Hydrodynamics-based Contamination Depositing Characteristics Research Of Suspension Insulator String

Contamination flashover is the main danger of the safe operation on the power system. Research on insulator pollution characteristics make us take measures to effectively reduce the occurrence of flashover after realizing contamination state in a variety of harsh weather conditions. Pollution is the hydrodynamics process of contamination particles impingement on composite insulator. While researchers at home and abroad have used a variety of artificial means analysis of insulator pollution characteristics, but they did not use of computational fluid dynamics analysis to analysis pollution characteristics. In this paper, CFD technology is taken to numerically simulate the external flow of suspension insulators in the contamination process, and to calculate contamination particle characteristics impacting on types of suspension insulators, which could make the choice of suspension insulators according to climate conditions and degree of contamination and other types of contamination factors.In this paper, the author analyzed the insulator of the contamination process and boundary layer separation and flow inclination on the contamination of insulators. Based on computational fluid dynamics methods and simulation software FLUENT, a suitable numerical simulation methods was established, which gave the swirling flow using RNG k-turbulence model of air flow field numerical calculation. By analyzing the mechanical properties of particles, the author tracked contamination particles trajectory with the Particle Trajectory Model of Lagrangian Coordinates. And taking into account the spread of turbulent pulsations on the particle effects, the collision coefficient of insulator surface contamination was obtained. On the basis of flow-field around insulators, the effects of free stream velocity(v), diameter of particles(dP), angle of the free stream on contamination depositing characteristics were investigated. Finally, based on insulator pollution Experimental Study at home and abroad, the author verified the simulation result, and obtained the Insulator choice law in designing power lines.Thesis shows that the insulator surface pollution process has matter with Brownian motion, the air drag force, turbulent diffusion, gravity. One weak wind conditions, surface pollution mainly related to Brownian motion and turbulent diffusion, under strong wind mainly associated with the air drag force. Overall, the insulator surface pollution process mainly matters with particle size and flow related to wind angle. The greater the contamination particle size, the greater the collision coefficient of the insulator upper surface. The greater the wind angle, the greater the impact coefficient of the insulator down surface. Although the increase of wind speed can lead to the accretion of the collision coefficient, but the effect is not large, relatively slow growth of the collision factor. Compared with three types of insulators, although the double-umbrella-type insulators XWP-160 has better flow linearity, with smaller collision coefficient in the horizontal stream, due to its relatively compact characteristic between the insulators, the whole surface of the bell-type insulator has the smallest collision coefficient in the non-horizontal stream.Due to the role of rain washing, the contamination circumstance in down surface of insulators is more serious than upper surface. So as far as possible the designers should avoid the area which products non-horizontal stream, such as mountains with high attitude and seaside, or choose composite insulators with a simple structure, when designing power circuit.The results of the research have an important reference value on the further analysis of suspension insulators'pollution characteristics and the design or insulators.