- #1
yabb dabba do
- 7
- 0
Why is there a shunt capacitance in a transmission line, but not in a normal circuit (non-transmission line).?
yabb dabba do said:Why is there a shunt capacitance in a transmission line, but not in a normal circuit (non-transmission line).?
anorlunda said:Do you mean a power transmission line? If yes, it is because power lines have very high voltages, and their length can be hundreds or even a thousand miles. So called stray capacitance is quite significant in those conditions.
The phrase transmission line also applies to communications. They should not be confused with power transmission lines.
In power grid simulations, we include shunt capacitance in all lines longer than about one kilometer. It has nothing to do with wavelength.yabb dabba do said:I think the same transmission line models are used as long as the length of the transmission line is quite long relative to wave length
anorlunda said:Do you mean a power transmission line? If yes, it is because power lines have very high voltages.
jaus tail said:But formula for capacitance is C = Q/V.
So higher voltage, lower capacitance... ?
Every wire in every circuit has capacitance. It exists, for instance, between the conductors of a telephone line, and also between every conductor and the rest of the Universe.yabb dabba do said:Why is there a shunt capacitance in a transmission line, but not in a normal circuit (non-transmission line).?
Transmission line shunt capacitance refers to the capacitance that exists between the conductors of a transmission line. It is a measure of the ability of the transmission line to store electrical energy when an alternating current is applied.
Transmission line shunt capacitance can cause signal distortion, power loss, and interference in the transmission line. Therefore, it is important to accurately calculate and account for the shunt capacitance in order to ensure efficient and reliable transmission of electrical signals.
The shunt capacitance of a transmission line can be calculated using the geometric mean radius (GMR) of the conductors, the distance between the conductors, and the permittivity of the surrounding medium. It can also be measured experimentally using specialized equipment.
The shunt capacitance of a transmission line is affected by the spacing between the conductors, the diameter of the conductors, and the dielectric materials surrounding the conductors. It is also influenced by the frequency and voltage of the signal being transmitted.
Transmission line shunt capacitance can be reduced by increasing the spacing between the conductors, using smaller diameter conductors, and using materials with lower permittivity. Additionally, using twisted pair or coaxial cables can help reduce shunt capacitance in transmission lines.