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Due to the greenhouse effect of SF6, the search for new environmentally friendly substitute gases has become an urgent task for the electrical industry. In this article, we have employed a 2-D fluid model to study the characteristic of streamer discharges in the C4F7N-N2 mixture. The discharge process and insulation performance of the C4F7N-N2 mixture with different C4F7N content are compared under the same conditions. In a5.07% C4F7N-N2 mixture, the streamer expands continuously and reaches the top boundary quickly. In 7% and 13.1% C4F7N-N2 mixture, the streamer is gradually stagnated in the simulation domain. The streamer radius shows a decreasing trend, and a low electron density area appears behind the streamer head as the streamer moves forward. The streamer discharge simulation in 50% SF6–50% N2 is also performed to compare its insulation performance to the C4F7N-N2 mixture. The results show that the discharge is suppressed more heavily in 13.1% C4F7N-N2 than in 50% SF6–50% N2. The influence of buffer gas is studied by comparing the discharge process in C4F7N-N2 and C4F7N-CO2 with 13.1% C4F7N content. It is found that the discharge is more easily to a breakdown in C4F7N-CO2 than that in C4F7N-N2 in our simulation configuration. The simulation provides a way to optimizing the buffer gas ratio of new environmentally friendly gases from a microscopic perspective. [ABSTRACT FROM AUTHOR]

An improved model for the motion dynamics of a metallic particle located in the non‐uniform electric field area in the gas insulated system is proposed. To represent the special area, a diverging conducting electrode is used in this study. Based on the fluid mechanics theory, the forces imposed on metallic particle are first developed. The motion process is then divided into two modes, i.e. the particle rolls on the electrode surface and moves in the gap. The collision and reflection processes between the particle and the electrode are crucial to the motion, and they are fully considered in the proposed model. The trajectory of the particle under different voltages is obtained. The evolution of metallic particle is divided into four stages, and it is featured by four quantities, i.e. the critical jumping point, the minimum horizontal position, the falling point, and the motion time. The characteristics for each stage are analysed, and the sensitivity analysis of the quantities are performed. The impacts of the applied voltage, the particle radius, the initial position etc. are discussed. The results provide guidance for particle trap design. [ABSTRACT FROM AUTHOR]

[Display omitted] • Develop an electrically assisted stereolithography 3D printing strategy to manufacture BaTiO 3 -resin composites with graded permittivity. • Optimize the printing parameters (e.g. , resin formulation, exposure time, the driven electric field strength and duration) to fabricate high-loaded BaTiO 3 -filled composites. • As proof of concept, an encapsulation component with graded permittivity and adaptive insulating properties for IGBTs was fabricated. Insulated gate bipolar transistors (IGBTs) find applications in diverse fields, such as integrated motor drives, controllable power systems, and electric vehicles. However, traditional IGBT encapsulation materials are unsuitable for high-voltage applications due to the excessive electric field stress generated at the triple junction; an insulation-enhanced encapsulation material is therefore necessary. Here, using an electrically assisted stereolithography (SLA) 3D printing strategy, we fabricate an encapsulation material with graded permittivity that can uniform the electric field stress distribution in IGBTs. Compared with pure resin and uniform-dispersed BaTiO 3 -resin composite encapsulation, the graded BaTiO 3 -resin composite reduces the generated maximum electric field stress (E m a x ) from 190.2 to 108.3 kV/mm (nearly a 50% decrease). Regarding the partial discharge inception voltage, the devices packaged with graded BaTiO 3 -resin composite (4.07 kV) also performed better than devices packaged with resin (1.96 kV) and uniform-dispersed BaTiO 3 -resin composite (2.51 kV). This novel electrically assisted SLA 3D printing strategy will open a new window for the in-situ encapsulation of IGBTs and other microelectronics. [ABSTRACT FROM AUTHOR]

