Transelectrica launches digital upgrade at Alba Iulia substation

Transelectrica has initiated a comprehensive digital modernisation programme at its Alba Iulia substation, structured as an operational pilot for wider deployment across the national transmission network. The scheme represents a capital commitment of €90.4 million, supported by €43 million of non-repayable funding. A turnkey consortium has secured the design and construction package, with academic research participation supporting technical execution.

The Alba Iulia node interfaces critical transmission and distribution corridors across the 220 kV, 110 kV and 20 kV levels. Full digital transformation of such multi-voltage nodes requires moving from conventional copper hardwiring to optical process-bus communications and digital instrumentation. For substation engineers, this shifts the operational profile of protection and control systems, requiring precise synchronisation between primary switchgear, instrument transformers and modern numerical protection relays.

Refurbishing an active substation without jeopardising regional security of supply creates complex staging demands. Power transformers linking the 220 kV transmission network to 110 kV and 20 kV distribution feeds must either undergo staged replacement or be retrofitted with intelligent electronic interfaces. Engineers face delicate commissioning sequences where legacy analogue signalling coexists alongside modern digital architectures during transition phases. If protection schemes fail to coordinate across these differing interfaces during transient grid disturbances, the risk of spurious tripping rises substantially. Furthermore, the integration of process-bus networks demands rigorous validation of switchgear to ensure circuit breakers respond correctly to sampled-value commands without latency.

What this means for asset owners in the Balkans and the Black Sea region: Transmission utilities and industrial operators in Romania and neighbouring systems face a narrow maintenance and commissioning window when implementing digital bus architectures on operating brownfield assets. Teams must schedule staged busbar outages well ahead of switchgear changeovers, while thoroughly pre-testing bay control units and circuit breakers before cutover, ensuring that legacy protection interfaces do not trigger spurious trips on vital supply lines during the transition to fully digital substations.