Integrating recovery strategies into a primary substation automation system

The DepAuDE architecture provides middleware to integrate fault tolerance support into distributed embedded automation applications. It allows error recovery to be expressed in terms of recovery strategies, i.e., lightweight code fragments separated from the application code. At run time, the middleware orchestrates their execution. This paper reports on the integration of different recovery scripts into a distributed run-time environment applied to the embedded automation system of a primary substation. An instrumented automata-based design environment allows the application to be deployed on a heterogeneous platform with several real-time operating systems. While the middleware detects the errors and selects the correct recovery scripts to be executed, the application functionality is maintained through system reconfiguration or graceful degradation. The added value comes from the flexibility to modify recovery strategies without requiring major modifications to the application, while tolerating the same physical faults as in the dedicated hardware solutions.