With the development of smart grids, efficient condition monitoring of high voltage transmission system has become crucial, necessitating reliable power supplies for distributed sensors. Traditional energy harvesters often focus on either internal or external sources, limiting overall efficiency. This study introduces a triboelectric‐electromagnetic‐electric field hybrid energy harvester (TEE‐HEH) that synergistically integrates triboelectric nanogenerators (TENGs), electromagnetic generators (EMGs), and electric field energy harvesters (EEHs) to simultaneously capture electric field and wind energy. Electric field energy is harvested via displacement currents between transmission lines and the ground, while TENGs and EMGs efficiently capture low‐ and high‐speed wind energy, respectively, enabling broadband harvesting (2.3–10 m s−1). The synergistic combination of TENG, EMG, and EEH within the TEE‐HEH leads to significantly enhanced energy capture efficiency from multiple sources. At a wind speed of 5 m s−1, a transmission line voltage of 25 kV, and a distance of 1.5 m, the TEE‐HEH achieved peak power outputs of 18.5 mW (TENG), 262 mW (EMG), and 1.85 mW (EEH), demonstrating enhanced energy collection efficiency. An environmental monitoring system has been powered, demonstrating the TEE‐HEH's practicality for dual‐source energy harvesting in smart grid applications. [ABSTRACT FROM AUTHOR]

[Display omitted] • The intrinsic mechanism of the external electric field effects on the N 2 adsorption and NN* dissociation performances of three-atom transition metal clusters (TATMCs) is investigated. • Electric fields regulate the charge transfer between TATMCs and NN*, thus affecting the N−N bond activation. • The ICOHP values of two N atoms and E N are not limited by the linear relationship under different electric fields. Three-atom transition metal clusters (TATMCs) with remarkable catalytic activities, especially Nb 3 , Zr 3 , and Y 3 , are proven to be suitable candidates for efficient ammonia production. The pursuit of effective strategies to further promote the ammonia synthesis performance of TATMCs is necessary. In this study, we systematically investigate the effect of external electric fields on tuning the N 2 adsorption and NN* activation performances of Nb 3 , Zr 3 , and Y 3. Our findings demonstrate that the medium and low positive fields promote the N 2 adsorption performance of Nb 3 , while both positive and negative fields enhance nitrogen adsorption on Zr 3. Additionally, electric fields may impede N 2 fixation on Y 3 , yet the N 2 adsorption performance of Y 3 remains considerable. Negative electric fields enhance the NN* activation performance of Nb 3 and Y 3. But only high negative fields weaken the N N bond on Zr 3 , which is attributed to the promotion of the charge accumulation around two N atoms. Notably, Nb 3 and Zr 3 are identified as two TATMCs with the potential for simultaneous optimization of their E N and ICOHP values. This work sheds light on the field effects on the N 2 adsorption and NN* activation performances of TATMCs and guides the design of catalysts for achieving more sustainable ammonia synthesis. [ABSTRACT FROM AUTHOR]

In damp and salt-fog environments, silicone rubber composite insulators are prone to forming dispersed droplets that absorb airborne salt nuclei, leading to charge accumulation and potentially causing flashovers that threaten transmission line stability. Regrettably, these concerns have not yet received sufficient attention from relevant researchers. This study examines the surface charge accumulation and flashover characteristics of silicone rubber insulators with droplets of varying electrical conductivity. The droplets can fix charges, as the conductivity of droplets on insulator surfaces increases, the migration rate of surface charges accelerates, causing distortion of the electric field and a significant increase the area of high-density charge regions on the sample surface. Compared with dry surfaces, increasing the equivalent salt density of salt-containing droplets attached to the surface from mild to severe (with conductivity increasing from 800 μS/cm to 2800 μS/cm) leads to a 25 %-40 % increase in the average surface charge density. After adsorbing charges, the salt droplets shorten the discharge development path, making it easier to trigger interface discharge. Compared with dry surfaces, the average flashover voltage of the salt droplets is reduced by at least 30 %. This study offers valuable analysis on charge accumulation and flashover for silicone rubber insulators in salt-fog environments. [Display omitted] [ABSTRACT FROM AUTHOR]