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For a long transmission line, for a particular receiving end voltage, when sending end voltage is calculated, it is more than the actual value when calculated by
Load end capacitance method
Nominal T method
Nominal ╧Аmethod
None of the above methods
Nominal ╧Аmethod
In long transmission lines, the Nominal ╧Аmethod approximates the line by placing half the total line capacitance at each end, whereas the actual distribution of parameters is uniform (distributed). For a fixed receiving end voltage, the Nominal ╧Аcalculation yields a higher sending end voltage because the current drawn by the shunt capacitors at the receiving end is overestimated compared to the actual distributed effects, leading to a higher calculated voltage drop across the series impedance.
In long transmission lines, the Nominal ╧Аmethod approximates the line by placing half the total line capacitance at each end, whereas the actual distribution of parameters is uniform (distributed). For a fixed receiving end voltage, the Nominal ╧Аcalculation yields a higher sending end voltage because the current drawn by the shunt capacitors at the receiving end is overestimated compared to the actual distributed effects, leading to a higher calculated voltage drop across the series impedance.
VsтАЛ=AVrтАЛ+BIrтАЛ
A=D=1+2YZтАЛ
B=Z(1+4YZтАЛ)
The Nominal ╧Аmethod lumps the shunt capacitance at both ends. By concentrating the total line capacitance into two discrete capacitors, the current supplied through the series impedance (R + j╧ЙL)is increased. This higher current magnitude results in a larger voltage drop across the series impedance according to VsтАЛ = VrтАЛ + IsтАЛ Z, thus calculating a sending end voltage that is mathematically higher than the actual line conditions.
Nominal ╧Аmethod lumps shunt capacitance at ends.
Distributed parameter line is the most accurate representation.
Lumping causes an overestimation of the current flow in the series branch.
Nominal ╧Аis preferred over Nominal T for long line analysis due to better representation of shunt capacitors.
Simpler calculation compared to rigorous hyperbolic equations.
Adequate for medium-length transmission lines (80-250 km).
Inaccurate for very long lines (> 250 km) due to lumped parameter assumptions.
Leads to higher error in sending end voltage estimation compared to distributed methods.
Performance analysis of medium-length power transmission lines.
Simplified power flow estimation for preliminary design.
The distributed parameter model using hyperbolic functions (cosh and sinh) provides the exact result for long lines.
Option A (Load end capacitance) is the least accurate method, typically used only for short lines where capacitance is neglected.
C is correct тАФ The Nominal ╧Аmethod results in an overestimation of the sending end voltage because the concentrated shunt capacitance at the receiving end causes a higher calculated series current drop.
Always remember that for long lines, calculations involving hyperbolic propagation constants (╬│=zyтАЛ)are essential for accuracy, whereas Nominal ╧Аis only an approximation.