OVERCURRENT RELAY COORDINATION EFFECTS ON RELIABILITY INDICES

ENGLISH ABSTRACT: Mechanical equipment used on process plants can be categorised into two main types, namely static and rotating equipment. A brief survey at a number of chemical process plants indicated that a number of maintenance strategies exist and are used for rotating equipment. However, some of these strategies are not directly applicable to static equipment, although the risk-based inspection (RBI) methodology has been developed for pressure vessels. A generalised risk-based maintenance strategy for all types of static equipment does not currently exist. This paper describes the development of an optimised model of inspection methodologies, maintenance strategies, and risk management principles that are generically applicable for static equipment. It enables maintenance managers and engineers to select an applicable maintenance strategy and inspection methodology, based on the operational and business risks posed by the individual pieces of equipment. AFRIKAANSE OPSOMMING: Mislukkings van beveiligingstelsels is hoofsaaklik verantwoordelik vir kaskadeonderbrekings van elektriese netwerke. Derhalwe is dit noodsaaklik dat betroubaarheidsindekse geevaleer moet word teen die agtergrond dat min aandag gegee word aan relêkoördinasie. Monte-Carlo simulasie word voorgehou as oplossing van die koördinasievraagstuk. Die voorgestelde algoritme word toegepas op die afsonderlike koördinasiemetodes van ‘n denkbeeldige network. Die resultate van die ondersoek toon dat die berekende betroubaarheidsindeks afhang van hoe koördinasiemetodes toegepas word.