New paradigm of smart transmission substation - practical experience with Ethernet based fiber optic switchyard at 500 kilovolts

This paper describes the experience from a design and implementation of a fully digital high voltage substation based on intelligent fiber optic switchyard. Ethernet based primary equipment including electronic instrument transformers was used in the project. The authors provide brief introduction to the concept of digital substation and process bus, then provide overview of IEEE 1588 standard for precise time synchronization and finally describe the details of network design and IEC 61850 engineering in a substation where the novel approach with process bus and IEEE 1588 has been implemented. The project described in this paper has been realized in a 500kV substation in China and was commissioned in 2011. The substation had been equipped with electronic CTs and PTs and Merging Units devices that convert analog signals to IEC 61850-9-2 digital format. Time synchronization had been realized with IEEE 1588 version 2. The described project is unique considering the size of the local communications network inside the substation that spanned virtually all primary and secondary apparatus. More than 160 Ethernet switches have been installed providing bidirectional communications to the large number of intelligent sensors, metering, protection and control devices.