Correct Answer - Option 4 : Change in load angle affects real power
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.
Important Points:
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.
