Please take a look at this book:

"PRACTICAL GENETIC ALGORITHMS - SECOND EDITION" by Randy L. Haupt

Sue Ellen Haupt from Wiley publication.

It contain an appendix which provide some Matlab implementation of methods.

Thank you, Ehsan and Milad.

I would like to suggestion you see some IEEE journal publications about PSO and GA applications in power systems.

http://www.particleswarm.info/Programs.html

https://code.google.com/p/psomatlab/