Define lines parameters, Electrical Engineering

Assignment Help:

Define Lines Parameters

In power system analysis, the parameters of interest when modelling power lines are:  inductance, capacitance, series resistance and leakage resistance. A 3-phase line with equilateral spacing of the conductors is shown in Figure. When performing power system studies on 3-phase systems it is usual to use a single-phase equivalent circuit. Therefore, the equivalent 1-phase or line to neutral (hypothetical neutral conductor) equivalent parameters are of interest. It can be shown that the 1-phase equivalent inductance and capacitance of a 3-phase line (assuming D > > r) are given as:

925_Lines Parameters 1.png

where D  is the distance between the centres of the conductors,

 r  is the radius of the conductors,

  μo = 4 π × 10-7   H/m   is the free space magnetic constant,

  εo = 8.854 × 10-12  F/m  is the free space electric constant.

It may be of interest to note that  L × C  =  μo × εo

If the conductors are not spaced in the equilateral formation, the flux linkages and hence the inductance of each phase are not the same. It follows that the resultant 3-phase circuit is unbalanced even when the supply voltages and the load currents are balanced. To provide for this problem, the position of the conductors are exchanged at regular intervals along the line, as shown in Figure.

This technique is called 'Transposition'.

In this case, an equivalent spacing between conductors is normally used as:

1103_Lines Parameters.png

The series resistance of the line is the effective a.c. resistance of the conductors which is higher than the d.c. resistance due to skin effect. The leakage resistance represents the combined effect of all various paths from the conductor to earth. It is difficult to assess the value of the leakage resistance due to its dependence on the weather conditions. Normally, its value is very high for most calculation purposes, and the leakage current is negligible.


Related Discussions:- Define lines parameters

Permeability and b-h curve for different magnetic materials, Permeability a...

Permeability and B-H curve for different magnetic materials Permeability is the ability of a magnetic circuit to create magnetic flux lines in a material or substance that prod

Effect of temperature on resistivity of conducting materials, Explain the e...

Explain the effect of temperature on the resistivity of conducting materials. The resistance of most metals rises with rise of temperature whereas that of semiconductors and el

Compute the minimum line current for the motor, A three-phase, wye-connecte...

A three-phase, wye-connected, four-pole, 400- V, 60-Hz, 15-hp synchronous motor has a synchronous reactance of 3  per phase and negligible armature resistance. The data for its no

Show procedure of divide the decimal number by 2, Q. Show procedure of divi...

Q. Show procedure of divide the decimal number by 2? For this procedure (method), divide the decimal number by 2, if the remainder is 0, on the side write down a 0. If the rema

555 timer ic, i wanted the exact names of the components of the internal ci...

i wanted the exact names of the components of the internal circuit of a 555 timer ic

Carrying out repairs on lt and ht switch gear, Precautions to be taken in c...

Precautions to be taken in carrying out repairs on HT and LT switch gear? Ans: The following precautions to be taken in carrying out repairs on LT and HT switch gears. a

Working out the function of a combination of gates, Working out the functio...

Working out the function of a combination of gates? Truth tables are able to be used to work out the function of a combination of gates. Inputs Outputs

Electronics, why inductive load is use in electronics circuit?

why inductive load is use in electronics circuit?

Illustrate about transfer functions, Q. Illustrate about Transfer Functions...

Q. Illustrate about Transfer Functions? The transfer function is a means by which the dynamic characteristics of devices or systems are described. The transfer function is a ma

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd