Time synchronization of protection and SCADA components in power utility systems

摘要

Rising digitization and consistent use of IEC 61850 requires a network-based communication in electrical energy systems. The use of network components as well as intelligent and automated functions increases the relevance of time synchronization for system operators. In the following, the demand is explained with reference to process bus communication and the differential protection systems. In particular the use of IEC 61850-9-2 communication, sampled values (SV), required high temporal accuracy in comparison to the requirements of the previously used functions. At present, the high precision time synchronization has been greatly neglected. Only a local synchronization with GPS or DCF77 is currently used. A continuous strategy for time synchronization in substations has not been required so far and is therefore not available. Because of the high requirements from for example the SV and the sensitivity of differential protection functions or other automated distributed functions, a strategy will be needed in the future. Therefore, different synchronization methods are considered and evaluated about their operational capability in power utility systems. This paper describes a concept for continuous time synchronization in substations which is also usable in the whole distribution grid.