One way that the line capacitance can affect the working of a transmission line is by causing losses due to charging current. As the length of the transmission line increases, the line capacitance also increases, which causes the charging current to increase. This in turn leads to increased losses in the line due to the resistance of the conductors and the ground.
Another way that the line capacitance can affect the working of a transmission line is by causing voltage drop due to reactive power flow. When a transmission line is transmitting reactive power, the capacitance of the line causes a voltage drop along the line. This voltage drop is due to the flow of current through the line capacitance, which consumes reactive power. As the length of the transmission line increases, the line capacitance also increases, which can cause the voltage drop to become more significant.
In addition, the line capacitance can also affect the stability of the system. When a transmission line is transmitting a large amount of reactive power, the capacitance of the line can cause oscillations in the voltage and current at the receiving end of the line. These oscillations, known as "capacitive ringing," can affect the stability of the system and may need to be dampened using special devices. As the length of the transmission line increases, the line capacitance also increases, which can exacerbate the issue of capacitive ringing.
Finally, the line capacitance can also affect the voltage at the receiving end of the line. As the length of the transmission line increases, the line capacitance becomes more dominant, which can cause the receiving end voltage to become greater than the sending end voltage under no-load or lightly loaded conditions. This is known as "stray capacitance" and can be caused by the capacitance between the lines and the earth, supporting structures, etc. Stray capacitance can significantly affect the power losses in transmission lines due to the large currents that are carried by the lines.
Overall, the capacitive nature of transmission lines can have significant effects on their working, including losses due to charging current, voltage drop due to reactive power flow, stability issues due to capacitive ringing, and voltage fluctuations due to stray capacitance. These effects become more pronounced as the length of the transmission line increases.