For a more detailed study, you can refer to the books:
1) https://link.springer.com/chapter/10....
2) C.L. Wadhwa
for research going on in this field, you can refer to the following review paper (In this paper, you can get good papers to refer to):
"Review of Active and Reactive Power Sharing Strategies in Hierarchical Controlled Microgrids"
To observe this phenomenon yourself in the simulation, you can download the model from here:
https://in.mathworks.com/matlabcentra...