Effects of Inductive and Capacitive Reactances in DC Transmission

In DC transmission, the correct statement is option 'C': there are no effects due to inductive and capacitive reactances. This is because in DC transmission, the current flows only in one direction, unlike in AC transmission where the current alternates. Let's understand this in detail.

No Effects of Inductive and Capacitive Reactances
- In AC transmission, the presence of inductive and capacitive reactances causes several issues such as voltage drop, power loss, and phase shift.
- Inductive reactance (XL) is caused by the inductance of the transmission line, while capacitive reactance (XC) is caused by the capacitance between the conductors.
- These reactances can lead to power loss due to energy dissipation, voltage drop along the transmission line, and phase shift between voltage and current waveforms.
- However, these effects are absent in DC transmission because the current flows continuously in one direction without any alternation.

Advantages of DC Transmission
- DC transmission offers several advantages over AC transmission, especially for long-distance power transmission.
- One major advantage is the absence of reactance-related issues, which simplifies the design and operation of the transmission system.
- Without the effects of inductive and capacitive reactances, DC transmission lines can achieve higher power transfer capability for the same rating compared to AC transmission lines.
- The absence of reactances also reduces power losses, voltage drop, and phase shift, resulting in a more efficient and stable transmission system.

Other Considerations in DC Transmission
- While DC transmission does not have the limitations imposed by inductive and capacitive reactances, it still has its own limitations.
- One of the main limitations is the high cost of converting AC power to DC power and vice versa using power electronic converters.
- Additionally, the control and protection of DC transmission systems are more complex compared to AC systems.
- Power transfer capability in DC transmission is limited by other factors such as stability considerations, voltage levels, and the capacity of the converter stations.

Conclusion
In DC transmission, the absence of inductive and capacitive reactances eliminates the related issues such as power loss, voltage drop, and phase shift. This simplifies the design and operation of the transmission system and allows for higher power transfer capability. However, other limitations such as cost and complexity of power converters and stability considerations still exist.