A new method for classification and characterization of voltage sags

This paper presents new software developments related to sag classification and characterization. A new fuzzy rule based algorithm for classifying the types of voltage sags is proposed. The voltage sags are categorized into three types, i.e. sags-due to the faults, large motor starting, or due to interaction between motor operation and faults. Three distinctive features of sag waveforms are defined and extracted first. Then a fuzzy logic based inference engine utilizing these features as inputs is implemented for decision making. Also presented are the characterization methods and suggested monitoring parameters for each of the three types of sags. Finally the application of the proposed characterization approaches for the equipment sensitivity study is illustrated. The results of case studies are reported. The presented approach has been implemented in MATLAB. (C) 2001 Elsevier Science B.V. All rights reserved.