Improved mathematical morphology transformation and application to single ground fault feature extraction in small current system

Single phase grounding fault occurs in small current grounding power system frequently, fault signal caused by which contains a large number of feature information, which is an important basis for the fault location. However, due to the weakness of the fault signal, collecting the fault feature information becomes a difficult point to detect the fault line and solve the fault location. In this paper, combining with the idea of multi-resolution structural elements, an improved mathematical morphology method to accomplish the extraction of the characteristics of the fault signal has been proposed. Firstly, the consistency distribution level has been introduced to ameliorate the traditional morphological filter, which reassigned the individual treatment effect of the signal of Open-Closing and Close-Opening operation and optimized the proportional coefficients of these two kinds of operations in this filter. As a result, it makes these two operations have a more thorough and effective influence on the feature signal extraction results. Then, it has taken the use of the principle of multi-resolution structural elements to complete feature extraction by choosing different kinds of linear structure element. By the simulation experiment, compared with the fault feature component extracted by wavelet transform, it shows that this measures has a good effect on the fault feature extraction of single phase grounding fault in neutral ineffective grounding system.