Simulation Of Contamination Deposition Characteristics On Typical Porcelain Insulators

Typical porcelain insulators are widely used in power transmission lines due to their self-cleaning properties,higher pollution-resistant voltage and less deposit amount under the same conditions.In recent years,the problems of wet deposition,brought by frequent haze environment,not only increased the amount of pollutants on the insulator surface,the properties of higher humidity also created the conditions for the occurrence of pollution-induced flashover accidents.Therefore,as the premise of the accident,it is of great practical significance to research the contamination deposition characteristics of typical porcelain insulators under haze environment.The forces which particles subjected to in their movement and collision adhesion process were analyzed,and the calculation method of air parameters,adhesion force and friction force in the humidity environment were discussed,and also the calculation method of surface energy.The wind tunnel test of typical porcelain insulators in our school were briefly described,and a corresponding physical model of wind tunnel pollution accumulation was established.The original pollution particle deposition model based on energy was optimized in a progressive manner from the perspectives of relative humidity and surface energy,and compared with the experimental results to reduce the relative error between the simulation results and the test results.The particle deposition optimization model was verified and obtained.Therefore,using the optimized model finally obtained,the difference on contamination deposition characteristics of the porcelain double umbrella insulators in non-haze and haze environments were simulated.Besides,the impacts of individual factors and multi-factors such as voltage type,wind speed,particle size,relative humidity,and contamination concentrations on the natural contamination characteristics of insulators were analyzed in the 110kV transmission lines.The results show that:1)Based on the simulation results of the humidity and surface energy models,the average relative error between the simulated results and the corresponding wind tunnel test results can be decreased by 41.83%and 15.46%on the basis of the previous step,and the error between the final optimized simulation results and test results can be reduced to 12.18%.The trend of the simulated results with the DC voltage is more similar to the experimental results,which verifies the rationality of the optimization model.2)Based on this optimized model eventually,in the non-haze environment,the porcelain double umbrella insulators has the largest deposit amount under DC voltage when the other conditions are the same.Besides,when the wind speed is less than 2m/s,the NSDD under unelectrified state is larger than that under AC voltage.However,when the wind speed was larger??2.5m/s?,the NSDD is smallest under unelectrified state.3)Under different wind speed conditions,the NSDD_DC/NSDD_ACC increased with the increase of particle size.When the particle size was different,the NSDD_DC/NSDD_AC decreased with the increase of wind speed.That is,greater the wind speed,the less difference of NSDD between DC voltage and AC voltage.4)In the non-haze environment,the NSDD under the DC voltage reaches the minimum at 2m/s,and the NSDD under AC voltage increases with the increase of wind speed,while under unelectrified state,the NSDD reaches the extreme value at the wind speed of 1.5m/s.5)Under the same conditions,the NSDD under haze environment is larger than that under un-haze environment,and the impact of polluting environment on AC transmission lines is greater than that of DC transmission lines.6)Under haze environment,with the increase of particle size and under DC voltage,the intersection wind speed gradually decreases or even disappears when the NSDD of the upper and lower surface of the insulator reaches the same level.7)Under the same conditions,the effects of wind speed on the NSDD_DC/NSDD_AC were similar and almost the same under the mild?i.e.the contamination concentration of 0.15mg/m³?and severe pollution?i.e.the contamination concentration of 0.45mg/m³?.8)When the humidity is 20%⁵0%and the other conditions are the same,the increase amount and the growth rate of the NSDD under the DC voltage are greater than that under the humidity of 50%⁸0%,while the change trend under the AC voltage is the opposite.