Study On The Contamination Deposition Characteristics Of Insulators With Typical Sheds Based On Computational Fluid Dynamics

Flashover accidents of transmission lines greatly threaten the safety and stability of power system. In order to decrease the flashover accidents, it is necessary to study the characteristics of insulator contamination and find the regularity of insulator contamination. Most of the existing researches are based on the natural contamination test and wind tunnel contamination test. These two methods have disadvantages of long test period and poor controllability. The rapid development of computational fluid dynamics(CFD) makes it possible to study the contamination characteristics of insulators based on CFD calculation. The current studies of insulator contamination based on fluid mechanics simulation are not comprehensive enough, and the combined analysis of simulation and test is less. In this paper, the gas-solid two-phase flow calculation method of CFD theory is adopted to study the contamination characteristics of typical insulators. Moreover, a wind tunnel test platform for insulator contamination is constructed to test the rationality of simulation results.In this paper, the 1:1 full sized insulator model is used in the simulation process. Flow field around insulators is calculated based on the Eulerian two-phase flow method by the CFD software Fluent. In the calculation of turbulent flow, the RNG k- ?turbulence model which has a higher precision than the standard model is used considering the complex structure of insulators. In the post processing, the static pressure on the insulator surface and velocity vectors around the insulator are extracted, and the contamination degree is characterized by the volume fraction of particles on insulator surface. The influence of wind velocity, particle concentration, particle diameter, flow angle and insulator type are studied and the nonuniform distribution of contamination is discussed.Research shows that the contamination deposition on insulators is greatly influenced by flow field around insulators and the forces acting on particles. The contamination distributed on the insulator surface is nonuniform. The windward and leeward side are heavy contaminated and the crosswind side is slightly contaminated. The increase of wind velocity leads to the intense particle collision and serious turbulence at the back of insulator cap. And hence, the pollution degree increases with the increasing of wind velocity, and it varies with the insulator types. The particle concentration influence the severity of contamination greatly and contamination can be serious at a high particle concentration. Particle diameter is another factor that mainly influence particle trajectory in the flow field. With increase of particle size, the forces acting on the particles vary a lot especially the gravity. And the contamination of insulator's bottom surface will have a reduction. The flow angle influences pollution distribution greatly. The simulation results displays the differences of the insulator contamination on different flow angles. Results in this study reveal the characteristics of insulator contamination influenced by different factors, and provide reference for pollution prevention and pollution monitoring of transmission line insulators.