VOLTAGE REGULATION of Transmission line:When a transmission line is carrying a current, there is a voltage drop in the line due to the resistance and inductance of the transmission line.Finally, the RECEIVING end voltage ( VR ) of the line is generally less than the sending end voltage (VS)The difference in voltage at the receiving end of the transmission line between the conditions of no-load and the full load is called voltage regulationVoltage regulation is expressed as a percentage of the receiving end voltage. \(V.R =\frac{V_S - V_R}{V_R} \times 100=\frac{{\left| {V_R^{NL}} \right| - \left| {{\rm{V}}_{\rm{R}}^{{\rm{FL}}}} \right|}}{{\left| {{\rm{V}}_{\rm{R}}^{{\rm{FL}}}} \right|}} \times 100\)Note: At no load, \(|V_S|=|V_R|\)