"Reliable Design and Operation of a Fast Industrial AC Electronic Arc-Flash Suppressor", This was the title of the paper presented by Professor Fernando Venâncio Amaral, from CEFET-MG, during his Doctoral Qualification Exam at UFMG. The work was guided by Professors Sidelmo Silva and Braz Cardoso, from lab TESLA - Power Engineering.

The research proposes innovative techniques for increasing the reliability and availability of electronic switch-based electric arc suppressors in industrial environments. During his presentation, Fernando pointed to the results of recent research on the seriousness of accidents caused by electric arcs, which cause injuries to workers and, in many cases, lead to death. According to the researcher, the effects of electric arcs are also detrimental to the financial objectives of organizations, which lose equipment and assume unplanned shutdowns due to events with electric arc. Since arc faults in electrical systems began to be recognized as a hazard in an industrial environment, solutions have been proposed to mitigate their effects on people and equipment. The most recent one is based on an electronic switch, consisting essentially of two antiparallel connected thyristors and in series with one current limiting impedance. This arrangement is immediately triggered when an arc fault is detected on a bus in a distribution panel or motor control center, suppressing the arc path within a time interval of microseconds order. The design of these elements is not a simple task, being dependent on many variables, such as the type of arc fault and the contribution of motors and generators to the current in the electronic switch. Thus, a detailed but simple procedure needs to be defined. In addition, since this solution is dedicated to ensuring workplace safety, its operation must be ensured, ie a failure is unacceptable. In this scenario, a resilient measurement and control system is required. In addition to avoiding operational failures, the electronic switch must not act inadvertently, as this could lead to an interruption in the power supply of the industrial process and consequent associated damages. Finally, it is desirable that the remaining life of the thyristors can be predicted so that an alarm is triggered as a warning that the electronic key will be replaced before any maintenance action is taken on the powered panel. The main contribution of the ongoing doctoral thesis lies in proposing, developing and testing a solution to the questions presented above, which make up the key aspects for the reliable operation of the electronic key. Simulation and experimental results were presented to support the effectiveness of the hypotheses discussed. The examining board was composed of, besides the advisors, the doctor Armando Souza Guedes, engineer of Petrobras (Brazilian oil Company) and the professors Doctors Anderson Vagner Rocha and Wallace de Couto Boaventura.