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Particles will aggregate in the presence of dense mist in the wet electrostatic precipitator (WESP), and larger size particles with changed distribution make discharge more significant. This article puts forward the simulation of corona discharge with the existence of particle aggregation effect, which shows the characteristics of electron density distribution during the propagation. Besides, we also provide propagation patterns of branching and quenching phenomenon of plasma channels in the presence of particle aggregation. The results indicate that particle aggregation will considerably influence the plasma patterns. When the electron avalanche reaches the particle distributing areas, there will be several plasma channels formed and a narrow diffusion radius around the aggregated particles. When particles gather around the electrode, which means dense particle distribution, corona quenching happens with dense particle distribution. [ABSTRACT FROM AUTHOR]

The SF6 gap switch has obvious advantages in the flexible control very fast switch of the controllable arrester used in hybrid UHVDC system. However, the plasma jet ability in SF6 atmosphere at high pressure is greatly restricted, which is easy to cause trigger failure. The triggering characteristics and induced breakdown mechanism are still unclear during the plasma jet-triggered process of the SF6 gap switch at extremely low working voltage. In this study, a plasma jet-induced breakdown research platform based on two-stage continuous surface-triggered gas gap switch (GGS) was established to investigate time-space distribution evolution characteristics, the critical triggering conditions parameters, and working voltage functioning rules of the SF6 gap. The jet plasma has a high-brightness-like conical shape, and its initial jet velocity can reach more than 2 km/s. Increasing capacitance value and charging voltage of the secondary chamber in SF6 gap switch trigger cavity, its creeping arc current is increased, and the time delay and dispersion will be reduced. Moreover, the geometric characteristics (including jet area, jet radial and axial length, and jet velocity) and electrical parameters of the jet plasma increase gradually. Increasing the working voltage of main gap in SF6 gap switch, the plasma jet velocity lift phenomenon appears at induced breakdown end of SF6 gap switch. With the continuous increase of the working voltage, the lift effect is more significant. The purpose of this study is to solve the key problem of plasma-induced breakdown failure of the SF6 gap switch, which will guide the design of fast self-recovery energy discharge protection switches for hybrid UHVDC transmission systems. [ABSTRACT FROM AUTHOR]