What is likely to happen after a severe disturbance on the interconnection when frequency oscillation occurs?

When a severe disturbance occurs on the interconnection, it can lead to significant frequency oscillations. One of the scenarios that can arise from this situation is the operation of an islanded system.

When parts of the power grid become isolated due to disturbances, such as faults or outages, they can no longer exchange power with the rest of the grid. This isolation can cause the frequency in the islanded system to drop or rise significantly because the balance between generation and load may be disrupted. In such conditions, only the localized power sources and loads can interact, effectively creating a smaller isolated network or "island." Monitoring systems would detect these conditions, and operators must take action to stabilize frequency and balance the generation and load within the islanded system.

The other choices presented do not adequately represent the implications of frequency oscillation following a severe disturbance. For example, a failure of the frequency meter or insufficient reactive resources does not directly relate to the scenario of an islanded system resulting from a frequency disturbance. While system collapse could be a theoretical consequence of extreme oscillation, it does not accurately capture the immediate response of the system transitioning to an islanded state. Thus, operating as an islanded system is the most relevant and logical consequence in this context.