O intemperismo tropical como agente de degradação de cadeias de isoladores de alta tensão em subestações na Amazônia Oriental: estudo de caso em Barcarena-PA e São Luís-MA

Abstract

The deposition of atmospheric particulates of the Belém-PA region, Barcarena-PA and São Luís-MA and the species geochemical characterization of the can help in understanding the effect of tropical weathering and how it acts in the degradation of chains of high voltage insulators in electrical substations in the Amazon. In the sampling, it was important to evaluate the seasonality (dry and rainy period) performed by 24 monthly surveys between January-2012 and February-2016, using the directional dust deposit gauge - DDDG ABNT NBR IEC 60815-1 (2015) and the wet candles of chloride (ABNT NBR 6211) and the lead oxide (ABNT NBR 6921) were used to determine chloride and sulfate rates, respectively. To characterize the samples of soluble material was made by ion chromatography (IC); the elemental analysis of the insoluble fraction was done by Laserinduced breakdown spectroscopy (LIBS) and the morphology was identified by scanning electron microscopy (SEM) and the X-ray source (EDS). In the Barcarena-PA rainwater the order of occurrence of the ions was Na+> Cl-> SO4 2- > Ca2+ > K+> F-> NH4 +-N > Mg2-> NO3 - -N. There is a marine contribution of Na+ and Cl- and anthropic of SO4 2-, F- and NO3 --N. The annual mean dust deposition rates of São Luís-MA (7 to 11 mg m -2 day -1) are similar to those of Barcarena-PA (7 to 14 mg m -2 day-1). However, the classification of local pollution severity according to ABNT NBR IEC 60815-1 (2015) is high for Barcarena-PA and medium for São Luís-MA due to conductive deposition (Type B). The deposition rates Cl- /SO4 -2, the presence of F-, SO4 2- and NO3 --N showed greater anthropic impact in the Barcarena-PA substation than in the São Luís-MA substation. Thus, there are indications that the atmospheric corrosively conditions in the study regions and the effects of degradation on the electrical insulators will follow this logic, the intensity and the risk of failure, relating to the more intense industrial anthropic contribution in the SEVC. Since marine, anthropogenic and crustal salt sources increase the potential risk to electrical components in transmission lines.