What does a gradual decrease in frequency and erratic net actual interchange typically indicate in a power system?

A gradual decrease in frequency along with erratic net actual interchange typically indicates instability within the power system. Frequency is a critical parameter that reflects the balance between power supply and demand. In a balanced system, the frequency remains relatively stable around its nominal value. When frequency begins to drop gradually, it suggests that generation is insufficient to meet the load demands, potentially leading to system stress or instability.

Additionally, erratic net actual interchange may imply issues with interconnections between different areas of the power grid—there could be fluctuations in power flow that disrupt the expected and stable interchange between regions. This instability could arise from various factors, such as equipment failures, insufficient generation resources, or sudden changes in load.

In contrast, a stable frequency and controlled net interchange are indicative of a well-functioning and balanced power system.