Glossary · Electrical · Grid
MVA — Megavolt-Ampere
The unit used to rate transformer and substation capacity in electrical grids.
Definition
MVA (Megavolt-Ampere) is the SI unit of apparent electrical power. It is the product of voltage (V) × current (A), expressed at the mega scale. Apparent power (MVA) differs from real power (MW) by the power factor (PF):
MW = MVA × Power Factor
For typical data center loads (PF 0.9–0.95): 650 MVA × 0.92 ≈ 598 MW
Why substations are rated in MVA
Transformers and switchgear are rated in MVA because they must handle both real (active) and reactive power components of the load. The MVA rating sets the thermal limit of the transformer — the maximum current it can carry without overheating.
650 MVA at Resita
The Transelectrica substation adjacent to the Resita Data site has 650 MVA installed capacity across 400/220/110 kV voltage levels. This represents the total transformer bank capacity at the substation — the physical infrastructure already installed and operational.
A data center consumer applying for an ATR at this node would request 50–200 MW of real power (approximately 54–217 MVA at PF 0.92). The 650 MVA substation has the headroom to accommodate this request alongside existing loads — confirmed by the ATR study initiated April 2026.