Interturn Fault Detection Algorithm for Shunt Reactors Based on Leakage Magnetic Field

When a turn to turn fault takes place in a dry-type iron-core reactor, the circulating current in the shorted turns is ten times or tens of times larger than the rated phase current, which could cause insulation and structure damage of windings. However, the changes of terminal voltage and phase current are very small, thus they cannot be regarded as the reliable criterion of turn to turn fault protection. In this paper, the characteristics of the magnetic field distribution in the reactor are analyzed as a criterion for the detection of turn to turn fault and its detection algorithm is further proposed. To investigate the effects of different numbers of shorted turns and fault regions on the spatial magnetic field distribution of the iron-core reactor, various finite element analysis simulations were performed by Maxwell. It provides a theoretical basis for the study of turn to turn fault detection algorithm. Simulation results verify the effectiveness and feasibility of the proposed detection algorithm in this paper.