How is the Frequency Response Obligation (FRO) of a Frequency Response Sharing Group determined?

The Frequency Response Obligation (FRO) of a Frequency Response Sharing Group is determined by summing the individual FROs of each member within the group. This approach recognizes that each member contributes to the overall frequency response capability of the collective group. Therefore, by aggregating the individual obligations, the group establishes a total frequency response requirement that reflects the combined capabilities and resources of all its members.

This summation process is essential for ensuring that the group can effectively respond to frequency deviations in the power system. It allows for a clear and measurable obligation that can be monitored and managed, ensuring that the frequency response provided by the group meets the operational standards and requirements established by regulatory bodies.

In contrast, averaging the individual FROs would not provide a comprehensive view of the group's capabilities since it would underrepresent the total response potential. Simply calculating the group's overall output or assessing system stability factors does not specifically address the obligation to respond to frequency changes, which is central to the concept of Frequency Response. Thus, summing the individual FROs ensures that every member’s contribution is accounted for in addressing the collective responsibility of maintaining system frequency stability.