Power System Transient Control by Capacitor Switching

Inserting and removing a series capacitor in a transmission line can remove the oscillatory transients due to a fault. The capacitor should be inserted in the remaining transmission lines when the fault is detected and removed by short circuiting when the time rate of change of power flow through the capacitor is zero or the rate of change of phase angle between line terminations is zero. The capacitor should be reinserted when the kinetic energy due to speed deviations equals the amount of kinetic energy that can be removed during the remaining swing to the target state independent of whether or not the line is restored to service.