Bi-directional Y-Source DC Circuit Breaker Design and Analysis Under Different Conditions of Coupling

摘要

A Y -source impedance network is introduced to be a bidirectional circuit breaker for medium voltage direct current (MVDC) power systems. In this paper, designing, analysis, and evaluation of the bidirectional Y -source DC circuit breaker are presented under different conditions of coupling among the inductors. Breaker's transfer functions of impedance, current, and voltage are derived with a variable coupling coefficient. The frequency response of these functions is plotted as a magnitude and phase. The limitations of the fault conductance for two cases of the fault slope rate are derived as well. Upon the results, the breaker interrupts the source current during faults in case of coupling coefficient is higher than the null value. The turns ratio affects this value as explained in the paper. The simulation results confirm the effect of the coupling level on the breaker performance for two different values of the turns ratio.