Definition of Flashover and Sparkover

Flashover

           Flashover is a disorder that occurs in the form of sparks that occur between insulator component or high voltage electricity. This can occur due to failure of the insulation of the high voltage system.The failure of the electrical insulator can be caused by the presence of small cavities in solid dielectric (porcelain) or due to the occurrence of flashover along the insulator surface. Small cavities in the insulator caused by isolator is made less than perfect at the time of manufacture, thereby insulating the electrical characteristics of the poor. A small cavity in the isolator will eventually cause mechanical damage to the insulator. The occurrence of flashover causes damage to the insulator by heat generated due to arc along the insulator surface. Therefore, the insulator must be made such that the voltage on a small cavity is higher than the voltage that causes flashover.

           Failure flashover (flashover) began with the formation of a dry band (dry band). As previously explained, that the formation of conductive layer on the surface of the insulator caused by the presence of pollutants that stick. Layer formed on the insulator surface is causing the flow of leakage current (leakage current). With the flow of leakage current, the heating occurs in the layer. This layer can form a ribbon of dry (dry band) due to leakage current flowing continuously. At a certain voltage, this condition can cause discharge across the dry band. A discharge can be elongated to form an electric arc (arc) and occur flashover (flashover) through the entire surface of the insulator.

Sparkover

           Sparkover is a disorder that occurs between the insulator due to the isolation factor less than the maximum. It usually occurs due to insulation failure in the air, solid and liquid. This disruption will cause a spark. Dry band formation is causing interference electric field along the surface of the resulting voltage spark (spark over) and cause discharge in the area certain. Dry band formation mechanism can be seen in Figure 6. Ribbon dry resistance, creep currents larger than the area that is still wet. Therefore, voltage drops that occur in arid regions (ΔV) is greater than the voltage falls in wet areas (ΔV '). At a distance d1 is equal to d2, this raises the voltage falls Great field strength so that air including not hold the terrain and happened discharge (discharge).