1. Project and commercial

• Project name, location and delivery destination
• Quantity and any phasing
• Required on-site date
• Incoterm: FOB, CIF or DDP
• Applicable standards (IEEE C57, IEC 60076, CSA, UL) and utility specification
• Approved-vendor, factory witness testing or documentation requirements

2. Electrical ratings

• Rating in kVA or MVA, including cooling stages (for example ONAN/ONAF)
• HV and LV voltages, phases and frequency (50 or 60 Hz)
• Vector group
• Impedance
• Basic insulation level (BIL) on each winding
• Tap changer: on-load or de-energized, and tap range

3. Construction

• Type: power, pad-mount, station-type, dry-type or special
• Cooling class and insulating fluid (mineral oil or natural ester such as FR3)
• Winding conductor preference, if any
• Enclosure, protection grade and paint requirements
• Sound level limit

4. Performance

• No-load and load loss limits, or efficiency standard (for example DOE 2023)
• Loss evaluation factors, if losses are capitalized
• Temperature rise limits

5. Accessories and monitoring

• Bushing types and terminations
• Current transformers and surge arresters
• Online monitoring and protection devices
• Gauges, relays and control cabinet requirements

6. Site conditions

• Altitude and ambient temperature range
• Seismic requirements
• Indoor or outdoor installation; pollution level

7. For battery storage

• Power (MW) and energy (MWh), or duration
• Use case and expected cycling
• Point-of-interconnection voltage and grid code
• Scope: batteries, PCS, MV transformer, controls

Documents to attach

• Single-line diagram
• Technical specification or RFP
• Utility interconnection requirements