Study On Methods Of Dynamic Security Quantitative Assessment For Receiving-End Power System Frequency

Frequency as one of the important operating parameters in power system reflectsthe power quality and the active power balance. It is closely related with safe andstable operation power system. With the larger generation unit installation, Scatteredpower grid connection, extra high voltage transmission establishment and largercapacity of power transmission over longer distance are becoming the main featuresof power systems. All these features make the dynamic frequency response verycomplex. So, the quantitative assessment and security alarm on the power systemdynamic frequency after the shedding of large-scale power is one of the difficultproblems to be solved in the study of power system frequency stability.Based on analyzing the characteristics of power system dynamic frequencyquantitative assessment, the paper analyzed the error source of System FrequencyResponse (SFR) model by using trajectory sensitivity theory for the defects of theSFR model, and then proposed a parameter identification algorithm of the SFR modelbased on trajectory sensitivity. The result of the test system proves the correctness andeffectiveness of this algorithm.A quantitative security assessment method was proposed for grid based on theanalysis on power system dynamic frequency response in depth. Based on the featureof the SFR, the paper proposed a new quantitative security assessment index whichonly depends on the initial measurement data. The safety states of dynamic frequencycan be assessed effectively because of the clear physical meanings of the index. Atthe same time, the proposed index has a number of advantages such as goodmonotonicity, good smoothness, and low computational cost. The numerical resultson IEEE test system demonstrate the reasonableness of the proposed index andeffectiveness of the developed security alarm assessment approach.