Transformer Sizing Calculation Record (Excel)
Free download · Excel (.xlsx)
Document transformer sizing decisions with this structured Excel template. Captures connected load, demand factors, maximum demand, future growth allowance, selected rating, impedance, fault level contribution, cooling type, vector group, tap range, and efficiency. Compliant with IEC 60076 and IEEE C57 methodology. Use for design verification and audit trail on projects requiring transformer specification justification.
What's Included
How to Print
- ●Open in Microsoft Excel 2016+, Google Sheets, or LibreOffice Calc
- ●Add your company logo and project details to the header
- ●Copy data rows to add more circuits or equipment
- ●Print on A4 or A3 landscape for site records
- ●Keep completed records for design verification and audit trail
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Frequently Asked Questions
What is a transformer sizing calculation record?
A transformer sizing calculation record documents the process of selecting an appropriately rated transformer based on connected load, demand factors, future growth, and system requirements per IEC 60076 and IEEE C57. It provides an auditable record of the sizing decision.
What should a transformer sizing record include?
Key fields include connected load kVA, demand factor, maximum demand, future growth percentage, selected transformer rating, impedance, X/R ratio, secondary fault level, cooling type (ONAN/ONAF), vector group, tap range, no-load and full-load losses, and efficiency.
How do you determine the correct transformer size?
Calculate maximum demand by applying demand factors to connected loads, add a margin for future growth (typically 10–20%), then select the nearest standard rating above the design load. Verify that impedance gives acceptable fault levels and voltage regulation. IEC 60076 defines standard ratings.