Development of Digital substation – Methodical approach in Utility context
Over a period of time with the development in communication and processing technologies Substation technology has evolved right from conventional substation to Digital substation. In this process, concept of SCADA substation based on IEC 61850 automation has taken place. Till recent years, the focus of Substation Automation was limited among Intelligent Electronic Devices (IEDs) installed in secondary network such as protection and control modules and station level systems. This technology is quite mature and being widely adopted across the industry.
But, with technological advancement as well as further development of IEC 61850 standard, digital technologies can be extended even to primary devices such as instrument transformers and switchgears.
As implied by international standards for digital substation, it is the substation of Ethernet links instead of hard wiring. We could say that it means paradigm shift in design of Substation Automation System. To adopt concept of Digital substation, mature and new technologies/standards coexist within the portfolio of technologies which are needed to build up the concept.
There are many standards (IEC 61869, IEC 61850-9-2LE, IEC 62271, IEC 62351 etc.) either developed but not implemented widely or under development for adoption of process bus technology. But, there is lack of standard methodology or guidelines for implementation. Also, there are concerns among users regarding reliability & performance due to digitization of primary inputs.
Looking to complexity and involvement of many standards, Digital substation cannot be built overnight. It is an evolving process having methodical approach in understanding complexities and gaining experience with various attributes. The approach should be;
Station Bus technology → Optimum utilization of technology → GOOSE for Interlocking → GOOSE for protection → Establishment of Network performance → Confidence building → Process Bus pilots with different configurations and complexities → IEC 61850 edition 2 adoption → Cyber security aspects → the Digital Substation.
GETCO initiatives and approaches in the direction of digital substation are discussed in the paper explaining challenges faced, configuration modifications and set of new configurations adopted at different stages of the processes. Finally, future outlook with planning of full-fledged 220/66 kV digital substation is discussed with a goal to establish a model substation and there by building confidence among users for wide adoption.
It is expected that standardization of the technical solutions and operational experience from pilot projects will address the challenges and digital substation will become reality as permanent solution to Substation Automation System.
MU, ICU, SCU, NCIT, PTP, ITIG-B, PRP, SV, GOOSE, GGIO, HSR, MMS, RSTP, SNTP.