulation needs to have excellent hydrophobic properties to ensure its weather resistance and operational reliability. By adding suitable reaction media in plasma, low surface energy thin films can be prepared through grafting, polymerization, cross-linking deposition, etc., or micro nano scale "lotus leaf shaped" rough structures can be constructed through etching, providing feasibility for regulating the surface wettability of insulation materials.

Surface flashover voltage

In high-voltage insulation systems, flashover usually causes serious damage to power equipment, and there is a significant correlation between flashover and surface charge transfer characteristics. Plasma surface modification can improve the surface insulation performance by altering the surface roughness, changing the electron creepage distance, and introducing chemical functional groups to regulate the trap distribution on the material surface.

Plasma modified nanocomposite insulation

In recent years, atmospheric pressure plasma has also shown great potential in modifying the surface of nanoparticles and optimizing the comprehensive electrical thermal mechanical properties of composite insulation. Plasma treatment of particles can improve the interfacial adhesion and wettability between powder and resin matrix by changing their surface chemical composition and physical morphology, increasing the polar functional groups and roughness of the surface, and enhancing the insulation performance of filled composite materials.

It is of great significance to develop new surface modification and performance improvement technologies for insulation materials in response to the practical demand for optimizing the comprehensive performance of surface electrical and weather resistance. Low temperature plasma technology has shown unique advantages in the field of material surface modification due to its high reactivity, controllable treatment effect, and green and pollution-free characteristics.