For a medium transmission line system if the sending end line voltage is 143 kV with the line impedance as 101.24∠74° Ω and shunt admittance of 7.38*10-4∠90° Ω-1 delivering 25 MVA at 0.8 power factor lagging in nature to the load at 132 kV. The voltage regulation is ___________

To calculate the voltage regulation of the medium transmission line, we can use the following formula:

[

text{Voltage Regulation} = frac{V_s – V_r}{V_r} times 100%

]

Where:

– ( V_s ) is the sending end voltage (143 kV or 143,000 V)

– ( V_r ) is the receiving end voltage (132 kV or 132,000 V)

Now we will calculate the receiving end voltage ( V_r ) in relation to the sending end voltage ( V_s ) considering the line impedance and shunt admittance.

1. Calculate the load current (( I_r )):

– The load is delivering 25 MVA at a power factor of 0.8 lagging.

– ( S = P + jQ )

– ( P = 25 times 0.8 = 20 , text{MW} )

– ( Q = P tan(cos^{-1}(0.8)) = 25 times 0.6 = 15 , text{MVar} )

– Thus, ( S = 20 + j15 , text{MVA} )

– The receiving end current can be calculated as:

[

I_r = frac{S^*}{V_r} = frac{20 – j15}{132,