Question

1. Suppose that you are designing an overhead transmission line that would operate in a polluted environment. Explain the procedure for selecting the appropriate insulators and their dimensions. 2. Explain how pollution flashover takes place. (Starting from a clean insulator, ending with complete flashover)

Answer 1

1. Suppose that you are designing an overhead transmission line that would operate in a polluted environment. Explain the procedure for selecting the appropriate insulators and their dimensions. Yes, an overhead transmission line may affect the environment from where it is passing by its magnetic field and radiations. Some of the measure by which we can reduce the pollution and make environment safer are as follows: # by putting at the safe height # by providing a thick cover of PVC or Teflon # by passing through barren area then a densly populated region # by reducing the radiation level and many more. 2. Explain how pollution flashover takes place. (Starting from a clean insulator, ending with complete flashover) Leakage current starts to flow along the surface and there are arcing discharges as well as dry band formation. This process can quickly progress to pollution flashover, leading to tripping of transmission lines or substations After there has been a pollution flashover on one insulator, it is likely that adjoining insulators will flash over after reclosing takes place. As such, once pollution flashovers occur, reclosing will tend to fail, causing long, extensive outages, i.e. a serious threat to the stable operation of any power system