A transient current energy based adaptive single-phase reclosure scheme for transmission line using generalized multi-resolution morphological gradient

It is well known that most adaptive auto-reclosure 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 limits the applications of voltage based schemes. To overcome this disadvantage, a criterion of dual-window transient energy ratio (ER) based on mode current to implement the adaptive auto-reclosure of transmission lines is proposed in this paper. It is demonstrated that the ER approaches to 1 during the steady state whereas it increases greatly during at some moments, for instance, 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 (HF) energy of the mode current, a novel concept of generalized multi-resolution morphological gradient (GMMG) is put forward on the basis of multi-resolution 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. EMTP based simulation results show that the GMMG based auto-reclosure scheme improves the reliability of fault discrimination and is promising to be applied in the real power systems.