Why a charging current exists in a line even when it is open circuited at the load end?
Table of Contents
- 1 Why a charging current exists in a line even when it is open circuited at the load end?
- 2 What is an open circuited transmission line?
- 3 What causes the charging current in transmission line?
- 4 How is the relation between charging reactance and length of the transmission line?
- 5 What purposes can short lengths of open or short-circuited transmission line be used?
Why a charging current exists in a line even when it is open circuited at the load end?
The line, with two parallel conducting wires with air dielectric in between, acts as capacitor and draws a leading reactive current from the generator. That’s line charging current and obviously it exists even when there is no load connected at the receiving end.
What is an open circuited transmission line?
When the transmission line is opened from the load end, it is known as open circuited transmission line. Open Circuited Transmission Line. As shown in the diagram, at the open circuited end the current is minimum and voltage is maximum.
What is the long transmission line?
A power transmission line with its effective length of around 250 Kms or above is referred to as a long transmission line. The line constants are uniformly distributed over the entire length of the line.
What causes the charging current in transmission line?
When the voltage is applied across the sending end of the transmission line, current starts flowing between the conductors (due to imperfections of the dielectric medium). This current is called the charging current in the transmission line.
How is the relation between charging reactance and length of the transmission line?
Charging reactance , is inversely proportional to AC capacitance C. and AC capacitance in Farads is directly proportional to length of charging reactance. so, charging reactance of 100 km length of line is 1500/2 = 750 ohms .
What is open stub?
In microwave and radio-frequency engineering, a stub or resonant stub is a length of transmission line or waveguide that is connected at one end only. The free end of the stub is either left open-circuit, or short-circuited (as is always the case for waveguides).
What purposes can short lengths of open or short-circuited transmission line be used?
Open-Circuited Transmission Lines Note that we can use open- and short-circuited transmission lines as substitutes for inductors and capacitors if a reactance is desired. This is often done in practice.