Research On Under Frequency Load Shedding Of Power System

This paper analyzes the necessity of the research on under frequency load shedding (UFLS) of power system, indicates the limitation of the traditional UFLS,and studies UFLS based on load frequency regulation characteristics. Detailed theoretical derivation and actual example indicate that it will advantage frequency stability if load whose active power is proportional to lower power of frequency would be cut off earlier than those proportional to higher power of frequency, or load with smaller load frequency regulation factor would be cut off earlier. The paper studies UFLS with several times accelerating shedding load function, analyzes dynamic frequency characteristic of power system during UFLS, derives the formula which is served as setting rate of frequency change for criterion of accelerating shedding load, and designs the logical diagram expressing UFLS operation. At last, with actual example, the superiority of the UFLS to the traditional UFLS and the semi-adaptive UFLS is indicated...