Q. Explain Steady-State Stability?

The property of a power system that ensures that it will remain in equilibrium under both normal and abnormal conditions is known as power-system stability. Steady-state stability is concerned with slow and gradual changes, whereas transient stability is concerned with severe disturbances, such as sudden changes in load or fault conditions. The largest possible flow of power through a particular point, without loss of stability, is known as the steady-state stability limit when the power is increased gradually, and as the transient-stability limit when a sudden disturbance occurs.

For a generator connected to a system that is very large compared to its own size, the system in Figure can be used. The power-angle equation (neglecting resistances) for the system under consideration becomes

where δgs is the angular difference between δg and δs , and X = X_d + X_e, with X_d being the direct-axis reactance of the synchronous generator. The power angle characteristic given by Equation is plotted in Figure. The peak of the power-angle curve, given by Pmax, is known as the steady-state power limit, representing the maximum power that can theoretically be transmitted in a stable manner. A machine is usually operated at less than the power limit, thereby leaving a steady-state margin, as otherwise even a slight increase in the angle δ_gs would lead to instability. Installing parallel transmission lines.