# Transmission Line Inductance

I went for an interview in BARC India for scientist position. They asked me to draw short transmission line. Then they started asking

What does inductance represent? I said leakage while transmission

Then they said how we can decrease it? I said keep a series capacitor in series.

Then they asked why we can't make it 0? It will be good that power transfer capability increases

Why we don't do that? Here I got confused. Please someone clarify this concept.

My question is that

What will happen if we use a zero inductance line for AC transmission?

What problems it might face?

• Did you learn anything in class? if so , what is Inductance ??? If you cannot anwswer this you should go back and learn properly. Jun 10 '18 at 12:21
• Since, the current is alternating so there is rate of change of current. So we are getting inductance property for transmission line when there is an AC current. Jun 10 '18 at 12:27
• Poor answer. You must master the basics. What is L? what is $\mu$ ? What physical ratios affect effective L? Jun 10 '18 at 12:29
• Sir I will work on it. I am preparing for an interview. So, please can you help me with the question. Jun 10 '18 at 12:31
• Sorry sir if I am sounding as not wiilling to learn kind of guy. But I have interviews going on for job. The teaching condition here in India is not very good. I have learned more from this website than from my teachers at college. Also I am from one of the top colleges in India but the condition is very bad. Jun 10 '18 at 12:44

The short transmission line model is a specific model in transmission line theory that is simplified and does not include shunt capacitance (-jX) as it does in the medium line model. Nor does it include the shunt admittance as it does in the long line model.

Its only impedance is Z = R + jX where X is positive because it is an inductance. (See first sketch in diagram, this is what you should have drawn. Vs is sending voltage and Vr is receiving voltage, so we have a frame of reference of this line.)

Inductance in this model relates to the transmission line's capacity to move real and reactive power across the line.