Direction of AC power flow 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.

http://www.pjm.com/~/media/training/new-pjm-cert-exams/bet-lesson5-power-flow-on-ac-transmission-lines.ashx

For DC only magnitude, higher voltage to lower voltage......

Dear Sangeetha Shanmugam In any circuit  the current & voltage drop takes place according to kirchhoff's law (KVL & KCL),when we look on power flow it also behave in same manner , we have to keep in mind that power flow takes place from generating point to load center ,so you should know the load center position to find out the way of power flow .in grid it also flow from generating point to further distribution points . 

For Converters interfacing to AC grid

Mainly real power depends on delta (i.e phase angle ) between AC bus and reactive power depends on voltage differences when X/R is high .

real power depends on voltage differences between AC buses and reactive power depends on delta (i.e phase angle )when X/R is low.

If X/R is medium then both powers depends on both voltage and angle

http://ieeexplore.ieee.org/xpls/abs_all.jsp?arnumber=6200347&tag=1

Simply, If phase difference between voltage and current is 180 degrees. You are generating the current as attached, and your reactive power Q=0, and your active power is a function of current and voltage.

Real Power flows from leading angle to lagging angle..

Reactive power flows from high voltage side to low voltage side..

Note:

1. Real power depends on angle delta between two ends ie., sending and receiving end

2.Reactive power depends on the difference in voltage between two ends ie., sending and receiving end

I agree with Mahamad Nabab Alam 

Hello Sangheeta,

In context to your question, everyone, who have answered are correct to my knowledge. I would like to add some content to it.

Power flow from each bus to other for any type of system can be followed by POWER TRACING method, which is done by many methods. On of the methods, I tried earlier is Proportional Sharing Method based on KCL and KVL. 

You can refer to some papers on POWER TRACING, where both real and reactive power can be traced.

If it helps you, kindly inform me.