Modifying the code for IEEE 13 Bus system

[Sadam Hussain]

Hi Valentin, 

I hope you are doing well, I am PhD student and working on the ACOPF using PYOMO with interaction to openDSS.

I am currently using your repository,  one question, i want to implement it for small network like 13 IEEE bus, but i do not know how to modify your network, can you guide me how to modify for 13 bus system ?