Correct option is D
Power flow in transmission system:
• In power system real power is related with load angle and reactive power is related with voltage magnitude.
• Therefore, change in voltage magnitude affects reactive power and the change in load angle affects real power.
Direction of power flows are as follows:
• Real Power Flow: Always from higher voltage angle of a bus to lover voltage angle of the bus.
• Reactive Power Flow: Always higher bus voltage magnitude to lower bus voltage magnitude.
