抄録
In the case of DC insulator strings, a special phenomenon, so called single unit flashover, has been recognized to occur under some special contaminated and wetted conditions not only in laboratories but also in actual lines.
Higher magnitudes of audible noise (AN), radio interference (RI), and television interference (TVI) from this single unit flashover may give a serious environmental impact to the neighbourhood of the transmission line. Some investigations have ever been made on this problem simulating such phenomenon under normal operating voltage conditions.
Here we explain the investigation results of single unit flashovers under cold-wet-switch-on conditions. Such a condition occurs when a de-energized transmission line is re-energized under a wet condition.
Higher occurrence probability of single unit flashovers was obtained under cold-wet-switch-on conditions compared with the case of normal operating voltage conditions.
Some candidates for countermeasures to suppress the single unit flashover have also been evaluated.
