The Phase Difference Method for Power Quality Disturbance Signals Detection Based on Complex Wavelet Transform

Existing methods of using complex wavelet to detect power quality disturbance signals almost use the form of combination information. For different disturbances, the differences of information combination and complexity of calculating affect detection accuracy and real-time characteristics. Based on the analysis of complex wavelet transform and its phase characteristics, a new disturbance detection method is proposed first in this article that uses the value of complex wavelet transform phase difference. Its information form is unique and calculation is simple, i.e. solving Gaussian complex wavelet transform of a standard sine wave and disturbance signals, then request the difference value of both phase to store in a array. According to the number of zero in this phase difference information array, disturbance time can be tested and disturbance type can be determined. The detailed calculation steps and practical criteria are given in this article. For four typical disturbance signals MATLAB simulation results show that when combination information method is failure, the phase difference method is still valid having better detection effect and higher precision than traditional combination information method, and can further determine the type of disturbances.