Frequent flashovers of high-voltage insulators can cause disruptions in electric transmission, leading to severe outages. It may be caused by pollution, or contamination of any kind, especially in coastal areas or where industrial emissions are common. The surfaces of the insulators get polluted over the years, which leads to an increase in flashover frequencies.
Let’s explain how this happens. The impurities in the air like moisture, fog, smoke, and industrial emissions accumulate on the surface of the insulator, which then develops a conductive film by absorbing the soluble salts from the impurities. This film then allows leakage current to flow along the surface, leading to electrical discharges and surface arcing, which form a dry band and cause pollution flashovers.
What are the disadvantages of frequent flashovers?
Pollution flashovers affect the efficiency and durability of the insulators, as well as lead to frequent outages in areas with higher chances of contamination. It can be triggered easily by moisture and pollutants, so care should be taken to clean the surfaces regularly.
Further, if there’s a flashover in one insulator, chances are that the insulators will also start experiencing the same, thus impacting the performance of the substation.
What can you do to prevent flashovers?
While it can’t be humanly possible to reduce the pollution density of the region overnight, you can always protect the insulators from getting polluted. The following suggestions will give you some ideas regarding that.
Occasional washing and regular cleaning
The insulators can be treated with water under high pressure to get rid of all impurities and pollutants that have accumulated on the surfaces. You should always hire professionals for the job, as a lot of safety measures need to be while washing the insulators.
You should also hire professionals to routinely clean the surface of the insulators using some special chemicals. The experts at https://www.utilityservice.net/ believe that blasting the insulators gently with pulverized limestone can help clean them without damaging the glazing. It also eliminates the need for de-energizing, after which the non-toxic dust and impurities can be blown away by air under high pressure.
Coating the insulators with silicone elastomer
One of the most effective ways to reduce contamination, coating the surface of the insulator with a specially-developed silicone elastomer can help confine the impurities and contaminants. The superior hydrophobicity of the coating reduces the chances of leakage and flashovers to a great extent. However, the job can be quite labor-intensive and requires professional expertise to be handled with precision.
Using a semiconducting glaze
The constant leakage current that flows through the glaze heats the surface of the insulator, thus ridding it off any moisture content. This apart, it also shunts the dry bands and provides an alternative route when they are formed, besides reducing surface acing.
In coastal areas and other places where the air has a high amount of moisture, the semiconducting glaze helps prevent flashovers to a great extent.
Wrapping it up
Contamination is one of the biggest enemies of high-voltage insulators, which increases the frequency of flashovers and reduces the efficiency of the entire substation. This can be prevented by using a semiconducting glaze, cleaning and washing the insulators regularly, and coating them with silicone elastomer.
All these tasks should be performed by seasoned experts, so you should find a reliable team with years of experience to handle the job successfully.