Safety related, distributed functions in substations and the standard IEC 61850

In a substation, a lot of distributed, safety related functions have to be performed. IEC 61850 is intended to replace all wires by serial communication. To achieve this goal IEC 61850 has to fulfill hard real-time criteria. Starting from the definition of these criteria the communication methods of IEC 61850 are investigated. The result shows the feasibility of these methods for interlocking and illustrates their usage. Some application rules are given.