Estudo da importância dos cálculos de energia incidente e correntes de arco na proteção de trabalhadores do SEP

Abstract

Arch flash is a natural event that occurs when an electrical current uses the air, which is an insulator in normal conditions, as a path in an electrical circuit. This phenomenon can happen in several kinds of electrical installations and may lead to accidents with risks of death. This happens due to the release of great levels of energy that can cause incurable burns and the high temperatures, that can reach 20.000°C, during an arch flash explosion. In the Brazilian context, there is the Norma Regulamentadora n° 10 - Segurança em Instalações e Serviços em Eletricidade (NR 10), which is the main Brazilian standard for safety in electrical installations, that demands from the employers the proper sizing of the personal protective equipment (PPE) for protecting the employees against electrical and arch flash hazards. The fulfillment of these demands is inspected by the Brazilian Labor Ministry. This research aims to present concepts about the arc flash’s nature, address the physical quantities related to the occurrence of this event, bring a perspective about the development of the knowledge of safety and preventions of accidents involving arch flash and discuss the main mathematical models used to predict the hazards that a person can be exposed to in an arch flash accident. In the mathematical models discussion presented in this research, a special attention is given to the IEEE 1584 method updated in 2018, with a presentation of the step by step implementation of the model and applying the method in a case study comparing the results obtained using the updated method to the results obtained from the application of the 2002 version. This research also approaches the relevance of using the latest update of the mathematical model in order to reach more precise and reliable results for sizing the correct PPE and attending to all normative demands.