Process Bus Design and Implementation Aspects for a Digital Substation

This paper describes the important design aspects for implementing an alternate solution called process bus in digital substations, replacing the traditional hardwired solutions utilizing integrated multi-function relays. IEC 61850-9-2 is a globally accepted standard for process bus solutions. However, its adoption by utilities has been gaining momentum in recent days after the implementation of the IEC 61850-based substation automation system at the station level, which offers various advantages of standardization and interoperability, including in India. It is important to understand the latest design aspects in IEDs related to the process bus to emphasize the various benefits of implementing such solutions. Process bus relates to the engineering, construction, commissioning, and routine maintenance for transitioning from traditional Protection and Control (P&C) based systems to modern systems. Although the benefits of deploying practical IEC 61850 process bus-based P&C systems are majorly accounted for as cost savings and reduced labour costs, particularly in greenfield installations, not all benefits can be understood as only specific monetary savings. Several advantages relate to the ability to better optimize the utilization and deployment of substation resources, improving the overall efficiency in using the substation equipment’s data and improving operations with increased situational awareness. This paper presents evidence of how process bus design, related architecture and features can provide several advantages in substation modernization and operation for widespread adoption in the Indian power sector.