Application of MOLET complex wavelet in adaptive current protection

In this paper, digital signal processor (DSP) processor characteristics and the basic structure of relay protection system hardware of DSP are introduced. MOLET complex wavelet algorithm, which investigated under grid frequency instability or the transition process of the initial phase of short circuit which contains non-periodic component and a rich harmonic amplitude, is conducted accurate calculation to meet the requirements of adaptive current protection. 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.