Load Parameters
Design Margins
System Voltages
Calculated Demands
Base Load (Sbase)
-
Design Load (Sdes)
-
Selection & Rating
Selected Transformer
- kVA
Loading Percentage
-%
Rated Currents (Full Load)
HV Current (IHV)
- A
LV Current (ILV)
- A
Technical Notes & Engineering Logic
Variable Definitions
- Sbase (kVA): Raw connected load converted to Apparent Power (kW / PF).
- Sdes (kVA): Final design load including Diversity, Growth, and Safety factors.
- IFL (Amps): Rated full-load current of the selected transformer.
Formulas
- Sdes: Sbase × Diversity% × (1+Growth%) × (1+Safety%)
- Current (3φ): I = (kVArated × 1000) / (√3 × VLL)
- Loading: (Sdes / kVArated) × 100%
Assumptions
- Standard IEC 60076 ratings used (e.g., 630, 800, 1000 kVA).
- Efficiency/Losses are not calculated here.
- Calculations assume a balanced 3-phase system.