Generalized morphological filter designed for zero-sequence voltage detection caused by ground fault

The detection of zero sequence voltage is the key of judging asymmetric fault. However, the original voltage may contain a lot of harmonic pollution which decrease the detection accuracy of zero sequence voltage. To increase the detection accuracy, a generalized morphological filter is proposed in this paper, An appropriate structural element for generalized morphological filter is selected. Meanwhile, the fault voltage signal is dilated and eroded. Finally, S transform is used to calculate the amplitude of zero sequence voltage. In order to verify the effectiveness, a simulation model was built in MATLAB, and the result are satisfactory.