How transformer matching works
BecSpec separates what the open register can prove from what still needs engineering verification.
1. Hard electrical filters
Primary and secondary voltage, phase, SWER status and transformer type are treated as compatibility constraints when specified. Required kVA is a minimum: a lower-rated transformer is excluded; a higher-rated unit is shown as a difference because upsizing can change protection, regulation and installation requirements.
2. Efficiency comes after compatibility
Registered tested power efficiency is compared with regulator-published MEPS and High Power Efficiency thresholds. Intermediate kVA thresholds are derived by linear interpolation. Candidates that otherwise tie are ordered with HPE-or-better units first, then by tested efficiency.
3. Unknown is not compatible
The GEMS export does not completely record vector group, impedance, tap range, mounting, bushings, footprint, mass or guaranteed no-load/load losses. BecSpec therefore marks these as verification items. It does not fill gaps from generic manufacturer ranges.
4. Network rules matter
Australian network standards show that nominal impedance, vector group and tap requirements can differ by network and even by region within one network. A future network-aware layer can strengthen a candidate verdict, but a public registration match is never a substitute for the applicable network/site design and supplier documentation.