Avaliação da utilização de supressores de surto instalados junto às cargas consumidoras frente a sobretensões atmosféricas

Abstract

One of the main causes of damage to electrical equipment connected to networks of medium and low voltage are those related to lightning effects. These effects are due to direct lightning strikes or due to electromagnetic fields associated with cloud to ground lightnings that affect the electrical system in the vicinity of the striking point. In both situations, the consumer may be subjected to transient overvoltages that can cause damage to their equipment and facilities. As overvoltage control provided by utilities in their networks is not always sufficient to ensure adequate protection to consumer devices, it becomes important to provide protection through the use of protective devices at the entrance of consumer units. In this context, the use of surge protective devices at consumer units aims at minimizing overvoltages and protecting equipment connected to the network, thus reducing the possibility of damage to both the consumer and to the utility. Based on this premise, this work is dedicated to evaluate the use of surge protective devices, as a form of protection of consumer loads from lightning overvoltages. To this end, the approach developed in this paper seeks, from simulations in computational platform ATP (Alternative Transients Program), to observe the influence surge protective devices on lightning overvoltages on consumer loads. Through the use of actual characteristics of surge suppressors available on the market, it is investigated the behavior of these suppressors installed at different locations in the consumer unit. For the representation of consumer loads, an RLC model obtained from experiments is used. Thus levels of overvoltages are evaluated, and as well as the configuration of surge suppressors that provides the best level of protection.