I want to design such a circuit by which i can deliver power as fixed as i desire. Say I consume those load from main power supply line and deliver different lines with fixed load.

Example: I want to deliver 1KVa or 500Va or 2KVa load in different three homes from my main power supply line. Though main power supply line can deliver more power than it.
But those homes do not use power than their dedicated load. If they want to use the power supply in their homes will cut off. And when their load less than their fixed power, automatically the power line will on. ...........

Now how can I make this such kind of fixed power supply from main power supply...........

 

Install a fuse or a circuit breaker. It will not reset itself, but it is safer than letting the power come back on when people are not expecting it.