Detection and Classification of Complex Power Quality Disturbances Using Stockwell Transform and Rule Based Decision Tree

This manuscript describes an algorithm based on Stockwell Transform and rule based decision tree for detection and classification of complex power quality disturbances. The multiple (complex) power quality (PQ) events are generated by various combinations of single stage PQ disturbances. These complex PQ disturbances are generated in conformity with IEEE Standard-1159 using the mathematical relations in MATLAB as per various combinations of voltage swell, voltage sag, momentary interruption (MI), oscillatory transient (OT), harmonics and impulsive transient (IT). These complex power quality signals are decomposed with the help of Stockwell transform to obtain S-matrix. Various plots are obtained from the S-matrix. Various features are extracted from these plots and given as input to the rule-based decision tree for classification of complex PQ disturbances. The effectiveness of proposed algorithm is established by testing 30 data sets of each complex PQ disturbance obtained by varying the parameters.