Performance of Transmission Line & Travelling Wave Analysis For Electrical Engineering

where, β = Phase shift in red/mile

Key Points

• Surge impedance for the transmission line is 400Ω and for cable, it is 40 Ω.
• The phase angle of surge impedance (Z_C) of transmission lines is in range of 0^o to -15^o.
• If loading of the = SIL, then the power factor will be unity. Hence, maximum power can be transferred and the line can be called as the flat line.
• If loading of line < SIL, then power factor will be leading.
• If loading of line > SIL, then power factor will be lagging.

Wave Phenomenon

Refracted (transmitted) wave = Incident (forward) wave + Reflected wave

V_T = V_F + V_R

where, V_T = Refracted (transmitted) voltage wave

V_F = Incident or forward voltage wave

V_R = Reflected voltage

Transmission Line Termination

Case (1) Open-Ended Line

• Current becomes at load end zero. Due to this electromagnetic energ

Transmission Line

A transmission line is a set of conductors being run from one place to another supported on transmission towers. Therefore, such lines have four distributed parameters, series resistance, inductance shunt capacitance and conductance.

Transmission lines are typically made of conductive materials, such as copper or aluminum, that have low resistance to allow for efficient power transmission. They are used in both overhead and underground applications, depending on the specific requirements and environmental factors.

Short Transmission Line

The effect of capacitance is ignored in these lines, length of short transmission line is less than 80 km.

where, V_s = Sending end voltage

l_s = Sending end current

V_R = Receiving end voltage

I_R = Receiving end current

I_S = I_R

V_R +l(R+ jX) = V_s