Configurations and architectures

When discussing configurations and architectures of substation automation systems, a factor is that computer and communication technologies double in performance every two years and that engineering technologies double in performance every three years. This means that during the life time of substation automation systems there will be changes or upgrades necessary to hardware or software. The question therefore becomes how to apply automation systems in substation that will have a total life time of over 25 years?
The main approach today is to standardize the substation. This however leads to a need for more detailed specifications that shall:

• identify the functionality, performance, security, availability, etc.
• define a robust logical architecture and map it on real devices
• define the communication and related aspects
• define the data model and related aspects
• initially consider various architectures until a well scoped one is found that is backed up by comprehensive tests

An advantage of modern automation systems is that hardware and software are becoming more and more independent. This leads to new possibilities such as adding functionality to existing systems. The impact of added functionality on system testing, availability and conformance requirements for the individual components is however a concern. Since hardware and software are never fully independent caution is advised. It is important that the performance and availability must be guaranteed during the system lifecycle and this can only be fulfilled through tested and certified products. A major benefit of IEC 61850 is that this can be supported by coordinating the possible IEDs and systems offered through the import and export of the standardized file formats in the System Configuration description Language (SCL).