Proteção de inversores de freqüência em sistemas não aterrados com faltas fase-terra intermitentes

• Ano de defesa: 2010
• Autor(a) principal: Marcelo Britto Martins
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Minas Gerais; UFMG
• Palavras-chave em Português: engenharia elétrica; Engenharia elétrica
• Link de acesso: http://hdl.handle.net/1843/BUOS-8M5H73

Adjustable Frequency Driving Systems are nowadays a reality in industrial drives. Occurrence of failures in these systems can compromise plants production severely. Therefore, risingthese systems reliability is highly desirable. With this in mind, grounding and protection systems have been developed over time. Particularly, the situation of a PWM (Pulse Width Modulated) drive in a non-grounded system deserves closer examination. If that drive is driving a systemwith insulation failures to ground (e.g. induction motor), at first the driving will not be interrupted by existing protections, what is good for operation continuity. However, phase-to-ground overvoltages will arise and may lead to insulation failure, equipment breakdown and undesirableunscheduled production stop. This thesis aims to qualitatively understand involved phenomena that can cause system failure, loss of drive equipment and the subsequent production stop or restriction. Based on this understanding, design and build a circuit capable of ensure operation continuity while motor failures are not eliminated, without the risk of drive loss.