Effects Of Simulated Haze Environment On External Overhead Line Insulation And Design Of Monitoring System

With the rapid development of China’s urbanization and industry， the hazephenomenon becomes more and more serious. Most of haze frequently occurrence areasare important power transmission corridor or high-load areas. Flashover incidents causedby haze will affect a wide range of users, and lead to a long time failure of power as wellas huge losses to national economy. In this paper, according to the impact of haze on theexternal insulation of transmission lines, spray, salt fog, acid fog environment aresimulated to carry out the experiments of rod-plate gap and discharge characteristics ofartificial contamination insulator, and haze monitoring methods are explored.An artificial fog chamber is constructed to provide spray, salt fog, acid fog and otherfog environment, and experiments for discharge characteristics of rod-plate gap andartificial contamination insulator are carried out. The results of the experiments show thatfog has great influence on the nod-plate gap and the discharge voltage of insulatorflashover. Fog can improve the breakdown voltage in small gap distance, but as the gapdistance increases, it can slightly decrease the breakdown voltage. Both of salt fog andacid fog can reduce the insulator flashover voltage, and the effect of acid fog is muchmore significant.Based on the experimental study, the discharge model of nod-plate gap under hazeenvironment is established. By using finite element analysis method to calculate thedistribution of space electric field, the impact of fog particles on the distortion of spaceelectric field is obtained. The effect mechanism of haze particles on the distortion ofspace electric field and space charge is put forward. This mechanism’s influence on thedischarge process of haze and the reasons why it can affect the breakdown voltage areanalyzed.On the basis of experiments and theoretical analysis above, real-time monitoring method of haze based on capacitive and current parameters is proposed. Experiments arecarried out to study the correlation between the capacitive and current parameters anddischarge characteristics of simulated haze. Founded on the data of a large number ofcorrelation experiments, the haze monitoring system is designed and the initial hazewarning value is set. This system uses solar power and GSM wireless networktechnology, which permit a long-term outdoor operation and the transfer and record ofmonitoring data. When the monitoring data exceeds the warning value, the system willissue an early warning, which ensures that the relevant departments can take timelyprecautionary measures to prevent the haze filthy discharge incidents of transmissionlines. Thus the security and stability of transmission line are improved.