What is the importance of reactive power in transmission lines?

Importance of Reactive Power
Reactive power is both the problem and solution to the power system network for several reasons. It plays an important role in the electrical power system for various functions such as satisfying the reactive power requirement, improving the voltage profiles, decreasing the network loss, providing sufficient reserve to ensure system security in emergencies, and other several functions. Let us discuss some of the reasons in brief, which makes reactive power so important.
1. Voltage Control
2. To Satisfy Reactive Power Demand
3. To Reduce Electrical Blackout
4. To Produce Magnetic Flux

• Active power is the energy supplied to  run a motor, heat a home, or illuminate an electric light bulb. Reactive  power provides the important function of regulating voltage.
• If voltage on the system is not high enough, active power cannot be supplied.
• Reactive power is used to provide the voltage levels necessary for active power to do useful work.
• Reactive power is essential to move active power through the transmission and distribution system to the customer .Reactive power is required to maintain the voltage to deliver active power (watts) through transmission lines.
• Motor loads and other loads require reactive power to convert the flow of electrons into useful work.
• When there is not enough reactive  power, the voltage sags down and it is not possible to push the power  demanded by loads through the lines.