Transmission lines can be modeled as two-port networks with characteristic impedance and can be connected in cascade or parallel configurations. Cascade connections increase effective line length while parallel connections increase current and power ratings, improve reliability, and reduce losses. Important transmission line parameters include voltage regulation, line charging current, and representation using phasor diagrams, especially for short lines.

5. ABCD Parameters
• Transmission Line can be modeled as two port
network with one port as sending end and other as
receiving end.

6. Receiving end Open

7. Receiving end Short

8. Characteristic Impedance

9. Cascade Connection
• Transmission Lines are connected in cascade to increase the effective length of the
line.

10. Cascade Connection

11. Parallel Connection
• Transmission Lines are connected in
parallel because of following reasons
• To increase current rating of the
system
• To increase maximum power
rating of the system
• To increase reliability
• To reduce voltage drop
• To reduce losses and increase
efficiency

12. Parallel Connection

13. Important Parameters
• Voltage Regulation
• Line charging Current

14. Short Transmission Line

15. Phasor Diagram