The investigation of the serial communication between the process level and the bay level of the substation automation system

The novel electronic current and voltage sensors have been hot topic these years, especially the electronic current transducer based on Rogowski coil has been in the practical stage. However the output of such kind of transducer is usually analog low-voltage signal, the digital signal transmission via optical fibres is required due to the EMC problems. The switchgear using microprocessors and electronic technology can supply plenty of status and self-monitoring information, and it is more compact and reliable than before. The digitization, integration and intelligence of primary equipments influence the design of substation protection and control equipment as a result, the parallel wiring to link the process level and the bay level of substation automation system (SAS) will be replaced by serial optical cable.