Typical Power Quality Disturbance Identification Based on Fractal Box Dimension

Power quality disturbance (PQD) identification is an important technology in power system especially when power market is realized. The producers of PQD are different which result in the difference of abnormity and complexity. Fractal dimension is a mean to characterize the abnormity and complexity of PQD and it is potential for PQD identification. Traditional fractal box counting dimension is based on the square which confuses the coordinate physical meaning in application. The dual-scale fractal box counting dimension is based on the rectangle in which time and range of PQD are included. The formulae for fractal scaleless range is developed based on the periodic or quasi-periodic characteristic of PQD. The formulae are tested by simple waveform and proved effective. Fractal box counting dimension of typical PQD depict the PQDs well especially in identification. The proposed method is a new time-based approach for PQD analysis.