Adaptive single‐phase reclosure scheme for transmission lines with shunt reactors based on current inner product

Abstract

In this study, two current inner products have been defined to implement adaptive single-phase autoreclose for high-voltage transmission lines with shunt reactors. The inner product of fault phase current in shunt reactor and the current in the neutral point reactor is defined as initialisation inner product, and the inner product of the derivative of fault phase current in shunt reactor and the current in the neutral point reactor is defined as compensation inner product. In case of permanent faults and transient faults in the second arc stage, the initialisation inner product will keep bigger than compensation inner product. As for transient faults after arc extinction, low-frequency oscillation is observed in both curves of current inner products which have 90° phase differences; and two curves will have points of intersection. According to this phenomenon, the intersection of two current inner product curves is used to identify fault nature and detect the arc extinction. The proposed algorithm needs no threshold and no calculation in frequency domain. The electromagnetic transients program simulations have verified its correctness and effectiveness.