What is the upper limit to the magnitude of CPS1?

The correct response is that there is no limit to the magnitude of CPS1, which stands for Control Performance Standard 1. This standard is established by NERC to ensure that the control performance of the power system is maintained reliably. CPS1 measures the effectiveness of frequency control by assessing how well a balancing authority is able to maintain its frequency within acceptable limits.

CPS1 is expressed as a percentage and assesses the percentage of time that the system frequency stays within predefined limits. Since frequency control is directly related to balancing generation and load, theoretically, as long as a balancing authority is effectively managing its resources and system operations, there is no upper limit placed on the CPS1 score. This allows the power systems to be continuously improved and optimized, promoting reliability and stability without an artificial cap.

In contrast, the other options suggest specific limits, which do not align with the way CPS1 is designed to function. The primary goal of the CPS metrics is to ensure continuous improvement in system performance, especially in response to varying conditions and loads, which is why no upper limit exists.