Smart substation case with optical/electronic CT/VT

With the development of information technology, the communication is extended to the switchyard and the substation is evolving from Substation Automation System (SAS) to Smart Substation Solution, becoming an important part of Smart Grid. The target of Smart Substation is to realize full digitization for the entire substation and achieve lower construction cost and lower maintenance cost. In this paper, the real smart substation project - Dalv substation is introduced. The 110kV Dalv substation is an Air-Insulated-Switchgear substation. It is the first smart substation employing IEEE 1588 at process bus. Both Optical CT and Electronic CT/VT are applied at 110kV voltage level. In the process bus, the double-star network is used for both IEC 61850-9-2 Sample value and IEC 618508-1 GOOSE for time-critical message. Merging Units with IEC 61850-9-2 are adopted to transmit the digitized current/voltage over Ethernet. In addition, Circuit Breaker Controllers complying with IEC 61850-8-1 GOOSE are installed to transmit the binary inputs/outputs such as tripping/closing commands. As well, the paper recommends a typical system structure for smart substation solution with station bus and process bus.