SPECIFICATION SHEET β€’ SI METRIC
CAT: ELECTRICAL-ENERGY

Transformer kVA Rating & Load Sizing (IEC 60076)

Calculate minimum required transformer kVA capacity rating and secondary full-load current based on active load (kW) and power factor.

πŸ’‘ Engineering Knowledge PrimerIndustrial electrical substations require sizing step-down transformers to handle active real power (kW) and reactive power (kVAR) while maintaining a 15–25% thermal capacity margin for future motor expansions per IEC 60076.
OPERATING LIMITS β€” kVA calculation only; equipment selection needs a load study, harmonics and protection coordination.
INPUT DESIGN PARAMETERS (SI)
kW
1
%
V
CALCULATED SPECIFICATION OUTPUT
Required Transformer Rating
⚑
705.9 kVA
Secondary Full Load Line Current982 A

Related planning checklists

This calculator appears in the following engineering planning checklists:

1. Three-Phase Electrical Power2. Motor Current Estimation3. Transformer kVA Rating & Load Sizing (IEC 60076)4. Plant Energy Consumption & Cost
1. Three-Phase Electrical Power2. Transformer kVA Rating & Load Sizing (IEC 60076)3. Battery Runtime & Backup Capacity
1. Three-Phase Electrical Power2. Power Factor Correction & Capacitor Sizing3. Transformer kVA Rating & Load Sizing (IEC 60076)

Technical Methodology & Engineering Principles

GOVERNING EQUATION
kVA = (kW / Power Factor) Γ— (1 + Margin% / 100) Secondary Current A = (kVA Γ— 1000) / (√3 Γ— Voltage_sec)
Assumptions & Scope

Standard 3-phase step-down transformer operating below rated thermal rise limit.

Operating Range & Boundary

Use finite, physically meaningful inputs within the stated operating assumptions.