Join 60,000+ competitive exam aspirants
or with email
Your Cart
SubtotalтВ╣0
TotalтВ╣0
Examoogle тАв User тАв info@examoogle.com тАв EE-2024-8821
Chapter 1 of 12 тАв Page 1 of 248ЁЯФТ Protected PDF тАв Watermarked
Join 60,000+ competitive exam aspirants
In which one of the following models of transmission lines, is the full charging current assumed to flow over half the length of the line only ?
Equivalent-╧А
Short line
Nominal-╧А
Nominal-T
Nominal-T
Quick Summary: In the Nominal-T model of a medium transmission line, the total shunt capacitance is concentrated at the center of the line. Consequently, the entire charging current is assumed to flow through the impedance of the first half of the line, effectively treating the line as two series sections of impedance $Z/2$ separated by a shunt admittance $Y$ at the midpoint.
In the Nominal-T model of a medium transmission line, the total shunt capacitance is concentrated at the center of the line. Consequently, the entire charging current is assumed to flow through the impedance of the first half of the line, effectively treating the line as two series sections of impedance Z/2 separated by a shunt admittance Y at the midpoint.
IchтАЛ=VmidтАЛтЛЕY тАФ Charging current flowing through the midpoint shunt element
VsтАЛ=VrтАЛ+IrтАЛ(Z+4ZYтАЛ) тАФ Voltage relationship for Nominal-T model
The Nominal-T model represents a medium line by dividing the series resistance and reactance into two equal parts, each R/2+jX/2. The shunt capacitive susceptance Y=j╧ЙC is placed at the node between these two series elements. Because all the shunt capacitance is concentrated at the middle, the full charging current IchтАЛ=VmidтАЛтЛЕY passes through the source-side half of the line impedance, while the load-side half carries the load current only.
Nominal-T model is used for medium transmission lines (80km to 250km).
Series impedance is split equally into two parts: Z/2.
Total shunt admittance is lumped at the exact center of the line.
Used for calculating ABCD parameters of medium lines.
Simpler mathematical analysis than rigorous distributed parameter model.
Provides reasonably accurate results for lines of medium length.
Lumping the parameters introduces approximation errors.
Not suitable for long transmission lines where distributed parameters are critical.
Medium length overhead transmission line analysis.
Calculation of voltage regulation and efficiency in power systems.
| Feature | Nominal-T | Nominal-╧А |
|---|---|---|
Capacitance Location | Mid-point | Divided at ends |
In the Nominal-╧А model, the total shunt capacitance is divided into two halves, each placed at the sending and receiving ends.
The Short line model ignores capacitance entirely and considers only series impedance.
D is correct тАФ In the Nominal-T model, the entire shunt capacitance is lumped at the midpoint, forcing the full charging current to pass through the first half of the line impedance.
Always remember: T-model lumps capacitance in the middle (T-shape), while ╧А-model splits capacitance at the ends (╧А-shape).