Effect of controlling the sequential interruption of a system fault on turbine-generator shaft torsional torques

A new method is presented to reduce the high torsional torques induced in turbine-generator shafts during the clearing of multiphase faults. This method is based on controlling the sequential interruption of such faults. In this context, investigations have been conducted on two turbine-generator units of different designs for both three-phase and double line-to-ground faults. The effectiveness of the proposed method is illustrated through parametric studies and simulation results. The effects of the fault clearing time, the strength of the system to which the unit is connected, and the fault incidence instant on the effectiveness of the method have also been investigated