Power Grid Corporation of India Ltd (PGCIL) recently commissioned a 400kV digital substation in Punjab, making it India’s first such.
Reliable media reports indicate that the digital substation based on IEC 61850 Process Bus technology, was commissioned at Malerkotla on December 16, 2020.
It is further learnt that the digital substation was a case of retrofitting the existing conventional Malerkotla substation (commissioned in 1992) with full digital technology. Such retrofitting also makes PGCIL one of the few power utilities in the world, to do so.
Extensive studies and testing carried out at POWERGRID’s Protection, Automation and Control (PAC) and Real-Time Simulation (RTS) Labs facilitating improved network design and architecture and multi-vendor IED interoperability which were recognized for standardization of various processes in IEC and CIGRE, it is learnt.
When used in EHV/UHV substations, this IEC 61850 process bus technology provides flexibility in engineering, paves the way for faster commissioning, reduced downtime, enhanced diagnostics, and ease in troubleshooting during asset management.
This technology also helps in reducing environmental footprint with a reduction in requirement of copper cables and civil works, it is learnt.
It is reliably learnt that PGCIL is developing its first fully digital 200kV greenfield substation at Chandigarh. The factory acceptance test (FAT) is complete and commissioning tests are currently underway.
The digital journey
In July 2020, PGCIL announced that the site commissioning activities at the then upcoming Malerkotla substation were in progress. Implementation of this first commercial 400kV fully digital substation was completed in April 2019.
Substation automation using IEC 61850 technology was something that PGCIL has been doing for the past ten years. Till July 2020, grid substation automation was completed in over 100 substations. However, the Malerkotla substation is PGCIL’s first fully digital substation to be put into commercial operations.
It may be recalled that in 2014, a pilot project using IEC 61850 process bus technology was commissioned at the 400/220kV Bhiwadi substation in Haryana. This substation has three 315 MVA 400/220kV transformers, ten 400kV feeders and eight 220kV feeders.
PGCIL used the pilot project at the Bhiwadi substation as a test bed for conducting performance evaluation studies on the network and devices, including examining the conformance of these devices to the IEC 61850 standard.
The complete digital upgrade of the Malerkotla substation required updating the protection and control systems, including the busbar protection system, for the entire substation. IEC 61850 process bus technology had to be installed on all the following components in the air-insulated substation (AIS) switchyard as follows:
- 400kV Malerkotla-Dadri transmission line
- 400kV Malerkotla-Patiala transmission line
- 400kV Malerkotla-Ludhiana transmission line
- Three 400/220kV transformers
- One 50 MVAR bus reactor
PGCIL incorporated advanced networking techniques, such as virtual local area networks and multicast filtering, for efficient network traffic management. As time synchronization was extremely stringent, the devices used were subject to rigorous validation testing.
Featured photograph, sourced from Electrical Engineering Portal, is for illustration only
