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This paper describes the addition of ZnO nanoparticles to epoxy resin at concentrations of 20, 25, and 30wt%, and the application of this ZnO/epoxy coating to the surface of an epoxy insulator. This coating significantly suppresses the charge accumulation on the surface of the insulator, reduces the number of charge speckles, and increases the flashover voltage. These effects are enhanced as the doping concentration of ZnO nanoparticles increases. Through isothermal surface potential decay tests, we find that the ZnO/epoxy coating introduces numerous shallow traps, which help to dissipate the surface charge. Analysis shows that the ZnO/epoxy coating promotes surface charge dissipation through its nonlinear conductivity. The nonlinear characteristics of the 30wt%-doped samples are 55.3% greater than those of the 20wt%-doped samples. The coating adapts to the external electric field and can achieve the effect of a uniform electric field. This article analyzes the feasibility of using ZnO/epoxy coatings to suppress the accumulation of charge on insulator surfaces, and provides a feasible solution for practical engineering applications. [ABSTRACT FROM AUTHOR]

In an HVDC gas-insulated system, the surface of the insulator accumulates electric charges that distort the surface electric field and reduce the flashover voltage. Therefore, it is crucial to find a material that can effectively suppress the surface charge accumulation. In this work, MXene, a two-dimensional nanomaterial, is doped into an epoxy resin at different concentrations. By doping a small amount of MXene (30ppm), the resistivity of the composite is improved by about 4 times compared to pure epoxy resin. At the same time, the trap level of deep traps increases to 1.07 from 1.04 eV of pure epoxy. Measuring the surface potential of the insulator and using an inversion algorithm to calculate the surface charge establishes that a doping level of 30 ppm of MXene effectively suppresses the accumulation of the surface charge of the insulator, which is only about 1/3 of that of the pure epoxy resin. The surface flashover voltage is also increased by 10%. However, when the doping amount of MXene is increased to 100 or 150 ppm, the insulation performance is lowered. We used a potential barrier model to explain the effect of MXene doping in the epoxy resin. This work presents a possible way to suppress the charge accumulation on the surface of insulators in HVDC gas-insulated systems and provides a link between the microstructure and the macroscopic properties in the material. [ABSTRACT FROM AUTHOR]

This paper proposes a method for controlling and extracting the truncated phase of AC voltage. Combined with surface potential measurement based on the active electrostatic probe and the inversion algorithm, charge accumulation on the insulator surface is obtained under various electrode configurations and AC voltage. Simulation and experimental results show that the active electrostatic probe method not only provides high measurement accuracy but also has an insignificant effect on the measured electric field. By combining the characteristics of surface charge distribution with the truncated phase of AC voltage, the off-line charge measurement results can be integrated with the microscopic discharge process, to overcome the drawbacks of the traditional off-line measurement method. Thus, we can gain a better understanding of the dynamic process of charge distribution under AC voltage. In addition, the accuracy and reliability of the inversion algorithm are verified using the dust figure method. [ABSTRACT FROM AUTHOR]