Practice and trend of DSAS in China

Digital Substation Automation Systems (DSAS), with some form of communication facility on station and/or bay level, have been in service for several decades. In recent years, the application of IEC 61850 is gradually achieved in China. The first application is MMS between station level and bay level, the second one is GOOSE message application in bay level and process level, and the last one is the SMV in process level. The most recent application is IEEE 1588 PTP (Precision Time Protocol) and GMRP (GARP Multicast Registration Protocol). Taking 110kV Dalv substation in Shaoxing, Zhejiang Province as an example, the practice of IEC 61850 applications is introduced. In this substation, single fibre optic network is utilized at station level to achieve MMS, station-wide interlocking GOOSE message and SNTP application; while duplicated networks are applied on process level to achieve GOOSE message and SMV application, one for each set of secondary equipments, and both transmit IEEE 1588 PTP message. Thanks to GMRP, SMV and GOOSE can share the same network. SMV transmission adopts IEC 61850-9-2. Electronic instrument transformers (EIT) -both active and passive ones, together with merging unit (MU) are applied in the substation, except 10kV level where LPIT (Low Power Instrument Transformer) are installed. 110kV lines are equipped with phase segregate current differential relays, which obtain SMV from EITs within substation, and at the same time cooperate with relays at remote ends, which work with conventional instrument transformers. Some relays are supplied by the third party to demonstrate inter-operability among different manufactures. SCD tools are adopted during engineering process to complete configuration of information exchanged among manufactures and intelligent electronic devices (lED). Considering the problems emerging during the implement of IEC 61850, the authors believe that the next step in this area would be: (1) the standardization of network topology,- EIT, MU, and IEC 61850 tools; (2) IEC 61850 application for communication between substations, substation and control center and within wind power plant; (3) on-line monitoring and on-condition maintenance of primary apparatus; (4) adaptive control of primary apparatus.