Resilient Protection System Through Centralized Substation Protection

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Abstract
Power systems are experiencing drastic changes with the introduction of renewables and customer owned resources. These changes introduce new challenges in protection, control and operation of power systems. In protection, it is necessary to develop new methods that are immune to the new characteristics and they avoid relay misoperations. In particular, any protection system is vulnerable to hidden failures. This paper introduces a new dynamic state estimation-based centralized protection scheme (DSEBCPS) at a substation level. This system supplements dynamic state estimation-based protection for individual zones known as “setting-less relays” to secure their operation against hidden failures. The DSEBCPS communicates with the setting-less relays via the station bus and obtains essential information from each protection zone, such as phasor quantities and breakers and disconnects status. This information is processed by DSEBCPS to perform dynamic state estimations in the quasi domain once per cycle to detect any sort of abnormality within the substation. Upon detecting abnormalities, the DSEBCPS performs hypothesis testing to distinguish between fault and hidden failure. Its capability to detect hidden failure in real time is used to secure setting-less relays from misoperation, which bridges a critical gap in protection systems. This capability is demonstrated through numerical experiments.