5. Criticality Analysis

This chapter concerns the evaluation of the strength of a measuring system known as criticality analysis, whose objective is to identify the elements minimally critical to network observability. The term critical conveys the idea of decisive importance, the belief of what things are essential, crucial, and indispensable for a given purpose (observability), supported by a careful judgment on the severity of consequences for power system state estimation (SE). Criticality analysis identifies which measurements taken individually or forming groups that participate in SE are indispensable in case their unavailability makes the grid unobservable. Data unavailability may happen by accident, programmed maintenance, cyberattack, or chance. Criticality analysis is vital since a SE crash can lead system operators to make decisions based on incomplete or incorrect information, leading to suboptimal or dangerous outcomes. The chapter includes illustrative examples of criticality analysis considering the measurements as a primary element of the study and measuring units (i.e., the aggregate of devices deployed at substations). Advanced topics and proposed problems, followed by a list of references, close the chapter.