The Accuracy of network models in Energy Management System (EMS) can significantly impact study qualities in State Estimation (SE) and Real Time Contingency Analysis (RTCA). For many utilities closely coupled with neighbouring companies, their EMS models consist of the internal parts, which represent their own service territories, and the external parts, which describe the interconnected external grids. The integration and updating of external grids into EMS remain a challenge in model maintenance for those utilities due to lack of common standard in information exchange, where differences in data format and structure complicates model sharing among entities.
To resolve the problem, AEP proposed and adopted a Common Information Model (CIM) based approach to facilitate external model update (XMU). This approach standardizes network models from different companies, therefore enables convenient inter-corporate model exchanging and customization to fit for individual specifications. Furthermore, the CIM based approach is able to clearly delineate boundaries between internal and external regions so that network components in need of updating can be sought out and managed easily.
Till now, AEP has used the CIM-based approach to facilitate multiple XMUs in all three of its service territories governed by ERCOT, SPP and PJM respectively. As a result, the time consumption of each XMU has reduced from weeks to hours and the external model revision cycle has shortened from years to months. With more frequent external model revisions, the accuracy of network model enhanced significantly, resulting in a more reliable system to support control room functions.