Natural rubber (NR) composites have been widely applied in damping products to reduce harmful vibrations, while rubber with only a single composition barely meets performance requirements. In this study, rubber blend composites including various ratios of NR and styrene butadiene rubber (SBR) were prepared via the conventional mechanical blending method. The effects of the rubber components on the compression set, compression fatigue temperature rising and the thermal oxidative aging properties of the NR/SBR blend composites were investigated. Meanwhile, the dynamic mechanical thermal analyzer and rubber processing analyzer were used to characterize the dynamic viscoelasticity of the NR/SBR blend composites. It was shown that, with the increase in the SBR ratio, the vulcanization rate of the composites increased significantly, while the compression fatigue temperature rising of the composites decreased gradually from 47 °C (0% SBR ratio) to 31 °C (50% SBR ratio). The compression set of the composites remained at ~33% when the SBR ratio was no more than 20%, and increased gradually when the SBR ratio was more than 20%.

Operation data show lightning faults account for >70% for the main ultra‐high voltage (UHV) DC transmission channels, very different from the design view. In order to accurately master the lightning characteristics and the lightning protection performance of the line so as to propose solutions to weak points, this study firstly obtains and analyses the density and strength distributions of lightning risk source. Then the study proposes a set of risk assessment process where the key model electrogeometric model is improved according to the polarity effect of DC line. Then the work realises the calculation of the lightning shielding failure risk of single tower and whole line. The example shows the assessment result is consistent to the line's actual operation. Next, to further evaluate and predict the lightning risk in real time, the study adopts the backpropagation neural network algorithm to integrate the lightning detection data, atmospheric electric fields, and radar echoes to develop the early warning model of lightning risk source, and proposed a method to realise the early warning of lightning damage risk for UHV DC channels. The results show that the effective warning ratio is 73% and the failure‐to‐warn ratio is 27% which indicates very good application effects.

The deep dielectric charging of the slip ring assembly caused by high-energy electron radiation leads to the failure of the solar array drive assembly (SADA), which accelerates the failure of the whole satellite. It is necessary to optimize the structure of the slip ring assembly according to the deep dielectric charging characteristics to reduce the risk of discharge accidents. In this article, based on the law of current conservation, a 3-D simulation model for deep charging of slip ring assembly is established by combining Geant4 with COMSOL. Under the FLUMIC3 electron radiation environment, the essential characteristics of the electric field and potential distributions in the slip ring assembly are studied. Based on these, optimization schemes for aluminum shielding structures, insulation baffles, and ground structures are proposed. The simulation results show that the simultaneous use of the three proposed optimization schemes can significantly reduce the electric field distortion caused by high-energy electron radiation, and the maximum reduction is about 70%. At the same time, the overall quality of the aluminum shield and the basic structure of the slip ring assembly can be maintained. It provides specific references for the actual design of slip ring assembly in SADA.

Gas-insulated equipment such as GIS (Gas-Insulated Substation) and GIL (Gas-Insulated transmission lines) faces critical insulation failure challenges caused by particles inside. However, the particle traps, as key devices available to inhibit the movement of particles, lack theoretical basis and quantitative methodology for trap design especially with high voltage ratings. In this paper, a particle motion excitation and observation platform is established to physically simulate the actual online operating conditions of HVAC/HVDC GIS/GIL and study the capture mechanism of particle traps. Experimental results illustrate that, the collision motion style is a principal factor to affect the particle capturing capability, and the capture behavior of AC and DC particle traps can be classified into three separate modes, depending on variation of the collision process which can be characterized by random probability and the lognormal distribution rebound angle. A particle trajectory simulation model incorporating motion randomness is thereby presented to realize quantitative analysis and further optimize the trap parameters. A hazard index and minimum collision times are defined and calculated to quantitatively evaluate the particle collision effect on trapping capability. Further, a novel trap design topology is proposed to enhance the anti-motion efficiency of the particle traps. Targeted at high objective capture probability, the particle trap parameters are optimized to reduce the hazard index and improve the minimum collision times by the Monte Carlo scheme. The obtained results indicated that, the capture probability of AC traps can reach 86.5% at a gap spacing of 5 mm, while that of DC traps can reach 74.1% with an 8 mm-width slot and a 50-degree inclination angle. Verification of the novel article trap is implemented on a test rig, which gives an increased capture probability by 30% compared with the traditional trap design. The proposed new trap topology and corresponding methodology present quantitative guidance for particle traps optimization and render application potential for different voltage levels.

High temperature tends to be one principal failure cause of silicone gel package insulation in high-power electronic devices, even leading to equipment damage under severe conditions. To clarify the aging characteristics and failure mechanism of silicone gel package insulation of high-power IGBT devices under the high-temperature scenario, this paper carries out experiments on silicone gel material samples by accelerated thermal aging procedures at 200 ℃. The experimental results show that temperature has a significant effect on the physicochemical properties of silicone gel. Further, molecular dynamics simulations are conducted to verify the high-temperature degradation characteristics of the gel. Finding the main cause of silicone gel package insulation failure under high-temperature is the random degradation of the silicone backbone into small molecule cyclosiloxanes. Finally, the Lifetime assessment model was established based on the pyrolysis kinetics and insulation failure mechanism. The unaged silicone gel's pyrolysis activation energy and insulation failure temperature were measured at 125.8 kJ/mol and 453°C, respectively. The evaluation results show that the package insulation life decreases by about 60% for every 10°C increase in temperature. The above achievement of this study presents a theoretical and methodological basis for reliable assessment of the insulation status of silicone gel package insulation for high-power electronic devices under high-temperature.