Electrical Formula Part-II

Transformer: 

Secondary Amperes 1-phase=VA/Volts

Secondary Amperes 3-phase=VA/Volts x 3

Secondary Available fault 1-phase=VA/(Volts x %impedance)

Secondary Available fault 3-phase=VA/(Volts x 3 x %impedance)

Delta: Line Voltage=Phase Voltage

Delta: Line Amperes=Phase Amps x Sqrt(3)

Wye : Line Voltage=Phase Voltage x Sqrt(3)

Wye: Line Amperes=Phase Amps

Base Current = Base KVA / Base Voltage

Base Impedance = Base Voltage / Base Current

Base Impedance=Base Voltage KV²/Base MVA

Per Unity Quantity = Actual Quantity / Base Quantity

Per Unit Impedance = Impedance in ohms x MVA(Base) / KV(base)²

Z_new(pu)=Z_old(pu) x (MVA_new/MVA_old) x (KV_old/KV_new)² 

BUSBAR: 

Fault withstand capacity of Busbar = 35 KA RMS for one second 

OTHERS: 

Area of Circle=π r2

Length of Coiled Wire=Diameter of coil x Number of coil x π
Temperature ^oC = (Temp F - 32) / 1.8
Temperature ^oF = (temp C x 1.8) + 32