Process bus technology - the Final leap towards fully digitized substations

From the last few years, POWERGRID has been actively adopting Substation Automation Systems (SAS) at Station Level (between control & protection IEDs and HMI), but, the point to point connections between the equipment in the switchyard and control & protection IEDs (Process Level)are still being provided using copper wiring. Although such systems are comparatively better than earlier conventional systems, they still have huge number of point to point copper wire connections between substation equipment and IEDs. Due to which protection engineers are still facing difficulties while trouble shooting and maintaining such systems.

To overcome these deficiencies, adoption of Process Bus Technology is a suitable option, which would help in complete digitization. In Process Bus technology, data gathered from equipment (like instrument transformers, circuit breakers, isolators and earth switches) is immediately sampled, digitalized, formatted and transmitted through the process bus LAN to Bay/Unit Level based on an internationally accepted standard (IEC 61850). Following an international standard ensures interoperability between substation equipment of various manufacturers and helps utilities in avoiding systems and solutions which are ‘closed’ and ‘vendor lock-in’ in nature. This technology is best utilized when used in conjunction with Non Conventional Instrument Transformers, though, conventional instrument transformers can also be integrated easily.

In the first step towards achieving fully digitized substations, POWERGRID has successfully commissioned a demo project on Process Bus Technology along with Optical Current Transformerat POWRGRID's 400 kV Bhiwadi Substation. This paper talks about the evolution of Substation Automation Systems in the context of achieving the aim of fully digitized substations. This paper would also throw some light on the implementation of POWERGRID's Process Bus pilot project.