Test: Long Transmission Line

Transmission lines having length more than 200 kilometres are categorised as long transmission lines. Transmission lines having length less than 200 kilometres are medium transmission lines.

Surge impedance is the characteristic impedance of a loss free transmission line. It is the square root of ratio of line impedance(Z) and shunt admittance (Y). Its value varies between 400 Ω and 600 Ω.

For constant voltage transmission, specially designed synchronous motors, called synchronous phase modifiers. Synchronous phase modifiers are installed at receiving end to maintain the voltage drop along the line constant.

The leakage current through the shunt admittance is maximum at the sending end of the transmission line. This current decreases continuously as it move towards the receiving end of the line and becomes zero at the receiving end.

The resistance and inductance parameters are series elements of long transmission line. Capacitive susceptance and conductance parameters are shunt elements of transmission lines.