Possible improvements of the ACE diversity interchange methodology

Balancing Authorities are responsible for managing their system imbalances including deviations caused by the integration of variable generation resources. As wind and solar penetration levels increase, the challenges of managing power variations also increase. Working independently, balancing areas (BAs) with limited regulation and load following capacity and high wind power penetration would face significant challenges with meeting their control performance objectives. Cooperation between BAs in dealing with the imbalances would help the participating BAs to address increasing variability, as well as to minimize the required generation balancing capacity and associated costs. One of the cooperation options is the area control error (ACE) diversity interchange (ADI). In this approach, participating BAs calculate a common ACE in real time, and then share the common ACE among them based on a predefined algorithm. Therefore, the participating BAs are balancing against their share of common ACE, which is expected to be smaller than their individual ACE. This technology is already in use in the Northeast (3 participants), in the Western interconnection (13 participants), among 3 BAs in Germany, and is currently under implementation among the 13 members of the Southwest Power Pool. In some ADI implementations, the amount of shared ACE is artificially limited by certain percentage to avoid congestion problems caused by the ADI scheme. This paper proposes a possible improvement to the ADI algorithm that incorporates transmission limits. This enhancement would additionally increase the maximum depth and the overall efficiency of the ACE sharing schemes, without creating congestion problems. Simulation results obtained in this study using 2006 Bonneville Power Administration and the California ISO data are presented and discussed in the paper. (The authors are not trying to premeditate or suggest an ADI between these 2 organizations; the sole purpose of this research is just to illustrate the performance of the proposed ADI approach on a real system example.) They have demonstrated good performance of the proposed advanced ADI methodology.