Sage-Tips

How do transmission lines work?

Transmission lines are sets of wires, called conductors, that carry electric power from generating plants to the substations that deliver power to customers. At a generating plant, electric power is “stepped up” to several thousand volts by a transformer and delivered to the transmission line.

What are the factors influencing the resistance of transmission line conductor?

The temperature of the conductor. The cross-sectional area of the conductor. Length of the conductor. Nature of the material of the conductor.

What is Ferranti effect on transmission line?

The Ferranti Effect is a voltage increase in the receiving end of an electrical transmission line when it is operated in a no-load, or low-load, condition. This results in a receiving end voltage value higher than the sending point. This phenomenon was discovered by electrical engineer Sebastian Ziani de Ferranti.

Why Ferranti effect is bad?

Therefore, the Ferranti effect tends to be a bigger problem on lightly loaded lines, and especially on underground cable circuits where the shunt capacitance is greater than with a corresponding overhead line. As inductive load is added, the VAR generated by the line capacitance is consumed by the load.

What is a transposed line?

This is called transposed lines. Transposition in Power Transmission Lines: Transposition of transmission lines is the periodic swapping of positions of the conductors of a transmission line, in order to reduce crosstalk and otherwise improve transmission.

Why are conductors not transposed in transmission lines?

When conductors such as telephone lines are run in parallel to transmission lines, there is a possibility of high voltages induced in the telephone lines. This can result in acoustic shock or noise. Transposition greatly reduces this undesired phenomenon. In practice, however, conductors are not transposed in the transmission lines.

What are the advantages of transposing transmission line?

Advantages of Transposing Transmission Line: When conductors are not transposed at regular intervals, the inductance and capacitance of the conductors will not be equal.

Why are voltage drops in transmission lines not the same everywhere?

So the voltage drops are not same as one place to another. To eliminate this effect can simply do by interchange the conductor position which is known as transposition. When the transmission line is more than 100 km long, then, as per electrical requirements three phases needed to be transposed.