Analysis of the Maximum Overvoltages Conducted to the Low Voltage Electric Installations

Studies indicate that approximately 100 million lightning flashes reach Brazilian soil per year, causing damages to both energy utilities and consumers. In critical periods, with great atmospheric activity, there is a significant increase in consumer complaints, due to high interruption rates and frequent fails in electrical equipment and installations. For that, data from previous researches, recent bibliographic sources, Brazilian standards and technical specifications of electric companies were used, in order to develop models that are as representative as possible in simulations in the ATPDraw. More than 1000 simulations were run out, resulting a data collection that allowed the elaboration of charts of occurrence cumulative probability of maximum overvoltages in the low voltage installations, due to direct lightning flashes in the medium and low voltage lines, in several types of lines and soil resistivity conditions. Analysis of these charts shows that the probability of high levels of overvoltage occurring at LV consumer electrical installations is low and, in the vast majority of cases, equipment malfunctions can be avoided with the proper use of surge suppression devices.