What is issued by the System Operator when Demand Reduction is expected within the next 30 minutes?

The System Operator issues a Demand Control Imminent Warning when there is an expectation of demand reduction within the next 30 minutes. This warning serves as an urgent alert indicating that immediate actions may need to be taken to manage electrical demand effectively. The use of "Imminent" signifies the short timeframe, emphasizing the need for quick responsiveness from stakeholders to prevent potential issues such as outages or system overloads.

This warning is crucial for ensuring that various players in the power distribution system—such as utility companies and large consumers—are informed promptly so they can alter or reduce their demand to maintain grid stability. The term "Control" implies that there are proactive measures to manage demand effectively, which is critical for the overall health and reliability of the power supply system.

Each of the other options does not carry the same urgency or specificity related to immediate action as the Demand Control Imminent Warning, making it the appropriate choice for this particular scenario.