failures in outdoor insulation caused by bird excrement

the bird excrement, combined with humidity, causes line outages in transmission lines. in order to standardize the criteria to solve the problem, a research project was developed in méxico. the solutions found in worldwide review can be classified into four groups: elimination of birds, devices of dissuasion, physical barriers, and covering devices. the first group includes all bird elimination techniques. these alternatives are forbidden in méxico, and in most of the countries. the second group has shown to be effective at the beginning of its application; however once the birds are habituated to the device, it loses its effectiveness. the efficiency of the third group, the use of physical barriers, is high, as demonstrated by more than a few review reports informing drastic reductions of flashovers on the transmission lines where they have been installed. the fourth group is conformed by components whose function is to protect or to cover the insulation. according to the experience in mexico, covering devices have shown to be very effective. the contamination by bird excrement has not a unique solution. the most viable solution is a combination of alternatives. even though, a solution adopted for a region may not be suitable for another region. therefore, each case should be approached according to the particular condition of the region.