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This paper presents a fuzzy control system to automate the operation of capacitor banks installed in a transmission substation. This automation intends to standardize operation and control voltage at the substation output bus. The system was implemented and tested with real data from a 345/138 kV transmission substation. The results obtained through the simulations are compared with the manual commands executed by the technicians from an operation center in Brazil. The outcomes showed the effectiveness of the proposed system to maintain the bar voltage considering the current load regime. In addition, the capacitor banks' operations numbers were reduced and standardized. [ABSTRACT FROM AUTHOR]

This paper depicts an accident that happened in 2010 in a Brazilian chemical plant. A combination of different events, installations, and commissioning errors coupled with equipment failures involving the primary substation resulted in catastrophic failure. A single-phase failure of a 138-kV disconnect switch, during closing, initiated events and phenomena that resulted in a complete plant shutdown. This paper will walk the reader through the events, forensics analysis, and power system analysis that allowed the authors to identify what happened, how it happened, and what to do to prevent it from happening again. This paper will show how the anatomy of the problem, involving equipment failure, single-phase arcing, switching transients, overvoltage, capacitive coupling, transferred surge voltages, ungrounded system, transient overvoltage due to an arcing ground fault on an ungrounded system, insulation coordination, flashover, and lack of adequate surge protection, all of which resulted in a catastrophic failure of an arc resistant switchgear and a potentially serious arc flash incident. The research followed some steps that will be commented on here as well as the lessons learned. [ABSTRACT FROM AUTHOR]