Transelectrica commissions STATCOM units at Sibiu Sud and Bradu

Romanian transmission system operator Transelectrica has marked the completion of modern reactive power compensation works, bringing online static synchronous compensator installations at the Sibiu Sud and Bradu hubs. Supported by European Modernisation Fund capital totalling 260 million lei, the project targets key transmission nodes that step down power across multiple voltage tiers, specifically 400 kV, 220 kV, 110 kV, 37 kV and 20 kV.

The installation of dynamic shunt compensation through voltage-source converter technology directly addresses systemic voltage control challenges across the transmission network. As asynchronous generation expands and conventional synchronous plant retires across South-East Europe, transmission corridors face diminishing short-circuit strength and heightened reactive power volatility. Multi-winding substations operating at 400 kV and 220 kV become vulnerable to voltage excursions during heavy inter-regional transfers or sudden generation trips.

Deploying STATCOM units at these multi-voltage nodes provides rapid, sub-cycle capacitive and inductive reactive power injection. For engineers managing substation infrastructure, dynamic compensation relieves high-voltage transformer banks from the thermal and mechanical stresses associated with continuous reactive power swings and frequent on-load tap changer operations. Alleviating circulating reactive currents lowers core and winding losses within auto-transformers, reducing overall hotspot temperatures and decelerating cellulose degradation under heavy transfer loads.

Moreover, integrating fast-acting solid-state compensation mitigates transient overvoltages, protecting switchgear, bushings and instrument transformers from harmonic resonance and switching surges. Co-locating reactive resources alongside complex multi-voltage busbars operating down to 110 kV, 37 kV and 20 kV also creates a stable local voltage profile for regional distribution systems interfacing with intermittent renewables.

What this means for asset owners in the Balkans and the Black Sea region: Transmission utilities and industrial plant operators across Romania must account for altered harmonics and protection settings when fast-acting converter equipment enters service alongside legacy transformers. Substations interfacing with these STATCOM installations should schedule specialised frequency-response screening and bushing condition assessments during planned maintenance windows, ensuring tap-changer controls and surge arresters are properly coordinated with high-speed dynamic voltage regulation.