SIL rated protection relays meet IEC 61508 safety requirements without lowering process availability
Résumé
For systems where safety is critical, it will soon be a requirement that the safety related systems be designed in accordance with the IEC 61508 set of standards. This applies to electrical as well as to electronic equipment - such as protection relays - used in safety related systems, which are subject to the requirements of IEC 61508. The objective of the paper is to demonstrate that the safety requirements defined by IEC 61508 have consequences for the whole engineering process including the design of elementary electronic devices such as protection relays. Applying IEC 61508 to these devices becomes a must for achieving the user's basic requirements - improving the safety and the availability of their industrial complexes. IEC 61508 constitutes is a very powerful tool from organizational and qualitative points of view and systematic failures analysis is an important topic of this standard, and the probabilistic quantification part may be improved.