In DG placement, it is better to find the location of the DG so that its placement with the fixed injection will lead to the minimum loss than any other position. As long as, optimization techniques are concerted,  any non-linear optimization approach including heuristics can be used.  

I agree with the just preceded answer, any heuristic optimization methods like, GA, PSO, ANN are the best choice

Try HQBC alhorithm

Optimal placement of DG depends on the network under consideration. It is always advisable to place DG near load centers in order to minimize losses. To get hold of such a location, it s best to use probabilistic algorithms as suggested by earlier posts.

Try also Bat algorithm, or hybrid between Bat algorithm and PSO to find the optimal location of DGs, taking into account the network structure and also the technical restrictions.

Use meta-heuristic algorithms . Optimize the objective function constructed considering several constraints .

Hi,

I have tried a comparison of Analytical and PSO based optimal placement of DG. Have a look!

https://www.researchgate.net/publication/284550417_Optimal_Allocation_and_Sizing_of_Distributed_Generators_in_Autonomous_Microgrids_based_on_LSF_and_PSO

Conference Paper Optimal Allocation and Sizing of Distributed Generators in A...

The most common considerations for DG placement are  voltage deviation, current limits, active and reactive power loss, and may be autonomous operation of network also. For techniques, as mentioned above, heuristic techniques are most popular and you may try any analytical method also.