Study on application of Morlet complex wavelet on adaptive current protection

Real-time calculating system equivalent parameters is one of keys of adaptive current protection. Full-wave Fourier algorithm will cause high error because of the non-periodic component and unstable power frequency. A Morlet complex wavelet based algorithm is presented which is better than general Fourier algorithm in stability and robustness and is unaffected by non-integer harmonics, non-periodic component and fluctuant frequency. The algorithm is to choose proper parameters and filter out fundamental frequency components of typical faults voltages and currents. The results of simulation show that the complex wavelet algorithm is of high accuracy and can satisfy adaptive protection’s need, so it is highly valuable for engineering practice.