In recent years, the demand of electric power has enlarged considerably. To satisfy this demand, electrical companies have had to improve the efficiency of their transmission lines. Also, with the liberalization of electrical markets, the individual clients will have the possibility to choose the supplier companies that provide them a better quality of service.

 

The efficiency of the system is based mainly on the continuity of the service, avoiding faults that suppose economical losses for companies and users. To maintain this continuity, one of the main problems that have been found is the effect produced by pollution in the insulators of electric lines. This pollution is one of the main causes of flashover in the insulators. The insulator begins to fail when the pollutants that exist in the air settle in the surface of the insulator and combine with the humidity of the fog, rain, or dew. The mixture of pollutants, plus the humidity form a layer that can become conductor and allow passing currents that will facilitate the conditions of short circuit. This is due to a decrease of the resistance of the insulator surface. Unless there is a natural cleaning or an adequate maintenance, the electrical activity will be affected by a possible flashover in the insulator.

 

In other words, the pollution degrades the insulators and affects severely to their electric characteristics, being one of the main causes of mis ¤C operation of the insultors. Therefore, the electric companies should prevent the interruptions of the service, produced by insulators contaminated. 

Most of the methods of pollution control are based mainly in:

 

@Analyzing the severity of the pollution, that is to say, to establish !zones of pollution!

 

@Controlling the situation of the pollution on the insulators, to determine when a cleaning or maintenance of the insulators is needed for prevent the problems due to pollution. 

 

@Comparing the behaviour of the different designs of insulators (form, length) and/or of the materials of the insulator that are going to work under contaminated environments.

 

The probability of appearance of fault situation depends on the type and material of the insulator, the weather of the zone, the type and level of pollution, as well as the working voltage of the insulator.

 

Other problems related to pollution are: corrosion and erosion of the insulator. Also in polymeric insulators, the phenomenon of dry bands, and the effect of pyrolysis, must be kept of analyzing the operation of the insulator.