First Digital Substation ? A journey, business case, lessons

Authors:Hinkley, TransGrid, and Chirag Mistry, GE Grid Solutions, Australia

IEC 61850 has now been accepted 'almost unequivocally' as the preferred standard for substation communications. Utilities and industries across the world are at various stages of adoption of this standard. The extent of utilization of this standard in the majority of installations around the world is at ‘station bus’ level with IEC 61850-8-1 reporting and GOOSE. Moving further along the digitization chain, it is foreseen that numerous benefits can be availed if process values (e.g. currents/voltages/switchgear status) are digitized as close to the source as possible (i.e. in the switchyard) and utilized in the automation system. 

Protection and control systems have come a long way since the time schemes were realized with discrete boxes per function and interconnections hardwired. Functional integration in static and numerical devices helped reduce the number of boxes, connections and eventually led to compact panels. 

This technological evolution curtailed capital costs for the materials for green field as well as Protection and Control expansion/replacement projects. With maturity in design, benefits along this axis seem to have plateaued.

The quest now is how to achieve further cost reduction. IEC 61850 standard offers numerous benefits along the life cycle of automation systems - right from design and engineering to deployment and operation. As opposed to being just a communication protocol, IEC 61850 addresses whole gamut of processes such as engineering, tools, validation and so on.

Utilities and industries world-wide have adopted IEC 61850 quite well. However, the implementation is predominantly focused on ‘Bay level’ and ‘Station level’. Figure 1 depicts conceptual segregation of substation automation systems on three levels - ‘Process’, ‘Bay’ and ‘Station.’

Digital substation, in which primary process data (currents, volts, status etc.) are digitized close to the source, has enormous potential to drive down CAPEX as well as OPEX. 

The example presented in this article, Digital Substation - Avon, is a culmination of TransGrid’s efforts to find a solution that can deliver low cost refurbishment projects for the secondary systems assets with 20 years life and also deliver cost effective connections for renewable connection projects.

BeijingSifang June 2016