Solution approaches by application area and criticality
Main Failure Modes and Safety Principles of Voltage Source Inverters

The notion of the "criticality" of an application, also referred to as the level of "risk" it represents, is a two-dimensional quantity. It is based on the product of the probability of occurrence of the feared event and the resulting level of severity (on a scale of 1 to 10, for example) should the event occur. The notion of severity is in turn defined by a two-dimensional quantity qualifying: on the one hand, the overall level of safety, i.e. maintaining the integrity of goods and people; on the other hand, the level of availability, i.e. total or partial continuity of nominal service. The classification of fields of application by "criticality" given in table 1 is a way of addressing the major families of solutions improving the operating reliability of the systems concerned.