This is a more detailed paper on adaptive UFLS for power systems with active distribution networks
With high penetration of Distributed Energy Resources the likelihood of cascading development of bulk power system emergencies will increase. Hence, UFLS should be adaptive to both single-event and cascading emergencies.
This article claims that with high penetration of Distributed Energy Resources the likelihood of cascading development of bulk power system emergencies will increase. Hence, the Under Frequency Load Shedding (UFLS) should be adaptive to both single-event and cascading development of generation deficits. Three designs of the UFLS are discussed in the paper: Conventional UFLS with two separate sets of UFLS groups – one discriminating by frequency and another by time; UFLS where the same group has setting discriminating either by frequency, or by time; and UFLS with frequency settings changing in time during the development of the emergency.