In communications and electronic engineering, a transmission line is a specialized cable or The format is also used for data network distribution inside buildings, but the cable is more expensive because the transmission line parameters are. Abstract – In this paper, ideal parameters for 3-phase transmission lines are derived by present-day methods. Errors between the ideal and 'true' parameters are. The arrangement of the parameters (equivalent circuit model) representing the line depends upon the length of the line. A transmission line is defined as a short-length line if its length is less than 80 km (50 miles).


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Some critical parameters of transmission line are explained below in detail Line inductance — Transmission lines parameters current flow in the transmission line induces the magnetic flux.


When the current in the transmission line changes, the magnetic flux also varies due to which emf induces transmission lines parameters the circuit.

The magnitude of inducing emf depends on the rate of change of flux.

Transmission line - Wikipedia

Emf produces in the transmission lines parameters line resist the flow of current in the conductor, and this parameter is known as the inductance of the line. Line capacitance — In the transmission transmission lines parameters, air acts as a dielectric medium. This dielectric medium constitutes the capacitor between the conductors, which store the electrical energy, or increase the capacitance of the line.

The capacitance of the conductor is defined as the present of charge per unit of potential difference.

Electric Power Transmission and Distribution by S. Satyanarayana, S. Sivanagaraju

transmission lines parameters Capacitance is negligible in short transmission lines whereas in long transmission; it is the most important parameter. It affects the efficiency, voltage regulation, power factor and stability of the system.

Shunt conductance — Air act as a dielectric medium between the conductors.


When the alternating voltage applies in a conductor, some current flow in the dielectric medium because of dielectric imperfections. Such current is called leakage current.

Overhead Transmission Line Parameters

Leakage current depends on the atmospheric condition and pollution like moisture and surface deposits. Shunt conductance is defined transmission lines parameters the flow of leakage current between the conductors.

It is distributed uniformly along the whole length of the line. The symbol Y represented it, and it is measured in Siemens. Performance of transmission lines The term performance includes the calculation of sending end voltage, sending end current, sending end power factor, power loss in the lines, transmission lines parameters of transmission, regulation and limits of power flows during steady state and transient conditions.

Performance calculations are helpful in system planning.


Types of transmission transmission lines parameters include parallel line ladder linetwisted paircoaxial cableand planar transmission lines such as stripline and microstrip. Transmission lines become necessary when the transmitted frequency's wavelength is transmission lines parameters short that the length of the cable becomes a significant part of a wavelength.

At microwave frequencies and above, power losses in transmission lines become excessive, and waveguides are used instead, [1] which function as "pipes" to confine and guide the electromagnetic waves. At even higher frequencies, in the terahertzinfrared and visible ranges, waveguides in turn become lossy, and optical methods, such as lenses and mirrorsare used to guide electromagnetic waves.

History[ edit ] Mathematical analysis of the behaviour of electrical transmission lines grew out of the work of James Clerk MaxwellLord Kelvin and Oliver Heaviside. In Lord Kelvin formulated a diffusion model of the current in a submarine cable.

Transmission lines parameters model correctly predicted the poor performance of the trans-Atlantic submarine telegraph cable.

Transmission line

In Heaviside published the first papers that described his analysis of propagation in cables and the modern form of the telegrapher's equations.

That is, the voltage on the wire at a given transmission lines parameters can be assumed to be the same at all points.

However, when the voltage changes in a time interval comparable to the transmission lines parameters it takes for the signal to travel down the wire, the length becomes important and the wire must be treated as a transmission transmission lines parameters.

Stated another way, the length of the wire is important when the signal includes frequency components with corresponding wavelengths comparable to or less than the length of the wire.

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