http://ieeexplore.ieee.org/document/6717838/

http://www.pennenergy.com/content/dam/pe/online-articles/2014/12/REW.pdf

Hi Himadri

I wasn't looking for papers. I am looking for any software that helps in drawing those figures.

I recommend you to try this website, it's easy to use and have a lot of stencils

https://www.draw.io/

Dear Mahmood,

Use of inkscape software will be helpful in this regard.

It is free vector graphics software available for multiple platform where you can edit any kind of vector graphics content

Best wishes

Bhaskar

Hi I face a difficulty to draw the following(Attached) system model diagram. What type of tools is good? Any help?

You can try smartcad

use draw.io it contains lot of Bibliotheque concerning electrical engineering and its easy to use

Microsoft Visio, it is the one that I adopted for all my drawings.....

Google drawing is also very helpful.