you can follow the video playlist on Youtube.

https://www.youtube.com/watch?v=SEb_kHuKVBo&list=PLA-K2z3YR_0uQc3pqRmHeMkwbIbf84T1y

Hope this might help

My way of doing simulations is:

1. Start from a very basic module of a DG source. Learn how to use it and see the various variables how they vary with a particular loads.

2. Make a simple control loop for the DG source and its converter.

3. Add upon 1) and 2) with more DG sources with a more complex control strategy till you have stable responses for voltage, frequency and power.

4. Add your details of smart grid at the very end.

You will come across many obstacles while you are starting but learning through your mistakes you will understand the working of your smart grid.

Matlab simulink must be started from a very simple system and I direct by the following importint points:

1. Determine the scientific branch of your design to select the suitable toolbox.

2. Define and know the available blocks within the selected tool box.

3. There are common used blocks that will be necessary with any application.

4. Study and analyze simple prepared designs.

5. Now you can build and develop your needed designs.

Good luck......