Insulator Flashover,Backflash Rate
Insulator Flashover,Backflash Rate
(OP)
Dear all,
Do you know what is the acceptable rate of failure on a 33kv line due to lightning.
Do you know what is the acceptable rate of failure on a 33kv line due to lightning.






RE: Insulator Flashover,Backflash Rate
RE: Insulator Flashover,Backflash Rate
RE: Insulator Flashover,Backflash Rate
The design of a transmission line agains lightning for a desired performance, is practically independent of operating voltage. The main consideration is how to obtain a protection level for the desired performance. The basic principles underlaying the design of a line based on the direct-stroke theory are:
1) Ground wires with sufficient mechanical strengh must be located to shield the line conductors adequately from direct strokes.
2) Adequate clearance from the line conductor to the tower or to ground must be maintained so that the full effectiveness of the insulation structure can be obtained.
3) Adequate clearance from ground wires to conductor must be maintained, especially at the midspan, to prevent flashover to the conductors up to the protective voltage level used for the line design.
4) Last, but equally as important, tower-footing resistances as low as are economically justified must be secured
RE: Insulator Flashover,Backflash Rate
11-66 kV rural lines : 0.7 - 3 outages / 100 km years