OpenPA is a Java-based API for real-time, uniform electrical model access regardless of data source, together with a set of basic utilities to facilitate rapid development and integration of power applications. An application can load an electrical model, retrieve information in a standard manner, and make any changes to reflect processing as desired. Changes can then be summarized for reporting or persistence. Data is primarily stored as primitive arrays, which can easily be handed off to applications running multi-threaded or on a cluster.

Back-end data sources could include:

• PSS/e raw file
• PowerSimulator CSV formats
• Realtime deployed environment

The API supports lists of standard equipment modeled for transmission or distribution (buses, generators, lines, etc). Other features include:

• Island detection
• Bus-bus branch model
• Automatic 3-winding transformer conversion to 2-winding
• Flexible grouping of buses with ability to get lists of each equipment type included
• Group buses by area, owner, station, voltage level, island and single-bus

The utilities available are:

• Sparse B-matrix formulation, factorization, forward reduction and backward substitution
• Branch flow calculations
• Two-terminal DC link calculation
• Bus MW and MVAr mismatch calculation
• Fast-decoupled power flow