Correct Answer - Option 3 : 192 V
Voltage Regulation:
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.
E2 = no-load secondary voltage
V2 = 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.
Voltage regulation \(= \frac{{{E_2} - {V_2}}}{{{E_2}}}\)
It can also be expressed as,
Regulation \(= \frac{{{I_2}{R_{02}}\cos {\phi _2} \pm {I_2}{X_{02}}\sin {\phi _2}}}{{{E_2}}}\)
Regulation = %R cos ϕ ± %X sin ϕ
+ sign is used for lagging loads
- ve sign is used for leading loads
Where %R = ohmic drop
%X = reactance drop
As the sign is + ve for lagging loads, the voltage regulation occurs at lagging loads only.
Calculation:
At resistive load, voltage regulation = %R, since reactive drop (%X) is equal to zero.
Total voltage regulation on secondary side = %R
= 4% of 200 V = 8 V
Voltage across the load = E2 – drop on secondary
= 200 – 8 = 192 V