What defines dynamic instability in a power system?

Dynamic instability in a power system refers to situations where oscillations do not settle down but instead increase or continue indefinitely, causing the system components to lose synchronization. This phenomenon is often the result of a disturbance in the system, such as a sudden increase or decrease in load, generator failures, or transmission line outages, leading to an inability of the system to return to a stable operating point.

When dynamic instability occurs, the system experiences continuous oscillations that can escalate in amplitude, resulting in a loss of synchronism among generators. This condition can ultimately lead to system failure or blackouts if not addressed promptly, highlighting the importance of effective system controls and stability measures.

In contrast, oscillations that dampen over time indicate that the system is regaining stability, whereas achieving a stable equilibrium means the system has successfully returned to a steady state after a disturbance. A quick recovery of power supply also suggests resilience and stability rather than instability within the system. Thus, the correct definition of dynamic instability captures the essence of continuous oscillations leading to loss of synchronization among system components.