Voltage regulation of transformer is given by

Voltage regulation is the change in secondary terminal voltage from no load to full load at a specific power factor of load and the change is expressed in percentage.

 V0 = no-load secondary voltage

V = full load secondary voltage

Voltage regulation for the transformer is given by the ratio of change in secondary terminal voltage from no load to full load to no load secondary voltage.

\(Volatge\;regulation = \frac{{{V_0} - {V}}}{{{V_0}}}\;\)  

Additional InformationVoltage regulation can be expressed as a fraction or unit-change of the no-load terminal voltage and can be defined in one of two ways,

1. Voltage regulation-down, (Regdown) and
2. Voltage regulation-up, (Regup)
    

• When the load is connected to the second output terminal, the terminal voltage goes down, or when the load is removed, the secondary terminal voltage goes up.
• Hence, the regulation of the transformer will depend on which voltage value is used as the reference voltage, load or non-load value.
   

Transformer Voltage Regulation as a Percentage Change:

Transformer when connected to load:

%Reg = \(\frac{V_{NL}-V_{FL}}{V_{NL}}\)

Transformer under no load:

%Reg = \(\frac{V_{NL}-V_{FL}}{V_{FL}}\)