Analysis of Electrical System Effectiveness using Layer of Protection Analysis

This paper reviews how the effectiveness (i.e. the ability to perform an intended function) of electrical systems can be analyzed using the technique of layer of protection analysis (LOPA). LOPA is a process currently in use to determine if instrumented systems are effective in reducing possible risks from the release of hazardous chemicals. This technique can be used to evaluate mandatory protection of electrical systems, non-mandatory protection of electrical systems, alternate system designs, and intervals of maintenance on electrical systems in terms of their potential reliability risks and/or personnel risks. It is shown how LOPA is an additional tool, which can be applied to existing systems or to systems about to be designed, so as to enhance the electrical system effectiveness, reliability, and availability