Research On Under Frequency Load Shedding Based On Long-term Stability Of Power System

This paper analyzes the necessity of the research on under frequency loadshedding (UFLS) based on long-term stability of power system, indicates thelimitation of the traditional UFLS,and studies UFLS based on load frequencyregulation characteristics. Detailed theoretical derivation and actual exampleindicate that it will advantage frequency stability if load whose active poweris proportional to lower power of frequency would be cut off earlier than thoseproportional to higher power of frequency, or load with smaller load frequencyregulation factor would be cut off earlier. The paper studies UFLS with severaltimes accelerating shedding load function, analyzes dynamic frequencycharacteristic of power system during UFLS, derivesthe formula which is served as setting rate of frequency change for criterionof accelerating shedding load, and designs the logical diagram expressing UFLSoperation. At last, with actual example, the superiority of the UFLS to thetraditional UFLS and the semi-adaptive UFLS is indicated...