Data Threshold Setting Using a New Approach Based on Otsu's Image Thresholding

This paper deals with a threshold setting approach based on Otsu's image thresholding applicable in different protections. Threshold setting is one of the most important steps in systems protection, which is usually handled using the trial and error method. Although there are many threshold setting techniques suggested in different engineering fields, a vacancy is sensed in power systems protection in this regard. A developed version of Otsu's image thresholding is suggested, which can be applied to values of a criterion in different scenarios. As a typical example, the level of the second harmonic is considered as the criterion for discriminating between internal faults and inrush current in a power transformer. Using the gathered data from an experimental test bench, the proposed methodology of threshold setting is presented in detail.