A novel adaptive single-phase reclosure scheme using dual-window transient energy ratio and mathematical morphology

It is well known that most adaptive autoreclosure schemes are dependent on the voltages sampled from the transmission lines to distinguish between the transient faults and the permanent faults; therefore, the transforming characteristics or required mounting position of the voltage transducer will limit the applications of voltage-based schemes. To overcome this disadvantage, a criterion of a dual-window transient energy ratio (ER) based on mode current to implement the adaptive autoreclosure of transmission lines is proposed in this paper. It is demonstrated that the ER approaches 1 during the steady-state where it increases greatly during some moments; for instance, for the fault occurrence, breaker opening and closing, the existences of primary and secondary arcs, and arc extinguishing. Therefore, the setting of the criterion is easy. To effectively extract the high-frequency energy of the mode current, a novel concept of generalized multiresolution morphological gradient (GMMG) is put forward on the basis of the multiresolution morphological gradient (MMG). The design of GMMG is more flexible and the relative factors of the structure element can be regulated according to the desirable effects. Electromagnetic Transients Program-based simulation results show that the GMMG-based autoreclosure scheme improves the reliability of fault discrimination and promises to be applied to the real power systems